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  • Magento: How do I get observers to work in an external script?

    - by Laizer
    As far as I can tell, when a script is run outside of Magento, observers are not invoked when an event is fired. Why? How do I fix it? Below is the original issue that lead me to this question. The issue is that the observer that would apply the catalog rule is never called. The event fires, but the observer doesn't pick it up. I'm running an external script that loads up a Magento session. Within that script, I'm loading products and grabbing a bunch of properties. The one issue is that getFinalPrice() does not apply the catalog rules that apply to the product. I'm doing everything I know to set the session, even a bunch of stuff that I think is superfluous. Nothing seems to get these rules applied. Here's a test script: require_once "app/Mage.php"; umask(0); $app = Mage::app("default"); $app->getTranslator()->init('frontend'); //Probably not needed Mage::getSingleton('core/session', array('name'=>'frontend')); $session = Mage::getSingleton("customer/session"); $session->start(); //Probably not needed $session->loginById(122); $product = Mage::getModel('catalog/product')->load(1429); echo $product->getFinalPrice(); Any insight is appreciated.

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  • VisualSVN How to roll back the revision number ?

    - by Ita
    The company I work in has suffered a major server failure. During this failure the SVN Repository was lost. But there is still hope ! We have an old backup of the repository which I've managed to successfully restore using VisualSVN. The problem I'm facing now is that I can't update / commit pre-failure checkedout folders. The reason for this problem is that for instance: a local folder has a revision number of 2361, while the repository itself holds a revision number of 2290, which is older. Is there a way to deal with this issue ? Can I some how change the revision numbers on either the local copy or the server copy? A few points: I'm using TortoiseSVN 1.6.6. I can checkout folders from the repo and the connection is active. I've picked one of my folders and used the Relocate option on it. This helped me see that there is something wrong with the revision number I've experimented a bit with the merge option but this lead me now where special. (I'm open for suggestions ) Thank you for your time, Ita

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  • What are CDN Best Practices?

    - by Wild Thing
    Hi, I have recently started using the Rackspace Cloudfiles CDN (Limelight), about which I have some questions: I am using jQuery, jQuery UI and jQuery tools in addition to custom JS code. Also, my site is written in ASP.Net, which means there is some ASP.Net generated JS code. Right now what I have done is that I have combined all of the js (including the jquery code), except the ASP.Net generated JS into one file. I am hosting this on the Rackspace CDN. I am wondering if it would make more sense to just get the jQuery, jQuery UI files from the Google hosted CDN (which I suspect would work very well in serving these files, since they will be in many users' cache already)? This would mean one extra HTTP request, so I'm not sure if it'll help. Right now I have multiple containers for my assets. For example, in Rackspace I have 3 containers: JS, CSS and Images. The URL subdomain for all 3 is different. Will that lead to a performance penalty? Should I just use one container (and thus one domain for the CDN)? Is there a way of having the MS ASP.Net generated JS loaded from MS CDN? Would this have a performance hit as per the above question? Thanks in advance, WT

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  • PHP loop hanging/interspersed/threaded through HTML

    - by sandyv
    I can't figure out how to say what I'm talking about which is a big part of why I'm stuck. In PHP I often see code like this html <?php language construct that uses brackets { some code; ?> more html <?php some more code; } ?> rest of html Is there any name for this? Having seen this lead me to try it out so here is a concrete example whose behavior doesn't make sense to me <div id="content"> <ul id="nav"> <?php $path = 'content'; $dir = dir($path); while(false !== ($file = $dir->read())) { if(preg_match('/.+\.txt/i', $file)) { echo "<li>$file</li>"; ?> </ul> <?php echo file_get_contents($path . '/' . $file); } } ?> </div> Which outputs roughly <div><ul><li></li></ul><li></li>...</div> instead of <div><ul><li></li>...</ul></div> which is what I thought would happen and what I want to happen.

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  • Prevent hash navigation url

    - by Koningh
    I have the following problem: I'm using a slider (coda) to let people navigate trough some 'pages'. The slider uses hash links to navigate to the next page/slide. If a user is at page one (#page1), there is a link which will lead the user to page 2 (#page2) and so on. At the top of the slider the numbers of the pages appear as a link, but only when the page is visited. So if there are six pages and the user navigates from the first to the second and then the third one, there are only three links at the top of the slider (to page one, two and three). The problem is that a user can navigate to page five (or any page actually) without first visiting the pages previous to page five by just using the hash URL and typing the whole link in their address bar. For example if I would type www.mydomain.com/slider/index.php#page5 the slider automatically navigates to the fifth slide/page of the slider and thereby skipping the first four. I want to allow users to navigate to #page5 only if they have visited the first four (So by clicking trough the slides). This means that if they would go to #page5 directly by typing the URL in the address bar, I would like them to be send to the first page (#page1). Does anyone have any idea on solving this?

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  • Should '#include' and 'using' statements be repeated in both header and implementation files (C++)?

    - by Dr. Monkey
    I'm fairly new to C++, but my understanding is that a #include statement will essentially just dump the contents of the #included file into the location of that statement. This means that if I have a number of '#include' and 'using' statements in my header file, my implementation file can just #include the header file, and the compiler won't mind if I don't repeat the other statements. What about people though? My main concern is that if I don't repeat the '#include', 'using', and also 'typedef' (now that I think of it) statements, it takes that information away from the file in which it's used, which could lead to confusion. I am just working on small projects at the moment where it won't really cause any issues, but I can imagine that in larger projects with more people working on them it could become a significant issue. An example follows: //Unit.h #include <string> #include <ostream> #include "StringSet.h" using std::string; using std::ostream; class Unit { public: //public members private: //private members //unrelated side-question: should private members //even be included in the header file? } ; //Unit.cpp #include "Unit.h" //The following are all redundant from a compiler perspective: #include <string> #include <ostream> #include "StringSet.h" using std::string; using std::ostream; //implementation goes here

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  • codeigniter cron job with http access

    - by user1313850
    Sorry if this is a duplicate question...I've searched around and found similar advice but nothing that helps my exact problem. And please excuse the noob questions, CRON is a new thing for me. I have a codeigniter script that scrapes the html DOM of another site and stores some of that in a database. I'd like to run this script at a regular interval. This has lead me to looking into cron jobs. The page I have is at myserver.com/index.php/update I realize I can run a cron job with curl and run this page. If I want to be a bit more secure I can put a string at the end like: myserver.com/index.php/update/asdfh2784fufds And check for that in my CI controller. This seems like it would be mostly secure, but doesn't seem like the "right" way to do things. I've looked into running CI from the command line, and can execute basic pages like: php index.php mycontroller But when I try to do: php index.php update It doesn't work. I suspect this is because it needs to use HTTP to scrape the DOM of the outside page. So, my question: How do I securely run a codeigniter script with a cron job that needs HTTP access?

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  • How good idea is it to use code contracts in Visual Studio 2010 Professional (ie. no static checking

    - by Lasse V. Karlsen
    I create class libraries, some which are used by others around the world, and now that I'm starting to use Visual Studio 2010 I'm wondering how good idea it is for me to switch to using code contracts, instead of regular old-style if-statements. ie. instead of this: if (String.IsNullOrWhiteSpace(fileName)) throw new ArgumentNullException("fileName"); (yes, I know, if it is whitespace, it isn't strictly null) use this: Contract.Requires(!String.IsNullOrWhiteSpace(fileName)); The reason I'm asking is that I know that the static checker is not available to me, so I'm a bit nervous about some assumptions that I make, that the compiler cannot verify. This might lead to the class library not compiling for someone that downloads it, when they have the static checker. This, coupled with the fact that I cannot even reproduce the problem, would make it tiresome to fix, and I would gather that it doesn't speak volumes to the quality of my class library if it seemingly doesn't even compile out of the box. So I have a few questions: Is the static checker on by default if you have access to it? Or is there a setting I need to switch on in the class library (and since I don't have the static checker, I won't) Are my fears unwarranted? Is the above scenario a real problem? Any advice would be welcome.

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  • Is it possible to create multi-tiered WHERE statements in mySQL

    - by Brendan
    I'm currently developing a program that will generate reports based upon lead data. My issue is that I'm running 3 queries for something that I would like to only have to run one query for. For instance, I want to gather data for leads generated in the past day submission_date > (NOW() - INTERVAL 1 DAY) and I would like to find out how many total leads there were, and how many sold leads there were in that timeframe. (sold=1 / sold=0). The issue comes with the fact that this query is currently being done with 2 queries, one with WHEREsold= 1 and one with WHEREsold= 0. This is all well and good, but when I want to generate this data for the past day,week,month,year,and all time I will have to run 10 queries to obtain this data. I feel like there HAS to be a more efficient way of doing this. I know I can create a mySQL function for this, but I don't see how this could solve the problem. Thanks!!

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  • How to optimalize my game calendar in C#?

    - by MartyIX
    Hi, I've implemented a simple calendar (message system) for my game which consists from: 1) List<Event> calendar; 2) public class Event { /// <summary> /// When to process the event /// </summary> public Int64 when; /// <summary> /// Which object should process the event /// </summary> public GameObject who; /// <summary> /// Type of event /// </summary> public EventType what; public int posX; public int posY; public int EventID; } 3) calendar.Add(new Event(...)) The problem with this code is that even thought the number of messages is not excessise per second. It allocates still new memory and GC will once need to take care of that. The garbage collection may lead to a slight lag in my game and therefore I'd like to optimalize my code. My considerations: To change Event class in a structure - but the structure is not entirely small and it takes some time to copy it wherever I need it. Reuse Event object somehow (add queue with used events and when new event is needed I'll just take from this queue). Does anybody has other idea how to solve the problem? Thanks for suggestions!

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  • log activity. intrusion detection. user event notification ( interraction ). messaging

    - by Julian Davchev
    Have three questions that I somehow find related so I put them in same place. Currently building relatively large LAMP system - making use of messaging(activeMQ) , memcache and other goodies. I wonder if there are best practices or nice tips and tricks on howto implement those. System is user aware - meaning all actions done can be bind to particular logged user. 1. How to log all actions/activities of users? So that stats/graphics might be extracted later for analysing. At best that will include all url calls, post data etc etc. Meaning tons of inserts. I am thinking sending messages to activeMQ and later cron dumping in DB and cron analysing might be good idea here. Since using Zend Framework I guess I may use some request plugin so I don't have to make the log() call all over the code. 2.How to log stuff so may be used for intrusion detection? I know most things might be done on http level using apache mods for example but there are also specific cases like (5 failed login attempts in a row (leads to captcha) etc etc..) This also would include tons of inserts. Here I guess direct usage of memcache might be best approach as data don't seem vital to be permanantly persisted. Not sure if cannot use data from point 1. 3.System will notify users of some events. Like need approval , something broke..whatever.Some events will need feedback(action) from user, others are just informational. Wonder if there is common solutions for needs like this. Example: Based on occuring event(s) user will be notifed (user inbox for example) what happend. There will be link or something to lead him to details of thingy that happend and take action accordingly. Those seem trivial at first look but problem I see if coding it directly is becoming really fast hard to maintain.

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  • ASP.NET DropDownList control doesn't postback correctly inside of UserControl

    - by RichardAZ
    I have a situation where a DropDownList control is not posting back correctly. The AutoPost property is set to true, so the postback does happen, but the SelectedValue is not set to the correct value. In addition, the onSelectedIndexChanged event doesn't fire. The exact same code works perfect fine on an ASPX page, but does not work in a ASCX control. I have tried all the obvious things, I hope, trying to figure this one out, but no luck so far. I have even investigated what comes back in Request.Form["__EVENTTARGET"] and __EVENTARGUMENT. __EVENTTARGET does point to the drop down list, but the argument is empty. Can the folks of StackOverflow help lead me in the right direction to debug this issue. Of course, it is further complicated by master pages and the usual overcomplication of ASP.NET. Here is the code: <div> <asp:DropDownList ID="testDrop" runat="server" AutoPostBack="true" EnableViewState="true" onselectedindexchanged="testDrop_SelectedIndexChanged"> <asp:ListItem Value="1" Text="1">1</asp:ListItem> <asp:ListItem Value="2" Text="2">2</asp:ListItem> </asp:DropDownList> </div> And here is the generated html: <select id="ctl00_MainContent_rptAccordion_ctl00_statControl_testDrop" onchange="javascript:setTimeout('__doPostBack(\'ctl00$MainContent$rptAccordion$ctl00$statControl$testDrop\',\'\')', 0)" name="ctl00$MainContent$rptAccordion$ctl00$statControl$testDrop"> <option value="1" selected="selected">1</option> <option value="2">2</option> THANKS!

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  • Do I need a spatial index in my database?

    - by Sanoj
    I am designing an application that needs to save geometric shapes in a database. I haven't choosen the database management system yet. In my application, all database queries will have an bounding box as input, and as output I want all shapes within that database. I know that databases with a spatial index is used for this kind of application. But in my application there will not be any queries of type "give me objects nearby x/y" or other more complex queries that are useful in a GIS application. I am planning of having a database without a spatial index and have queries looking like: SELECT * FROM shapes WHERE x < max_x AND x > min_x AND y < max_y AND y > min_y And have an index on the columns x (double) and y (double). As long I can see, I don't really need a database with an spatial index, howsoever my application is close to that kind of applications. And even if I would like to have nearby queries, then I could create a big enough bounding box around that point. Or will this lead to poor performance? Do I really need a spatial database? And when is a spatial index needed?

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  • How do I make a lock that allows only ONE thread to read from the resource ?

    - by mare
    I have a file that holds an integer ID value. Currently reading the file is protected with ReaderWriterLockSlim as such: public int GetId() { _fileLock.EnterUpgradeableReadLock(); int id = 0; try { if(!File.Exists(_filePath)) CreateIdentityFile(); FileStream readStream = new FileStream(_filePath, FileMode.Open, FileAccess.Read); StreamReader sr = new StreamReader(readStream); string line = sr.ReadLine(); sr.Close(); readStream.Close(); id = int.Parse(line); return int.Parse(line); } finally { SaveNextId(id); // increment the id _fileLock.ExitUpgradeableReadLock(); } } The problem is that subsequent actions after GetId() might fail. As you can see the GetId() method increments the ID every single time, disregarding what happens after it has issued an ID. The issued ID might be left hanging (as said, exceptions might occur). As the ID is incremented, some IDs might be left unused. So I was thinking of moving the SaveNextId(id) out, remove it (the SaveNextId() actually uses the lock too, except that it's EnterWriteLock). And call it manually from outside after all the required methods have executed. That brings out another problem - multiple threads might enter the GetId() method before the SaveNextId() gets executed and they might all receive the same ID. I don't want any solutions where I have to alter the IDs after the operation, correcting them in any way because that's not nice and might lead to more problems. I need a solution where I can somehow callback into the FileIdentityManager (that's the class that handles these IDs) and let the manager know that it can perform the saving of the next ID and then release the read lock on the file containing the ID. Essentialy I want to replicate the relational databases autoincrement behaviour - if anything goes wrong during row insertion, the ID is not used, it is still available for use but it also never happens that the same ID is issued. Hopefully the question is understandable enough for you to provide some solutions..

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  • How are table headers supposed to be used?

    - by stevebot
    Hi, Recently I saw some code like this: <tr> <th> Some label: </th> <td> <input type="text" value=""/> </td> <th> Another label: </th> <td> <input type="text" value=""/> </td> </tr> I am used to table headers being used like <tr> <th> Some label: </th> <th> Another label: </th> </tr> <tr> <td> <input type="text" value=""/> </td> <td> <input type="text" value=""/> </td> </tr> How are table headers supposed to be used? The first example above, lead me to some pretty funky formatting issues, and it seems like in example 1 <label> should be used in place of <th>.

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  • Rails dealing with blank params at controller level

    - by stephenmurdoch
    I have a User model: class User < ActiveRecord::Base has_secure_password # validation lets users update accounts without entering password validates :password, presence: { on: :create }, allow_blank: { on: :update } validates :password_confirmation, presence: { if: :password_digest_changed? } end I also have a password_reset_controller: def update # this is emailed to the user by the create action - not shown @user=User.find_by_password_reset_token!(params[:id]) if @user.update_attributes(params[:user]) # user is signed in if password and confirmation pass validations sign_in @user redirect_to root_url, :notice => "Password has been reset." else flash.now[:error] = "Something went wrong, please try again." render :edit end end Can you see the problem here? A user can submit a blank a password/confirmation and rails will sign them in, because the User model allows blank on update. It's not a security concern, since an attacker would still need access to a user's email account before they could get anywhere near this action, but my problem is that a user submitting 6 blank chars would be signed in, and their password would not be changed for them, which could lead to confusion later on. So, I've come up with the following solution, and I'd like to check if there's a better way of doing it, before I push to production: def update @user=User.find_by_password_reset_token!(params[:id]) # if user submits blank password, add an error, and render edit action if params[:user][:password].blank? @user.errors.add(:password_digest, "can't be blank.") render :edit elsif @user.update_attributes(params[:user]) sign_in @user redirect_to root_url, :notice => "Password has been reset." else flash.now[:error] = "Something went wrong, please try again." render :edit end end Should I be checking for nil as well as blank? Are there any rails patterns or idiomatic ruby techniques for solving this? [Fwiw, I've got required: true on the html inputs, but want this handled server side too.]

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  • Detecting what the target object is when NullReferenceException is thrown.

    - by StingyJack
    I'm sure we all have received the wonderfully vague "Object reference not set to instance of an Object" exception at some time or another. Identifying the object that is the problem is often a tedious task of setting breakpoints and inspecting all members in each statement. Does anyone have any tricks to easily and efficiently identify the object that causes the exception, either via programmatical means or otherwise? --edit It seems I was vague like the exception =). The point is to _not have to debug the app to find the errant object. The compiler/runtime does know that the object has been allocated, and that the object has not yet been instantiated. Is there a way to extract / identify those details in a caught exception @ W. Craig Trader Your explanation that it is a result of a design problem is probably the best answer I could get. I am fairly compulsive with defensive coding and have managed to get rid of most of these errors after fixing my habits over time. The remaining ones just tweak me to no end, and lead me to posting this question to the community. Thanks for everyone's suggestions.

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  • iPhone application purchase verification -- possible?

    - by Sedate Alien
    The iPhone 3.0 SDK's StoreKit.framework provides support for in-app purchases to give the user additional content, functionality and so on. It is possible for an app to send the transactionReceipt property of SKPaymentTransaction objects to the developer's server for verification of successful purchasing before granting service. Is there any analogous SDK to verify the initial application purchase itself? A developer that wishes for their server to only provide services to genuine applications (i.e. not pirated) without using IAP could do so by verifying the application in this manner, e.g. ensure that only users with the correct transactionReceipt are catered for. I understand that this approach would still be vulnerable to replay attacks; a dedicated group of pirates could share a valid transactionReceipt. However, my server provides a consumable service to users, i.e. once they've connected and done the work, it needn't work a second time so replay attacks are nullified. The service that my app provides is relatively niche. I could distribute it on the App Store as a free application that requires at least one IAP to do anything useful, but I am lead to believe that this would be a very unpopular move among users as it would be considered misleading. If I distribute it as a paid app, I do not know how to ensure that only genuine apps can access the webservice. This is important as every invocation of the webservice costs me money! What are my options?

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  • How to call a method after asynchronous task is complete

    - by doctordoder
    I have a class called WikiWebView which is a subclass of UIWebView which loads Wikipedia subjects and is designed to fetch all the links of the webpage, in order to create a sort of site map for the subject. My problem is that I can only create the links once the web page has loaded, but the loading isn't done right after [self loadRequest:requestObj] is called. - (void)loadSubject:(NSString *)subject { // load the actual webpage NSString *wiki = @"http://www.wikipedia.org/wiki/"; NSString *fullURL = [wiki stringByAppendingString:subject]; NSURL *url = [NSURL URLWithString:fullURL]; NSURLRequest *requestObj = [NSURLRequest requestWithURL:url]; [self loadRequest:requestObj]; // [self createLinks]; // need this to be called after the view has loaded } - (void)createLinks { NSString *javascript = @"var string = \"\";" "var arr = document.getElementsByClassName(\"mw-redirect\");" "for (var i = 0; i < arr.length; ++i)" "{" "var redirectLink = arr[i].href;" "string = string + redirectLink + \" \";" "}" "string;"; NSString *links = [self stringByEvaluatingJavaScriptFromString:javascript]; self.links = [links componentsSeparatedByString:@" "]; } I tried the normal delegation technique, which lead to this code being added: - (id)init { if (self = [super init]) { self.delegate = self; // weird } return self; } #pragma mark - UIWebViewDelegate - (void)webViewDidStartLoad:(UIWebView *)webView { ++_numProcesses; } - (void)webView:(UIWebView *)webView didFailLoadWithError:(NSError *)error { --_numProcesses; } - (void)webViewDidFinishLoad:(UIWebView *)webView { --_numProcesses; if (_numProcesses == 0) { [self createLinks]; } } However, the delegate methods are never called.. I've seen similar questions where the answers are to use blocks, but how would I do that in this case?

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  • Overlaying several CLR reference fields with each other in explicit struct?

    - by thr
    Edit: I'm well aware of that this works very well with value types, my specific question is about using this for reference types. I've been tinkering around with structs in .NET/C#, and I just found out that you can do this: using System; using System.Runtime.InteropServices; namespace ConsoleApplication1 { class Foo { } class Bar { } [StructLayout(LayoutKind.Explicit)] struct Overlaid { [FieldOffset(0)] public object AsObject; [FieldOffset(0)] public Foo AsFoo; [FieldOffset(0)] public Bar AsBar; } class Program { static void Main(string[] args) { var overlaid = new Overlaid(); overlaid.AsObject = new Bar(); Console.WriteLine(overlaid.AsBar); overlaid.AsObject = new Foo(); Console.WriteLine(overlaid.AsFoo); Console.ReadLine(); } } } Basically circumventing having to do dynamic casting during runtime by using a struct that has an explicit field layout and then accessing the object inside as it's correct type. Now my question is: Can this lead to memory leaks somehow, or any other undefined behavior inside the CLR? Or is this a fully supported convention that is usable without any issues? I'm aware that this is one of the darker corners of the CLR, and that this technique is only a viable option in very few specific cases.

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  • How to optimize my game calendar in C#?

    - by MartyIX
    Hi, I've implemented a simple calendar (message system) for my game which consists from: 1) List<Event> calendar; 2) public class Event { /// <summary> /// When to process the event /// </summary> public Int64 when; /// <summary> /// Which object should process the event /// </summary> public GameObject who; /// <summary> /// Type of event /// </summary> public EventType what; public int posX; public int posY; public int EventID; } 3) calendar.Add(new Event(...)) The problem with this code is that even thought the number of messages is not excessise per second. It allocates still new memory and GC will once need to take care of that. The garbage collection may lead to a slight lag in my game and therefore I'd like to optimalize my code. My considerations: To change Event class in a structure - but the structure is not entirely small and it takes some time to copy it wherever I need it. Reuse Event object somehow (add queue with used events and when new event is needed I'll just take from this queue). Does anybody has other idea how to solve the problem? Thanks for suggestions!

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  • SVN Version Rollback Question

    - by phimuemue
    Hello, I'm using SVN (TortoiseSVN) and often came into the following situation: I wanted to discard any changes since a specific (old) revision and turn all files back to this specific (old) version. Then I wanted to work further as if this specific (old) revision was the newest one, i.e. I wanted to be able to commit the specific old revision as a new revision. I found several solutions for this problem (for example stackoverflow.com/questions/402159/roll-back-or-revert-entire-svn-repository-to-an-older-revision or rustyrazorblade.com/2007/04/how-to-roll-back-commits-to-an-earlier-version-of-a-repository-in-svn/). However, I wonder if there is a simple way to roll back to a specific revision. I thought version control is just good for such things (or am I misunderstanding something?). Is there a simple command/button/etc. that takes an updates my local repository to an old revision and declares it to be the newest one? Since I suppose that there is no "built-in" function to do this, I wanted to know what reason lead the developers to the decision not to integrate this feature. Does anybody know this?

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  • Question about singleton property

    - by Jack
    I'm reading the java tutorial for enums located here and have a question: http://java.sun.com/j2se/1.5.0/docs/guide/language/enums.html#Card The part i'm confused about is as follows: "The Card class, above, contains a static factory that returns a deck, but there is no way to get an individual card from its rank and suit. Merely exposing the constructor would destroy the singleton property (that only a single instance of each card is allowed to exist). Here is how to write a static factory that preserves the singleton property, using a nested EnumMap: " Now as I understand, changing the original private "Card" constructor to public would allow us to instantiate an unlimited number of copies of a "Card" object with a given suit+rank. The solution as proposed was to create an EnumMap which would store four Maps (one for each suit), which themselves contained 13 Card objects with the rank as their keys. And so now if you wanted to retrieve a specific Card object from the deck, you would just call the "valueOf" method. My question now is, what's the prevent you with calling the valueOf method as many times as you like? Wouldn't that lead to the same problem as making the original private constructor public? Thanks.

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  • While in a transaction, how can reads to an affected row be prevented until the transaction is done?

    - by Mahn
    I'm fairly sure this has a simple solution, but I haven't been able to find it so far. Provided an InnoDB MySQL database with the isolation level set to SERIALIZABLE, and given the following operation: BEGIN WORK; SELECT * FROM users WHERE userID=1; UPDATE users SET credits=100 WHERE userID=1; COMMIT; I would like to make sure that as soon as the select inside the transaction is issued, the row corresponding to userID=1 is locked for reads until the transaction is done. As it stands now, UPDATEs to this row will wait for the transaction to be finished if it is in process, but SELECTs simply will read the previous value. I understand this is the expected behaviour in this case, but I wonder if there is a way to lock the row in such a way that SELECTs will also wait until the transaction is finished to return the values? The reason I'm looking for that is that at some point, and with enough concurrent users, it could happen that while the previous transaction is in process someone else reads the "credits" to calculate something else. Ideally the code run by that someone else should wait for the transaction to finish to use the new value, because otherwise it could lead to irreversible desync issues. Note that I don't want to lock the entire table for reads, just the specific row. Also, I could add a boolean "locked" field to the tables and set it to 1 every time I'm starting a transaction but I don't really feel this is the most elegant solution here, unless there is absolutely no other way to handle this through mysql directly.

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  • Trigger alert when database entries are added, not when they are removed

    - by Jeremy
    I have a jQuery script running that makes a periodic AJAX call using the following code. var a = moment(); var dayOfMonth = a.format("MMM Do"); var timeSubmitted = a.format("h:mm a"); var count_cases = -1; var count_claimed = -1; setInterval(function(){ //check if new lead was added to the db $.ajax({ type : "POST", url : "inc/new_lead_alerts_process.php", dataType: 'json', cache: false, success : function(response){ $.getJSON("inc/new_lead_alerts_process.php", function(data) { if (count_cases != -1 && count_cases != data.count) { window.location = "new_lead_alerts.php?id="+data.id; } count_cases = data.count; }); } }); This is the PHP that runs with each call: $count = mysql_fetch_array(mysql_query("SELECT count(*) as count FROM leads")); $client_id = mysql_fetch_array(mysql_query("SELECT id, client_id FROM leads ORDER BY id DESC LIMIT 1")); echo json_encode(array("count" => $count['count'], "id" => $client_id['id'], "client_id" => $client_id['client_id'])); I need to change the code so that the alert only triggers when a new entry is added to the database, not when an existing entry is removed. As it stands, the alert fires on both events. Any help is greatly appreciated.

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