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  • CLR Stored Procedures

    - by Paul Hatcherian
    In an ASP.NET application, I have a small number of fairly complex, frequently used operations to execute against a database. In these operations, one or more of several tables needs updates or inserts based a logical evaluation of both input parameters and values of certain tables. I've maintained a separation of logic and data access, so the operation currently looks like this: Request received from client Business layer invokes data layer to retrieve data from database Business layer processes result and determines which operation to execute Business layer invokes appropriate data operation Response sent to client As you can see, the client is kept waiting while two separate requests are made to the database. In searching for a solution to this, I've found CLR Stored Procedures, but I'm not sure if I have the right idea about what they are useful for. I have written a replacement for the code above which especially places steps 2-4 in a CLR SP. My understanding is that the SP will be executed locally by SQL Server and result in only one call being made to the server. My initial benchmark tests show this is actually orders of magnitude slower than my original code, but I attribute that recompilation of the code I have not worked out yet and/or some flaw in my environment. My question is basically, is this the intended use of CLR SPs or am I missing something? I realize this is a bit of a compromise structurally, so if there's a better way to do it I'd love to hear it.

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  • TCL TDom: Looping through Objects

    - by pws5068
    Using TDom, I would like to cycle through a list of objects in the following format: <object> <type>Hardware</type> <name>System Name</name> <description>Basic Description of System.</description> <attributes> <vendor>Dell</vendor> <contract>MM/DD/YY</contract> <supportExpiration>MM/DD/YY</supportExpiration> <location>Building 123</location> <serial>xxx-xxx-xxxx</serial> <mac>some-mac-address</mac> </attributes> </object> <object> <type>Software</type> <name>Second Object</name> ... Then I use TDom to make a list of objects: set dom [dom parse $xml] set doc [$dom documentElement] set nodeList [$doc selectNodes /systems/object] So far I've done this to (theoretically) select every "Object" node from the list. How can I loop through them? Is it just: foreach node $nodeList { For each object, I need to retrieve the association of each attribute. From the example, I need to remember that the "name" is "System Name", "vendor" is "Dell", etc. I'm new to TCL but in other languages I would use an object or an associative list to store these. Is this possible? Can you show me an example of the syntax to select an attribute in this manner?

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  • Best way to pass image to server?

    - by Chris
    I have an SL3 application that needs to be able to pass an image to the server, and then the server will generate a PDF file with the image in it, and display it to the user. What I already have in place are the following: (1) Code to convert image to byte array (2) Code to generate PDF file with image The main problem that I am running into is the following: In order to bypass the pop-up blocker, which is a requirement for my application, I am using the following code: var button = new NavigationButton(); button.NavigateUri = new Uri("http://localhost:3616/PrintReport.aspx?ReportIndex=11&ActionType=Get&ReportIdentifier=" + reportIdentifier.ToString() + ""); button.TargetName = "_blank"; button.PerformClick(); Initially, I would pass the image to a WCF web service (as a byte array), and then "navigate" to the ASP.NET page that would display the report. However, if I do this, then I can not use my custom HyperlinkButton class, and, certain browsers, including Safari, will block a new window from opening up. Therefore, it appears that the only option is to use the HyperlinkButton class. What I need to be able to do is to somehow pass the image, as a byte array or some other data type, to the server, such that it can temporarily store the image, even if it is in a server variable, and then immediately retrieve it when I navigate to the PrintReport.aspx page. If I upload the image to an ASP.NET form and then use the HyperlinkButton class to navigate to the PrintReport page, it doesn't work, as the app navigates to the PrintReport page before the system has finished uploading the image. I can't pass it to a web service, as that would require that I navigate to the PrintReport.aspx page in the callback code of the web method that I would be passing the image to, and the HyperlinkButton will not allow that, based on security rules. Any help or ideas would be appreciated. Thanks. Chris

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  • Best pratice: How do I implement a list similar to Stackoverflow's Users List?

    - by André Pena
    Technologies involved: ASP.NET Web-forms Javascript (jQuery for instance) Case To make it clearer let's give the Stackoverflow Users list as an example. This list can be manipulated at client-side. I can search, page and so forth. So obviously we would need to call jQuery.ajax to retrieve the HTML of each page given a search. Alright. Now this leaves me with the first question: What is the best way to render the response for the jQuery.ajax at server-side? I can't use templates I suppose, so the most obvious solution I think is to create the HTML tags as server-controls and render them as the result of an ASHX request? Is this is best approach? Nice. That solved we have yet another problem: When the user first enters the Authors List the first list page should already come from the server completely rendered alright? Of course we could render the first page as well as an ajax call but I don't think it's better. This time I CAN use templates to render the list but this template couldn't be reused in case 1. What do I do? Now the final question: Now we have 2 rendering strategies: 1) Client and 2) Server. How do I reuse code for the 2 renderings? What are the best pratices for solving these problems?

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  • Overlaying 2D paths on UIImage without scaling artifacts

    - by tat0
    I need to draw a path along the shape of an image in a way that it is always matching its position on the image independent of the image scale. Think of this like the hybrid view of Google Maps where streets names and roads are superimposed on top of the aerial pictures. Furthermore, this path will be drawn by the user's finger movements and I need to be able to retrieve the path keypoints on the image pixel coordinates. The user zooms-in in order to more precisely set the paths location. I manage to somehow make it work using this approach: -Create a custom UIView called CanvasView that handles touches interaction and delivers scaling, rotation, translation values to either the UIImageView or PathsView (see bellow) depending on a flag: deliverToImageOrPaths. -Create a UIImageView holding the base image. This is set as a children of CanvasView -Create a custom UIView called PathsView that keeps track of the 2D paths geometry and draws itself with a custom drawRect. This is set as children of the UIImageView. So hierarchy: CanvasView - UIImageView -PathsView In this way when deliverToImageOrPaths is YES, finger gestures transforms both the UIImageView and its child PathsView. When deliverToImageOrPaths is NO the gestures affect only the PathsView altering its geometry. So far so good. QUESTION: The problem I have is that when scaling the base UIImageView (via its .transform property) the PathsView is scaled with aliasing artifacts. drawRect is still being called on the PathsView but I guess it's performing the drawing using the original buffer size and then interpolating. How can I solve this issue? Are there better ways to implement these features? PS: I tried changing the PathsView layer class to CATiledLayer with levelsOfDetailBias 4 and levelsOfDetail 4. It solves the aliasing problem to some extent but it's unacceptable slow to render.

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  • custom wordpress page

    - by sharon
    I'd like to implement a custom post retrieval page in wordpress. Basically, I'm using AJAX to call this page that will be passed a post ID and retrieve certain data from that post. Note: please don't mistake this as a template question. I do not want a template for one single page -- I am looking to make this page query multiple different posts based on postID and return certain data from that post. So I tried creating a page <?php $args=array( 'p'=>'77' ); $friends = new WP_Query($args); ?> <?php if ($friends->have_posts()) : the_post(); ?> <?php the_title(); ?> <?php the_content(); ?> <?php else: ?> <p>Sorry, no posts are available.</p> <?php endif; ?> But this does not work since it is not loading in the wp functions to handle the query. Thanks in advance for any help!

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  • Ldap query returns null result when deployed.

    - by Trey Carroll
    I'm using a very simple Ldap query in my asp.net mvc 2.0 site: String ldapPath = ConfigReader.LdapPath; String emailAddress = null; try { DirectorySearcher search = new DirectorySearcher(ConfigReader.LdapPath); search.Filter = String.Format("(&(objectClass=user)(objectCategory=person)(objectSid={0})) ", securityIdentifierValue); // add the mail property to the list of props to retrieve search.PropertiesToLoad.Add("mail"); var result = search.FindOne(); if (result == null) { throw new Exception("Ldap Query with filter:" + search.Filter.ToString() + " returned a null value (no match found)"); } else { emailAddress = result.Properties["mail"][0].ToString(); } } catch (ArgumentOutOfRangeException aoorEx) { throw new Exception( "The query could not find an email for this user."); } catch (Exception ex) { //_log.Error(string.Format("======!!!!!! ERROR ERROR ERROR !!!!! in LdapLookupUtil.cs getEmailFromLdap Exception: {0}", ex)); throw ex; } return emailAddress; It works fine on my localhost machine. It works fine when I run it in VS2010 on the server. It always returns a null result when deployed. Here is my web.config: Asp.Net Configuration option in Visual Studio. A full list of settings and comments can be found in machine.config.comments usually located in \Windows\Microsoft.Net\Framework\v2.x\Config -- section enables configuration of the security authentication mode used by ASP.NET to identify an incoming user. -- <!-- -- section enables configuration of what to do if/when an unhandled error occurs during the execution of a request. Specifically, it enables developers to configure html error pages to be displayed in place of a error stack trace. -- I'm running it under the default app pool. Does anybody see the problem? This is driving me crazy!

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  • Jsp page getting called from cache rather than getting loaded from server

    - by sam4u-optimistic86
    I am calling a jsp based on 2 parameters which is passed from jsp 1 in this way.Below i pass 2 parameters into 2.jsp and based on these 2 parameters data is displayed in 2.jsp.I have a loop in which i have a number of hrefs like the one i have described below.Each of these href passes a different set of value to 2.jsp. out.println("<a href=\"2.jsp?prId=" + prog.getId() + count + "\">" + prog.getName() + "</a>"); I retrieve these 2 parameters in 2.jsp using the following lines count_id = request.getParameter( "country_id" ); prog_id = Integer.parseInt(request.getParameter( "program_id" )); Based on these 2 parameters i show the corresponding data in 2.jsp Now i have a back button in 2.jsp and i call 1.jsp in 2.jsp using the following code <a href="1.jsp"><img src="/image/back.gif" border="0"></a> The problem is when i use the back button and go back to 1.jsp and select another href like the one i have described above i get the data related to the previous href selected. I guess the problem is when i request the page is loaded from cache rather than from the server. Please advice

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  • Can't get SFTP to work in PHP

    - by Chris Kloberdanz
    I am writing a simple SFTP client in PHP because we have the need to programatically retrieve files via n remote servers. I am using the PECL SSH2 extension. I have run up against a road block, though. The documentation on php.net suggests that you can do this: $stream = fopen("ssh2.sftp://$sftp/path/to/file", 'r'); However, I have an ls method that attempts to something similar public function ls($dir) { $rd = "ssh2.sftp://{$this->sftp}/$dir"; $handle = opendir($rd); if (!is_resource($handle)) { throw new SFTPException("Could not open directory."); } while (false !== ($file = readdir($handle))) { if (substr($file, 0, 1) != '.'){ print $file . "\n"; } } closedir($handle); } I get the following error: PHP Warning: opendir(): Unable to open ssh2.sftp://Resource id #5/outgoing on remote host This makes perfect sense because that's what happens when you cast a resource to string. Is the documentation wrong? I tried replacing the resource with host, username, and host and that didn't work either. I know the path is correct because I can run SFTP from the command line and it works fine. Has anyone else tried to use the SSH2 extenstion with SFTP? Am I missing something obvious here? UPDATE: I setup sftp on another machine in-house and it works just fine. So, there must be something about the server I am trying to connect to that isn't working.

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  • Fast JSON serialization (and comparison with Pickle) for cluster computing in Python?

    - by user248237
    I have a set of data points, each described by a dictionary. The processing of each data point is independent and I submit each one as a separate job to a cluster. Each data point has a unique name, and my cluster submission wrapper simply calls a script that takes a data point's name and a file describing all the data points. That script then accesses the data point from the file and performs the computation. Since each job has to load the set of all points only to retrieve the point to be run, I wanted to optimize this step by serializing the file describing the set of points into an easily retrievable format. I tried using JSONpickle, using the following method, to serialize a dictionary describing all the data points to file: def json_serialize(obj, filename, use_jsonpickle=True): f = open(filename, 'w') if use_jsonpickle: import jsonpickle json_obj = jsonpickle.encode(obj) f.write(json_obj) else: simplejson.dump(obj, f, indent=1) f.close() The dictionary contains very simple objects (lists, strings, floats, etc.) and has a total of 54,000 keys. The json file is ~20 Megabytes in size. It takes ~20 seconds to load this file into memory, which seems very slow to me. I switched to using pickle with the same exact object, and found that it generates a file that's about 7.8 megabytes in size, and can be loaded in ~1-2 seconds. This is a significant improvement, but it still seems like loading of a small object (less than 100,000 entries) should be faster. Aside from that, pickle is not human readable, which was the big advantage of JSON for me. Is there a way to use JSON to get similar or better speed ups? If not, do you have other ideas on structuring this? (Is the right solution to simply "slice" the file describing each event into a separate file and pass that on to the script that runs a data point in a cluster job? It seems like that could lead to a proliferation of files). thanks.

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  • Android Loading listview items from service results in hang

    - by Isaac Waller
    Hello, In my Android application, I have a ListActivity. This ListActivity uses a SimpleAdapter that I fill with items from my service. So, in my code, I do: MySuperCoolService.Binder serviceBinder = null; private ServiceConnection serviceConnection = new ServiceConnection() { public void onServiceConnected(ComponentName className, IBinder service) { Log.d(TAG, "Service connection: connected!"); serviceBinder = (MySuperCoolService.Binder)service; } public void onServiceDisconnected(ComponentName className) { Log.d(TAG, "Service connection: disconnected"); serviceBinder = null; } }; bindService(new Intent(this, MySuperCoolService.class), serviceConnection, BIND_AUTO_CREATE); while(serviceBinder==null) { Thread.Sleep(1000); } // now retrieve from service using binder and set list adapter This whole operation takes hardly any time (less than a second), so I want it to run in the UI thread. See my onCreate: public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); fillDataUsingCodeAbove(); } The reason I want this to run in the UI thread is that if you have a list item selected, or you have scrolled to a certain position in the ListView, and you rotate the device or take out the keyboard or something (to trigger a configuration change) when my activity is restarted, Android will try to restore the state right after onCreate. But, if I run it in a separate thread, it will not. Also there is a cool fadein animation too :) The problem I am having with running it in the UI thread is that when I try to bind to the service, that service bind request gets put onto the message queue. But then when I go into my loop, I stop the message queue from looping. So my program hangs, because it's waiting for the service to get bound, and the service won't get bound until the loop ends. I have thought of putting Looper.loop() inside my loop, but that just hangs it at Looper.loop() (I don't know why.) Sorry for such a long question, Isaac Waller

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  • Making HTTP POST request

    - by infrared
    I'm trying to make a POST request to retrieve information about a book. Here is the code that returns HTTP code: 302, Moved import httplib, urllib params = urllib.urlencode({ 'isbn' : '9780131185838', 'catalogId' : '10001', 'schoolStoreId' : '15828', 'search' : 'Search' }) headers = {"Content-type": "application/x-www-form-urlencoded", "Accept": "text/plain"} conn = httplib.HTTPConnection("bkstr.com:80") conn.request("POST", "/webapp/wcs/stores/servlet/BuybackSearch", params, headers) response = conn.getresponse() print response.status, response.reason data = response.read() conn.close() When I try from a browser, from this page: http://www.bkstr.com/webapp/wcs/stores/servlet/BuybackMaterialsView?langId=-1&catalogId=10001&storeId=10051&schoolStoreId=15828 , it works. What am I missing in my code? Thanks EDIT: Here's what I get when I call print response.msg 302 Moved Date: Tue, 07 Sep 2010 16:54:29 GMT Vary: Host,Accept-Encoding,User-Agent Location: http://www.bkstr.com/webapp/wcs/stores/servlet/BuybackSearch X-UA-Compatible: IE=EmulateIE7 Content-Length: 0 Content-Type: text/plain; charset=utf-8 Seems that the location points to the same url I'm trying to access in the first place? EDIT2: I've tried using urllib2 as suggested here. Here is the code: import urllib, urllib2 url = 'http://www.bkstr.com/webapp/wcs/stores/servlet/BuybackSearch' values = {'isbn' : '9780131185838', 'catalogId' : '10001', 'schoolStoreId' : '15828', 'search' : 'Search' } data = urllib.urlencode(values) req = urllib2.Request(url, data) response = urllib2.urlopen(req) print response.geturl() print response.info() the_page = response.read() print the_page And here is the output: http://www.bkstr.com/webapp/wcs/stores/servlet/BuybackSearch Date: Tue, 07 Sep 2010 16:58:35 GMT Pragma: No-cache Cache-Control: no-cache Expires: Thu, 01 Jan 1970 00:00:00 GMT Set-Cookie: JSESSIONID=0001REjqgX2axkzlR6SvIJlgJkt:1311s25dm; Path=/ Vary: Accept-Encoding,User-Agent X-UA-Compatible: IE=EmulateIE7 Content-Length: 0 Connection: close Content-Type: text/html; charset=utf-8 Content-Language: en-US Set-Cookie: TSde3575=225ec58bcb0fdddfad7332c2816f1f152224db2f71e1b0474c866f3b; Path=/

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  • How to export Configuration of each IIS 6 Web Site using WMI

    - by Diego
    Hi all, I need to export the WebSite Configuration (MetaBase) from IIS6 for a whole server, but I need each web site configuration to be saved separately. The result should be the same that can be obtained by right clicking on each Web Site in IIS Snap-in and selecting All Tasks-Save Configuration to a File. My idea is quite simple: 1- Using WMI, retrieve a list of Web Sites. 2- Also via WMI, export each configuration to a file having the same name of the Web Site. However, I'm having some difficulties, mainly due to the complexity of WMI and, in my opinion, the poor documentation of its classes. At the moment I found out how to enumerate Virtual Directories, but not Web Sites; while it's true that this method returns Web Sites as well, I can't see how to identify them among other virtual folders (a Web Site has different properties, which are not returned in the Virtual Directory Object), and I can't find the Web Site Description property, which I'd like to use to name the exported file. I thought about a workaround for all the above issues, but it would be more a hack than a real solution... Any help if appreciated. Thanks.

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  • How to access a method on a generic datacontext which is only created at runtime

    - by Jeremy Holt
    I'm creating my generic DataContext using only the connectionString in the ctor. I have no issues in retrieving the table using DataContext.GetTable(). However, I need to also be able to retrieve entities of inline table functions. The dbml designer generates public IQueryable<testFunctionResult> testFunction() { return this.CreateMethodCallQuery<testFunctionResult>(this, ((MethodInfo)(MethodInfo.GetCurrentMethod()))); } The question is how do I get the MethodInfo.GetCurrentMethod() when the DataContext has no method called "testFunction", i.e.typeof(DataContext).GetMethod("testFunction") returns null? What I'm trying to achieve is something like: public class UnitofWork<T> { public UnitofWork(string connectionString) { this.DataContext = new DataContext(connectionString); } public UnitofWork(IQueryable<T> tableEntity) { _tableEntity = tableEntity; } public IQueryable<T> TableEntity { get { if (DataContext == null) return _tableEntity; var metaType = DataContext.Mapping.GetMetaType(typeof (T)); if (metaType.IsEntity) _tableEntity = DataContext.GetTable<T>(); else { var s = typeof(T).Name; string methodName = s.Substring(0, s.IndexOf("Result")) + "()"; // the designer automatically affixes "Result" to the type name // Make a method from methodName // _tableEntity = DataContext.CreateMethodCallQuery(DataContext, method, new object[]{}); } return _tableEntity; } set { _tableEntity = value; } } ) Thanks in advance for any insight Jeremy

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  • How do you deal with denormalization / secondary indexes in database sharding?

    - by Continuation
    Say I have a "message" table with 2 secondary indexes: "recipient_id" "sender_id" I want to shard the "message" table by "recipient_id". That way to retrieve all messages sent to a certain recipient I only need to query one shard. But at the same time, I want to be able to make a query that ask for all messages sent by a certain sender. Now I don't want to send that query to every single shard of the "message" table. One way to do this is to duplicate the data and have a "message_by_sender" table sharded by "sender_id". The problem with that approach is that every time a message has been sent, I need to insert the message into both "message" and "message_by_sender" tables. But what if after inserting into "message" the insertion into "message_by_sender" fail? In that case the message exists in "message" but not in "message_by_sender". How do I make sure that if a message exists in "message" then it also exists in "message_by_sender" without resorting to 2 phase commit? This must be a very common issue for anyone who shards their databases. How do you deal woth it?

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  • Rails 2.3 session

    - by Sam Kong
    Hi, I am developing a rails 2.3.2 app. I need to keep session_id for an order record, retrieve it and finally delete the session_id when the order is completed. It worked when I used cookies as session store but it doesn't for active_record store. (I restarted my browser, so no cache issue.) I know rails 2.3 implements lazy session load. I read some info about it but am still confused. Can somebody clarify how I use session_id for such a case? What I am doing is... A user make an order going through several pages. There is no sign-up, neither login. So I keep session_id in the order record so that no other user can access the order. @order = Order.last :conditions = {:id = params[:id], :session_id = session[:session_id] } When the order is finished, I set nil to session_id column. How would you implement such a case in lazy session(and active_record store) environment? Thanks. Sam

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  • 3 Servers, is this is a cluster?

    - by Andy Barlow
    Hello, At the moment I have one Ubuntu server, 9.10, running with a simple Samba share, a mail server, DNS server and DHCP server. Mostly its just there for file sharing and email server. I also have 2 other servers that are exactly the same hardware and spec as the first, which have an rsync set up to retrieve the shared folders and backs them up. However, if the first server goes down, all of our shares disappear along with our mail and the system must be rebuilt. Also I tend to find if people are downloading a large amount from the file server, no-one can access there emails - especially in the morning when everyone is signing in at once. Would it be more beneficial for me to have all 3 servers, all running the same services, doing the same thing with some sort of cluster with load balancing? I'm not really sure where to begin looking, or how to go about such a setup where 3 servers are all identical, but perhaps one acts as the main load balancer?? If someone can point me in the right direction, or if this simply sounds like one of those Enterprise Cloud's that is now a default setup in Ubuntu Server 9.10+, then I'll go down that route. Cheers in advance. Andy

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  • Sharepoint OLE DB - cannot insert records? "Field not updateable" error

    - by Pandincus
    I need to write a simple C# .NET application to retrieve, update, and insert some data in a Sharepoint list. I am NOT a Sharepoint developer, and I don't have control over our Sharepoint server. I would prefer not to have to develop this in a proper sharepoint development environment simply because I don't want to have to deploy my application on the Sharepoint server -- I'd rather just access data externally. Anyway, I found out that you can access Sharepoint data using OLE DB, and I tried it successfully using some ADO.NET: var db = DatabaseFactory.CreateDatabase(); DataSet ds = new DataSet(); using (var command = db.GetSqlStringCommand("SELECT * FROM List")) { db.LoadDataSet(command, ds, "List"); } The above works. However, when I try to insert: using (var command = db.GetSqlStringCommand("INSERT INTO List ([HeaderName], [Description], [Number]) VALUES ('Blah', 'Blah', 100)")) { db.ExecuteNonQuery(command); } I get this error: Cannot update 'HeaderName'; field not updateable. I did some Googling and apparently you cannot insert data through OLE DB! Does anyone know if there are some possible workarounds? I could try using Sharepoint Web Services, but I tried that initially and was having a heck of a time authenticating. Is that my only option?

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  • How to form submit and show a different page in ASP.Net MVC?

    - by melaos
    hi guys i'm new to asp.net mvc.. so basically i just build up a two page app which takes the registration information of the user and post it to the database. i use a lot of jquery and ajax calls to retrieve data from the database using linq to sql stored proc object. and currently i'm stuck at one page where after the user submits the form it should redirect him to /Home/AddProduct. What i found was the error: Validation of viewstate MAC failed. If this application is hosted by a Web Farm or cluster, ensure that <machineKey> configuration specifies the same validationKey and validation algorithm. AutoGenerate cannot be used in a cluster. Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. Exception Details: System.Web.HttpException: Validation of viewstate MAC failed. If this application is hosted by a Web Farm or cluster, ensure that <machineKey> configuration specifies the same validationKey and validation algorithm. AutoGenerate cannot be used in a cluster. what used on my form are basically a combination of html controls, asp.net controls and some asp.net mvc type controls. i submit the form using action="/Home/ProductAdded" and after doing some googling i found i was supposed to add in the machine key but after doing so, the index page becomes unviewable. because it couldn't find the index file now. removing the action helps, but now it just doesn't go anywhere. so what am i missing here? i feel i'm missing a lot of fundamentals understanding about asp.net mvc and i don't even know how to submit a form and go to a different page here!!

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  • How to implement Session timeout in Web Server Side?

    - by Morgan Cheng
    I beheld a web framework implementing in-memory session in this way. The session object is added to Cache with timeout. When the time is out, the session is removed from Cache automatically. To protect race condition, each request should acquire lock on given session object to proceed. Each request will "touch" the session in Cache to refresh the timeout. Everything looks fine, until this scenario is discovered. Say, one operation takes a long time, longer than timeout. Another request comes and wait on session lock which is currently hold by the long-time request. Finally, the long-time request is over, it releases the lock. But, since it already takes longer time than timeout, the session object is already removed from Cache. This is obvious because the only request holding the lock doesn't have a chance to "touch" the session object in cache. The second request gets the lock but cannot retrieve the expired Session object. Oops... To fix this issue, the second request has to re-create the Session object. But, this is just like digging a buried dead body from tomb and try to bring it back to life. It causes buggy code. I'm wondering what's the best way to implement timeout in session to handle such scenario. I know that current platform must have good session mechanism. I just want to know the under-the-hood how.

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  • Link to RSS/Atom feed, relative, doesn't work in Firefox

    - by Adrian Smith
    I have a weird problem. I generate a HTML page, hosted let's say at http://www.x.com/stuff which contains <head> <link type="application/atom+xml" rel="alternate" href="/stuff/feed"/> .. </head> The result is: In IE7 all works well - you can click on the feed icon in the browser and the feed is displayed In Firefox, view source, click on the linked /stuff/feed and you see the source of the feed, so that works as expected In Firefox, view the page (not source), then click on the feed icon in the address bar, I get an error that it can't retrieve the URL feed://http//www.x.com/stuff/feed So the problem is, that it's appending feed:// to the front of the URL and then taking out the colon : after the http. I understand that feed: is HTTP anyway so perhaps the adding of that isn't a big problem. But anyway, the fact is, that URL Firefox generates out of my <link> tag doesn't work. I have considered making the URL absolute, but I haven't found any evidence that those URLs have to be absolute, nor can I understand why that would be the case. And for various reasons it would be inconvenient in my code to generate an absolute URL. I can do it if necessary but I would prefer to see proof (e.g. specification, or Mozilla bug report) that it's necessary before making my code messy What do you think? Does anyone know of any evidence that the URL should be absolute? Or am I doing something else wrong? It seems such a simple/obvious tag, where nothing could go wrong, but I can't get it to work.

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  • Persist changes in C

    - by Mohit Deshpande
    I am developing a database-like application that stores a a structure containing: struct Dictionary { char *key; char *value; struct Dictionary *next; }; As you can see, I am using a linked list to store information. But the problem begins when the user exits out of the program. I want the information to be stored somewhere. So I was thinking of storing the linked list in a permanent or temporary file using fopen, then, when the user starts the program, retrieve the linked list. Here is the method that prints the linked list to the console: void PrintList() { int count = 0; struct Dictionary *current; current = head; if (current == NULL) { printf("\nThe list is empty!"); return; } printf(" Key \t Value\n"); printf(" ======== \t ========\n"); while (current != NULL) { count++; printf("%d. %s \t %s\n", count, current->key, current->value); current = current->next; } } So I am thinking of modifying this method to print the information through fprintf instead of printf and then the program would just get the infomation from the file. Could someone help me on how I can read and write to this file? What kind of file should it be, temporary or regular? How should I format the file (like I was thinking of just having the key first, then the value, then a newline character)?

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  • Self-referencing tables in Linq2Sql

    - by J-Man
    Hi, I've seen a lot of questions on self-referencing tables in Linq2Sql and how to eagerly load all child records for a particular root object. I've implemented a temporary solution by accessing all underlying properties, but you can see that this doesn't do the performance any good. The thing is though, that all records are correlated with each-other using a correlation GUID. Example below: RootElement - Id: 1 - ParentId: null - CorrelationId: 4D68E512-4B55-44f4-BA5A-174B630A03DD ChildElement1 - Id: 2 - ParentId: 1 - CorrelationId: 4D68E512-4B55-44f4-BA5A-174B630A03DD ChildElement2 - Id: 3 - ParentId: 2 - CorrelationId: 4D68E512-4B55-44f4-BA5A-174B630A03DD ChildElement1 - Id: 4 - ParentId: 2 - CorrelationId: 4D68E512-4B55-44f4-BA5A-174B630A03DD In my case, I do have access to the correlationId, so I can retrieve all of my records by performing the following query: from element in db.Elements where element.CorrelationId == '4D68E512-4B55-44f4-BA5A-174B630A03DD' select element; But, of course, I want these elements associated with each other by executing this query: from element in db.Elements where element.CorrelationId == '4D68E512-4B55-44f4-BA5A-174B630A03DD' && element.ParentId == null select element; My question is: is it possible to combine the results the first query as some sort of 'caching mechanism' for the query where I get the root element? Thanks for the input. J.

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  • Which PHP library I should choose to work with CouchDB?

    - by Guss
    I want to try playing with CouchDB for a new project I'm writing (as a hobby, not part of my job). I'm well versed in PHP, but I haven't programmed with CouchDB at all, and also I have little experience with non-SQL databases. From looking at CouchDB's "Getting Started with PHP" document they recommend using a third-party library or writing your own client using their RESTful HTTP API. I think I'd rather not mess with writing protocol implementations myself at this point, but what is your experience with writing PHP to work with CouchDB? I haven't tested any of the alternatives yet, but I looked at: PHPillow : I'm interested in the way they implement ORM. I wasn't planning to do ORM, but my problem domain probably map well to that method. PHP Object Freezer: seems like a poor man's ORM - I can use it to implement an actual ORM, or just as an easy store/retrieve document API but it seems too primitive. PHP-on-Couch : Also a bit simple, but they have an interesting API for views and from the documentation it looks usable enough. PHP CouchDB Extension : From the listed options this looks like it has the best chance of making it into the PHP mainline itself, and also has the most complete API. Any opinion one wish to share on each library is welcome.

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  • Map element position in data file to class property

    - by Augusto
    I need to read/write files, following a format provided by a third party specification. The specification itself is pretty simple: it says the position and the size of the data that will be saved in the file. For example: Position Size Description -------------------------------------------------- 0001 10 Device serial number 0011 02 Hour 0013 02 Minute 0015 02 Second 0017 02 Day 0019 02 Month 0021 02 Year The list is very long, it has about 400 elements. But lots of them can be combined. For example, hour, minute, second, day, month and year can be combined in a single DateTime object. I've splitted the elements into about 4 categories, and created separeted classes for holding the data. So, instead of a big structure representing the data, I have some smaller classes. I've also created different classes for reading and writing the data. The problem is: how to map the positions in the file to the objects properties, so that I don't need to repeat the values in the reading/writing class? I could use some custom attributes and retrieve them via reflection. But since the code will be running on devices with small memory and processor, it would be nice to find another way. My current read code looks like this: public void Read() { DataFile dataFile = new DataFile(); // the arguments are: position, size dataFile.SerialNumber = ReadLong(1, 10); //... } Any ideas on this one? Thanks!

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