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  • Fix N+1 query in "declarative_authorization" gem using gem "bullet"

    - by makaroni4
    Currently I am working on one big web application and to make it work faster I decided to refactor all N+1 queries (to decrease number of requests to database, http://rails-bestpractices.com/posts/29-fix-n-1-queries). So I installed gem "bullet" which doesn`t work with Rails 3.1.1 now (you can use fork from https://github.com/flyerhzm/bullet). When using declarative_authorization gem on each page I get same alerts: N+1 Query detected Role => [:permissions] Add to your finder: :include => [:permissions] N+1 Query detected Permission => [:permission_rules] Add to your finder: :include => [:permission_rules] CACHE (0.0ms) SELECT "roles".* FROM "roles" CACHE (0.0ms) SELECT "permissions".* FROM "permissions" WHERE "permissions"."role_id" = 1 CACHE (0.0ms) SELECT "permissions".* FROM "permissions" WHERE "permissions"."role_id" = 2 CACHE (0.0ms) SELECT "permissions".* FROM "permissions" WHERE "permissions"."role_id" = 3 CACHE (0.0ms) SELECT "permissions".* FROM "permissions" WHERE "permissions"."role_id" = 4 CACHE (0.0ms) SELECT "permissions".* FROM "permissions" WHERE "permissions"."role_id" = 6 CACHE (0.0ms) SELECT "permissions".* FROM "permissions" WHERE "permissions"."role_id" = 7 CACHE (0.0ms) SELECT "permissions".* FROM "permissions" WHERE "permissions"."role_id" = 8 CACHE (0.0ms) SELECT "permission_rules".* FROM "permission_rules" INNER JOIN "permission_rules_permissions" ON "permission_rules"."id" = "permission_rules_permissions"."permission_rule_id" WHERE "permission_rules_permissions"."permission_id" = 30 CACHE (0.0ms) SELECT "permission_rules".* FROM "permission_rules" INNER JOIN "permission_rules_permissions" ON "permission_rules"."id" = "permission_rules_permissions"."permission_rule_id" WHERE "permission_rules_permissions"."permission_id" = 31 ... Could you please help me with that and to make this queries faster?

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  • How can I make hundreds of simultaneously running processes communicate with a database through one

    - by Olfan
    Long speech short: How can I make hundreds of simultaneously running processes communicate with a database through one or few permanent sessions? The whole story: I once built a number crunching engine that handles vast amounts of large data files by forking off one child after another giving each a small number of files to work on. File locking, progress monitoring and result propagation happen in an Oracle database which all (sub-)processes access at various times using an application-specific module which encapsulates DBI. This worked well at first, but now with higher volumes of input data, the number of database sessions (one per child, and they can be very short-lived) constantly being opened and closed is becoming an issue. I now want to centralise database access so that there are only one or few fixed database sessions which handle all database access for all the (sub-)processes. The presence of the database abstraction module should make the changes easy because the function calls in the worker instances can stay the same. My problem is that I cannot think of a suitable way to enhance said module in order to establish communication between all the processes and the database connector(s). I thought of message queueing, but couldn't come up with a way of connecting a large herd of requestors with one or few database connectors in a way so that bidirectional communication is possible (for collecting the query result). An asynchronous approach could help here in that all requests are written to the same queue and the database connector servicing the request will "call back" to submit the result. But my mind fails me in generating an image clear enough so that I can paint into code. Threading instead of forking might have given me an easier start, but this would now require massive changes to the code base that I'm not prepared to do to a live system. The more I think of it, the more the base idea looks like a pre-forked web server to me only that it doesn't serve web pages but database queries. Any ideas on what to dig into, and where? Sample (pseudo) code to inspire me, links to possibly related articles, ready solutions on CPAN maybe?

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  • Can tomcat perform ssl redirection by filtering host alias?

    - by Stephen
    Hi, We have a tomcat server (6.0.20) running one web application behind two urls, e.g. www.foo and secure.foo This is configured in the server.xml as one host with a single alias: <Host name="www.foo" appBase="webapps"> <Context docBase="foo" path=""></Context> <Alias>secure.foo</Alias> </Host> Ideally we'd like any requests to secure.foo on port 80 to be automatically redirected to use ssl. However, I can only find instructions for redirecting based on the path after the hostname, so I could add a /* security constraint but then this would apply to both urls. Does anyone know if it's possible to apply the redirection by filtering on hostname requested? (We've already got the ssl connector, certificate, etc. working ok). I know we could do it by sticking an apache server in front of tomcat and handling the redirection there, but I'm curious to know if tomcat can do this on its own. Thanks

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  • Quick and easy flood protection?

    - by James P
    I have a site where a user submits a message using AJAX to a file called like.php. In this file the users message is submitted to a database and it then sends a link back to the user. In my Javascript code I disabled the text box the user types into when they submit the AJAX request. The only problem is, a malicious user can just constantly send POST requests to like.php and flood my database. So I would like to implement simple flood protection. I don't really want the hassle of another database table logging users IPs and such... as if they are flooding my site there will be a lot of database read/writes slowing it down. I thought about using sessions, like have a session that contains a timestamp that gets checked every time they send data to like.php, and if the current time is before the timestamp let them add data to the database, otherwise send out an error and block them. If they are allowed to enter something into the database, update their session with a new timestamp. What do you think? Would this be the best way to go about it or are there easier alternatives? Thanks for any help. :)

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  • Etiquette: Version bump my fork of opensource project?

    - by Ross
    This question is about etiquette and open source projects. I have forked an application from github and added two new features. The first feature has been request frequently elsewhere. I have added it. Code & implementation are clean (I think). The second feature is more of a hack. It will be of use to others, but the implementation is a little dirty in useage and more so in code. I need the feature but I don't have the skills to fully implement it properly or to a level that could be considered a worth while contrabution to the main project. How should the versioning work? Do I just bump up my version numbers care-free and push to my master branch? It is annoying to know which version is running, modifed or original, as both have the same version number. But will it be confusing when, months later, my github page has a version number the same as the original but both are actually completely different. (I have made pull requests etc. but that is not the context of my question.) The project I have forked uses ruby jeweler so has a versioning format of: Jeweler tracks the version of your project. It assumes you will be using a version in the format x.y.z. x is the 'major' version, y is the 'minor' version, and z is the patch version. Is this standard for other projects/langauges too? Are my changes patches? Thanks

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  • Ajax request not receiving xml from Django

    - by amougeot
    I have a Django server which handles requests to a URL which will return some HTML for use in an image gallery. I can navigate to the URL and the browser will display the HTML that is returned, but I can't get that same HTML by doing an AJAX call (using jQuery) to the same URL. This is the view that generates the response: def gallery_images(request, gallery_name): return render_to_response('galleryimages.html', {'images': get_images_of_gallery(gallery_name)}, mimetype='text/xml') This is the 'galleryimages.html' template: {% for image in images %} <div id="{{image.name}}big"> <div class="actualImage" style="background-image:url({{image.image.name}});"> <h1>{{image.caption|safe}}</h1> </div> </div> {% endfor %} This is the jQuery call I am making: $("#allImages").load("http://localhost:8000/galleryimages/Web"); However, this loads nothing into my #allImages div. I've used firebug and ran jQuery's Ajax method .get("http://localhost:8000/galleryimages/Web") and firebug says that the response text is completely empty. When I check my Django server log, this is the entry I see for when I navigate to the URL manually, through my browser: [16/Jan/2010 17:34:10] "GET /galleryimages/Web HTTP/1.1" 200 215 This is the entry in the server log for when I make the AJAX call: [16/Jan/2010 17:36:19] "OPTIONS /galleryimages/Web HTTP/1.1" 200 215 Why does the AJAX request not get the xml that my Django page is serving?

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  • Cross-platform HTML application options

    - by Charles
    I'd like to develop a stand-alone desktop application targeting Windows (XP through 7) and Mac (Tiger through Snow Leopard), and if possible iPhone and Android. In order to make it all work with as much common code as possible (and because it's the only thing I'm good at), I'd like to handle the main logic with HTML and JS. Using Adobe AIR is a possibility. And I think I can do this with various application wrappers, using .NET for Windows XP, Objective C for iPhone, Java for Android and native "widget" platform support for Mac and Windows Vista & 7 (though I'd like to keep the widget in the foreground, so the Mac dashboard isn't ideal). Does anyone have any suggestions on where to start? The two sticking points are: I'll certainly need some form of persistent storage (cookies perhaps) to keep state between sessions I'll also probably need access to remote data files, so if I use AJAX and the hosting HTML file resides on the device, it will need to be able to do cross-domain requests. I've done this on the iPhone without any problems, but I'd be surprised if this were possible on other platforms. For me, Android and iPhone will be the easiest to handle, and it looks like I can use Adobe AIR to handle the rest. But I wanted to know if there are any other alternatives. Does anyone have any suggesions?

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  • JAR files, don't they just bloat and slow Java down?

    - by Josamoto
    Okay, the question might seem dumb, but I'm asking it anyways. After struggling for hours to get a Spring + BlazeDS project up and running, I discovered that I was having problems with my project as a result of not including the right dependencies for Spring etc. There were .jars missing from my WEB-INF/lib folder, yes, silly me. After a while, I managed to get all the .jar files where they belong, and it comes at a whopping 12.5MB at that, and there's more than 30 of them! Which concerns me, but it probably and hopefully shouldn't be concerned. How does Java operate in terms of these JAR files, they do take up quite a bit of hard drive space, taking into account that it's compressed and compiled source code. So that can really quickly populate a lot of RAM and in an instant. My questions are: Does Java load an entire .jar file into memory when say for instance a class in that .jar is instantiated? What about stuff that's in the .jar that never gets used. Do .jars get cached somehow, for optimized application performance? When a single .jar is loaded, I understand that the thing sits in memory and is available across multiple HTTP requests (i.e. for the lifetime of the server instance running), unlike PHP where objects are created on the fly with each request, is this assumption correct? When using Spring, I'm thinking, I had to include all those fiddly .jars, wouldn't I just be better off just using native Java, with say at least and ORM solution like Hibernate? So far, Spring just took extra time configuring, extra hard drive space, extra memory, cpu consumption, so I'm concerned that the framework is going to cost too much application performance just to get for example, IoC implemented with my BlazeDS server. There still has to come ORM, a unit testing framework and bits and pieces here and there. It's just so easy to bloat up a project quickly and irresponsibly easily. Where do I draw the line?

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  • How can I take advantage of IObservable/IObserver to get rid of my "god object"?

    - by Will
    In a system I'm currently working on, I have many components which are defined as interfaces and base classes. Each part of the system has some specific points where they interact with other parts of the system. For example, the data readying component readies some data which eventually needs to go to the data processing portion, the communications component needs to query different components for their status for relaying to the outside, etc. Currently, I glue these parts of the system together using a "god object", or an object with intimate knowledge of different parts of the system. It registers with events over here and shuttles the results to methods over there, creates a callback method here and returns the result of that method over there, and passes many requests through a multi-threaded queue for processing because it "knows" certain actions have to run on STA threads, etc. While its convenient, it concerns me that this one type knows so much about how everybody else in the system is designed. I'd much prefer a more generic hub that can be given instances which can expose events or methods or callbacks or that can consume these. I've been seeing more about the IObservable/IObserver features of the reactive framework and that are being rolled into .NET 4.0 (I believe). Can I leverage this pattern to help replace my "god object"? How should I go about doing this? Are there any resources for using this pattern for this specific purpose?

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  • Understanding REST through an example

    - by grifaton
    My only real exposure to the ideas of REST has been through Ruby on Rails' RESTful routing. This has suited me well for the kind of CRUD-based applications I have built with Rails, but consequently my understanding of RESTfulness is somewhat limited. Let's say we have a finite collection of Items, each of which has a unique ID, and a number of properties, such as colour, shape, and size (which might be undefined for some Items). Items can be used by a client for a period of time, but each Item can only be used by one client at once. Access to Items is regulated by a server. Clients can request the temporary use of certain items from a server. Usually, clients will only be interested in getting access to a number of Items with particular properties, rather than getting access to specific Items. When a client requests use of a number of Items, the server responds with a list of IDs corresponding to the request, or with a response that says that the requested Items are not currently available or do not exist. A client can make the following kinds of request: Tell me how many green triangle Items there are (in total/available). Give me use of 200 large red Items. I have finished with Items 21, 23, 23. Add 100 new red square Items. Delete 50 small green Items. Modify all big yellow pentagon Items to be blue. The toy example above is like a resource allocation problem I have had to deal with recently. How should I go about thinking about it RESTfully?

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  • Firefox not honoring must-revalidate cache headers returned by jQuery.ajax() request

    - by Oliver Weichhold
    UPDATE 1: Judging by this thread I am not the only one having this problem in FF 12 and only in 12. UPDATE 2: The problem does not seem to be limited to Ajax requests. From the looks of it everything that makes it into Firefox 12's cache will be fetched from there. No matter what. The server can specify cache control headers all day long. Bummer! What I'm trying to achieve is the following behavior: Browser may cache the response without revalidating for up to 5 minutes I don't care if the browser revalidates on every request (Both Chrome and IE9 do for example) When the expiration is up the browser MUST revalidate (which in my case will result in fresh data) Chrome and IE9 exhibit the desired behavior when issuing a jquery.ajax() request with ifModified: true and cache: true while Firefox 12 never revalidates, which poses a serious problem. These are the actual response headers: HTTP/1.1 200 OK Server: nginx Date: Sun, 03 Jun 2012 07:13:43 GMT Content-Type: text/javascript; charset=UTF-8 Transfer-Encoding: chunked Connection: keep-alive Vary: Accept-Encoding Cache-Control: private, must-revalidate, max-age=300 Last-Modified: Sun, 03 Jun 2012 07:07:13 GMT Content-Encoding: gzip Any suggestions?

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  • Working with PHP and MySQL - need a good and secure design with OO design

    - by Andrew
    I am new to PHP- first time developer. I am working on my web application and it is nearly done; nevertheless, most of my sql was done directly via code using direct mysql requests. This is the way I approached it: In classes_db.php I declared the db settings and created methods that I use to open and close DB connections. I declare those objects on my regular pages: class classes_db { public $dbserver = 'server; public $dbusername = 'user'; public $dbpassword = 'pass'; public $dbname = 'db'; function openDb() { $dbhandle = mysql_connect($this->dbserver, $this->dbusername, $this->dbpassword); if (!$dbhandle) { die('Could not connect: ' . mysql_error()); } $selected = mysql_select_db($this->dbname, $dbhandle) or die("Could not select the database"); return $dbhandle; } function closeDb($con) { mysql_close($con); } } On my regular page, I do this: <?php require 'classes_db.php'; session_start(); //create instance of the DB class $db = new classes_db(); //get dbhandle $dbhandle = $db->openDb(); //process query $result = mysql_query("update user set username = '" . $usernameFromForm . "' where iduser= " . $_SESSION['user']->iduser); //close the connection if (isset($dbhandle)) { $db->closeDb($dbhandle); } ?> My questions is: how to do it right and make it OO and secure? I know that I need incorporate prepared queries- how to do it the best way? Please provide some code

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  • Expanders inside listbox leaving blank space on collapse

    - by siz
    We have a rather complex UI that is presenting some problems for us. I have a ListBox that contains a set of DataItems. The DataTemplate for each item is an Expander. The header is text, the content of the Expander is a ListBox. The ListBox contains SubDataItems. The DataTemplate for each SubDataItem is an Expander. Here is a simplified XAML in which I reproduce the issue: <ListBox ItemsSource="{Binding Items}"> <ListBox.ItemTemplate> <DataTemplate> <Expander Header="{Binding Header}"> <ListBox ItemsSource="{Binding SubItems}"> <ListBox.ItemTemplate> <DataTemplate> <Expander Header="{Binding SubHeader}"> <Grid Height="40"> <TextBlock Text="{Binding SubText}" /> </Grid> </Expander> </DataTemplate> </ListBox.ItemTemplate> </ListBox> </Expander> </DataTemplate> </ListBox.ItemTemplate> </ListBox> There is a problem with how the layout is produced. If any Expander corresponding to the SubDataItem is expanded, the ListBoxItem containing this ListBox (the Expander.Content in the parent DataTemplate) correctly requests more space. So I can expand all SubDataItems and correctly see my data. However, when I collapse, the space I previously asked to expand, remains blank, instead of being reclaimed by the ListBoxItem. This is a problem because if I have say 10 SubDataItems and happen to expand all of them at the same time and then collapse, there is a significant amount of white space wasting my real estate. How can I force WPF to resize the ListBoxItem to the correct state?

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  • Best way of showing more results with javascript/css

    - by Ricardo Neves
    I'm developing a website and i'm having troubles showing the search results to the user the way I want. Basically, after the user search, the page makes a couple of ajax requests and as soon as a response arrive it appends the info to a specific element on my page. Each results is shown as a line... The problem is that in most case there are going to be more than 1000 results and this would make the page have a large scroll. My idea was to show only the first 15 results and when the user clicks "show more" the element would expand and show the next 15 results and so on... This would be easier to do if the website wasn't responsive, but because it is I can't find the proper way of implementing what I want without lowering the website perfomance. I have "2 ideas": The first is by using something like #element .div:nth-child(-n+15) on my css and figure a way of changing the "15" to how much results I want to show... I don't know if this can be done. Is it possible to call css rules with parameters? Maybe with less css? The second option is probably a bad option if i don't want to lower the website performance. Using javascript I would check if there is a specific css class(like .show-15 .show30 .show45) and add that class to my element and if it don't exist, create it somehow.. Any help would be appreciated.

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  • Code Analysis Warning CA1004 with generic method

    - by Vaccano
    I have the following generic method: // Load an object from the disk public static T DeserializeObject<T>(String filename) where T : class { XmlSerializer xmlSerializer = new XmlSerializer(typeof(T)); try { TextReader textReader = new StreamReader(filename); var result = (T)xmlSerializer.Deserialize(textReader); textReader.Close(); return result; } catch (FileNotFoundException) { } return null; } When I compile I get the following warning: CA1004 : Microsoft.Design : Consider a design where 'MiscHelpers.DeserializeObject(string)' doesn't require explicit type parameter 'T' in any call to it. I have considered this and I don't know a way to do what it requests with out limiting the types that can be deserialized. I freely admit that I might be missing an easy way to fix this. But if I am not, then is my only recourse to suppress this warning? I have a clean project with no warnings or messages. I would like to keep it that way. I guess I am asking "why this is a warning?" At best this seems like it should be a message. And even that seems a bit much. Either it can or it can't be fixed. If it can't then you are just stuck with the warning with no recourse but suppressing it. Am I wrong?

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  • Can I add a spring mvc filter using jetty with a jar file?

    - by Juan Manuel
    I have a simple web application disguised as a java application (as in, it's a .jar instead of a .war), and I'd like to use a filter for my requests. If it was a .war, I could initialize it with a WebAppContext and specify a web.xml file where I'd have my filter declaration like this <filter> <filter-name>myFilter</filter-name> <filter-class>MyFilterClass</filter-class> </filter> <filter-mapping> <filter-name>myFilter</filter-name> <url-pattern>/*</url-pattern> </filter-mapping> However, I'm using a simple Context to initialize my application with Spring. Server server = new Server(8082); Context root = new Context(server, "/", Context.SESSIONS); DispatcherServlet dispatcherServlet = new DispatcherServlet(); dispatcherServlet.setContextConfigLocation("classpath:application-context.xml"); root.addServlet(new ServletHolder(dispatcherServlet), "/*"); server.start(); Is there a way to programmatically specify filters for the spring servlet, without using a web.xml file?

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  • Cannot redeclare class on a copy of a site

    - by Polity
    I've developed a small SMS utility for a customer in PHP. The details are of non-importance. This project is hosted in: http://project.example.com/customer1 Now a second customer requests almost the same functionality, one cheap way of providing this is to copy the project from the first customer and modify it slightly. So i made a direct copy of the project for customer1 to another folder for customer 2. This project is hosted in: http://project.example.com/customer2 Now when i try and run the project for customer2 (calling a single page), i get the error message: Fatal error: Cannot redeclare class SmsService in /var/www/html/project/customer1/application/service.class.php on line 3 Here, service.class.php is a simple interface with 3 methods: interface SmsService { public function SendSms($mobile, $customerId, $customerName, $message); public function QueryIncomingResponse(); public function CleanExpiredConfirmations($maxConfirmationDays); } printing the backtrace in service.class.php reveals something interresting: #0 require_once() called at [/var/www/html/project/customer2/endpoint/queryIncomingResponse.php:2] Fatal error: Cannot redeclare class SmsService in /var/www/html/project/customer1/application/service.class.php on line 3 Line 2 in queryIncomingResponses is the very first require line there is. Line 3 in service.class.php is the first statement there is in the file (Line 2 is an empty line and line 1 is the php file opening tag). Naturally, I only work with relative requires (double checked this) so there is no way one include/require from customer2 actually refers to a file for customer1. It seems to me that in some way SmsService and other classes gets cached by PHP. (I have little control over the server environment). One solution to this would be namespaces. Unfortunatly, we work with PHP 5.1.7 where namespaces are not a part of the language feature just yet. Another way would be to mimic namespaces by prefixing all classes but this approach just feels dirty. Does anyone have more information on this problem and possibly solutions? Many thanks in advance!

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  • Repeated host lookups failing in urllib2

    - by reve_etrange
    I have code which issues many HTTP GET requests using Python's urllib2, in several threads, writing the responses into files (one per thread). During execution, it looks like many of the host lookups fail (causing a name or service unknown error, see appended error log for an example). Is this due to a flaky DNS service? Is it bad practice to rely on DNS caching, if the host name isn't changing? I.e. should a single lookup's result be passed into the urlopen? Exception in thread Thread-16: Traceback (most recent call last): File "/usr/lib/python2.6/threading.py", line 532, in __bootstrap_inner self.run() File "/home/da/local/bin/ThreadedDownloader.py", line 61, in run page = urllib2.urlopen(url) # get the page File "/usr/lib/python2.6/urllib2.py", line 126, in urlopen return _opener.open(url, data, timeout) File "/usr/lib/python2.6/urllib2.py", line 391, in open response = self._open(req, data) File "/usr/lib/python2.6/urllib2.py", line 409, in _open '_open', req) File "/usr/lib/python2.6/urllib2.py", line 369, in _call_chain result = func(*args) File "/usr/lib/python2.6/urllib2.py", line 1170, in http_open return self.do_open(httplib.HTTPConnection, req) File "/usr/lib/python2.6/urllib2.py", line 1145, in do_open raise URLError(err) URLError: <urlopen error [Errno -2] Name or service not known>

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  • multiple ajax request to action in asp.net mvc

    - by persian Dev
    I am developing an asp.net mvc application and have ajax calls on my page. Here is a form which I load by ajax call to page : The form is located in a partial view <div id="CreateCultureArea"> <% using (Ajax.BeginForm("CreateCulture", "Admin", new AjaxOptions() { OnSuccess = "handleCreateCulture" })) { %> ..... <% } %> </div> The following script is located in a view $('.CreateCulture').live('click', function (e) { e.preventDefault(); var idval = this.id; $.ajax({ url: "/Admin/CreateCulture", dataType: 'html', data: { id: idval }, success: function (mydata) { $("#CultureContentArea").empty(); $("#CultureContentArea").empty().hide().append(mydata).fadeIn(2000); $("form").removeData("validator"); $("form").removeData("unobtrusiveValidation"); $.validator.unobtrusive.parse("form"); }, type: "GET" }); return false; }) </script> When users click on a link with CreateCulture class, the form is loaded to page. But as I saw the requests in firebug, it calls the action multiple times. I read similar posts like mine on stackoverflow.com and most of them suggested removing repetitive "jquery.unobtrusive-ajax.min.js" calss in page, but as I saw the output page I only see on link to the "jquery.unobtrusive-ajax.min.js" script.

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  • Locking database edit by key name

    - by Will Glass
    I need to prevent simultaneous edits to a database field. Users are executing a push operation on a structured data field, so I want to sequence the operations, not simply ignore one edit and take the second. Essentially I want to do synchronized(key name) { push value onto the database field } and set up the synchronized item so that only one operation on "key name" will occur at a time. (note: I'm simplifying, it's not always a simple push). A crude way to do this would be a global synchronization, but that bottlenecks the entire app. All I need to do is sequence two simultaneous writes with the same key, which is rare but annoying occurrence. This is a web-based java app, written with Spring (and using JPA/MySQL). The operation is triggered by a user web service call. (the root cause is when a user sends two simultaneous http requests with the same key). I've glanced through the Doug Lea/Josh Bloch/et al Concurrency in Action, but don't see an obvious solution. Still, this seems simple enough I feel there must be an elegant way to do this.

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  • Creating multiple instances of a generic database

    - by sagekilla
    Hi all, currently I'm trying to have a setup where a generic database is distributed to students. They would develop an application using this database (Say a shopping cart application), submit their project onto our server, and then it would be graded automatically. These databases are being run in Microsoft SQL Server 2005. We're using user instances to instantiate each database, and multiple requests could be serviced at once. But, the problem is when more than one student submitted a project to be graded, the first database to be instantiated would be the only one and would overwrite all other copies that were currently open. So if stu1 modified his database and stu2 and stu3 had their projects being graded concurrently, at the end of the grading stu1, stu2, and stu3 would have identical DB's at the end. Is there any way I can have multiple independent copies of a generic database, each of which I can load concurrently and modify without having any changes made to any one affecting the others? I did a little reading, and thought it might be possible to do something along the lines of: Student submits project Attach the database with unique db name (specified by student) Do all necessary operations Detach the database I'm unsure if this would fix our problem or be possible, so any help would be much appreciated!

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  • I just discovered why all ASP.Net websites are slow, and I am trying to work out what to do about it

    - by James
    I just discovered that every request in an ASP.Net web application gets a Session lock at the begging of a request, and then releases it at the end of the request!!! I mean, WTF Microsoft! In case the implication is lost on you, as it was from me at first, this basically means the following: Anytime an ASP.Net webpage is taking a long time to load (maybe due to a slow database call or whatever), and the user decides they want to navigate to a different page because they are tired of waiting, THEY CANT! The ASP.Net session lock forces the new page request to wait until the original request has finished its painfully slow load. Arrrgh. Anytime an UpdatePanel is loading slowly, and the user decides to navigate to a different page before the UpdadePanel has finished updating... THEY CANT! The ASP.Net session lock forces the new page request to wait until the original request has finished its painfully slow load. Double Arrrgh! So what are the options? So far I have come up with: Implement a Custom SessionStateDataStore, which ASP.Net supports. I haven't found too many out there to copy, and it seems kind of high risk and easy to mess up. Keep track of all requests in progress, and if a request comes in from the same user, cancel the original request. Seems kind of extreme, but it would work (I think) Don't user Session! When I need some kind of state for the user, I could just user Cache instead, and key items on the authenticated user's name, or some such thing. Again seems kind of extreme I really can't believe that the ASP.Net Microsoft team would have left such a huge performance bottleneck in the framework at version 4.0! Am I missing something obvious? How hard would it be to use a ThreadSafe collection for the Session? Arrrrghhhhhh. Any advice much appreciated.

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  • Prompting for authentication from a wxPython program and passing it along to IIS?

    - by MetaHyperBolic
    I have a client (written in Python, with a wxPython front end in dead-simple wizard style) which communicates a website running IIS. A python script receives requests and does the usual client-server dance. I would have written this as a browser application, but for the requirement that certain things happen on the local PC that the web can't help with (file manipulation, interfacing with certain USB hardware, etc.) Right now, I am simply using the logon credentials, compounded as a string from os.environ['USERDOMAIN'] and os.environ['USERNAME'], to pass along to the server, which connects to Active Directory and enumerates the members of the group, looking for those logon credentials. It's an ugly hack, but it works. Obviously, I could make people log out of the generic helper accounts and log back into Windows using specific accounts. However, I wondered how feasible it would be to provide some kind of logon prompt wherein the user can type in a name and password, then some kind of authorization token could be passed on to IIS. This seems like something I would not want to do myself, given that amateurs almost always make huge security mistakes. Now you can see why I am wishing this was purely web-based. What's a good way to handle this?

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  • Apache Cordova (Phonegap): is jsop needed for cross-site scripting?

    - by DEX
    I've just started using Apache Cordova. I have an library that makes calls (via ajax) to a soap server. When I run these on my local machine in chrome, I get cross site scripting errors when trying to make calls to the service. When I run the same exact code using the Cordova browser in the iOS emulator, the scripts seem to hit the server fine and the response data is received properly. So my question is how is the Cordova browser able to make these requests without cross-site scripting permissions & JSONP ? One thing I noticed is that when the request is sent from iOS, there is no "Origin" header. Is this allowing the Cordova browser to stealthily circumvent cross-site scripting requirements? Is it possible that the node.js server on the device (I believe this is how Cordova works) is manipulating the headers to allow this? I'd like to avoid enabling cross-site scripting on my site so I think this "feature" is nice, but I'm wondering if it's a security hole as well. Anyone have experience with this?

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  • AJAX/JSONP Question. Access id denied using IE while requesting corss domain.

    - by Sisir
    Ok, Here we go. I have already searched the Stack for the answer i have found some useful info but i want to clear up some more things. I also search the net for the answer but no real help. I have worked with some api (yelp, ouside.in). In yelp i use to inject the script to head with the url request to the api with a callback funcion. I worked fine in all browsers. But while using outside.in api when i call the url the callback in not working. In yelp they have a url field can be used like that callback=callbackfuncion so the callback will automatically called. But in outside.in there is not such field available. Is there are any standard command for callback function which will work regardless of any server/api? I also tried a standard ajax request using jQuery $.ajax() function. It worked for my local pc for both IE and other browser but did not working in IE showing the error: access denied, other borwser seems ok. Firebug in my FF also don't notice any errors. Outside.in has an javascript example but it is too hard to me to understand github.com/outsidein/api-examples/tree/master/javascript/browser/ site i am working: http://citystir.com yelp: yelp.com outside.in: outside.in Techniqual info: i am using: wampserver in local, wordpress for hosting, Godaddy, apache for remote with linux. Codes: Using Jquery $.ajax url is like: "http://hyperlocal-api.outside.in/v1.1/states/Illinois/cities/chicago/stories?dev_key="+key+"&sig="+signeture+"&limit=3 function makeOutsideRequest(url){ $.ajax({ url: url, dataType: 'json', type: 'GET', success: function (data, status, xhr) { if (data == null) { alert("An error occurred connecting to " + url + ". Please ensure that the server is running and configured to allow cross-origin requests."); }else{ printHomeNews(data); } }, error: function (xhr, status, error) { alert("An error occurred - check the server log for a stack trace."); } }); } Thanks!

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