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• How duplicate an object in a list and update property of duplicated objects ?

  - by user359706

  Hello What would be the best way to duplicate an object placed in a list of items and change a property of duplicated objects ? I thought proceed in the following manner: - get object in the list by "ref" + "article" - Cloned the found object as many times as desired (n times) - Remove the object found - Add the clones in the list What do you think? A concrete example: Private List<Product> listProduct; listProduct= new List<Product>(); Product objProduit_1 = new Produit; objProduct_1.ref = "001"; objProduct_1.article = "G900"; objProduct_1.quantity = 30; listProducts.Add(objProduct_1); ProductobjProduit_2 = new Product; objProduct_2.ref = "002"; objProduct_2.article = "G900"; objProduct_2.quantity = 35; listProduits.Add(objProduct_2); desired method: public void updateProductsList(List<Product> paramListProducts,Produit objProductToUpdate, int32 nbrDuplication, int32 newQuantity){ ... } Calling method example: updateProductsList(listProducts,objProduct_1,2,15); Waiting result: Replace follow object : ref = "001"; article = "G900"; quantite = 30; By: ref = "001"; article = "G900"; quantite = 15; ref = "001"; article = "G900"; quantite = 15; The Algorithm is correct? Would you have an idea of the method implementation "updateProductsList" Thank you in advance for your help.

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• How to convert System.Object that's really an int32[] to a double[] ?

  - by fs_tech

  Hello- I get data from a 3rd party API that just gives me back a System.Object, which I know to be a double[] under the covers. And to deal with that return type, I have found the code below to work wonderfully. However, I also get back some int[] arrays that are also masquerading as System.Object, specifically dates in the form YYYYMMDD (e.g. 20100310). The conversion to float fails, and it just says that the specified cast is not valid. Does anyone out there know how to make this work for integers? let oIsNull (obj : System.Object) = obj = null let oIsArray (obj : System.Object) = obj.GetType().IsArray let o2f (obj : System.Object) = let mutable arr = [|Double.NaN|] if (oIsNull obj = false) && (oIsArray obj = true) then let objArr = obj :?> obj[] let u = objArr.GetUpperBound(0) let floatArr : float[] = Array.zeroCreate (u + 1); for i in 0..u do if objArr.[i] = null then floatArr.[i] <- Double.NaN else let t = objArr.[i].GetType() floatArr.[i] <- objArr.[i] :?> float //else floatArr.[i] <- float objArr.[i] arr <- floatArr arr

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• #altnetseattle &ndash; REST Services

  - by GeekAgilistMercenary

  Below are the notes I made in the REST Architecture Session I helped kick off with Andrew. RSS, ATOM, and such needed for better discovery.  i.e. there still is a need for some type of discovery. Difficult is modeling behaviors in a RESTful way.  ??  Invoking some type of state against an object.  For instance in the case of a POST vs. a GET.  The GET is easy, comes back as is, but what about a POST, which often changes some state or something. Challenge is doing multiple workflows with stateful workflows.  How does batch work.  Maybe model the batch as a resource. Frameworks aren’t particularly part of REST, REST is REST.  But point argued that REST is modeled, or part of modeling a state machine of some sort… ? Nothing is 100% reliable w/ REST – comparisons drawn with TCP/IP.  Sufficient probability is made however for the communications, but the idea of a possible failure has to be built into the usage model of REST. Ruby on Rails / RESTfully, and others used.  What were their issues, what do they do.  ATOM feeds, object serialized, using LINQ to XML w/ this.  No state machine libraries. Idempotent areas around REST and single change POST changes are inherent in the architecture. REST – one of the constrained languages is for the interaction w/ the system.  Limiting what can be done on the resources.  - disagreement, there is no agreed upon REST verbs. Sam Ruby – RESTful services.  Expanded the verbs within REST/HTTP pushes you off the web.  Of the existing verbs POST leaves the most up for debate. Robert Reem used Factory to deal with the POST to handle the new state.  The POST identifying what it just did by the return. Different states are put into POST, so that new prospective verbs, without creating verbs for REST/HTTP can be used to advantage without breaking universal clients. Biggest issue with REST services is their lack of state, yet it is also one of their biggest strengths.  What happens is that the client takes up the often onerous task of handling all state, state machines, and other extraneous resource management.  All the GETs, POSTs, DELETEs, INSERTs get all pushed into abstraction.  My 2 cents is that this in a way ends up pushing a huge proprietary burden onto the REST services often removing the point of REST to be simple and to the point. WADL does provide discovery and some state control (sort of?) Statement made, "WADL" isn't needed.  The JSON, XML, or other client side returned data handles this. I then applied the law of 2 feet rule for myself and headed to finish up these notes, post to the Wiki, and figure out what I was going to do next.  For the original Wiki entry check it out here. I will be adding more to this post with a subsequent post.  Please do feel free to post your thoughts and ideas about this, as I am sure everyone in the session will have more for elaboration.

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• WiX, MSDeploy and an appealing configuration/deployment paradigm

  - by alexhildyard

  I do a lot of application and server configuration; I've done this for many years and have tended to view the complexity of this strictly in terms of the complexity of the ultimate configuration to be deployed. For example, specific APIs aside, I would tend to regard installing a server certificate as a more complex activity than, say, copying a file or adding a Registry entry.My prejudice revolved around the idea of a sequential deployment script that not only had the explicit prescription to apply a specific server configuration, but also made the implicit presumption that the server in question was in a good known state. Scripts like this fail for hundreds of reasons -- the Default Website didn't exist; the application had already been deployed; the application had already been partially deployed and failed to rollback fully, and so on. And so the problem is that the more complex the configuration activity, the more scope for error in any individual part of that activity, and therefore the greater the chance the server in question will not end up at exactly the desired configuration level.Recently I was introduced to a completely different mindset, which, for want of a better turn of phrase, I will call the "make it so" mindset. It's extremely simple both to explain and to implement. In place of the head-down, imperative script you used to use, you substitute a set of checks -- much like exception handlers -- around each configuration activity, starting with a check of the current system state. Thus the configuration logic becomes: "IF these services aren't started then start them, and IF XYZ website doesn't exist then create it, and IF these shares don't exist then create them, and IF these shares aren't permissioned in some particular way, then permission them so." This works. Really well, in my experience. Scenario 1: You want to get a system into a good known state; it's already in a good known state; you quickly realise there is nothing to do.Scenario 2: You want to get the system into a good known state; your script is flawed or the system is bust; it cannot be put into that state. You know exactly where (at least part of) the problem is and why.Scenario 3: You want to get the system into a good known state; people are fiddling around with the system just now. That's fine. You do what you can, and later you come back and try it againScenario 4: No one wants to deploy anything; they want you to prove that the previous deployment was successful. So you re-run the deployment script with the "-WhatIf" flag. It reports that there was nothing to change. There's your proof.I mentioned two technologies in the title -- MSI and MSDeploy. I am thinking specifically of the conversation that took place here. Having worked with both technologies, I think Rob Mensching's response is appropriately nuanced, and in essence the difference is this: sometimes your target is either to achieve a specific new server state, or to rollback to a known good one. Then again, your target may be to configure what you can, and to understand what you can't. Implicitly MSDeploy's "rollback" is simply to redeploy the previous version, whereas a well-crafted MSI will actively put your system into that state without further intervention. Either way, if all goes well it will leave you with a system in one of two states, whereas MSDeploy could leave your system in one of many states. The key is that MSDeploy and MSI are complementary technologies; which suits you best depends as much on Operational guidance as your Configuration remit.What I wanted to say was that I have always been for atomic, transactional-based configuration, but having worked with the "make it so" paradigm, I have been favourably impressed by the actual results. I'm tempted to put a more technical post up on this in due course.

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• Flushing iptables broke my pipe, how can I save my instance?

  - by Niels

  I was setting up my iptables when I performed a iptables -F and my ssh pipe broke. This is the last output of my session: root@alfapaints:~# iptables -L Chain INPUT (policy DROP) target prot opt source destination ACCEPT all -- anywhere anywhere ACCEPT tcp -- anywhere anywhere state NEW,ESTABLISHED tcp dpt:2222 ACCEPT tcp -- li465-68.members.linode.com anywhere state NEW,ESTABLISHED tcp dpt:nrpe ACCEPT tcp -- anywhere anywhere tcp dpt:9200 state NEW,ESTABLISHED ACCEPT tcp -- anywhere anywhere tcp dpt:http state NEW,ESTABLISHED ACCEPT udp -- anywhere anywhere udp spt:domain Chain FORWARD (policy DROP) target prot opt source destination Chain OUTPUT (policy DROP) target prot opt source destination ACCEPT all -- anywhere anywhere ACCEPT tcp -- anywhere anywhere state ESTABLISHED tcp spt:2222 ACCEPT tcp -- anywhere anywhere state ESTABLISHED tcp spt:nrpe ACCEPT tcp -- anywhere anywhere tcp spt:9200 state ESTABLISHED ACCEPT tcp -- anywhere anywhere tcp spt:http state ESTABLISHED ACCEPT udp -- anywhere anywhere udp dpt:domain root@alfapaints:~# iptables -F Write failed: Broken pipe I tested my connection just before and I was able to connect with ssh. Now I did a nmap scan and not a single port is open anymore. I know my VPS is running on VMWare ESXi, could a reboot help? Or if not could I attach and mount the disk to another vm to save the data? Does anybody have some advise? And maybe an explanation what happend or what could have cause my pipe to break? ps: I didn't save my rules on the config directories of iptables. But used a file I stored in ~/rules.config to apply my rules like this: iptables-restore < rules.config So probably a reboot would help? Thanks a lot in advance.

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• Bypassing SQUID on freebsd with PF

  - by epema

  I have PF+SQUID31 on FREEBSD-9.0, and I want to have some hosts(aka goodguys) to bypass the proxy, so that torrents are not logged. Also, I am not sure about transparent. It means that I dont have to configure proxy settings on the client side right? I have tried doing a redirect no rdr on $int_if inet proto {tcp,udp} from 192.168.1.233/32 to any However, no luck :( Here is a quick look of my conf files: SQUID /usr/local/etc/squid/squid.conf http_port 192.168.1.1:8080 transparent RC /etc/rc.conf: gateway_enable="YES" pf_enable="YES" pf_rules="/usr/local/etc/pf.conf" pflog_enable="YES" squid_enable="YES" I have squid31 installed from ports with SQUID_PF "Enable transparent proxying with PF" on PF /usr/loca/etc/pf.conf: int_if="re0" ext_if="bge0" localnet="{ 192.168.1.0/24 }" table <goodguys> const { "192.168.1.219", "192.168.1.233" } set block-policy drop set skip on lo0 scrub in all fragment reassemble scrub out all random-id max-mss 1440 block in on $ext_if pass out on $ext_if keep state block in on $int_if pass in on $int_if inet proto tcp from $int_if:network to $int_if port 8080 keep state pass in on $int_if inet proto udp from $int_if:network to $int_if port 21 keep state pass in on $int_if inet proto udp from $int_if:network to $int_if port 22 keep state pass in on $int_if inet proto udp from $int_if:network to $int_if port 53 keep state pass in on $int_if inet proto tcp from $int_if:network to any port { smtp, pop3 } keep state pass in on $int_if inet proto icmp from $int_if:network to $int_if keep state pass out on $int_if keep state What lines should I add in conf files? I am assuming that the problem is on the firewall(pf).

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• Gathering buslogic SCSI hardware and virtual machine operating system

  - by Julian

  I'm trying to use Powershell to get SCSI hardware from several virtual servers and get the operating system of each specific server. I've managed to get the specific SCSI hardware that I want to find with my code, however I'm unable to figure out how to properly get the operating system of each of the servers. Also, I'm trying to send all the data that I find into a csv log file, however I'm unsure of how you can make a powershell script create multiple columns. Here is my code (almost works but something's wrong): $log = "C:\Users\me\Documents\Scripts\ScsiLog.csv" Get-VM | Foreach-Object { $vm = $_ Get-ScsiController -VM $vm | Where-Object { $_.Type -eq "VirtualBusLogic" } | Foreach-Object { get-VMGuest -VM $vm } | Foreach-Object{ Write-output $vm.Guest.VmName >> $log } } I don't receive any errors when I run this code however whenever I run it I'm only getting the name of the servers and not the OS. Also I'm not sure what I need to do to make the OS appear in a different column from the name of the server in the csv log that I'm creating. What do I need to change in my code to get the OS version of each virtual machine and output it in a different column in my csv log file? EDIT: Here's a more in depth look at things I've tried that have all failed: Get-VM | Foreach-Object { $vm = $_ $svm = Get-ScsiController -VM $vm | Where-Object { $_.Type -eq "VirtualBusLogic" } Foreach-Object {get-VMGuest -VM $svm } | Foreach-Object{Write-output $svm >> $log} } #Get-VM | Foreach-Object { # $vm = $_ # Get-ScsiController -VM $vm | Where-Object { $_.Type -eq "VirtualBusLogic"} #| write-host $vm # | Foreach-Object { # # #get-VMGuest -VM $_ | # #write-host $vm # #get-VMGuest -VM $vm } | Foreach-Object{ # #write-output $vm.VmName >> $log # #write-output $vm.guest.VmName, get-VmGuest -VM $vm >> $log NO GOOD # # Write-host $vm.Guest.VmName #+ get-vmGuest -vm $VM >> $log # # # } # } I'm not sure why get-VmGuest fails though. I'm getting the scsi hardware, filtering the hardware to only get buslogic, and then wanting to get the operating system of just the filtered VMs. I don't see where my code fails though.

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• How to access a port via OpenVpn only

  - by Andy M

  I've set up an openvpn server alongside an apache website that can only be accessed on port 8100 on the same machine. My /etc/openvpn/server.conf file looks like this: port 1194 proto tcp dev tun ca ./easy-rsa2/keys/ca.crt cert ./easy-rsa2/keys/server.crt key ./easy-rsa2/keys/server.key # This file should be kept secret dh ./easy-rsa2/keys/dh1024.pem # Diffie-Hellman parameter server 10.8.0.0 255.255.255.0 ifconfig-pool-persist ipp.txt # make sure clients can still connect to the internet push "redirect-gateway def1 bypass-dhcp" keepalive 10 120 comp-lzo persist-key persist-tun status openvpn-status.log verb 3 Now I tried to let only clients connected to the vpn network access the website on apache via port 8100. So I defined a few iptables rules: #!/bin/sh # My system IP/set ip address of server SERVER_IP="192.168.0.2" # Flushing all rules iptables -F iptables -X # Setting default filter policy iptables -P INPUT DROP iptables -P OUTPUT DROP iptables -P FORWARD DROP # Allow incoming access to port 8100 from OpenVPN 10.8.0.1 iptables -A INPUT -i tun0 -p tcp --dport 80 -m state --state NEW,ESTABLISHED -j ACCEPT iptables -A OUTPUT -o tun0 -p tcp --sport 80 -m state --state ESTABLISHED -j ACCEPT # outgoing http iptables -A OUTPUT -o tun0 -p tcp --dport 80 -m state --state NEW,ESTABLISHED -j ACCEPT iptables -A INPUT -i tun0 -p tcp --sport 80 -m state --state ESTABLISHED -j ACCEPT Now when I connect to the server from my client computer and try to access the website on 192.168.0.2:8100, my browser can't open it. Will I have to forward traffic from tun0 to eth0? Or is there anything else I'm missing?

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• NumLock is so weired in Ubuntu

  - by ???

  The NumLock and the keypad is so weired in Ubuntu. I have two computers, A is a desktop, with USB keyboard, B is a laptop, with laptop keyboard and another USB keyboard. On the desktop A, whether the NumLock is on or off, the number keys on the keypad just don't work. Also the NumLock LED is always off. The logs shown in xev: KeyPress event, serial 36, synthetic NO, window 0x6800001, root 0xb0, subw 0x0, time 9541332, (172,-12), root:(1846,452), state 0x0, keycode 77 (keysym 0xff7f, Num_Lock), same_screen YES, XLookupString gives 0 bytes: XmbLookupString gives 0 bytes: XFilterEvent returns: False KeyRelease event, serial 36, synthetic NO, window 0x6800001, root 0xb0, subw 0x0, time 9541412, (172,-12), root:(1846,452), state 0x0, keycode 77 (keysym 0xff7f, Num_Lock), same_screen YES, XLookupString gives 0 bytes: XFilterEvent returns: False And on the laptop B, I found that, when the NumLock is on, then many key combinations won't work. For example, generally Ctrl-A is used to select all, but it won't work when NumLock is on. The logs shown in xev: (no log when pressed Fn+NumLock on the laptop keyboard) Logs when pressed the NumLock on the USB keyboard: (Switch On) KeyPress event, serial 40, synthetic NO, window 0xb600001, root 0xac, subw 0x0, time 22187595, (102,107), root:(1198,133), state 0x10, keycode 77 (keysym 0xff7f, Num_Lock), same_screen YES, XLookupString gives 0 bytes: XmbLookupString gives 0 bytes: XFilterEvent returns: False PropertyNotify event, serial 40, synthetic NO, window 0xb600001, atom 0x1b8 (XKLAVIER_STATE), time 22187601, state PropertyNewValue KeyRelease event, serial 40, synthetic NO, window 0xb600001, root 0xac, subw 0x0, time 22187723, (102,107), root:(1198,133), state 0x10, keycode 77 (keysym 0xff7f, Num_Lock), same_screen YES, XLookupString gives 0 bytes: XFilterEvent returns: False (Switch Off) KeyPress event, serial 40, synthetic NO, window 0xb600001, root 0xac, subw 0x0, time 22187899, (102,107), root:(1198,133), state 0x0, keycode 77 (keysym 0xff7f, Num_Lock), same_screen YES, XLookupString gives 0 bytes: XmbLookupString gives 0 bytes: XFilterEvent returns: False PropertyNotify event, serial 40, synthetic NO, window 0xb600001, atom 0x1b8 (XKLAVIER_STATE), time 22187904, state PropertyNewValue KeyRelease event, serial 40, synthetic NO, window 0xb600001, root 0xac, subw 0x0, time 22188003, (102,107), root:(1198,133), state 0x10, keycode 77 (keysym 0xff7f, Num_Lock), same_screen YES, XLookupString gives 0 bytes: XFilterEvent returns: False

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• How to make NumLock behavior just like in Windows?

  - by ???

  The NumLock and the keypad is so weired in Ubuntu. I have two computers, A is a desktop, with USB keyboard, B is a laptop, with laptop keyboard and another USB keyboard. On the desktop A, whether the NumLock is on or off, the number keys on the keypad just don't work. Also the NumLock LED is always off. The logs shown in xev: KeyPress event, serial 36, synthetic NO, window 0x6800001, root 0xb0, subw 0x0, time 9541332, (172,-12), root:(1846,452), state 0x0, keycode 77 (keysym 0xff7f, Num_Lock), same_screen YES, XLookupString gives 0 bytes: XmbLookupString gives 0 bytes: XFilterEvent returns: False KeyRelease event, serial 36, synthetic NO, window 0x6800001, root 0xb0, subw 0x0, time 9541412, (172,-12), root:(1846,452), state 0x0, keycode 77 (keysym 0xff7f, Num_Lock), same_screen YES, XLookupString gives 0 bytes: XFilterEvent returns: False And on the laptop B, I found that, when the NumLock is on, then many key combinations won't work. For example, generally Ctrl-A is used to select all, but it won't work when NumLock is on. The logs shown in xev: (no log when pressed Fn+NumLock on the laptop keyboard) Logs when pressed the NumLock on the USB keyboard: (Switch On) KeyPress event, serial 40, synthetic NO, window 0xb600001, root 0xac, subw 0x0, time 22187595, (102,107), root:(1198,133), state 0x10, keycode 77 (keysym 0xff7f, Num_Lock), same_screen YES, XLookupString gives 0 bytes: XmbLookupString gives 0 bytes: XFilterEvent returns: False PropertyNotify event, serial 40, synthetic NO, window 0xb600001, atom 0x1b8 (XKLAVIER_STATE), time 22187601, state PropertyNewValue KeyRelease event, serial 40, synthetic NO, window 0xb600001, root 0xac, subw 0x0, time 22187723, (102,107), root:(1198,133), state 0x10, keycode 77 (keysym 0xff7f, Num_Lock), same_screen YES, XLookupString gives 0 bytes: XFilterEvent returns: False (Switch Off) KeyPress event, serial 40, synthetic NO, window 0xb600001, root 0xac, subw 0x0, time 22187899, (102,107), root:(1198,133), state 0x0, keycode 77 (keysym 0xff7f, Num_Lock), same_screen YES, XLookupString gives 0 bytes: XmbLookupString gives 0 bytes: XFilterEvent returns: False PropertyNotify event, serial 40, synthetic NO, window 0xb600001, atom 0x1b8 (XKLAVIER_STATE), time 22187904, state PropertyNewValue KeyRelease event, serial 40, synthetic NO, window 0xb600001, root 0xac, subw 0x0, time 22188003, (102,107), root:(1198,133), state 0x10, keycode 77 (keysym 0xff7f, Num_Lock), same_screen YES, XLookupString gives 0 bytes: XFilterEvent returns: False

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• How long will a "safely stored" Solid-State-Drive (SSD) keep its data? (e.g. bank safety-deposit box)

  - by user31575

  Here's my usecase: once-and-only-once copy off photos/videos to an internal SATA Solid State Drive (SSD) put this drive in a well-ventilated, air-conditioned bank "safety deposit box" for safe keeping The question: How long can I safely store a solid-state-drive in such an environment? i.e. 0% bitrot, 100% success when "plugged in" Are some SSD drives more reliable than other for this usecase? (e.g. smaller size vs larger size, SLC vs MLC, different brands, etc) More fodder: I have read that solid state memory cards (e..g compactflash, or sd cards) have much longer durability than other media (DVD's, CD's, hard drives) for this usecase (guaranteed against bitrot/other dysfunction on the order of ~ a decades vs a year ). I don't know if this applies to "SSD hard drives". Copying to one 500Gb ssd vs 8 64gb flash drives is easier SSD SATA hard drives have no moving parts, but they have more "visible electronics" than a compact flash card. I don't know if this "visible electronics" can fail, i.e. in contr I know many will point to carbonite, other cloud backup stuff, but I like the simplicity of having physical copies and wanted to understand the risks/implications thanks,

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• How to set a static route for an external IP address

  - by HorusKol

  Further to my earlier question about bridging different subnets - I now need to route requests for one particular IP address differently to all other traffic. I have the following routing in my iptables on our router: # Allow established connections, and those !not! coming from the public interface # eth0 = public interface # eth1 = private interface #1 (10.1.1.0/24) # eth2 = private interface #2 (129.2.2.0/25) iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT iptables -A INPUT -m state --state NEW ! -i eth0 -j ACCEPT iptables -A FORWARD -i eth0 -o eth1 -m state --state ESTABLISHED,RELATED -j ACCEPT iptables -A FORWARD -i eth0 -o eth2 -m state --state ESTABLISHED,RELATED -j ACCEPT # Allow outgoing connections from the private interfaces iptables -A FORWARD -i eth1 -o eth0 -j ACCEPT iptables -A FORWARD -i eth2 -o eth0 -j ACCEPT # Allow the two private connections to talk to each other iptables -A FORWARD -i eth1 -o eth2 -j ACCEPT iptables -A FORWARD -i eth2 -o eth1 -j ACCEPT # Masquerade (NAT) iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE # Don't forward any other traffic from the public to the private iptables -A FORWARD -i eth0 -o eth1 -j REJECT iptables -A FORWARD -i eth0 -o eth2 -j REJECT This configuration means that users will be forwarded through a modem/router with a public address - this is all well and good for most purposes, and in the main it doesn't matter that all computers are hidden behind the one public IP. However, some users need to be able to access a proxy at 192.111.222.111:8080 - and the proxy needs to identify this traffic as coming through a gateway at 129.2.2.126 - it won't respond otherwise. I tried adding a static route on our local gateway with: route add -host 192.111.222.111 gw 129.2.2.126 dev eth2 I can successfully ping 192.111.222.111 from the router. When I trace the route, it lists the 129.2.2.126 gateway, but I just get * on each of the following hops (I think this makes sense since this is just a web-proxy and requires authentication). When I try to ping this address from a host on the 129.2.2.0/25 network it fails. Should I do this in the iptables chain instead? How would I configure this routing?

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• Problems creating a functioning table

  - by Hoser

  This is a pretty simple SQL query I would assume, but I'm having problems getting it to work. if (object_id('#InfoTable')is not null) Begin Drop Table #InfoTable End create table #InfoTable (NameOfObject varchar(50), NameOfCounter varchar(50), SampledValue float(30), DayStamp datetime) insert into #InfoTable(NameOfObject, NameOfCounter, SampledValue, DayStamp) select vPerformanceRule.ObjectName AS NameOfObject, vPerformanceRule.CounterName AS NameOfCounter, Perf.vPerfRaw.SampleValue AS SampledValue, Perf.vPerfHourly.DateTime AS DayStamp from vPerformanceRule, vPerformanceRuleInstance, Perf.vPerfHourly, Perf.vPerfRaw where (ObjectName like 'Logical Disk' and CounterName like '% Free Space' AND SampleValue > 95 AND SampleValue < 100) order by DayStamp desc select NameOfObject, NameOfCounter, SampledValue, DayStamp from #InfoTable Drop Table #InfoTable I've tried various other forms of syntax, but no matter what I do, I get these error messages. Msg 207, Level 16, State 1, Line 10 Invalid column name 'NameOfObject'. Msg 207, Level 16, State 1, Line 10 Invalid column name 'NameOfCounter'. Msg 207, Level 16, State 1, Line 10 Invalid column name 'SampledValue'. Msg 207, Level 16, State 1, Line 10 Invalid column name 'DayStamp'. Msg 207, Level 16, State 1, Line 22 Invalid column name 'NameOfObject'. Msg 207, Level 16, State 1, Line 22 Invalid column name 'NameOfCounter'. Msg 207, Level 16, State 1, Line 22 Invalid column name 'SampledValue'. Msg 207, Level 16, State 1, Line 22 Invalid column name 'DayStamp'. Line 10 is the first 'insert into' line, and line 22 is the second select line. Any ideas?

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• SNMP query - operation not permitted

  - by jperovic

  I am working on API that reads a lot of data via SNMP (routes, interfaces, QoS policies, etc...). Lately, I have experienced a random error stating: Operation not permitted Now, I use SNMP4J as core library and cannot really pinpoint the source of error. Some Stackoverflow questions have suggested OS being unable to open sufficient number of file handles but increasing that parameter did not help much. The strange thing is that error occurs only when iptables is up and running. Could it be that firewall is blocking some traffic? I have tried writing JUnit test that mimicked application's logic but no errors were fired... Any help would be appreciated! Thanks! IPTABLES *nat :PREROUTING ACCEPT [2:96] :POSTROUTING ACCEPT [68:4218] :OUTPUT ACCEPT [68:4218] # route redirect za SNMP Trap i syslog -A PREROUTING -i eth0 -p udp -m udp --dport 514 -j REDIRECT --to-ports 33514 -A PREROUTING -i eth0 -p udp -m udp --dport 162 -j REDIRECT --to-ports 33162 COMMIT *filter :INPUT ACCEPT [0:0] :FORWARD ACCEPT [0:0] :OUTPUT ACCEPT [0:0] -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT -A INPUT -p icmp -j ACCEPT -A INPUT -i lo -j ACCEPT ..... # SNMP -A INPUT -p udp -m state --state NEW -m udp --dport 161 -j ACCEPT # SNMP trap -A INPUT -p udp -m state --state NEW -m udp --dport 162 -j ACCEPT -A INPUT -p udp -m state --state NEW -m udp --dport 33162 -j ACCEPT ..... -A INPUT -j REJECT --reject-with icmp-host-prohibited -A FORWARD -j REJECT --reject-with icmp-host-prohibited COMMIT

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• Writing Unit Tests for ASP.NET Web API Controller

  - by shiju

  In this blog post, I will write unit tests for a ASP.NET Web API controller in the EFMVC reference application. Let me introduce the EFMVC app, If you haven't heard about EFMVC. EFMVC is a simple app, developed as a reference implementation for demonstrating ASP.NET MVC, EF Code First, ASP.NET Web API, Domain-Driven Design (DDD), Test-Driven Development (DDD). The current version is built with ASP.NET MVC 4, EF Code First 5, ASP.NET Web API, Autofac, AutoMapper, Nunit and Moq. All unit tests were written with Nunit and Moq. You can download the latest version of the reference app from http://efmvc.codeplex.com/ Unit Test for HTTP Get Let’s write a unit test class for verifying the behaviour of a ASP.NET Web API controller named CategoryController. Let’s define mock implementation for Repository class, and a Command Bus that is used for executing write operations.  [TestFixture] public class CategoryApiControllerTest { private Mock<ICategoryRepository> categoryRepository; private Mock<ICommandBus> commandBus; [SetUp] public void SetUp() {     categoryRepository = new Mock<ICategoryRepository>();     commandBus = new Mock<ICommandBus>(); } The code block below provides the unit test for a HTTP Get operation. [Test] public void Get_All_Returns_AllCategory() {     // Arrange        IEnumerable<CategoryWithExpense> fakeCategories = GetCategories();     categoryRepository.Setup(x => x.GetCategoryWithExpenses()).Returns(fakeCategories);     CategoryController controller = new CategoryController(commandBus.Object, categoryRepository.Object)     {         Request = new HttpRequestMessage()                 {                     Properties = { { HttpPropertyKeys.HttpConfigurationKey, new HttpConfiguration() } }                 }     };     // Act     var categories = controller.Get();     // Assert     Assert.IsNotNull(categories, "Result is null");     Assert.IsInstanceOf(typeof(IEnumerable<CategoryWithExpense>),categories, "Wrong Model");             Assert.AreEqual(3, categories.Count(), "Got wrong number of Categories"); }        The GetCategories method is provided below: private static IEnumerable<CategoryWithExpense> GetCategories() {     IEnumerable<CategoryWithExpense> fakeCategories = new List<CategoryWithExpense> {     new CategoryWithExpense {CategoryId=1, CategoryName = "Test1", Description="Test1Desc", TotalExpenses=1000},     new CategoryWithExpense {CategoryId=2, CategoryName = "Test2", Description="Test2Desc",TotalExpenses=2000},     new CategoryWithExpense { CategoryId=3, CategoryName = "Test3", Description="Test3Desc",TotalExpenses=3000}       }.AsEnumerable();     return fakeCategories; } In the unit test method Get_All_Returns_AllCategory, we specify setup on the mocked type ICategoryrepository, for a call to GetCategoryWithExpenses method returns dummy data. We create an instance of the ApiController, where we have specified the Request property of the ApiController since the Request property is used to create a new HttpResponseMessage that will provide the appropriate HTTP status code along with response content data. Unit Tests are using for specifying the behaviour of components so that we have specified that Get operation will use the model type IEnumerable<CategoryWithExpense> for sending the Content data. The implementation of HTTP Get in the CategoryController is provided below: public IQueryable<CategoryWithExpense> Get() {     var categories = categoryRepository.GetCategoryWithExpenses().AsQueryable();     return categories; } Unit Test for HTTP Post The following are the behaviours we are going to implement for the HTTP Post: A successful HTTP Post  operation should return HTTP status code Created An empty Category should return HTTP status code BadRequest A successful HTTP Post operation should provide correct Location header information in the response for the newly created resource. Writing unit test for HTTP Post is required more information than we write for HTTP Get. In the HTTP Post implementation, we will call to Url.Link for specifying the header Location of Response as shown in below code block. var response = Request.CreateResponse(HttpStatusCode.Created, category); string uri = Url.Link("DefaultApi", new { id = category.CategoryId }); response.Headers.Location = new Uri(uri); return response; While we are executing Url.Link from unit tests, we have to specify HttpRouteData information from the unit test method. Otherwise, Url.Link will get a null value. The code block below shows the unit tests for specifying the behaviours for the HTTP Post operation. [Test] public void Post_Category_Returns_CreatedStatusCode() {     // Arrange        commandBus.Setup(c => c.Submit(It.IsAny<CreateOrUpdateCategoryCommand>())).Returns(new CommandResult(true));     Mapper.CreateMap<CategoryFormModel, CreateOrUpdateCategoryCommand>();          var httpConfiguration = new HttpConfiguration();     WebApiConfig.Register(httpConfiguration);     var httpRouteData = new HttpRouteData(httpConfiguration.Routes["DefaultApi"],         new HttpRouteValueDictionary { { "controller", "category" } });     var controller = new CategoryController(commandBus.Object, categoryRepository.Object)     {         Request = new HttpRequestMessage(HttpMethod.Post, "http://localhost/api/category/")         {             Properties =             {                 { HttpPropertyKeys.HttpConfigurationKey, httpConfiguration },                 { HttpPropertyKeys.HttpRouteDataKey, httpRouteData }             }         }     };     // Act     CategoryModel category = new CategoryModel();     category.CategoryId = 1;     category.CategoryName = "Mock Category";     var response = controller.Post(category);               // Assert     Assert.AreEqual(HttpStatusCode.Created, response.StatusCode);     var newCategory = JsonConvert.DeserializeObject<CategoryModel>(response.Content.ReadAsStringAsync().Result);     Assert.AreEqual(string.Format("http://localhost/api/category/{0}", newCategory.CategoryId), response.Headers.Location.ToString()); } [Test] public void Post_EmptyCategory_Returns_BadRequestStatusCode() {     // Arrange        commandBus.Setup(c => c.Submit(It.IsAny<CreateOrUpdateCategoryCommand>())).Returns(new CommandResult(true));     Mapper.CreateMap<CategoryFormModel, CreateOrUpdateCategoryCommand>();     var httpConfiguration = new HttpConfiguration();     WebApiConfig.Register(httpConfiguration);     var httpRouteData = new HttpRouteData(httpConfiguration.Routes["DefaultApi"],         new HttpRouteValueDictionary { { "controller", "category" } });     var controller = new CategoryController(commandBus.Object, categoryRepository.Object)     {         Request = new HttpRequestMessage(HttpMethod.Post, "http://localhost/api/category/")         {             Properties =             {                 { HttpPropertyKeys.HttpConfigurationKey, httpConfiguration },                 { HttpPropertyKeys.HttpRouteDataKey, httpRouteData }             }         }     };     // Act     CategoryModel category = new CategoryModel();     category.CategoryId = 0;     category.CategoryName = "";     // The ASP.NET pipeline doesn't run, so validation don't run.     controller.ModelState.AddModelError("", "mock error message");     var response = controller.Post(category);     // Assert     Assert.AreEqual(HttpStatusCode.BadRequest, response.StatusCode);   } In the above code block, we have written two unit methods, Post_Category_Returns_CreatedStatusCode and Post_EmptyCategory_Returns_BadRequestStatusCode. The unit test method Post_Category_Returns_CreatedStatusCode  verifies the behaviour 1 and 3, that we have defined in the beginning of the section “Unit Test for HTTP Post”. The unit test method Post_EmptyCategory_Returns_BadRequestStatusCode verifies the behaviour 2. For extracting the data from response, we call Content.ReadAsStringAsync().Result of HttpResponseMessage object and deserializeit it with Json Convertor. The implementation of HTTP Post in the CategoryController is provided below: // POST /api/category public HttpResponseMessage Post(CategoryModel category) {       if (ModelState.IsValid)     {         var command = new CreateOrUpdateCategoryCommand(category.CategoryId, category.CategoryName, category.Description);         var result = commandBus.Submit(command);         if (result.Success)         {                               var response = Request.CreateResponse(HttpStatusCode.Created, category);             string uri = Url.Link("DefaultApi", new { id = category.CategoryId });             response.Headers.Location = new Uri(uri);             return response;         }     }     else     {         return Request.CreateErrorResponse(HttpStatusCode.BadRequest, ModelState);     }     throw new HttpResponseException(HttpStatusCode.BadRequest); } The unit test implementation for HTTP Put and HTTP Delete are very similar to the unit test we have written for  HTTP Get. The complete unit tests for the CategoryController is given below: [TestFixture] public class CategoryApiControllerTest { private Mock<ICategoryRepository> categoryRepository; private Mock<ICommandBus> commandBus; [SetUp] public void SetUp() {     categoryRepository = new Mock<ICategoryRepository>();     commandBus = new Mock<ICommandBus>(); } [Test] public void Get_All_Returns_AllCategory() {     // Arrange        IEnumerable<CategoryWithExpense> fakeCategories = GetCategories();     categoryRepository.Setup(x => x.GetCategoryWithExpenses()).Returns(fakeCategories);     CategoryController controller = new CategoryController(commandBus.Object, categoryRepository.Object)     {         Request = new HttpRequestMessage()                 {                     Properties = { { HttpPropertyKeys.HttpConfigurationKey, new HttpConfiguration() } }                 }     };     // Act     var categories = controller.Get();     // Assert     Assert.IsNotNull(categories, "Result is null");     Assert.IsInstanceOf(typeof(IEnumerable<CategoryWithExpense>),categories, "Wrong Model");             Assert.AreEqual(3, categories.Count(), "Got wrong number of Categories"); }        [Test] public void Get_CorrectCategoryId_Returns_Category() {     // Arrange        IEnumerable<CategoryWithExpense> fakeCategories = GetCategories();     categoryRepository.Setup(x => x.GetCategoryWithExpenses()).Returns(fakeCategories);     CategoryController controller = new CategoryController(commandBus.Object, categoryRepository.Object)     {         Request = new HttpRequestMessage()         {             Properties = { { HttpPropertyKeys.HttpConfigurationKey, new HttpConfiguration() } }         }     };     // Act     var response = controller.Get(1);     // Assert     Assert.AreEqual(HttpStatusCode.OK, response.StatusCode);     var category = JsonConvert.DeserializeObject<CategoryWithExpense>(response.Content.ReadAsStringAsync().Result);     Assert.AreEqual(1, category.CategoryId, "Got wrong number of Categories"); } [Test] public void Get_InValidCategoryId_Returns_NotFound() {     // Arrange        IEnumerable<CategoryWithExpense> fakeCategories = GetCategories();     categoryRepository.Setup(x => x.GetCategoryWithExpenses()).Returns(fakeCategories);     CategoryController controller = new CategoryController(commandBus.Object, categoryRepository.Object)     {         Request = new HttpRequestMessage()         {             Properties = { { HttpPropertyKeys.HttpConfigurationKey, new HttpConfiguration() } }         }     };     // Act     var response = controller.Get(5);     // Assert     Assert.AreEqual(HttpStatusCode.NotFound, response.StatusCode);            } [Test] public void Post_Category_Returns_CreatedStatusCode() {     // Arrange        commandBus.Setup(c => c.Submit(It.IsAny<CreateOrUpdateCategoryCommand>())).Returns(new CommandResult(true));     Mapper.CreateMap<CategoryFormModel, CreateOrUpdateCategoryCommand>();          var httpConfiguration = new HttpConfiguration();     WebApiConfig.Register(httpConfiguration);     var httpRouteData = new HttpRouteData(httpConfiguration.Routes["DefaultApi"],         new HttpRouteValueDictionary { { "controller", "category" } });     var controller = new CategoryController(commandBus.Object, categoryRepository.Object)     {         Request = new HttpRequestMessage(HttpMethod.Post, "http://localhost/api/category/")         {             Properties =             {                 { HttpPropertyKeys.HttpConfigurationKey, httpConfiguration },                 { HttpPropertyKeys.HttpRouteDataKey, httpRouteData }             }         }     };     // Act     CategoryModel category = new CategoryModel();     category.CategoryId = 1;     category.CategoryName = "Mock Category";     var response = controller.Post(category);               // Assert     Assert.AreEqual(HttpStatusCode.Created, response.StatusCode);     var newCategory = JsonConvert.DeserializeObject<CategoryModel>(response.Content.ReadAsStringAsync().Result);     Assert.AreEqual(string.Format("http://localhost/api/category/{0}", newCategory.CategoryId), response.Headers.Location.ToString()); } [Test] public void Post_EmptyCategory_Returns_BadRequestStatusCode() {     // Arrange        commandBus.Setup(c => c.Submit(It.IsAny<CreateOrUpdateCategoryCommand>())).Returns(new CommandResult(true));     Mapper.CreateMap<CategoryFormModel, CreateOrUpdateCategoryCommand>();     var httpConfiguration = new HttpConfiguration();     WebApiConfig.Register(httpConfiguration);     var httpRouteData = new HttpRouteData(httpConfiguration.Routes["DefaultApi"],         new HttpRouteValueDictionary { { "controller", "category" } });     var controller = new CategoryController(commandBus.Object, categoryRepository.Object)     {         Request = new HttpRequestMessage(HttpMethod.Post, "http://localhost/api/category/")         {             Properties =             {                 { HttpPropertyKeys.HttpConfigurationKey, httpConfiguration },                 { HttpPropertyKeys.HttpRouteDataKey, httpRouteData }             }         }     };     // Act     CategoryModel category = new CategoryModel();     category.CategoryId = 0;     category.CategoryName = "";     // The ASP.NET pipeline doesn't run, so validation don't run.     controller.ModelState.AddModelError("", "mock error message");     var response = controller.Post(category);     // Assert     Assert.AreEqual(HttpStatusCode.BadRequest, response.StatusCode);   } [Test] public void Put_Category_Returns_OKStatusCode() {     // Arrange        commandBus.Setup(c => c.Submit(It.IsAny<CreateOrUpdateCategoryCommand>())).Returns(new CommandResult(true));     Mapper.CreateMap<CategoryFormModel, CreateOrUpdateCategoryCommand>();     CategoryController controller = new CategoryController(commandBus.Object, categoryRepository.Object)     {         Request = new HttpRequestMessage()         {             Properties = { { HttpPropertyKeys.HttpConfigurationKey, new HttpConfiguration() } }         }     };     // Act     CategoryModel category = new CategoryModel();     category.CategoryId = 1;     category.CategoryName = "Mock Category";     var response = controller.Put(category.CategoryId,category);     // Assert     Assert.AreEqual(HttpStatusCode.OK, response.StatusCode);    } [Test] public void Delete_Category_Returns_NoContentStatusCode() {     // Arrange              commandBus.Setup(c => c.Submit(It.IsAny<DeleteCategoryCommand >())).Returns(new CommandResult(true));     CategoryController controller = new CategoryController(commandBus.Object, categoryRepository.Object)     {         Request = new HttpRequestMessage()         {             Properties = { { HttpPropertyKeys.HttpConfigurationKey, new HttpConfiguration() } }         }     };     // Act               var response = controller.Delete(1);     // Assert     Assert.AreEqual(HttpStatusCode.NoContent, response.StatusCode);   } private static IEnumerable<CategoryWithExpense> GetCategories() {     IEnumerable<CategoryWithExpense> fakeCategories = new List<CategoryWithExpense> {     new CategoryWithExpense {CategoryId=1, CategoryName = "Test1", Description="Test1Desc", TotalExpenses=1000},     new CategoryWithExpense {CategoryId=2, CategoryName = "Test2", Description="Test2Desc",TotalExpenses=2000},     new CategoryWithExpense { CategoryId=3, CategoryName = "Test3", Description="Test3Desc",TotalExpenses=3000}       }.AsEnumerable();     return fakeCategories; } }  The complete implementation for the Api Controller, CategoryController is given below: public class CategoryController : ApiController {       private readonly ICommandBus commandBus;     private readonly ICategoryRepository categoryRepository;     public CategoryController(ICommandBus commandBus, ICategoryRepository categoryRepository)     {         this.commandBus = commandBus;         this.categoryRepository = categoryRepository;     } public IQueryable<CategoryWithExpense> Get() {     var categories = categoryRepository.GetCategoryWithExpenses().AsQueryable();     return categories; }   // GET /api/category/5 public HttpResponseMessage Get(int id) {     var category = categoryRepository.GetCategoryWithExpenses().Where(c => c.CategoryId == id).SingleOrDefault();     if (category == null)     {         return Request.CreateResponse(HttpStatusCode.NotFound);     }     return Request.CreateResponse(HttpStatusCode.OK, category); }   // POST /api/category public HttpResponseMessage Post(CategoryModel category) {       if (ModelState.IsValid)     {         var command = new CreateOrUpdateCategoryCommand(category.CategoryId, category.CategoryName, category.Description);         var result = commandBus.Submit(command);         if (result.Success)         {                               var response = Request.CreateResponse(HttpStatusCode.Created, category);             string uri = Url.Link("DefaultApi", new { id = category.CategoryId });             response.Headers.Location = new Uri(uri);             return response;         }     }     else     {         return Request.CreateErrorResponse(HttpStatusCode.BadRequest, ModelState);     }     throw new HttpResponseException(HttpStatusCode.BadRequest); }   // PUT /api/category/5 public HttpResponseMessage Put(int id, CategoryModel category) {     if (ModelState.IsValid)     {         var command = new CreateOrUpdateCategoryCommand(category.CategoryId, category.CategoryName, category.Description);         var result = commandBus.Submit(command);         return Request.CreateResponse(HttpStatusCode.OK, category);     }     else     {         return Request.CreateErrorResponse(HttpStatusCode.BadRequest, ModelState);     }     throw new HttpResponseException(HttpStatusCode.BadRequest); }       // DELETE /api/category/5     public HttpResponseMessage Delete(int id)     {         var command = new DeleteCategoryCommand { CategoryId = id };         var result = commandBus.Submit(command);         if (result.Success)         {             return new HttpResponseMessage(HttpStatusCode.NoContent);         }             throw new HttpResponseException(HttpStatusCode.BadRequest);     } } Source Code The EFMVC app can download from http://efmvc.codeplex.com/ . The unit test project can be found from the project EFMVC.Tests and Web API project can be found from EFMVC.Web.API.

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• Using the ASP.NET Cache to cache data in a Model or Business Object layer, without a dependency on System.Web in the layer - Part One.

  - by Rhames

  ASP.NET applications can make use of the System.Web.Caching.Cache object to cache data and prevent repeated expensive calls to a database or other store. However, ideally an application should make use of caching at the point where data is retrieved from the database, which typically is inside a Business Objects or Model layer. One of the key features of using a UI pattern such as Model-View-Presenter (MVP) or Model-View-Controller (MVC) is that the Model and Presenter (or Controller) layers are developed without any knowledge of the UI layer. Introducing a dependency on System.Web into the Model layer would break this independence of the Model from the View. This article gives a solution to this problem, using dependency injection to inject the caching implementation into the Model layer at runtime. This allows caching to be used within the Model layer, without any knowledge of the actual caching mechanism that will be used. Create a sample application to use the caching solution Create a test SQL Server database This solution uses a SQL Server database with the same Sales data used in my previous post on calculating running totals. The advantage of using this data is that it gives nice slow queries that will exaggerate the effect of using caching! To create the data, first create a new SQL database called CacheSample. Next run the following script to create the Sale table and populate it: USE CacheSample GO   CREATE TABLE Sale(DayCount smallint, Sales money) CREATE CLUSTERED INDEX ndx_DayCount ON Sale(DayCount) go INSERT Sale VALUES (1,120) INSERT Sale VALUES (2,60) INSERT Sale VALUES (3,125) INSERT Sale VALUES (4,40)   DECLARE @DayCount smallint, @Sales money SET @DayCount = 5 SET @Sales = 10   WHILE @DayCount < 5000  BEGIN  INSERT Sale VALUES (@DayCount,@Sales)  SET @DayCount = @DayCount + 1  SET @Sales = @Sales + 15  END Next create a stored procedure to calculate the running total, and return a specified number of rows from the Sale table, using the following script: USE [CacheSample] GO   SET ANSI_NULLS ON GO   SET QUOTED_IDENTIFIER ON GO   -- ============================================= -- Author:        Robin -- Create date: -- Description:   -- ============================================= CREATE PROCEDURE [dbo].[spGetRunningTotals]       -- Add the parameters for the stored procedure here       @HighestDayCount smallint = null AS BEGIN       -- SET NOCOUNT ON added to prevent extra result sets from       -- interfering with SELECT statements.       SET NOCOUNT ON;         IF @HighestDayCount IS NULL             SELECT @HighestDayCount = MAX(DayCount) FROM dbo.Sale                   DECLARE @SaleTbl TABLE (DayCount smallint, Sales money, RunningTotal money)         DECLARE @DayCount smallint,                   @Sales money,                   @RunningTotal money         SET @RunningTotal = 0       SET @DayCount = 0         DECLARE rt_cursor CURSOR       FOR       SELECT DayCount, Sales       FROM Sale       ORDER BY DayCount         OPEN rt_cursor         FETCH NEXT FROM rt_cursor INTO @DayCount,@Sales         WHILE @@FETCH_STATUS = 0 AND @DayCount <= @HighestDayCount        BEGIN        SET @RunningTotal = @RunningTotal + @Sales        INSERT @SaleTbl VALUES (@DayCount,@Sales,@RunningTotal)        FETCH NEXT FROM rt_cursor INTO @DayCount,@Sales        END         CLOSE rt_cursor       DEALLOCATE rt_cursor         SELECT DayCount, Sales, RunningTotal       FROM @SaleTbl   END   GO   Create the Sample ASP.NET application In Visual Studio create a new solution and add a class library project called CacheSample.BusinessObjects and an ASP.NET web application called CacheSample.UI. The CacheSample.BusinessObjects project will contain a single class to represent a Sale data item, with all the code to retrieve the sales from the database included in it for simplicity (normally I would at least have a separate Repository or other object that is responsible for retrieving data, and probably a data access layer as well, but for this sample I want to keep it simple). The C# code for the Sale class is shown below: using System; using System.Collections.Generic; using System.Data; using System.Data.SqlClient;   namespace CacheSample.BusinessObjects {     public class Sale     {         public Int16 DayCount { get; set; }         public decimal Sales { get; set; }         public decimal RunningTotal { get; set; }           public static IEnumerable<Sale> GetSales(int? highestDayCount)         {             List<Sale> sales = new List<Sale>();               SqlParameter highestDayCountParameter = new SqlParameter("@HighestDayCount", SqlDbType.SmallInt);             if (highestDayCount.HasValue)                 highestDayCountParameter.Value = highestDayCount;             else                 highestDayCountParameter.Value = DBNull.Value;               string connectionStr = System.Configuration.ConfigurationManager .ConnectionStrings["CacheSample"].ConnectionString;               using(SqlConnection sqlConn = new SqlConnection(connectionStr))             using (SqlCommand sqlCmd = sqlConn.CreateCommand())             {                 sqlCmd.CommandText = "spGetRunningTotals";                 sqlCmd.CommandType = CommandType.StoredProcedure;                 sqlCmd.Parameters.Add(highestDayCountParameter);                   sqlConn.Open();                   using (SqlDataReader dr = sqlCmd.ExecuteReader())                 {                     while (dr.Read())                     {                         Sale newSale = new Sale();                         newSale.DayCount = dr.GetInt16(0);                         newSale.Sales = dr.GetDecimal(1);                         newSale.RunningTotal = dr.GetDecimal(2);                           sales.Add(newSale);                     }                 }             }               return sales;         }     } }   The static GetSale() method makes a call to the spGetRunningTotals stored procedure and then reads each row from the returned SqlDataReader into an instance of the Sale class, it then returns a List of the Sale objects, as IEnnumerable<Sale>. A reference to System.Configuration needs to be added to the CacheSample.BusinessObjects project so that the connection string can be read from the web.config file. In the CacheSample.UI ASP.NET project, create a single web page called ShowSales.aspx, and make this the default start up page. This page will contain a single button to call the GetSales() method and a label to display the results. The html mark up and the C# code behind are shown below: ShowSales.aspx <%@ Page Language="C#" AutoEventWireup="true" CodeBehind="ShowSales.aspx.cs" Inherits="CacheSample.UI.ShowSales" %>   <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">   <html xmlns="http://www.w3.org/1999/xhtml"> <head runat="server">     <title>Cache Sample - Show All Sales</title> </head> <body>     <form id="form1" runat="server">     <div>         <asp:Button ID="btnTest1" runat="server" onclick="btnTest1_Click"             Text="Get All Sales" />         &nbsp;&nbsp;&nbsp;         <asp:Label ID="lblResults" runat="server"></asp:Label>         </div>     </form> </body> </html>   ShowSales.aspx.cs using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.UI; using System.Web.UI.WebControls;   using CacheSample.BusinessObjects;   namespace CacheSample.UI {     public partial class ShowSales : System.Web.UI.Page     {         protected void Page_Load(object sender, EventArgs e)         {         }           protected void btnTest1_Click(object sender, EventArgs e)         {             System.Diagnostics.Stopwatch stopWatch = new System.Diagnostics.Stopwatch();             stopWatch.Start();               var sales = Sale.GetSales(null);               var lastSales = sales.Last();               stopWatch.Stop();               lblResults.Text = string.Format( "Count of Sales: {0}, Last DayCount: {1}, Total Sales: {2}. Query took {3} ms", sales.Count(), lastSales.DayCount, lastSales.RunningTotal, stopWatch.ElapsedMilliseconds);         }       } }   Finally we need to add a connection string to the CacheSample SQL Server database, called CacheSample, to the web.config file: <?xmlversion="1.0"?>   <configuration>    <connectionStrings>     <addname="CacheSample"          connectionString="data source=.\SQLEXPRESS;Integrated Security=SSPI;Initial Catalog=CacheSample"          providerName="System.Data.SqlClient" />  </connectionStrings>    <system.web>     <compilationdebug="true"targetFramework="4.0" />  </system.web>   </configuration>   Run the application and click the button a few times to see how long each call to the database takes. On my system, each query takes about 450ms. Next I shall look at a solution to use the ASP.NET caching to cache the data returned by the query, so that subsequent requests to the GetSales() method are much faster. Adding Data Caching Support I am going to create my caching support in a separate project called CacheSample.Caching, so the next step is to add a class library to the solution. We shall be using the application configuration to define the implementation of our caching system, so we need a reference to System.Configuration adding to the project. ICacheProvider<T> Interface The first step in adding caching to our application is to define an interface, called ICacheProvider, in the CacheSample.Caching project, with methods to retrieve any data from the cache or to retrieve the data from the data source if it is not present in the cache. Dependency Injection will then be used to inject an implementation of this interface at runtime, allowing the users of the interface (i.e. the CacheSample.BusinessObjects project) to be completely unaware of how the caching is actually implemented. As data of any type maybe retrieved from the data source, it makes sense to use generics in the interface, with a generic type parameter defining the data type associated with a particular instance of the cache interface implementation. The C# code for the ICacheProvider interface is shown below: using System; using System.Collections.Generic;   namespace CacheSample.Caching {     public interface ICacheProvider     {     }       public interface ICacheProvider<T> : ICacheProvider     {         T Fetch(string key, Func<T> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry);           IEnumerable<T> Fetch(string key, Func<IEnumerable<T>> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry);     } }   The empty non-generic interface will be used as a type in a Dictionary generic collection later to store instances of the ICacheProvider<T> implementation for reuse, I prefer to use a base interface when doing this, as I think the alternative of using object makes for less clear code. The ICacheProvider<T> interface defines two overloaded Fetch methods, the difference between these is that one will return a single instance of the type T and the other will return an IEnumerable<T>, providing support for easy caching of collections of data items. Both methods will take a key parameter, which will uniquely identify the cached data, a delegate of type Func<T> or Func<IEnumerable<T>> which will provide the code to retrieve the data from the store if it is not present in the cache, and absolute or relative expiry policies to define when a cached item should expire. Note that at present there is no support for cache dependencies, but I shall be showing a method of adding this in part two of this article. CacheProviderFactory Class We need a mechanism of creating instances of our ICacheProvider<T> interface, using Dependency Injection to get the implementation of the interface. To do this we shall create a CacheProviderFactory static class in the CacheSample.Caching project. This factory will provide a generic static method called GetCacheProvider<T>(), which shall return instances of ICacheProvider<T>. We can then call this factory method with the relevant data type (for example the Sale class in the CacheSample.BusinessObject project) to get a instance of ICacheProvider for that type (e.g. call CacheProviderFactory.GetCacheProvider<Sale>() to get the ICacheProvider<Sale> implementation). The C# code for the CacheProviderFactory is shown below: using System; using System.Collections.Generic;   using CacheSample.Caching.Configuration;   namespace CacheSample.Caching {     public static class CacheProviderFactory     {         private static Dictionary<Type, ICacheProvider> cacheProviders = new Dictionary<Type, ICacheProvider>();         private static object syncRoot = new object();           ///<summary>         /// Factory method to create or retrieve an implementation of the  /// ICacheProvider interface for type <typeparamref name="T"/>.         ///</summary>         ///<typeparam name="T">  /// The type that this cache provider instance will work with  ///</typeparam>         ///<returns>An instance of the implementation of ICacheProvider for type  ///<typeparamref name="T"/>, as specified by the application  /// configuration</returns>         public static ICacheProvider<T> GetCacheProvider<T>()         {             ICacheProvider<T> cacheProvider = null;             // Get the Type reference for the type parameter T             Type typeOfT = typeof(T);               // Lock the access to the cacheProviders dictionary             // so multiple threads can work with it             lock (syncRoot)             {                 // First check if an instance of the ICacheProvider implementation  // already exists in the cacheProviders dictionary for the type T                 if (cacheProviders.ContainsKey(typeOfT))                     cacheProvider = (ICacheProvider<T>)cacheProviders[typeOfT];                 else                 {                     // There is not already an instance of the ICacheProvider in       // cacheProviders for the type T                     // so we need to create one                       // Get the Type reference for the application's implementation of       // ICacheProvider from the configuration                     Type cacheProviderType = Type.GetType(CacheProviderConfigurationSection.Current. CacheProviderType);                     if (cacheProviderType != null)                     {                         // Now get a Type reference for the Cache Provider with the                         // type T generic parameter                         Type typeOfCacheProviderTypeForT = cacheProviderType.MakeGenericType(new Type[] { typeOfT });                         if (typeOfCacheProviderTypeForT != null)                         {                             // Create the instance of the Cache Provider and add it to // the cacheProviders dictionary for future use                             cacheProvider = (ICacheProvider<T>)Activator. CreateInstance(typeOfCacheProviderTypeForT);                             cacheProviders.Add(typeOfT, cacheProvider);                         }                     }                 }             }               return cacheProvider;                 }     } }   As this code uses Activator.CreateInstance() to create instances of the ICacheProvider<T> implementation, which is a slow process, the factory class maintains a Dictionary of the previously created instances so that a cache provider needs to be created only once for each type. The type of the implementation of ICacheProvider<T> is read from a custom configuration section in the application configuration file, via the CacheProviderConfigurationSection class, which is described below. CacheProviderConfigurationSection Class The implementation of ICacheProvider<T> will be specified in a custom configuration section in the application’s configuration. To handle this create a folder in the CacheSample.Caching project called Configuration, and add a class called CacheProviderConfigurationSection to this folder. This class will extend the System.Configuration.ConfigurationSection class, and will contain a single string property called CacheProviderType. The C# code for this class is shown below: using System; using System.Configuration;   namespace CacheSample.Caching.Configuration {     internal class CacheProviderConfigurationSection : ConfigurationSection     {         public static CacheProviderConfigurationSection Current         {             get             {                 return (CacheProviderConfigurationSection) ConfigurationManager.GetSection("cacheProvider");             }         }           [ConfigurationProperty("type", IsRequired=true)]         public string CacheProviderType         {             get             {                 return (string)this["type"];             }         }     } }   Adding Data Caching to the Sales Class We now have enough code in place to add caching to the GetSales() method in the CacheSample.BusinessObjects.Sale class, even though we do not yet have an implementation of the ICacheProvider<T> interface. We need to add a reference to the CacheSample.Caching project to CacheSample.BusinessObjects so that we can use the ICacheProvider<T> interface within the GetSales() method. Once the reference is added, we can first create a unique string key based on the method name and the parameter value, so that the same cache key is used for repeated calls to the method with the same parameter values. Then we get an instance of the cache provider for the Sales type, using the CacheProviderFactory, and pass the existing code to retrieve the data from the database as the retrievalMethod delegate in a call to the Cache Provider Fetch() method. The C# code for the modified GetSales() method is shown below: public static IEnumerable<Sale> GetSales(int? highestDayCount) {     string cacheKey = string.Format("CacheSample.BusinessObjects.GetSalesWithCache({0})", highestDayCount);       return CacheSample.Caching.CacheProviderFactory. GetCacheProvider<Sale>().Fetch(cacheKey,         delegate()         {             List<Sale> sales = new List<Sale>();               SqlParameter highestDayCountParameter = new SqlParameter("@HighestDayCount", SqlDbType.SmallInt);             if (highestDayCount.HasValue)                 highestDayCountParameter.Value = highestDayCount;             else                 highestDayCountParameter.Value = DBNull.Value;               string connectionStr = System.Configuration.ConfigurationManager. ConnectionStrings["CacheSample"].ConnectionString;               using (SqlConnection sqlConn = new SqlConnection(connectionStr))             using (SqlCommand sqlCmd = sqlConn.CreateCommand())             {                 sqlCmd.CommandText = "spGetRunningTotals";                 sqlCmd.CommandType = CommandType.StoredProcedure;                 sqlCmd.Parameters.Add(highestDayCountParameter);                   sqlConn.Open();                   using (SqlDataReader dr = sqlCmd.ExecuteReader())                 {                     while (dr.Read())                     {                         Sale newSale = new Sale();                         newSale.DayCount = dr.GetInt16(0);                         newSale.Sales = dr.GetDecimal(1);                         newSale.RunningTotal = dr.GetDecimal(2);                           sales.Add(newSale);                     }                 }             }               return sales;         },         null,         new TimeSpan(0, 10, 0)); }     This example passes the code to retrieve the Sales data from the database to the Cache Provider as an anonymous method, however it could also be written as a lambda. The main advantage of using an anonymous function (method or lambda) is that the code inside the anonymous function can access the parameters passed to the GetSales() method. Finally the absolute expiry is set to null, and the relative expiry set to 10 minutes, to indicate that the cache entry should be removed 10 minutes after the last request for the data. As the ICacheProvider<T> has a Fetch() method that returns IEnumerable<T>, we can simply return the results of the Fetch() method to the caller of the GetSales() method. This should be all that is needed for the GetSales() method to now retrieve data from a cache after the first time the data has be retrieved from the database. Implementing a ASP.NET Cache Provider The final step is to actually implement the ICacheProvider<T> interface, and add the implementation details to the web.config file for the dependency injection. The cache provider implementation needs to have access to System.Web. Therefore it could be placed in the CacheSample.UI project, or in its own project that has a reference to System.Web. Implementing the Cache Provider in a separate project is my favoured approach. Create a new project inside the solution called CacheSample.CacheProvider, and add references to System.Web and CacheSample.Caching to this project. Add a class to the project called AspNetCacheProvider. Make the class a generic class by adding the generic parameter <T> and indicate that the class implements ICacheProvider<T>. The C# code for the AspNetCacheProvider class is shown below: using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.Caching;   using CacheSample.Caching;   namespace CacheSample.CacheProvider {     public class AspNetCacheProvider<T> : ICacheProvider<T>     {         #region ICacheProvider<T> Members           public T Fetch(string key, Func<T> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry)         {             return FetchAndCache<T>(key, retrieveData, absoluteExpiry, relativeExpiry);         }           public IEnumerable<T> Fetch(string key, Func<IEnumerable<T>> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry)         {             return FetchAndCache<IEnumerable<T>>(key, retrieveData, absoluteExpiry, relativeExpiry);         }           #endregion           #region Helper Methods           private U FetchAndCache<U>(string key, Func<U> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry)         {             U value;             if (!TryGetValue<U>(key, out value))             {                 value = retrieveData();                 if (!absoluteExpiry.HasValue)                     absoluteExpiry = Cache.NoAbsoluteExpiration;                   if (!relativeExpiry.HasValue)                     relativeExpiry = Cache.NoSlidingExpiration;                   HttpContext.Current.Cache.Insert(key, value, null, absoluteExpiry.Value, relativeExpiry.Value);             }             return value;         }           private bool TryGetValue<U>(string key, out U value)         {             object cachedValue = HttpContext.Current.Cache.Get(key);             if (cachedValue == null)             {                 value = default(U);                 return false;             }             else             {                 try                 {                     value = (U)cachedValue;                     return true;                 }                 catch                 {                     value = default(U);                     return false;                 }             }         }           #endregion       } }   The two interface Fetch() methods call a private method called FetchAndCache(). This method first checks for a element in the HttpContext.Current.Cache with the specified cache key, and if so tries to cast this to the specified type (either T or IEnumerable<T>). If the cached element is found, the FetchAndCache() method simply returns it. If it is not found in the cache, the method calls the retrievalMethod delegate to get the data from the data source, and then adds this to the HttpContext.Current.Cache. The final step is to add the AspNetCacheProvider class to the relevant custom configuration section in the CacheSample.UI.Web.Config file. To do this there needs to be a <configSections> element added as the first element in <configuration>. This will match a custom section called <cacheProvider> with the CacheProviderConfigurationSection. Then we add a <cacheProvider> element, with a type property set to the fully qualified assembly name of the AspNetCacheProvider class, as shown below: <?xmlversion="1.0"?>   <configuration>  <configSections>     <sectionname="cacheProvider" type="CacheSample.Base.Configuration.CacheProviderConfigurationSection, CacheSample.Base" />  </configSections>    <connectionStrings>     <addname="CacheSample"          connectionString="data source=.\SQLEXPRESS;Integrated Security=SSPI;Initial Catalog=CacheSample"          providerName="System.Data.SqlClient" />  </connectionStrings>    <cacheProvidertype="CacheSample.CacheProvider.AspNetCacheProvider`1, CacheSample.CacheProvider, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null">  </cacheProvider>    <system.web>     <compilationdebug="true"targetFramework="4.0" />  </system.web>   </configuration>   One point to note is that the fully qualified assembly name of the AspNetCacheProvider class includes the notation `1 after the class name, which indicates that it is a generic class with a single generic type parameter. The CacheSample.UI project needs to have references added to CacheSample.Caching and CacheSample.CacheProvider so that the actual application is aware of the relevant cache provider implementation. Conclusion After implementing this solution, you should have a working cache provider mechanism, that will allow the middle and data access layers to implement caching support when retrieving data, without any knowledge of the actually caching implementation. If the UI is not ASP.NET based, if for example it is Winforms or WPF, the implementation of ICacheProvider<T> would be written around whatever technology is available. It could even be a standalone caching system that takes full responsibility for adding and removing items from a global store. The next part of this article will show how this caching mechanism may be extended to provide support for cache dependencies, such as the System.Web.Caching.SqlCacheDependency. Another possible extension would be to cache the cache provider implementations instead of storing them in a static Dictionary in the CacheProviderFactory. This would prevent a build up of seldom used cache providers in the application memory, as they could be removed from the cache if not used often enough, although in reality there are probably unlikely to be vast numbers of cache provider implementation instances, as most applications do not have a massive number of business object or model types.

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• Rails - How to use modal form to add object in one model, then reflect that change on main page?

  - by Jim

  I'm working on a Rails app and I've come across a situation where I'm unsure of the cleanest way to proceed. I posted a question on SO with code samples and such - it has received no answers, and the more I think about the problem, the more I think I might be approaching this the wrong way. (See the SO question at http://stackoverflow.com/questions/9521319/how-to-reference-form-when-rendering-partial-from-js-erb-file) So, in more of a generic architecture type question: Right now I have a form where a user can add a new recipe. The form also allows the user to select ingredients (it uses a collection_select which contains Ingredient.all). The catch is - I'd like the user to be able to add a new ingredient on the fly, without leaving the recipe form. Using a hidden div and some jQuery/AJAX, I have a link the user can click to popup a modal form containing ingredients/new.html.erb which is a simple form. When that form is submitted, I call ingredients/create.js.erb to validate the ingredient was saved and hide the modal div. Now I am back to my recipe form, but my collection_select hasn't updated. It seems I have a few choices here: try and re-render the collection_select portion of the form so it grabs a new list of ingredients. This was the method I was attempting when I wrote the SO question. The problem I run into is the partial I use for the collection_select needs the parent form passed in, and when I try and render from the JS file I don't know how to pass it the form object. Reload the recipe form. This works (the collection_select now contains the new ingredient), but the user loses any progress they made on the recipe form. I would need a way to persist the form data - I thought about manually passing the values back and forth, but that is sloppy and there has to be a better way... Try and manually insert the tags using jQuery - this would be simple, but because I'm allowing for multiple ingredients to be added, I can't be certain what ID to target. Now, I can't be the only person to have this issue - so is there an easier way I'm missing? I like option 2 above, but I don't know if there's an easy way to grab the entire params hash as if I had submitted the main recipes form. Hopefully someone can point me in the right direction so I can find an answer to this... If this doesn't make any sense at all, let me know - I can post code samples if you want, but most of the pertinent code is up on the SO question. Thanks!

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• Linux - Only first virtual interface can ping external gateway

  - by husvar

  I created 3 virtual interfaces with different mac addresses all linked to the same physical interface. I see that they successfully arp for the gw and they can ping (the request is coming in the packet capture in wireshark). However the ping utility does not count the responses. Does anyone knows the issue? I am running Ubuntu 14.04 in a VmWare. root@ubuntu:~# ip link sh 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT group default qlen 1000 link/ether 00:0c:29:bc:fc:8b brd ff:ff:ff:ff:ff:ff root@ubuntu:~# ip addr sh 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127.0.0.1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000 link/ether 00:0c:29:bc:fc:8b brd ff:ff:ff:ff:ff:ff inet6 fe80::20c:29ff:febc:fc8b/64 scope link valid_lft forever preferred_lft forever root@ubuntu:~# ip route sh root@ubuntu:~# ip link add link eth0 eth0.1 addr 00:00:00:00:00:11 type macvlan root@ubuntu:~# ip link add link eth0 eth0.2 addr 00:00:00:00:00:22 type macvlan root@ubuntu:~# ip link add link eth0 eth0.3 addr 00:00:00:00:00:33 type macvlan root@ubuntu:~# ip -4 link sh 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT group default qlen 1000 link/ether 00:0c:29:bc:fc:8b brd ff:ff:ff:ff:ff:ff 18: eth0.1@eth0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN mode DEFAULT group default link/ether 00:00:00:00:00:11 brd ff:ff:ff:ff:ff:ff 19: eth0.2@eth0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN mode DEFAULT group default link/ether 00:00:00:00:00:22 brd ff:ff:ff:ff:ff:ff 20: eth0.3@eth0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN mode DEFAULT group default link/ether 00:00:00:00:00:33 brd ff:ff:ff:ff:ff:ff root@ubuntu:~# ip -4 addr sh 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default inet 127.0.0.1/8 scope host lo valid_lft forever preferred_lft forever root@ubuntu:~# ip -4 route sh root@ubuntu:~# dhclient -v eth0.1 Internet Systems Consortium DHCP Client 4.2.4 Copyright 2004-2012 Internet Systems Consortium. All rights reserved. For info, please visit https://www.isc.org/software/dhcp/ Listening on LPF/eth0.1/00:00:00:00:00:11 Sending on LPF/eth0.1/00:00:00:00:00:11 Sending on Socket/fallback DHCPDISCOVER on eth0.1 to 255.255.255.255 port 67 interval 3 (xid=0x568eac05) DHCPREQUEST of 192.168.1.145 on eth0.1 to 255.255.255.255 port 67 (xid=0x568eac05) DHCPOFFER of 192.168.1.145 from 192.168.1.254 DHCPACK of 192.168.1.145 from 192.168.1.254 bound to 192.168.1.145 -- renewal in 1473 seconds. root@ubuntu:~# dhclient -v eth0.2 Internet Systems Consortium DHCP Client 4.2.4 Copyright 2004-2012 Internet Systems Consortium. All rights reserved. For info, please visit https://www.isc.org/software/dhcp/ Listening on LPF/eth0.2/00:00:00:00:00:22 Sending on LPF/eth0.2/00:00:00:00:00:22 Sending on Socket/fallback DHCPDISCOVER on eth0.2 to 255.255.255.255 port 67 interval 3 (xid=0x21e3114e) DHCPREQUEST of 192.168.1.146 on eth0.2 to 255.255.255.255 port 67 (xid=0x21e3114e) DHCPOFFER of 192.168.1.146 from 192.168.1.254 DHCPACK of 192.168.1.146 from 192.168.1.254 bound to 192.168.1.146 -- renewal in 1366 seconds. root@ubuntu:~# dhclient -v eth0.3 Internet Systems Consortium DHCP Client 4.2.4 Copyright 2004-2012 Internet Systems Consortium. All rights reserved. For info, please visit https://www.isc.org/software/dhcp/ Listening on LPF/eth0.3/00:00:00:00:00:33 Sending on LPF/eth0.3/00:00:00:00:00:33 Sending on Socket/fallback DHCPDISCOVER on eth0.3 to 255.255.255.255 port 67 interval 3 (xid=0x11dc5f03) DHCPREQUEST of 192.168.1.147 on eth0.3 to 255.255.255.255 port 67 (xid=0x11dc5f03) DHCPOFFER of 192.168.1.147 from 192.168.1.254 DHCPACK of 192.168.1.147 from 192.168.1.254 bound to 192.168.1.147 -- renewal in 1657 seconds. root@ubuntu:~# ip -4 link sh 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT group default qlen 1000 link/ether 00:0c:29:bc:fc:8b brd ff:ff:ff:ff:ff:ff 18: eth0.1@eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN mode DEFAULT group default link/ether 00:00:00:00:00:11 brd ff:ff:ff:ff:ff:ff 19: eth0.2@eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN mode DEFAULT group default link/ether 00:00:00:00:00:22 brd ff:ff:ff:ff:ff:ff 20: eth0.3@eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN mode DEFAULT group default link/ether 00:00:00:00:00:33 brd ff:ff:ff:ff:ff:ff root@ubuntu:~# ip -4 addr sh 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default inet 127.0.0.1/8 scope host lo valid_lft forever preferred_lft forever 18: eth0.1@eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN group default inet 192.168.1.145/24 brd 192.168.1.255 scope global eth0.1 valid_lft forever preferred_lft forever 19: eth0.2@eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN group default inet 192.168.1.146/24 brd 192.168.1.255 scope global eth0.2 valid_lft forever preferred_lft forever 20: eth0.3@eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN group default inet 192.168.1.147/24 brd 192.168.1.255 scope global eth0.3 valid_lft forever preferred_lft forever root@ubuntu:~# ip -4 route sh default via 192.168.1.254 dev eth0.1 192.168.1.0/24 dev eth0.1 proto kernel scope link src 192.168.1.145 192.168.1.0/24 dev eth0.2 proto kernel scope link src 192.168.1.146 192.168.1.0/24 dev eth0.3 proto kernel scope link src 192.168.1.147 root@ubuntu:~# arping -c 5 -I eth0.1 192.168.1.254 ARPING 192.168.1.254 from 192.168.1.145 eth0.1 Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 6.936ms Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 2.986ms Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 0.654ms Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 5.137ms Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 2.426ms Sent 5 probes (1 broadcast(s)) Received 5 response(s) root@ubuntu:~# arping -c 5 -I eth0.2 192.168.1.254 ARPING 192.168.1.254 from 192.168.1.146 eth0.2 Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 5.665ms Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 3.753ms Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 16.500ms Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 3.287ms Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 32.438ms Sent 5 probes (1 broadcast(s)) Received 5 response(s) root@ubuntu:~# arping -c 5 -I eth0.3 192.168.1.254 ARPING 192.168.1.254 from 192.168.1.147 eth0.3 Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 4.422ms Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 2.429ms Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 2.321ms Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 40.423ms Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 2.268ms Sent 5 probes (1 broadcast(s)) Received 5 response(s) root@ubuntu:~# tcpdump -n -i eth0.1 -v & [1] 5317 root@ubuntu:~# ping -c5 -q -I eth0.1 192.168.1.254 PING 192.168.1.254 (192.168.1.254) from 192.168.1.145 eth0.1: 56(84) bytes of data. tcpdump: listening on eth0.1, link-type EN10MB (Ethernet), capture size 65535 bytes 13:18:37.612558 IP (tos 0x0, ttl 64, id 2595, offset 0, flags [DF], proto ICMP (1), length 84) 192.168.1.145 > 192.168.1.254: ICMP echo request, id 5318, seq 2, length 64 13:18:37.618864 IP (tos 0x68, ttl 64, id 14493, offset 0, flags [none], proto ICMP (1), length 84) 192.168.1.254 > 192.168.1.145: ICMP echo reply, id 5318, seq 2, length 64 13:18:37.743650 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has 192.168.1.87 tell 192.168.1.86, length 46 13:18:38.134997 IP (tos 0x0, ttl 128, id 23547, offset 0, flags [none], proto UDP (17), length 229) 192.168.1.86.138 > 192.168.1.255.138: NBT UDP PACKET(138) 13:18:38.614580 IP (tos 0x0, ttl 64, id 2596, offset 0, flags [DF], proto ICMP (1), length 84) 192.168.1.145 > 192.168.1.254: ICMP echo request, id 5318, seq 3, length 64 13:18:38.793479 IP (tos 0x68, ttl 64, id 14495, offset 0, flags [none], proto ICMP (1), length 84) 192.168.1.254 > 192.168.1.145: ICMP echo reply, id 5318, seq 3, length 64 13:18:39.151282 IP6 (class 0x68, hlim 255, next-header ICMPv6 (58) payload length: 32) fe80::5a98:35ff:fe57:e070 > ff02::1:ff6b:e9b4: [icmp6 sum ok] ICMP6, neighbor solicitation, length 32, who has 2001:818:d812:da00:8ae3:abff:fe6b:e9b4 source link-address option (1), length 8 (1): 58:98:35:57:a0:70 13:18:39.615612 IP (tos 0x0, ttl 64, id 2597, offset 0, flags [DF], proto ICMP (1), length 84) 192.168.1.145 > 192.168.1.254: ICMP echo request, id 5318, seq 4, length 64 13:18:39.746981 IP (tos 0x68, ttl 64, id 14496, offset 0, flags [none], proto ICMP (1), length 84) 192.168.1.254 > 192.168.1.145: ICMP echo reply, id 5318, seq 4, length 64 --- 192.168.1.254 ping statistics --- 5 packets transmitted, 5 received, 0% packet loss, time 4008ms rtt min/avg/max/mdev = 2.793/67.810/178.934/73.108 ms root@ubuntu:~# killall tcpdump >> /dev/null 2>&1 9 packets captured 12 packets received by filter 0 packets dropped by kernel [1]+ Done tcpdump -n -i eth0.1 -v root@ubuntu:~# tcpdump -n -i eth0.2 -v & [1] 5320 root@ubuntu:~# ping -c5 -q -I eth0.2 192.168.1.254 PING 192.168.1.254 (192.168.1.254) from 192.168.1.146 eth0.2: 56(84) bytes of data. tcpdump: listening on eth0.2, link-type EN10MB (Ethernet), capture size 65535 bytes 13:18:41.536874 ARP, Ethernet (len 6), IPv4 (len 4), Reply 192.168.1.254 is-at 58:98:35:57:a0:70, length 46 13:18:41.536933 IP (tos 0x0, ttl 64, id 2599, offset 0, flags [DF], proto ICMP (1), length 84) 192.168.1.146 > 192.168.1.254: ICMP echo request, id 5321, seq 1, length 64 13:18:41.539255 IP (tos 0x68, ttl 64, id 14507, offset 0, flags [none], proto ICMP (1), length 84) 192.168.1.254 > 192.168.1.146: ICMP echo reply, id 5321, seq 1, length 64 13:18:42.127715 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has 192.168.1.87 tell 192.168.1.86, length 46 13:18:42.511725 IP (tos 0x0, ttl 64, id 2600, offset 0, flags [DF], proto ICMP (1), length 84) 192.168.1.146 > 192.168.1.254: ICMP echo request, id 5321, seq 2, length 64 13:18:42.514385 IP (tos 0x68, ttl 64, id 14527, offset 0, flags [none], proto ICMP (1), length 84) 192.168.1.254 > 192.168.1.146: ICMP echo reply, id 5321, seq 2, length 64 13:18:42.743856 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has 192.168.1.87 tell 192.168.1.86, length 46 13:18:43.511727 IP (tos 0x0, ttl 64, id 2601, offset 0, flags [DF], proto ICMP (1), length 84) 192.168.1.146 > 192.168.1.254: ICMP echo request, id 5321, seq 3, length 64 13:18:43.513768 IP (tos 0x68, ttl 64, id 14528, offset 0, flags [none], proto ICMP (1), length 84) 192.168.1.254 > 192.168.1.146: ICMP echo reply, id 5321, seq 3, length 64 13:18:43.637598 IP (tos 0x0, ttl 128, id 23551, offset 0, flags [none], proto UDP (17), length 225) 192.168.1.86.17500 > 255.255.255.255.17500: UDP, length 197 13:18:43.641185 IP (tos 0x0, ttl 128, id 23552, offset 0, flags [none], proto UDP (17), length 225) 192.168.1.86.17500 > 192.168.1.255.17500: UDP, length 197 13:18:43.641201 IP (tos 0x0, ttl 128, id 23553, offset 0, flags [none], proto UDP (17), length 225) 192.168.1.86.17500 > 255.255.255.255.17500: UDP, length 197 13:18:43.743890 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has 192.168.1.87 tell 192.168.1.86, length 46 13:18:44.510758 IP (tos 0x0, ttl 64, id 2602, offset 0, flags [DF], proto ICMP (1), length 84) 192.168.1.146 > 192.168.1.254: ICMP echo request, id 5321, seq 4, length 64 13:18:44.512892 IP (tos 0x68, ttl 64, id 14538, offset 0, flags [none], proto ICMP (1), length 84) 192.168.1.254 > 192.168.1.146: ICMP echo reply, id 5321, seq 4, length 64 13:18:45.510794 IP (tos 0x0, ttl 64, id 2603, offset 0, flags [DF], proto ICMP (1), length 84) 192.168.1.146 > 192.168.1.254: ICMP echo request, id 5321, seq 5, length 64 13:18:45.519701 IP (tos 0x68, ttl 64, id 14539, offset 0, flags [none], proto ICMP (1), length 84) 192.168.1.254 > 192.168.1.146: ICMP echo reply, id 5321, seq 5, length 64 13:18:49.287554 IP6 (class 0x68, hlim 255, next-header ICMPv6 (58) payload length: 32) fe80::5a98:35ff:fe57:e070 > ff02::1:ff6b:e9b4: [icmp6 sum ok] ICMP6, neighbor solicitation, length 32, who has 2001:818:d812:da00:8ae3:abff:fe6b:e9b4 source link-address option (1), length 8 (1): 58:98:35:57:a0:70 13:18:50.013463 IP (tos 0x0, ttl 255, id 50737, offset 0, flags [DF], proto UDP (17), length 73) 192.168.1.146.5353 > 224.0.0.251.5353: 0 [2q] PTR (QM)? _ipps._tcp.local. PTR (QM)? _ipp._tcp.local. (45) 13:18:50.218874 IP6 (class 0x68, hlim 255, next-header ICMPv6 (58) payload length: 32) fe80::5a98:35ff:fe57:e070 > ff02::1:ff6b:e9b4: [icmp6 sum ok] ICMP6, neighbor solicitation, length 32, who has 2001:818:d812:da00:8ae3:abff:fe6b:e9b4 source link-address option (1), length 8 (1): 58:98:35:57:a0:70 13:18:51.129961 IP6 (class 0x68, hlim 255, next-header ICMPv6 (58) payload length: 32) fe80::5a98:35ff:fe57:e070 > ff02::1:ff6b:e9b4: [icmp6 sum ok] ICMP6, neighbor solicitation, length 32, who has 2001:818:d812:da00:8ae3:abff:fe6b:e9b4 source link-address option (1), length 8 (1): 58:98:35:57:a0:70 13:18:52.197074 IP6 (hlim 255, next-header UDP (17) payload length: 53) 2001:818:d812:da00:200:ff:fe00:22.5353 > ff02::fb.5353: [udp sum ok] 0 [2q] PTR (QM)? _ipps._tcp.local. PTR (QM)? _ipp._tcp.local. (45) 13:18:54.128240 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has 192.168.1.87 tell 192.168.1.86, length 46 --- 192.168.1.254 ping statistics --- 5 packets transmitted, 0 received, 100% packet loss, time 4000ms root@ubuntu:~# killall tcpdump >> /dev/null 2>&1 13:18:54.657731 IP6 (class 0x68, hlim 255, next-header ICMPv6 (58) payload length: 32) fe80::5a98:35ff:fe57:e070 > ff02::1:ff6b:e9b4: [icmp6 sum ok] ICMP6, neighbor solicitation, length 32, who has 2001:818:d812:da00:8ae3:abff:fe6b:e9b4 source link-address option (1), length 8 (1): 58:98:35:57:a0:70 13:18:54.743174 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has 192.168.1.87 tell 192.168.1.86, length 46 25 packets captured 26 packets received by filter 0 packets dropped by kernel [1]+ Done tcpdump -n -i eth0.2 -v root@ubuntu:~# tcpdump -n -i eth0.3 icmp & [1] 5324 root@ubuntu:~# ping -c5 -q -I eth0.3 192.168.1.254 PING 192.168.1.254 (192.168.1.254) from 192.168.1.147 eth0.3: 56(84) bytes of data. tcpdump: verbose output suppressed, use -v or -vv for full protocol decode listening on eth0.3, link-type EN10MB (Ethernet), capture size 65535 bytes 13:18:56.373434 IP 192.168.1.147 > 192.168.1.254: ICMP echo request, id 5325, seq 1, length 64 13:18:57.372116 IP 192.168.1.147 > 192.168.1.254: ICMP echo request, id 5325, seq 2, length 64 13:18:57.381263 IP 192.168.1.254 > 192.168.1.147: ICMP echo reply, id 5325, seq 2, length 64 13:18:58.371141 IP 192.168.1.147 > 192.168.1.254: ICMP echo request, id 5325, seq 3, length 64 13:18:58.373275 IP 192.168.1.254 > 192.168.1.147: ICMP echo reply, id 5325, seq 3, length 64 13:18:59.371165 IP 192.168.1.147 > 192.168.1.254: ICMP echo request, id 5325, seq 4, length 64 13:18:59.373259 IP 192.168.1.254 > 192.168.1.147: ICMP echo reply, id 5325, seq 4, length 64 13:19:00.371211 IP 192.168.1.147 > 192.168.1.254: ICMP echo request, id 5325, seq 5, length 64 13:19:00.373278 IP 192.168.1.254 > 192.168.1.147: ICMP echo reply, id 5325, seq 5, length 64 --- 192.168.1.254 ping statistics --- 5 packets transmitted, 1 received, 80% packet loss, time 4001ms rtt min/avg/max/mdev = 13.666/13.666/13.666/0.000 ms root@ubuntu:~# killall tcpdump >> /dev/null 2>&1 9 packets captured 10 packets received by filter 0 packets dropped by kernel [1]+ Done tcpdump -n -i eth0.3 icmp root@ubuntu:~# arp -n Address HWtype HWaddress Flags Mask Iface 192.168.1.254 ether 58:98:35:57:a0:70 C eth0.1 192.168.1.254 ether 58:98:35:57:a0:70 C eth0.2 192.168.1.254 ether 58:98:35:57:a0:70 C eth0.3

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• Random Access Violation Exception in WPF Application

  - by PT1984

  Hi, I am facing weird problem while running regression tests on my WPF Application. I am getting AccessViolationException with different stacktraces each time. First : Message :Attempted to read or write protected memory. This is often an indication that other memory is corrupt. StackTrace : at MS.Win32.PresentationCore.UnsafeNativeMethods.MILUnknown.Release(IntPtr pIUnkown) at MS.Win32.PresentationCore.UnsafeNativeMethods.MILUnknown.ReleaseInterface(IntPtr& ptr) at System.Windows.Media.SafeMILHandle.ReleaseHandle() at System.Runtime.InteropServices.SafeHandle.InternalFinalize() at System.Runtime.InteropServices.SafeHandle.Dispose(Boolean disposing) at System.Runtime.InteropServices.SafeHandle.Finalize() Source :PresentationCore Type : System.AccessViolationException. Second : Message :Attempted to read or write protected memory. This is often an indication that other memory is corrupt. StackTrace : at MS.Win32.PresentationCore.UnsafeNativeMethods.IMILBitmapEffect.GetOutput(SafeHandle THIS_PTR, UInt32 uiIndex, SafeMILHandle pContext, BitmapSourceSafeMILHandle& ppBitmapSource) at System.Windows.Media.Effects.BitmapEffect.GetOutput(SafeHandle unmanagedEffect, Int32 index, BitmapEffectRenderContext context) at System.Windows.Media.Effects.BitmapEffect.GetOutput(BitmapEffectInput input) at System.Windows.Media.Effects.BitmapEffectState.GetEffectOutput(Visual visual, RenderTargetBitmap& renderBitmap, Matrix worldTransform, Rect windowClip, Matrix& finalTransform) at System.Windows.Media.Effects.BitmapEffectVisualState.RenderBitmapEffect(Visual visual, Channel channel) at System.Windows.Media.Effects.BitmapEffectContent.ExecuteRealizationsUpdate() at System.Windows.Media.RealizationContext.RealizationUpdateSchedule.Execute() at System.Windows.Media.MediaContext.Render(ICompositionTarget resizedCompositionTarget) at System.Windows.Media.MediaContext.RenderMessageHandlerCore(Object resizedCompositionTarget) at System.Windows.Media.MediaContext.AnimatedRenderMessageHandler(Object resizedCompositionTarget) at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Boolean isSingleParameter) at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Boolean isSingleParameter, Delegate catchHandler) at System.Windows.Threading.Dispatcher.WrappedInvoke(Delegate callback, Object args, Boolean isSingleParameter, Delegate catchHandler) at System.Windows.Threading.DispatcherOperation.InvokeImpl() at System.Windows.Threading.DispatcherOperation.InvokeInSecurityContext(Object state) at System.Threading.ExecutionContext.runTryCode(Object userData) at System.Runtime.CompilerServices.RuntimeHelpers.ExecuteCodeWithGuaranteedCleanup(TryCode code, CleanupCode backoutCode, Object userData) at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state) at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state) at System.Windows.Threading.DispatcherOperation.Invoke() at System.Windows.Threading.Dispatcher.ProcessQueue() at System.Windows.Threading.Dispatcher.WndProcHook(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled) at MS.Win32.HwndWrapper.WndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled) at MS.Win32.HwndSubclass.DispatcherCallbackOperation(Object o) at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Boolean isSingleParameter) at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Boolean isSingleParameter, Delegate catchHandler) at System.Windows.Threading.Dispatcher.WrappedInvoke(Delegate callback, Object args, Boolean isSingleParameter, Delegate catchHandler) at System.Windows.Threading.Dispatcher.InvokeImpl(DispatcherPriority priority, TimeSpan timeout, Delegate method, Object args, Boolean isSingleParameter) at System.Windows.Threading.Dispatcher.Invoke(DispatcherPriority priority, Delegate method, Object arg) at MS.Win32.HwndSubclass.SubclassWndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam) at MS.Win32.UnsafeNativeMethods.DispatchMessage(MSG& msg) at System.Windows.Threading.Dispatcher.PushFrameImpl(DispatcherFrame frame) at System.Windows.Threading.Dispatcher.PushFrame(DispatcherFrame frame) at System.Windows.Threading.Dispatcher.Run() at System.Windows.Application.RunDispatcher(Object ignore) at System.Windows.Application.RunInternal(Window window) at System.Windows.Application.Run(Window window) at System.Windows.Application.Run() at Main() Source :PresentationCore Type :System.AccessViolationException In Application Event Log I found following entries : Dispatcher processing has been suspended, but messages are still being processed. Faulting application **.exe, version 1.0.0.*, stamp 4c08d288, faulting module wpfgfx_v0300.dll, version 3.0.6920.1427, stamp 488f3056, debug? 0, fault address 0x0012ec36. My Application uses Dispatcher from another thread, to change the values of the controls , enable - disable those, change visibility etc., the thred is run multiple times in a second. Please let me know if anybody has faced this problem? Thanks in advance, -Prasad

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• Using Dynamic Proxies to centralize JPA code

  - by Daziplqa

  Hi All, Actually, This is not a question but really I need your opinions in a matter... I put his post here because I know you always active, so please don't consider this a bad question and share me your opinions. I've used Java dynamic proxies to Centralize The code of JPA that I used in a standalone mode, and Here's the dynamic proxy code: package com.forat.service; import java.lang.reflect.InvocationHandler; import java.lang.reflect.Method; import java.lang.reflect.Proxy; import java.util.logging.Level; import java.util.logging.Logger; import javax.persistence.EntityManager; import javax.persistence.EntityManagerFactory; import javax.persistence.EntityTransaction; import javax.persistence.Persistence; import com.forat.service.exceptions.DAOException; /** * Example of usage : * <pre> * OnlineFromService onfromService = * (OnlineFromService) DAOProxy.newInstance(new OnlineFormServiceImpl()); * try { * Student s = new Student(); * s.setName("Mohammed"); * s.setNationalNumber("123456"); * onfromService.addStudent(s); * }catch (Exception ex) { * System.out.println(ex.getMessage()); * } *</pre> * @author mohammed hewedy * */ public class DAOProxy implements InvocationHandler{ private Object object; private Logger logger = Logger.getLogger(this.getClass().getSimpleName()); private DAOProxy(Object object) { this.object = object; } public static Object newInstance(Object object) { return Proxy.newProxyInstance(object.getClass().getClassLoader(), object.getClass().getInterfaces(), new DAOProxy(object)); } @Override public Object invoke(Object proxy, Method method, Object[] args) throws Throwable { EntityManagerFactory emf = null; EntityManager em = null; EntityTransaction et = null; Object result = null; try { emf = Persistence.createEntityManagerFactory(Constants.UNIT_NAME); em = emf.createEntityManager();; Method entityManagerSetter = object.getClass(). getDeclaredMethod(Constants.ENTITY_MANAGER_SETTER_METHOD, EntityManager.class); entityManagerSetter.invoke(object, em); et = em.getTransaction(); et.begin(); result = method.invoke(object, args); et.commit(); return result; }catch (Exception ex) { et.rollback(); Throwable cause = ex.getCause(); logger.log(Level.SEVERE, cause.getMessage()); if (cause instanceof DAOException) throw new DAOException(cause.getMessage(), cause); else throw new RuntimeException(cause.getMessage(), cause); }finally { em.close(); emf.close(); } } } And here's the link that contains more info (http://m-hewedy.blogspot.com/2010/04/using-dynamic-proxies-to-centralize-jpa.html) (plz don't consider this as adds, as I can copy and past the entire topic here if you want that) So, Please give me your opinions. Thanks.

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• Entity Framework v1 &hellip; Brief Synopsis and Tips &ndash; Part 2

  - by Rohit Gupta

  Using Entity Framework with ASMX Web sErvices and WCF Web Service: If you use ASMX WebService to expose Entity objects from Entity Framework... then the ASMX Webservice does not  include object graphs, one work around is to use Facade pattern or to use WCF Service. The other important aspect of using ASMX Web Services along with Entity Framework is that the ASMX Client is not aware of the existence of EF v1 since the client solely deals with C# objects (not EntityObjects or ObjectContext). Since the client is not aware of the ObjectContext hence the client cannot participate in change tracking since the client only receives the Current Values and not the Orginal values when the service sends the the Entity objects to the client. Thus there are 2 drawbacks to using EntityFramework with ASMX Web Service: 1. Object state is not maintained... so to overcome this limitation we need insert/update single entity at a time and retrieve the original values for the entity being updated on the server/service end before calling Save Changes. 2. ASMX does not maintain object graphs... i.e. Customer.Reservations or Customer.Reservations.Trip relationships are not maintained. Thus you need to send these relationships separately from service to client. WCF Web Service overcomes the object graph limitation of ASMX Web Service, but we need to insure that we are populating all the non-null scalar properties of all the objects in the object graph before calling Update. WCF Web service still cannot overcome the second limitation of tracking changes to entities at the client end. Also note that the "Customer" class in the Client is very different from the "Customer" class in the Entity Framework Model Entities. They are incompatible with each other hence we cannot cast one to the other. However the .NET Framework translates the client "Customer" Entity to the EFv1 Model "customer" Entity once the entity is serialzed back on the ASMX server end. If you need change tracking enabled on the client then we need to use WCF Data Services which is available with VS 2010. ====================================================================================================== In WCF when adding an object that has relationships, the framework assumes that every object in the object graph needs to be added to store. for e.g. in a Customer.Reservations.Trip object graph, when a Customer Entity is added to the store, the EFv1 assumes that it needs to a add a Reservations collection and also Trips for each Reservation. Thus if we need to use existing Trips for reservations then we need to insure that we null out the Trip object reference from Reservations and set the TripReference to the EntityKey of the desired Trip instead. ====================================================================================================== Understanding Relationships and Associations in EFv1 The Golden Rule of EF is that it does not load entities/relationships unless you ask it to explicitly do so. However there is 1 exception to this rule. This exception happens when you attach/detach entities from the ObjectContext. If you detach an Entity in a ObjectGraph from the ObjectContext, then the ObjectContext removes the ObjectStateEntry for this Entity and all the relationship Objects associated with this Entity. For e.g. in a Customer.Order.OrderDetails if the Customer Entity is detached from the ObjectContext then you cannot traverse to the Order and OrderDetails Entities (that still exist in the ObjectContext) from the Customer Entity(which does not exist in the Object Context) Conversely, if you JOIN a entity that is not in the ObjectContext with a Entity that is in the ObjContext then the First Entity will automatically be added to the ObjContext since relationships for the 2 Entities need to exist in the ObjContext. ========================================================= You cannot attach an EntityCollection to an entity through its navigation property for e.g. you cannot code myContact.Addresses = myAddressEntityCollection ========================================================== Cascade Deletes in EDM: The Designer does not support specifying cascase deletes for a Entity. To enable cascasde deletes on a Entity in EDM use the Association definition in CSDL for the Entity. for e.g. SalesOrderDetail (SOD) has a Foreign Key relationship with SalesOrderHeader (SalesOrderHeader 1 : SalesOrderDetail *) if you specify a cascade Delete on SalesOrderHeader Entity then calling deleteObject on SalesOrderHeader (SOH) Entity will send delete commands for SOH record and all the SOD records that reference the SOH record. ========================================================== As a good design practise, if you use Cascade Deletes insure that Cascade delete facet is used both in the EDM as well as in the database. Even though it is not absolutely mandatory to have Cascade deletes on both Database and EDM (since you can see that just the Cascade delete spec on the SOH Entity in EDM will insure that SOH record and all related SOD records will be deleted from the database ... even though you dont have cascade delete configured in the database in the SOD table) ============================================================== Maintaining relationships in Code When Setting a Navigation property of a Entity (for e.g. setting the Contact Navigation property of Address Entity) the following rules apply : If both objects are detached, no relationship object will be created. You are simply setting a property the CLR way. If both objects are attached, a relationship object will be created. If only one of the objects is attached, the other will become attached and a relationship object will be created. If that detached object is new, when it is attached to the context its EntityState will be Added. One important rule to remember regarding synchronizing the EntityReference.Value and EntityReference.EntityKey properties is that when attaching an Entity which has a EntityReference (e.g. Address Entity with ContactReference) the Value property will take precedence and if the Value and EntityKey are out of sync, the EntityKey will be updated to match the Value. ====================================================== If you call .Load() method on a detached Entity then the .Load() operation will throw an exception. There is one exception to this rule. If you load entities using MergeOption.NoTracking, you will be able to call .Load() on such entities since these Entities are accessible by the ObjectContext. So the bottomline is that we need Objectontext to be able to call .Load() method to do deffered loading on EntityReference or EntityCollection. Another rule to remember is that you cannot call .Load() on entities that have a EntityState.Added State since the ObjectContext uses the EntityKey of the Primary (Parent) Entity when loading the related (Child) Entity (and not the EntityKey of the child (even if the EntityKey of the child is present before calling .Load()) ====================================================== You can use ObjContext.Add() to add a entity to the ObjContext and set the EntityState of the new Entity to EntityState.Added. here no relationships are added/updated. You can also use EntityCollection.Add() method to add an entity to another entity's related EntityCollection for e.g. contact has a Addresses EntityCollection so to add a new address use contact.Addresses.Add(newAddress) to add a new address to the Addresses EntityCollection. Note that if the entity does not already exist in the ObjectContext then calling contact.Addresses.Add(myAddress) will cause a new Address Entity to be added to the ObjContext with EntityState.Added and it will also add a RelationshipEntry (a relationship object) with EntityState.Added which connects the Contact (contact) with the new address newAddress. Note that if the entity already exists in the Objectcontext (being part theOtherContact.Addresses Collection), then calling contact.Addresses.Add(existingAddress) will add 2 RelationshipEntry objects to the ObjectStateEntry Collection, one with EntityState.Deleted and the other with EntityState.Added. This implies that the existingAddress Entity is removed from the theOtherContact.Addresses Collection and Added to the contact.Addresses Collection..effectively reassigning the address entity from the theOtherContact to "contact". This is called moving an existing entity to a new object graph. ====================================================== You usually use ObjectContext.Attach() and EntityCollection.Attach() methods usually when you need to reconstruct the ObjectGraph after deserializing the objects as received from a ASMX Web Service Client. Attach is usually used to connect existing Entities in the ObjectContext. When EntityCollection.Attach() is called the EntityState of the RelationshipEntry (the relationship object) remains as EntityState.unchanged whereas when EntityCollection.Add() method is called the EntityState of the relationship object changes to EntityState.Added or EntityState.Deleted as the situation demands. ========================================================= LINQ To Entities Tips: Select Many does Inner Join by default.   for e.g. from c in Contact from a in c.Address select c ... this will do a Inner Join between the Contacts and Addresses Table and return only those Contacts that have a Address. ======================================================== Group Joins Do LEFT Join by default. e.g. from a in Address join c in Contact ON a.Contact.ContactID == c.ContactID Into g WHERE a.CountryRegion == "US" select g; This query will do a left join on the Contact table and return contacts that have a address in "US" region The following query : from c in Contact join a in Address.Where(a1 => a1.CountryRegion == "US") on c.ContactID  equals a.Contact.ContactID into addresses select new {c, addresses} will do a left join on the Address table and return All Contacts. In these Contacts only those will have its Address EntityCollection Populated which have a Address in the "US" region, the other contacts will have 0 Addresses in the Address collection (even if addresses for those contacts exist in the database but are in a different region) ======================================================== Linq to Entities does not support DefaultIfEmpty().... instead use .Include("Address") Query Builder method to do a Left JOIN or use Group Joins if you need more control like Filtering on the Address EntityCollection of Contact Entity =================================================================== Use CreateSourceQuery() on the EntityReference or EntityCollection if you need to add filters during deferred loading of Entities (Deferred loading in EFv1 happens when you call Load() method on the EntityReference or EntityCollection. for e.g. var cust=context.Contacts.OfType<Customer>().First(); var sq = cust.Reservations.CreateSourceQuery().Where(r => r.ReservationDate > new DateTime(2008,1,1)); cust.Reservations.Attach(sq); This populates only those reservations that are older than Jan 1 2008. This is the only way (in EFv1) to Attach a Range of Entities to a EntityCollection using the Attach() method ================================================================== If you need to get the Foreign Key value for a entity e.g. to get the ContactID value from a Address Entity use this :                                address.ContactReference.EntityKey.EntityKeyValues.Where(k=> k.Key == "ContactID")

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• verilog / systemverilog -- What is the behavior of blocking statements across two always blocks?

  - by miles.sherman

  I am wondering about the behavior of the below code. There are two always blocks, one is combinational to calculate the next_state signal, the other is sequential which will perform some logic and determine whether or not to shutdown the system. It does this by setting the shutdown_now signal high and then calling state <= next_state. My question is if the conditions become true that the shutdown_now signal is set (during clock cycle n) in a blocking manner before the state <= next_state line, will the state during clock cycle n+1 be SHUTDOWN or RUNNING? In other words, does the shutdown_now = 1'b1 line block across both state machines since the state signal is dependent on it through the next_state determination? enum {IDLE, RUNNING, SHUTDOWN} state, next_state; logic shutdown_now; // State machine (combinational) always_comb begin case (state) IDLE: next_state <= RUNNING; RUNNING: next_state <= shutdown ? SHUTDOWN : RUNNING; SHUTDOWN: next_state <= SHUTDOWN; default: next_state <= SHUTDOWN; endcase end // Sequential Behavior always_ff @ (posedge clk) begin // Some code here if (/*some condition) begin shutdown_now = 1'b0; end else begin shutdown_now = 1'b1; end state <= next_state; end

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• How can I SETF an element in a tree by an accessor?

  - by Willi Ballenthin

  We've been using Lisp in my AI course. The assignments I've received have involved searching and generating tree-like structures. For each assignment, I've ended up writing something like: (defun initial-state () (list 0 ; score nil ; children 0 ; value 0)) ; something else and building my functions around these "states", which are really just nested lists with some loosely defined structure. To make the structure more rigid, I've tried to write accessors, such as: (defun state-score ( state ) (nth 2 state)) This works for reading the value (which should be all I need to do in a nicely functional world. However, as time crunches, and I start to madly hack, sometimes I want a mutable structure). I don't seem to be able to SETF the returned ...thing (place? value? pointer?). I get an error with something like: (setf (state-score *state*) 10) Sometimes I seem to have a little more luck writing the accessor/mutator as a macro: (defmacro state-score ( state ) `(nth 2 ,state)) However I don't know why this should be a macro, so I certainly shouldn't write it as a macro (except that sometimes it works. Programming by coincidence is bad). What is an appropriate strategy to build up such structures? More importantly, where can I learn about whats going on here (what operations affect the memory in what way)?

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• Dynamic select menu Rails, Javascript HABTM

  - by Jack

  Hi, I am following a tutorial in one of Ryan Bates' Railscasts here. Basically I want a form where there are 2 drop down menus, the contents of one are dependent on the other. I have Years and Courses, where Years HABMT Courses and Courses HABTM Years. In the tutorial, the javascript is as follows: var states = new Array(); <% for state in @states -%> states.push(new Array(<%= state.country_id %>, '<%=h state.name %>', <%= state.id %>)); <% end -%> function countrySelected() { country_id = $('person_country_id').getValue(); options = $('person_state_id').options; options.length = 1; states.each(function(state) { if (state[0] == country_id) { options[options.length] = new Option(state[1], state[2]); } }); if (options.length == 1) { $('state_field').hide(); } else { $('state_field').show(); } } document.observe('dom:loaded', function() { countrySelected(); $('person_country_id').observe('change', countrySelected); }); Where I guess country has many states and state belongs to country. I think what I need to do is edit the first for statement to somehow loop through all of the courses for each year_id, but don't know how to do this. Any ideas? Thanks

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• HiddenField.Value is an empty string upon postback inside my custom control

  - by Matthew Cox

  I have a custom control that has a hidden field. Upon postback I want to obtain the value stored in it, but it's always an empty string. any thoughts? I am performing client-side manipulation of the hidden field values and have verified in firebug that the fields are correct before issue a post back Here is the setup: public class DualListPanel : SWebControl, INamingContainer { protected IList<DlpItem> UnassignedList { get; set; } protected IList<DlpItem> AssignedList { get; set; } private HiddenField assignedItemsField, unassignedItemsField; public DualListPanel() { CssClass = "DualListPanel"; EnableViewState = true; } #region ViewState protected override void LoadViewState(object savedState) { var state = savedState as object[]; UnassignedList = state[0] as List<DlpItem>; AssignedList = state[1] as List<DlpItem>; base.LoadViewState(state[2]); } protected override object SaveViewState() { object[] state = new object[3]; state[0] = UnassignedList; state[1] = AssignedList; state[2] = base.SaveViewState(); return state; } #endregion #region WebControl Overrides protected override void CreateChildControls() { assignedItemsField = new HiddenField(); assignedItemsField.ID = "HiddenAssignedItems"; assignedItemsField.EnableViewState = true; unassignedItemsField = new HiddenField(); unassignedItemsField.ID = "HiddenUnassignedItems"; unassignedItemsField.EnableViewState = true; Controls.Add(assignedItemsField); Controls.Add(unassignedItemsField); base.CreateChildControls(); } #endregion #region Item Lists Retrieval public string GetCommaDelimUnassignedItems() { return unassignedItemsField.Value; } public string GetCommaDelimAssignedItems() { return assignedItemsField.Value; } #endregion }

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