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  • @dynamic property needs setter with multiple behaviors

    - by ambertch
    I have a class that contains multiple user objects and as such has an array of them as an instance variable: NSMutableArray *users; The tricky part is setting it. I am deserializing these objects from a server via Objective Resource, and for backend reasons users can only be returned as a long string of UIDs - what I have locally is a separate dictionary of users keyed to UIDs. Given the string uidString of comma separated UIDs I override the default setter and populate the actual user objects: @dynamic users; - (void)setUsers:(id)uidString { users = [NSMutableArray arrayWithArray: [[User allUsersDictionary] objectsForKeys:[(NSString*)uidString componentsSeparatedByString:@","]]]; } The problem is this: I now serialize these to database using SQLitePO, which stores these as the array of user objects, not the original string. So when I retrieve it from database the setter mistakenly treats this array of user objects as a string! Where I actually want to adjust the setter's behavior when it gets this object from DB vs. over the network. I can't just make the getter serialize back into a string without tearing up large code that reference this array of user objects, and I tried to detect in the setter whether I have a string or an array coming in: if ([uidString respondsToSelector:@selector(addObject)]) { // Already an array, so don't do anything - just assign users = uidString but no success... so I'm kind of stuck - any suggestions? Thanks in advance!

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  • why create CLSID_CaptureGraphBuilder2 instance always failed in a machine

    - by Yigang Wu
    It's a real strange issue, the machine information below is from DXDiag. There is no error reported, but create CLSID_CaptureGraphBuilder2 instance always failed in the machine. It's okay to create CLSID_FilterGraph. Before create CLSID_CaptureGraphBuilder2, I have called CoInitialize and created CLSID_FilterGraph. Only this machine has the error, what dll related with this interface or any function needed to call before to make it work? Thanks in advance. System Information Time of this report: 4/24/2010, 09:46:58 Machine name: TURION Operating System: Windows XP Home Edition (5.1, Build 2600) Service Pack 3 (2600.xpsp_sp3_qfe.100216-1510) Language: Japanese (Regional Setting: Japanese) System Manufacturer: To Be Filled By O.E.M. System Model: MS-7145 BIOS: Default System BIOS Processor: AMD Turion(tm) 64 Mobile Technology MT-30, MMX, 3DNow, ~1.6GHz Memory: 768MB RAM Page File: 376MB used, 1401MB available Windows Dir: C:\WINDOWS DirectX Version: DirectX 9.0c (4.09.0000.0904) DX Setup Parameters: Not found DxDiag Version: 5.03.2600.5512 32bit Unicode DxDiag Notes DirectX Files Tab: No problems found. Display Tab 1: No problems found. Sound Tab 1: No problems found. Sound Tab 2: No problems found. Music Tab: No problems found. Input Tab: No problems found. Network Tab: No problems found.

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  • Where can I view rountrip information in my ASP.NET application?

    - by ajax81
    Hi All, I'm playing around with storing application settings in my database, but I think I may have created a situation where superfluous roundtrips are being made. Is there an easy way to view roundtrips made to an MS Access (I know, I know) backend? I guess while I'm here, I should ask for advice on the best way to handle this project. I'm building an app that generates links based on file names (files are numbered ints, 0-5000). The files are stored on network shares, arranged by name, and the paths change frequently as files are bulk transfered to create space, etc. Example: Files 1000 - 2000 go to /path/1000s Files 2001 - 3000 go to /path/2000s Files 3001 - 4000 go to /path/3000s etc I'm sure by now you can see where I'm going with this. Ultimately, I'm trying to avoid making a roundtrip to get the paths for every single file as they are displayed in a gridview. I'm open to the notion that I've gone about this all wrong and that my idea might be rubbish. I've toyed around with the notion of just creating a flat file, but if I do that, do I still run into the problem of having that file opened and closed for every file displayed in a gridview?

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  • App Crashing Inspite of Being ARC Enabled

    - by proctr
    I have been working on an iOS App for sometime now and its almost ready to submit. However, when I gave it to few people for testing purposes (running iOS 5)..they reported cases where the app crashes and the home screen is displayed on the phone OR a frozen app screen appears with no response whatsoever The app is ARC enabled and Xcode shows no warnings. So, I'm relli tensed about what's going wrong. I have declared properties in the following fashion: @property (nonatomic) IBOutlet UILabel *devCountLabel; @property (nonatomic) IBOutlet UIView *splashView; Likewise other properties are declared. Could anyone provide a solution ASAP. It is mainly a network based app and thus, CoreData usage is minimum.. Anyway, I'm running out of time..So Please provide a fix asap..oh and thanks a ton for it. PS: The App doesn't crash in the simulator, so I'm guessing it has something related to memory. And the crashes are random. So, repeating a set of steps to reproduce the crash doesn't help either. For Eg. When I click a button, modalViewControllerAnimation results in normal case. Now this occurs as expected most of the time and freezes the app other times.

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  • What could trigger a change of http status to 500 on the client's end?

    - by VexedPanda
    We have a PHP web application that posts data to itself, and either displays an updated page based on that data, or redirects to another page. An example of this is a script with a paged list on it, where clicking on the Next link causes a post to the same page, which then returns an updated version of the page showing the new set of list items. One client is reporting that IE is displaying friendly error messages when the page updates itself instead of the correct behavior of displaying the updated page. Turning friendly error messages off "corrects" this problem, and displays the updated page normally, indicating no actual server error occurred. When testing from any location other than this client's our web app does not produce any http error statuses, and in this specific situation only produces 200 statuses. (According to Fiddler.) What could be interfering with the HTTP POST and changing the response's http status code to 500 (or another code that would trigger friendly errors in IE)? Are there certain proxies or other network tools that could be misconfigured or buggy in this manner? Is there any way we can alter our application (apart from avoiding posts to the same script, which is not feasible) to get around this misbehavior?

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  • Basic user authentication with records in AngularFire

    - by ajkochanowicz
    Having spent literally days trying the different, various recommended ways to do this, I've landed on what I think is the most simple and promising. Also thanks to the kind gents from this SO question: Get the index ID of an item in Firebase AngularFire Curent setup Users can log in with email and social networks, so when they create a record, it saves the userId as a sort of foreign key. Good so far. But I want to create a rule so twitter2934392 cannot read facebook63203497's records. Off to the security panel Match the IDs on the backend Unfortunately, the docs are inconsistent with the method from is firebase user id unique per provider (facebook, twitter, password) which suggest appending the social network to the ID. The docs expect you to create a different rule for each of the login method's ids. Why anyone using 1 login method would want to do that is beyond me. (From: https://www.firebase.com/docs/security/rule-expressions/auth.html) So I'll try to match the concatenated auth.provider with auth.id to the record in userId for the respective registry item. According to the API, this should be as easy as In my case using $registry instead of $user of course. { "rules": { ".read": true, ".write": true, "registry": { "$registry": { ".read": "$registry == auth.id" } } } } But that won't work, because (see the first image above), AngularFire sets each record under an index value. In the image above, it's 0. Here's where things get complicated. Also, I can't test anything in the simulator, as I cannot edit {some: 'json'} To even authenticate. The input box rejects any input. My best guess is the following. { "rules": { ".write": true, "registry": { "$registry": { ".read": "data.child('userId').val() == (auth.provider + auth.id)" } } } } Which both throws authentication errors and simultaneously grants full read access to all users. I'm losing my mind. What am I supposed to do here?

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  • Login failed for user ''. The user is not associated with a trusted SQL Server connection

    - by Tony_Henrich
    My web service app on my Windows XP box is trying to log in to my sql server 2005 database on the same box. The machine is part of a domain. I am logged in in the domain and I am an admin on my machine. I am using Windows Authentication in my connection string as in "Server=myServerAddress;Database=myDataBase;Trusted_Connection=True". SQLServer is configured for both types of authentication (mixed mode) and accepts remote connections and accepts tcp and named pipes protocols. Integrated authentication is enabled in IIS and with and without anonymous access. 'Everyone' has access to computer from network setting in local security settings. ASPNET is a user in the sql server and has access to the daatabase. user is mapped to the login. The app works fine for other developers which means the app shouldn't be changed (It's not new code). So it seems it's my machine which has an issue. I am getting the error "Login failed for user ''. The user is not associated with a trusted SQL Server connection" Note the blank user name. Why am I getting this error when both the app and database are on my machine? I can use SQL Server authentication but don't want to. I can connect to the database using SSMS and my Windows credentials. It might be related to setspn, kerberos, delegation, AD. I am not sure what further checks to make?

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  • Benefits of "Don't Fragment" on TCP Packets?

    - by taspeotis
    One of our customers is having trouble submitting data from our application (on their PC) to a server (different geographical location). When sending packets under 1100 bytes everything works fine, but above this we see TCP retransmitting the packet every few seconds and getting no response. The packets we are using for testing are about 1400 bytes (but less than 1472). I can send an ICMP ping to www.google.com that is 1472 bytes and get a response (so it's not their router/first few hops). I found that our application sets the DF flag for these packets, and I believe a router along the way to the server has an MTU less than/equal to 1100 and dropping the packet. This affects 1 client in 5000, but since everybody's routes will be different this is expected. The data is a SOAP envelope and we expect a SOAP response back. I can't justify WHY we do it, the code to do this was written by a previous developer. So... Are there are benefits OR justification to setting the DF flag on TCP packets for application data? I can think of reasons it is needed for network diagnostics applications but not in our situation (we want the data to get to the endpoint, fragmented or not). One of our sysadmins said that it might have something to do with us using SSL, but as far as I know SSL is like a stream and regardless of fragmentation, as long as the stream is rebuilt at the end, there's no problem. If there's no good justification I will be changing the behaviour of our application. Thanks in advance.

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  • How can multiple variables be passed to a function cleanly in C?

    - by aquanar
    I am working on an embedded system that has different output capabilities (digital out, serial, analog, etc). I am trying to figure out a clean way to pass many of the variables that will control those functions. I don't need to pass ALL of them too often, but I was hoping to have a function that would read the input data (in this case from a TCP network), and then parse the data (IE, the 3rd byte contains the states of 8 of the digital outputs (according to which bit in that byte is high or low)), and put that into a variable where I can then use elsewhere in the program. I wanted that function to be separate from the main() function, but to do so would require passing pointers to some 20 or so variables that it would be writing to. I know I could make the variables global, but I am trying to make it easier to debug by making it obvious when a function is allowed to edit that variable, by passing it to the function. My best idea was a struct, and just pass a pointer to it, but wasn't sure if there was a more efficient way, especially since there is only really 1 function that would need to access all of them at once, while most others only require parts of the information that will be stored in this bunch of state variables. So anyway, is there a clean way to send many variables between functions at once that need to be edited?

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  • Windows Azure Worldwide availability

    - by Insomniac
    Hi, I've been reviewing Windows Azure platform for some time, and can't find answer to one very important question. If I deploy my application within a cloud, how it will be reached from different places worldwide? For example if I have a web application with a database and want it to be accessible to users in UK, US, China and etc. Can I be sure that any user in the world will get almost the same request processing time? I think of it this way. 1. User sends request (navigates in browser to my web site) 2. This request gets in a cloud in a nearest location (closest to user MS Data Center?) 3. It is processed by an instance of my web application (in nearest location, with request to my centralized DB which can be far away but SQL request goes via MS internal network, which I believe should be very fast). 4. Response sent to user. Please let me know if I'm wrong. Thanks.

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  • Python-based password tracker (or dictionary)

    - by Arrieta
    Hello: Where we work we need to remember about 10 long passwords which need to change every so often. I would like to create a utility which can potentially save these passwords in an encrypted file so that we can keep track of them. I can think of some sort of dictionary passwd = {'host1':'pass1', 'host2':'pass2'}, etc, but I don't know what to do about encryption (absolutely zero experience in the topic). So, my question is really two questions: Is there a Linux-based utility which lets you do that? If you were to program it in Python, how would you go about it? A perk of approach two, would be for the software to update the ssh public keys after the password has been changed (you know the pain of updating ~15 tokens once you change your password). As it can be expected, I have zero control over the actual network configuration and the management of scp keys. I can only hope to provide a simple utility to me an my very few coworkers so that, if we need to, we can retrieve a password on demand. Cheers.

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  • Send Automated Email through Windows Service that has an embedded image using C#

    - by Refracted Paladin
    I already have a C# windows service that we use internally to monitor a directory on our network and when it detects a change sends off an email using our internal SMTP server to the specified groups of people. Now I need to embedd an image in that automated email. I understand that I need to create an AlternateView and a Linked Resource and use the Linked Resource's cID in the AlternateView, correct. What I do not understand is where do I put the image? Should I add it to my service project and set Copy to Output Directory = Copy Always? If so, how would I then access when creating my LinkedResource? Also, where do I put the image on the Server hosting the Service? Here is what I have so far but it doesn't seem to work. I don't get any errors, that I am aware of, but I do not get an email either. I am guessing it is looking for the image but that I do not have it in the correct location. // This event is called when an object(file,folder) is created in the srcPath void WatcherCreated(object source , FileSystemEventArgs e) { var folderName = e.Name; var folderPath = e.FullPath; MailMessage mail = new MailMessage(); mail.From = new MailAddress("[email protected]"); mail.To.Add("[email protected]"); mail.Subject = "New Enrollment for " + folderName; AlternateView plainView = AlternateView.CreateAlternateViewFromString("This is the plain text view", null, "text/html"); AlternateView htmlView = AlternateView.CreateAlternateViewFromString("Here is an embedded image. <img src=cid:enrollProcessID>", null, "text/html"); LinkedResource imageResourceLink = new LinkedResource("EnrollmentProcess.jpg") {ContentId = "enrollProcessID"}; htmlView.LinkedResources.Add(imageResourceLink); mail.AlternateViews.Add(plainView); mail.AlternateViews.Add(htmlView); var smtp = new SmtpClient("internalSMTP"); smtp.Send(mail); }

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  • Objective-C Definedness

    - by Dan Ray
    This is an agonizingly rookie question, but here I am learning a new language and framework, and I'm trying to answer the question "What is Truth?" as pertains to Obj-C. I'm trying to lazy-load images across the network. I have a data class called Event that has properties including: @property (nonatomic, retain) UIImage image; @property (nonatomic, retain) UIImage thumbnail; in my AppDelegate, I fetch up a bunch of data about my events (this is an app that shows local arts event listings), and pre-sets each event.image to my default "no-image.png". Then in the UITableViewController where I view these things, I do: if (thisEvent.image == NULL) { NSLog(@"Going for this item's image"); UIImage *tempImage = [UIImage imageWithData:[NSData dataWithContentsOfURL: [NSURL URLWithString: [NSString stringWithFormat: @"http://www.mysite.com/content_elements/%@_image_1.jpg", thisEvent.guid]]]]; thisEvent.image = tempImage; } We never get that NSLog call. Testing thisEvent.image for NULLness isn't the thing. I've tried == nil as well, but that also doesn't work.

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  • How to check Internet status in iPhone

    - by Radix
    Hello; I wanted to check whether internet is connected or not using either the SystemConfiguration or the CFNetwork i am not quite sure which one. Then i want to know that if the internet is connected then is it connected through wifi or not. I tried an example where i used the below code -(IBAction) shownetworkStatus { NSURL *url = [NSURL URLWithString:@"www.google.com"]; if (url!=NULL) { lbl.text = @"Connected"; } else { lbl.text = @"notConnected"; } } some say that its not valid as per apple and you have to use the SystemConfiguration Framework, Please let me know what needs to be done. Also i personally think that what i am doing in the above code is not proper as if one day google may also be down due to maintenance or some other factors. Also if you could provide me a link where i could display the name of the WIFI network then it would be really cool. I searched the internet then i got these Reachability.h code which again is a bouncer as i wana learn the concepts not copy paste them Thanks and Regards Radix

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  • ActionListener isn't Implementing

    - by Nick Gibson
    JFrameWithPanel is not abstract and does not override abstract method actionPerformed(java.awt.event.ActionEvent) in java.awt.event.ActionListener public class JFrameWithPanel extends JFrame implements ActionListener I Don't get this code. Book and Java site tells me this is the syntax for the method, but again this error shows up constantly. import javax.swing.*; import javax.swing.JOptionPane; import java.awt.*; import java.awt.event.*; import java.lang.Math.*; import java.lang.Integer.*; import java.util.*; import java.util.Random; import java.io.*; import java.text.*; import java.text.DecimalFormat.*; public class JFrameWithPanel extends JFrame implements ActionListener { JButton button = new JButton("Exit"); public JFrameWithPanel() { super("JFrame with Panel"); JComboBox packageChoice = new JComboBox(); packageChoice.addItem("A+ Certification"); packageChoice.addItem("Network+ Certification "); packageChoice.addItem("Security+ Certifictation"); packageChoice.addItem("CIT Full Test Package"); packageChoice.addActionListener(this); setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); JPanel pane = new JPanel(); pane.add(button); pane.add(packageChoice); setContentPane(pane); setSize(200,100); setVisible(true); } } then later public class CreateJFrameWithPanel { public static void main(String[] args) { JFrameWithPanel panel = new JFrameWithPanel(); } }

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  • how to create a https proxy?

    - by davidshen84
    hi, i want to implement a simple ssl web proxy. i do not want to work with the network connection problems. so i think i can utilize a web server (like apache) to help me establish the connection, and my program works like a cgi app on the web server to redirect the web browser request. below is how i want to implement it: client make http/https requests to the target web site, and setting to use my http/https proxy; apache get the request, and use a rewrite rule to redirect the to my cgi app; my app parse the request and make request to the real web site; my app get the response from the real web site, then send the response back to the client; currently, http requests seem to work. but https requests do not work at all. i tried to use curl to make a request to a https web site through my proxy, and the result is CONNECTION FAILED. my question is, will my idea work? if yes, how to make the https requests work.

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  • ThreadExceptionEventHandler and invoking delegates

    - by QmunkE
    If I assign a ThreadExceptionEventHandler to Application.ThreadException, why when I invoke a delegate method using a control on the main application thread are any exceptions thrown by that delegate not triggering the event handler? i.e. static void Main() { ... Application.ThreadException += new System.Threading.ThreadExceptionEventHandler(Application_ThreadException); Application.Run(new Form1()); } static void Application_ThreadException(object sender, System.Threading.ThreadExceptionEventArgs e) { Console.Error.Write("A thread exception occurred!"); } ... private void Form1_Load(object sender, EventArgs e) { Thread syncThread = new Thread(new ThreadStart(this.ThrowException)); syncThread.Start(); } private void ThrowException() { button1.Invoke(new MethodInvoker(delegate { // Not handled by ThreadExceptionEventHandler? throw new Exception(); })); } The context on this is that I have a background thread started from a form which is throwing an unhandled exception which terminates the application. I know this thread is going to be unreliable since it is network connectivity reliant and so subject to being terminated at any point, but I'm just interested as to why this scenario doesn't play out as I expect?

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  • Does Socket open another thread? Does it return something?

    - by Roman
    In the client application I call new Socket(serverIP,serverPort). As a result the client application sends a request to the server application to open a socket. Does it start a new thread? I mean which of the following is true? Client application sends a request and immediately starts to execute following commands (not weighting for the answer). Client sends the request and weights for the answer. As soon as the answer is obtained, the client application continues to execute following commands. The second case seems to be more realistic and logical for me. However, I do not understand what happens if the server does not open a socket and it does not say that it does not "want" to open the second (it can happen if the server does not exist or network is broken). What will happen in this case? Will server weight forever? In general it would be nice for the client to know what is the result of its request for the socket. For example I can imagine the following situations: The socket is opened by the server. The server refuses to open a socket. So, server exists, it got the request from the client but it says "no". There is no response from the server. I know that new Socket(serverIP,serverPort) does not "return" this kind of information. But it throws exceptions. One of them is "UnkownHostException". When it is thrown? When the server is not responding for a while (for how long)? ADDED: I just found out that UnknownHostException is thrown to indicate that the IP address of a host could not be determined. So, it is unrelated with the above described situations (server is not responding, server refuses to open a socket).

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  • How to run stored procedures and ad-hoc scripts asynchronously with "loosely" connected SQL Server 2

    - by sanga
    Is there a way to initiate a script against an instance of SQL server when it is not connected then have it run on the instance the next time it connects? This needs to happen without any intervention from me. Background situation if you are interested: We have about 120 machines each with their own instance of SQL Server 2000. Most of them are laptops. We have merge replication set up with each one. From time to time, there is a need to delete "rogue" guids from some tables in some instances that overwrite legitimate records on the main publisher as well as perform administrative tasks via stored procedure or adhoc sql statements. The problem is there is no telling when each machine is going to be connected to the network. Some folks turn their machines completely off at the end of the day. Others disconnect their machines and take them on business trips, home for the weekend etc. Did I mention that about 35 of these machines are in utility trucks and "attempt" to sync over a wireless connection. Thanks in advance for any assistance or suggestions. Sanga

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  • Why changing the images name on server results in calling the old ones?

    - by moderns
    I am running a slideshow on Ubuntu 12.04.1 that loads the images (slide1.jpg, slide2.jpg, slide3.jpg.., slide5.jpg) using the Javascript and styles as below: document.getElementById('slide_area').className='slide'+step; .slide1{background-image: url(../upload/slide1.jpg)} .slide2{background-image: url(../upload/slide2.jpg)} .slide3{background-image: url(../upload/slide3.jpg)} .slide4{background-image: url(../upload/slide4.jpg)} .slide5{background-image: url(../upload/slide5.jpg)} When I change the images names (show1.jpg, show2.jpg, show3.jpg.., show5.jpg) and also change the style as below: .slide1{background-image: url(../upload/show1.jpg)} .slide2{background-image: url(../upload/show2.jpg)} .slide3{background-image: url(../upload/show3.jpg)} .slide4{background-image: url(../upload/show4.jpg)} .slide5{background-image: url(../upload/show5.jpg)} And open the network section on Chrome, I see the server is calling the new name and old name for images! I added the header in the index.php: header("Cache-Control: no-store, no-cache, must-revalidate, max-age=0"); header("Expires: Sat, 26 Jul 1997 05:00:00 GMT"); // Date in the past header("Cache-Control: post-check=0, pre-check=0", false); header("Pragma: no-cache"); Nothing worked out with me and the slideshow doesn't work properly when I change the name of images even when clearing the browser cache as I load images sequentially (one by one) depending on imageObject.complete property! But without changing the name everything is going perfect and the images are loaded smoothly! Thank you for your help!

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  • queued view updates not happening when performSelector afterDelay:0 used

    - by JosephH
    Hi all, I have an app that performs some calculations based on data arriving on a socket or local user interaction. I want to show an 'activity spinner' whilst the calculation happens. spinner = [[UIActivityIndiactorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhiteLarge]; [spinner setCenter:self.view.center]; [self.view addSubview:spinner]; [spinner startAnimating]; [self performSelector:@selector(doCalcs) withObject:nil afterDelay:0]; This works well, except in the case where the code is run as a result of a message arriving over the network. I'm using http://code.google.com/p/cocoaasyncsocket/ to handle sockets and the code is running in the onSocket:didReadData:withTag: method. 'doCalcs' takes a few seconds. The spinner doesn't appear whilst it's running. If I change afterDelay:0 to afterDelay:1 then the spinner does appear the whole time doCalcs is running, but with the downside that it takes an extra second. So it seems the code is all correct, but for whatever reason the spinner isn't getting a chance to get on screen before doCalcs runs. Any suggestions would be most welcome.

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  • ASP.NET problem - Firebug shows odd behaviour

    - by Brandi
    I have an ASP.NET application that does a large database read. It loads up a gridview inside an update panel. In VS2008, just running on my local machine, it runs fantastically. In production (identical code, just published and put on one of our network servers), it runs slow as dirt. Debug is set to false, so this is not the cause of the slow down. I'm not an experienced web developer, so besides that, feel free to suggest the obvious. I have been using Firebug to determine what's going on, and here is what that has turned up: On production, there are around 500 requests. The timeline bar is very short. The size column varies from run to run, but is always the same for the duration of the run. Locally, there are about 30 requests. The timeline bar takes up the entire space. Can anyone shed some light on why this is happening and what I can do to fix it? Also, I can't find much of anything on the web about this, so any references are helpful too.

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  • File IO with Streams - Best Memory Buffer Size

    - by AJ
    I am writing a small IO library to assist with a larger (hobby) project. A part of this library performs various functions on a file, which is read / written via the FileStream object. On each StreamReader.Read(...) pass, I fire off an event which will be used in the main app to display progress information. The processing that goes on in the loop is vaired, but is not too time consuming (it could just be a simple file copy, for example, or may involve encryption...). My main question is: What is the best memory buffer size to use? Thinking about physical disk layouts, I could pick 2k, which would cover a CD sector size and is a nice multiple of a 512 byte hard disk sector. Higher up the abstraction tree, you could go for a larger buffer which could read an entire FAT cluster at a time. I realise with today's PC's, I could go for a more memory hungry option (a couple of MiB, for example), but then I increase the time between UI updates and the user perceives a less responsive app. As an aside, I'm eventually hoping to provide a similar interface to files hosted on FTP / HTTP servers (over a local network / fastish DSL). What would be the best memory buffer size for those (again, a "best-case" tradeoff between perceived responsiveness vs. performance).

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  • Receiving UDP on different Android phones gives different results

    - by user1868982
    I am willing to create a server and client program on my android mobile devices. The devices communicate with each other on the same wifi network, therefore, some simple scanning mechanism must be implemented - The client phones search for a server phone through some kind of broadcast. What I did: My protocol - the client phone broadcasts a message port p on the wifi, the server listens on port p. when the server gets the broadcast message it sends a message back, therefore discovering itself to the client. My code - I have opened a broadcast socket on my app, it sends a broadcast message. Meanwhile there is a python script on my PC that listens and replies - I use python so that my testing will be easier - Wireshark on the PC and I can see everything. What happens: When I use one of my Galaxy S phones - it works and I get a response. When I use the other Galaxy S phone - it doesn't work. Now this is what I know: The phone that works actually has Nexus ROM on it Ver. 4.1.1 The phone that doesn't work has 2.3.3 regular galaxy ROM The python code says it receives both of the broadcasts sent from both phones, and replies to both of them without raising any exception. So far I was thought the problem may be 1. the older version'd phone. 2. the windows firewall 3. the router firewall So I have opened Wireshark, and Indeed I saw that both phones are sending their broadcasts - it was logged on Wireshark. But the python script only responded to the first one. So this is why 1 & 3 are irrelevant - if the router firewall was blocking my UDP I would have still seen the python server response, same with the older versioned phone. To get rid of 2 i just disabled the windows firewall - still same problem. Does anyone has a clue to why this effect might happen? Thanks!

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  • Is there a way to receive data as unsigned char over UDP on Qt?

    - by user269037
    I need to send floating point numbers using a UDP connection to a Qt application. Now in Qt the only function available is qint64 readDatagram ( char * data, qint64 maxSize, QHostAddress * address = 0, quint16 * port = 0 ) which accepts data in the form of signed character buffer. I can convert my float into a string and send it but it will obviously not be very efficient converting a 4 byte float into a much longer sized character buffer. I got hold of these 2 functions to convert a 4 byte float into an unsinged 32 bit integer to transfer over network which works fine for a simple C++ UDP program but for Qt I need to receive the data as unsigned char. Is it possible to avoid converting the floatinf point data into a string and then sending it? uint32_t htonf(float f) { uint32_t p; uint32_t sign; if (f < 0) { sign = 1; f = -f; } else { sign = 0; } p = ((((uint32_t)f)&0x7fff)<<16) | (sign<<31); // Whole part and sign. p |= (uint32_t)(((f - (int)f) * 65536.0f))&0xffff; // Fraction. return p; } float ntohf(uint32_t p) { float f = ((p>>16)&0x7fff); // Whole part. f += (p&0xffff) / 65536.0f; // Fraction. if (((p>>31)&0x1) == 0x1) { f = -f; } // Sign bit set. return f; }

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