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Request-local storage in ASP.NET (accessible to the code from IHttpModule implementation)

- by IgorK

I need to have some object hanging around between two events I'm interested in: PreRequestHandlerExecute (where I create an instance of my object and want to save it) and PostRequestHandlerExecute (where I want to get to the object). After the second event the object is not needed for my purposes and should be discarded either by storage or my explicit action. So the ideal context where my object should be stored is per request (with guaranteed no sharing issues when different threads are serving requests... or processes/servers :) ) Take into account that actual implementation I can do is being made from a HttpModule and is supposed to be a pluggable solution for already written web apps (so the option to provide some state using static/instance variables in Global.asax doesn't look good - I will have to modify Global.asax on every web application). Cache seems to be too broad for this use. I tried to see whether httpContext.Application (of type HttpApplicationState) is good for me or not, but cannot get whether it is exactly per HttpApplication instance or not (AFAIK you can have several instances of HttpApplications used on different threads and therefore serving several requests simultaneously - then using storage shared between threads will not work correctly; otherwise I would use it because one HttpApplication instance serves exactly one request at a time). Something could be done with storing state on the HttpModule instances if I know for sure that it's exactly bound 1-to-1 with every HttpApplication instance running (but again I need a proof that HttpApplication instance is 1-to-1 with my HttpModule's instance). Any valuable and reputable links on these topics are much appreciated... Would be great to find something particularly well-suited for per request situation (because otherwise I may end up with something ulgy... probably either some 'broader' scoped storage and some hacks to have different keys in the storage for different requests, OR using a thread-local thing and in this way commit to the theory that IIS/ASP.NET will not ever serve first event from one thread and the second event from the other thread and so on)

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Keeping cached browser data inside ASP update panel textboxes/dropdowns for browser back click

- by pmlevere

I'm new in VB.net/asp and am running a VB web application in a visual database program called IronSpeed designer. I'm primarily using IronSpeed in this case for its login/role security features. I have a basic two page setup for this app. The user logs in then is taken to AccountEntry.aspx, they enter data into textboxes and select some dropdown values that are linked to a sql database, then they click "submit" to move to Results.aspx. On Results.aspx, the user can change data and then generate several types of reports (PDF, Excel, etc). I'm used to setting up ASP controls inside ASPContent areas, and in these areas if a user performs a browser back click the previously entered data will still be on the page for potential user modification. However in this web app, IronSpeed is setting up the page and asp controls inside an asp update panel. It appears inside an asp update panel, cached values can't be seen on a browser back click. In this case, it's important that the orginally entered values still be there for the user experience if the user advances to Results.aspx then clicks browser back to modify a value on AccountEntry.aspx. If I have to I'll setup Session Variables and disable browser clicking, but that is last resort. Is there any way to save cached data inside an asp update panel and have it there for a browser back click?

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SQL wont work? It doesn't come up with errors either

- by Stefan

Hey there, I have php function which checks to see if variables are set and then adds them onto my sql query. However I am don't seem to be getting any results back!? $where_array = array(); if (array_key_exists("location", $_GET)) { $location = addslashes($_GET['location']); $where_array[] = "`mainID` = '".$location."'"; } if (array_key_exists("gender", $_GET)) { $gender = addslashes($_GET["gender"]); $where_array[] = "`gender` = '".$gender."'"; } if (array_key_exists("hair", $_GET)) { $hair = addslashes($_GET["hair"]); $where_array[] = "`hair` = '".$hair."'"; } if (array_key_exists("area", $_GET)) { $area = addslashes($_GET["area"]); $where_array[] = "`locationID` = '".$area."'"; } $where_expr = ''; if ($where_array) { $where_expr = "WHERE " . implode(" AND ", $where_array); } $sql = "SELECT `postID` FROM `posts` ". $where_expr; $dbi = new db(); $result = $dbi->query($sql); $r = mysql_fetch_row($result); I'm trying to call the data after in a list like so: $dbi = new db(); $offset = ($currentpage - 1) * $rowsperpage; // get the info from the db $sql .= " ORDER BY `time` DESC LIMIT $offset, $rowsperpage"; $result = $dbi->query($sql); // while there are rows to be fetched... while ($row = mysql_fetch_object($result)){ // echo data echo $row['text']; } // end while Anyone got any ideas why I am not retrieving any data? -Stefan

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How Can I Find What's Causing My Transaction to Get Promoted?

- by Damian Powell

I have web site which serves web services (a mixture of .asmx and WCF) which is mostly using LINQ to SQL and System.Transactions. Occaisionally we see the transaction get promoted to a distributed transaction which causes problems because our web servers are isolated from our databases in such a way that it is not possible for us to use MSDTC. I have configured tracing for System.Transactions by adding the following to my web.config: <system.diagnostics> <sources> <source name="System.Transactions" switchValue="Information"> <listeners> <add name="tx" type="System.Diagnostics.XmlWriterTraceListener" initializeData="tx.log" /> </listeners> </source> </sources> </system.diagnostics> It's very interesting and shows me when the transaction is promoted, but I find that it doesn't really help be discover why. Is there an equivalent tracing mechanism for ADO.NET that will show me when connections are created, including the variables that affect pooling (user, cnn string, transaction scope)?

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Connect Rails model to non-rails database

- by the_snitch

I'm creating a new web application (Rails 3 beta), of which pieces of it will access data from a legacy mysql database that a current php application is using. I do not wish to modify the legacy db schema, I just want to be able to read/write to it, as well as the rails application having it's own database using activerecord for the newer stuff. I'm using mysql for the rails app, so I have the adapter installed. How is the best way to do this? For example, I want contacts to come from the old database. Should I create a contacts controller, and manually call sql to get the variables for the views? Or should I create a Contact model, and define attributes that match the fields in the database, and am I able to use it like Contact.mail_address to have it call "SELECT mailaddr FROM contacts WHERE id=Contact.id". Sorry, I've never done much in Rails outside of the standard stuff that is documented well. I'm not sure of what the best approach would be. Ideally, I want the contacts to be presented to my rails application as native as possible, so that I can expose them RESTfully for API access. Any suggestions and code examples would be much appreciated

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Setting hidden input value in Javascript, then accessing it in c# codebehind

- by Siegesmith

Thank you for reading my question. I have been trying to set the value of a hidden input by using Javascript and then access the value from within my C# codebehind. When I run the code that is copied below, the value that is assigned to assignedIDs is "", which I assume is the default value for a hidden input. If I manually set the value in the html tag, then assignedIDs is set to that value. This behavior suggests to me that the value of the input is being reset (re-rendered?) between the onClientClick and onClick events firing. I would appreciate any help with the matter. I have spent hours trying to solve what seems like a very simple problem. html/javascript: <html xmlns="http://www.w3.org/1999/xhtml" > <head runat="server"> <title>Admin Page - Manage Tasks</title> <script language="javascript" type="text/javascript"> function PopulateAssignedIDHiddenInput() { var source = document.getElementById('assignedLinguistListBox'); var s = ""; var count = source.length; for (var i = count - 1; i >= 0; i--) { var item = source.options[i]; if (s == "") { s = source.options[i].value; } else { s = s.concat(",",source.options[i].value); } } document.getElementById('assignedIDHiddenInput').Value = s; // I have confirmed that, at this point, the value of // the hidden input is set properly } </script> </head> <body> <form id="form1" runat="server"> <div> <asp:Panel id="EditMode" runat="server"> <table style="border: none;"> <tr> <td> <asp:Label ID="availableLinguistLabel" runat="server" Text="Available"></asp:Label><br /> <asp:ListBox ID="availableLinguistListBox" runat="server" Rows="10" SelectionMode="Multiple"></asp:ListBox> </td> <td> <input type="button" name="right" value=">>" onclick="Javascript:MoveItem('availableLinguistListBox', 'assignedLinguistListBox');" /><br /><br /> <input type="button" name="left" value="<<" onclick="Javascript:MoveItem('assignedLinguistListBox', 'availableLinguistListBox');" /> </td> <td> <asp:Label ID="assignedLinguistLabel" runat="server" Text="Assigned To"></asp:Label><br /> <asp:ListBox ID="assignedLinguistListBox" runat="server" Rows="10" SelectionMode="Multiple"></asp:ListBox> </td> </tr> </table> //-snip- <asp:Button ID="save_task_changes_button" runat="server" ToolTip="Click to save changes to task" Text="Save Changes" OnClick="save_task_changes_button_click" OnClientClick="Javascript:PopulateAssignedIDHiddenInput()" /> </asp:Panel>   <input id="assignedIDHiddenInput" name="assignedIDHiddenInput" type="hidden" /> </div> </form> </body> c# protected void save_task_changes_button_click(object sender, EventArgs e) { string assignedIDs = Request.Form["assignedIDHiddenInput"]; // Here, assignedIDs == ""; also, Request.Params["assignedIDHiddenInput"] == "" // -snip- }

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High precision event timer

- by rahul jv

#include "target.h" #include "xcp.h" #include "LocatedVars.h" #include "osek.h" /** * This task is activated every 10ms. */ long OSTICKDURATION; TASK( Task10ms ) { void XCP_FN_TYPE Xcp_CmdProcessor( void ); uint32 startTime = GetQueryPerformanceCounter(); /* Trigger DAQ for the 10ms XCP raster. */ if( XCPEVENT_DAQ_OVERLOAD & Xcp_DoDaqForEvent_10msRstr() ) { ++numDaqOverload10ms; } /* Update those variables which are modified every 10ms. */ counter16 += slope16; /* Trigger STIM for the 10ms XCP raster. */ if( enableBypass10ms ) { if( XCPEVENT_MISSING_DTO & Xcp_DoStimForEvent_10msRstr() ) { ++numMissingDto10ms; } } duration10ms = (uint32)( ( GetQueryPerformanceCounter() - startTime ) / STOPWATCH_TICKS_PER_US ); } What would be the easiest (and/or best) way to synchronise to some accurate clock to call a function at a specific time interval, with little jitter during normal circumstances, from C++? I am working on WINDOWS operating system now. The above code is for RTAS OSEK but I want to call a function at a specific time interval for windows operating system. Could anyone assist me in c++ language ??

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Finding cause of memory leaks in large PHP stacks

- by Mike B

I have CLI script that runs over several thousand iterations between runs and it appears to have a memory leak. I'm using a tweaked version of Zend Framework with Smarty for view templating and each iteration uses several MB worth of code. The first run immediately uses nearly 8MB of memory (which is fine) but every following run adds about 80kb. My main loop looks like this (very simplified) $users = UsersModel::getUsers(); foreach($users as $user) { $obj = new doSomethingAwesome(); $obj->run($user); $obj = null; unset($obj); } The point is that everything in scope should be unset and the memory freed. My understanding is that PHP runs through its garbage collection process at it's own desire but it does so at the end of functions/methods/scripts. So something must be leaking memory inside doSomethingAwesome() but as I said it is a huge stack of code. Ideally, I would love to find some sort of tool that displayed all my variables no matter the scope at some point during execution. Some sort of symbol-table viewer for php. Does anything like that or any other tools that could help nail down memory leaks in php exist?

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Thread locking issue with FileHelpers between calling engine.ReadNext() method and readign engine.Li

- by Rad

I use producer/consumer pattern with FileHelpers library to import data from one file (which can be huge) using multiple threads. Each thread is supposed to import a chunk of that file and I would like to use LineNumber property of the FileHelperAsyncEngine instance that is reading the file as primary key for imported rows. FileHelperAsyncEngine internally has an IEnumerator IEnumerable.GetEnumerator(); which is iterated over using engine.ReadNext() method. That internally sets LineNumber property (which seems is not thread safe). Consumers will have Producers assiciated with them that will supply DataTables to Consumers which will consume them via SqlBulkLoad class which will use IDataReader implementation which will iterate over a collection of DataTables which are internal to a Consumer instance. Each instance of will have one SqlBulkCopy instance associate with it. I have thread locking issue. Below is how I create multiple Producer threads. I start each thread afterwords. Produce method on a producer instance will be called determining which chunk of input file will be processed. It seems that engine.LineNumber is not thread safe and I doesn't import a proper LineNumber in the database. It seems that by the time engine.LineNumber is read some other thread called engine.ReadNext() and changed engine.LineNumber property. I don't want to lock the loop that is supposed to process a chunk of input file because I loose parallelism. How to reorganize the code to solve this threading issue? Thanks Rad for (int i = 0; i < numberOfProducerThreads; i++) DataConsumer consumer = dataConsumers[i]; //create a new producer DataProducer producer = new DataProducer(); //consumer has already being created consumer.Subscribe(producer); FileHelperAsyncEngine orderDetailEngine = new FileHelperAsyncEngine(recordType); orderDetailEngine.Options.RecordCondition.Condition = RecordCondition.ExcludeIfBegins; orderDetailEngine.Options.RecordCondition.Selector = STR_ORDR; int skipLines = i * numberOfBufferTablesToProcess * DataBuffer.MaxBufferRowCount; Thread newThread = new Thread(() => { producer.Produce(consumer, inputFilePath, lineNumberFieldName, dict, orderDetailEngine, skipLines, numberOfBufferTablesToProcess); consumer.SetEndOfData(producer); }); producerThreads.Add(newThread); thread.Start();} public void Produce(DataConsumer consumer, string inputFilePath, string lineNumberFieldName, Dictionary<string, object> dict, FileHelperAsyncEngine engine, int skipLines, int numberOfBufferTablesToProcess) { lock (this) { engine.Options.IgnoreFirstLines = skipLines; engine.BeginReadFile(inputFilePath); } int rowCount = 1; DataTable buffer = consumer.BufferDataTable; while (engine.ReadNext() != null) { lock (this) { dict[lineNumberFieldName] = engine.LineNumber; buffer.Rows.Add(ObjectFieldsDataRowMapper.MapObjectFieldsToDataRow(engine.LastRecord, dict, buffer)); if (rowCount % DataBuffer.MaxBufferRowCount == 0) { consumer.AddBufferDataTable(buffer); buffer = consumer.BufferDataTable; } if (rowCount % (numberOfBufferTablesToProcess * DataBuffer.MaxBufferRowCount) == 0) { break; } rowCount++; } } if (buffer.Rows.Count > 0) { consumer.AddBufferDataTable(buffer); } engine.Close(); }

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How to check whether user is login in web application?

- by Morgan Cheng

I want to learn the whole details of web application authentication. So, I decided to write a CodeIgniter authentication library from scratch. Now, I have to make design decision about how to determine whether one user is login. Basically, after user input username & password pair. A cookie is set for this session, following navigations in the web application will not require username & password. The server side will check whether the session cookie is valid to determine whether current user is login. The question is: how to determine whether cookie is valid cookie issued from server side? I can image the most simple way is to have the cookie value stored in session status as well. For each HTTP request, compare the value from cookie and the value from server session. (Since CodeIgniter session library store session variables in cookies, it is not applicable without some tweak.) This method requires storage in server side. For huge web application that is deployed in multiple datacenters. It is possible that user input username & password when browsing in one datacenter, while he/she access the web application in another datacenter later. The expected behavior is that user just input username & password once. As a result, all datacenters should be able to access the session status. That is possible not applicable even the session status is stored in external storage such as database. I tried Google. I login Google with Asian proxy which is supposed to direct me to datacenters in Asian. Then I switch to North American proxy which should direct me to datacenters in North America. It recognize my login without asking username and password again. So, is there any way to determine whether user is login without server side session status?

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Clever Next and Previous Buttons in jQuery

- by matt

I have created a webpage which when you press 'down' automatically scrolls down to the next ID (a section which isn't visible due to overflow: hidden) When you press 'up' it scrolls back up. At the moment each arrow simply tells the webpage to go to a specific div e.g. the 'down arrow' says <a class="tab" href="#page2">Down</a> This is ok for just two pages however as I will be having more pages what I would like is to be able to specify the amount of pages and for the arrows to automatically change which link it needs to go to next. For example, on page 1 the 'up arrow' is not visible and when you press the 'down arrow' it scrolls to #page2 whereupon the 'up arrow' is then visible. If you now press the down arrow again it will take you to #page3 whereupon it then becomes hidden as page 3 is the last page. I'm guessing I need to create a 'var' which specifies the amount of pages and that to make the arrows invisible it will change the css property 'display' to none yet I don't know how to do this nor to make the links work out which number to go to next! edit: Just botched together some code which hides the arrows based on the page number however still need to work out how to update the variables and change the links the arrows go to. (please exclude the coding, it's my first time trying to write script as opposed to just editing plugins!) var PageNumber = 1; var PageAmount = 2; function getPageNumber() { } function hideUpArrow() { if(PageNumber==1) { $("#up_arrow").css({ "display": "none" }); } } function hideDownArrow() { if(PageNumber==PageAmount) { $("#down_arrow").css({ "display": "none" }); } } $(document).ready(function(){ hideUpArrow(); });

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mod_rewrite to redirect URL with query string

- by meeble

I've searched all over stackoverflow, but none of the answers seem to be working for this situation. I have a lot of working mod_rewrite rules already in my httpd.conf file. I just recently found that Google had indexed one of my non-rewritten URLs with a query string in it: http://domain.com/?state=arizona I would like to use mod_rewrite to do a 301 redirect to this URL: http://domain.com/arizona The issue is that later on in my rewrite rules, that 2nd URL is being rewritten to pass query variables on to WordPress. It ends up getting rewritten to: http://domain.com/index.php?state=arizona Which is the proper functionality. Everything I have tried so far has either not worked at all or put me in an endless rewrite loop. This is what I have right now, which is getting stuck in a loop: RewriteCond %{QUERY_STRING} state=arizona [NC] RewriteRule .* http://domain.com/arizona [R=301,L] #older rewrite rule that passes query string based on URL: RewriteRule ^([A-Za-z-]+)$ index.php?state=$1 [L] which gives me an endless rewrite loop and takes me to this URL: http://domain.com/arizona?state=arizona I then tried this: RewriteRule .* http://domain.com/arizona? [R=301,L] which got rid of the query string in the URL, but still creates a loop.

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Unresolved external symbol error in c++

- by Crystal

I am trying to do a simple hw problem involving namespace, static data members and functions. I am getting an unresolved external symbol error Error 1 error LNK2001: unresolved external symbol "private: static double JWong::SavingsAccount::annualInterestRate" (?annualInterestRate@SavingsAccount@JWong@@0NA) SavingsAccount.obj SavingsAccount And I don't see why I am getting this error. Maybe I don't know something about static variables compared to regular data members that is causing this error. Here is my code: SavingsAccount.h file #ifndef JWONG_SAVINGSACCOUNT_H #define JWONG_SAVINGSACCOUNT_H namespace JWong { class SavingsAccount { public: // default constructor SavingsAccount(); // constructor SavingsAccount(double savingsBalance); double getSavingsBalance(); void setSavingsBalance(double savingsBalance); double calculateMonthlyInterest(); // static functions static void modifyInterestRate(double newInterestRate); static double getAnnualInterestRest(); private: double savingsBalance; // static members static double annualInterestRate; }; } #endif SavingsAccount.cpp file #include <iostream> #include "SavingsAccount.h" // default constructor, set savingsBalance to 0 JWong::SavingsAccount::SavingsAccount() : savingsBalance(0) {} // constructor JWong::SavingsAccount::SavingsAccount(double savingsBalance) : savingsBalance(savingsBalance) {} double JWong::SavingsAccount::getSavingsBalance() { return savingsBalance; } void JWong::SavingsAccount::setSavingsBalance(double savingsBalance) { this->savingsBalance = savingsBalance; } // returns monthly interest and sets savingsBalance to new amount double JWong::SavingsAccount::calculateMonthlyInterest() { double monthlyInterest = savingsBalance * SavingsAccount::annualInterestRate / 12; setSavingsBalance(savingsBalance + monthlyInterest); return monthlyInterest; } void JWong::SavingsAccount::modifyInterestRate(double newInterestRate) { SavingsAccount::annualInterestRate = newInterestRate; } double JWong::SavingsAccount::getAnnualInterestRest() { return SavingsAccount::annualInterestRate; }

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temporary tables within stored procedures on slave servers with readonly set

- by lau

Hi, We have set up a replication scheme master/slave and we've had problems lately because some users wrote directly on the slave instead of the master, making the whole setup inconsistent. To prevent these problems from happening again, we've decided to remove the insert, delete, update, etc... rights from the users accessing the slave. Problems is that some stored procedure (for reading) require temporary tables. I read that changing the global variable read_only to true would do what I want and allow the stored procedures to work correctly ( http://dev.mysql.com/doc/refman/5.0/en/server-system-variables.html#sysvar_read_only ) but I keep getting the error : The MySQL server is running with the --read-only option so it cannot execute this statement (1290) The stored procedure that I used (for testing purpose) is this one : DELIMITER $$ DROP PROCEDURE IF EXISTS test_readonly $$ CREATE DEFINER=dbuser@% PROCEDURE test_readonly() BEGIN CREATE TEMPORARY TABLE IF NOT EXISTS temp ( BT_INDEX int(11), BT_DESC VARCHAR(10) ); INSERT INTO temp (BT_INDEX, BT_DESC) VALUES (222,'walou'), (111,'bidouille'); DROP TABLE temp; END $$ DELIMITER ; The create temporary table and the drop table work fine with the readonly flag - if I comment the INSERT line, it runs fine- but whenever I want to insert or delete from that temporary table, I get the error message. I use Mysql 5.1.29-rc. My default storage engine is InnoDB. Thanks in advance, this problem is really driving me crazy.

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barebones sort algorithm

- by user309322

i have been asked to make a simple sort aglorithm to sort a random series of 6 numbers into numerical order. However i have been asked to do this using "Barebones" a theoretical language put forward in the Book Computer Science an overview. Some information on the language can be found here http://www.brouhaha.com/~eric/software/barebones/ Just to clarify i am a student teacher and have been doing anaysis on "mini-programing languages" and their uses in a teaching environment, i suggested to my tutor that i look at barebones and asked what sort of exmaple program i should write . He suggested a simple sort algorithm. Now since looking at the language i cant understand how i can do this without using arrays and if statements. The code to swap the value of variables would be while a not 0 do; incr Aux1; decr a; end; while b not 0 do; incr Aux2 decr b end; while Aux1 not 0 do; incr a; decr Aux1; end; while Aux2 not 0 do; incr b; decr Aux2; end; however the language does not provide < or operators

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How to handle 'this' pointer in constructor?

- by Kyle

I have objects which create other child objects within their constructors, passing 'this' so the child can save a pointer back to its parent. I use boost::shared_ptr extensively in my programming as a safer alternative to std::auto_ptr or raw pointers. So the child would have code such as shared_ptr<Parent>, and boost provides the shared_from_this() method which the parent can give to the child. My problem is that shared_from_this() cannot be used in a constructor, which isn't really a crime because 'this' should not be used in a constructor anyways unless you know what you're doing and don't mind the limitations. Google's C++ Style Guide states that constructors should merely set member variables to their initial values. Any complex initialization should go in an explicit Init() method. This solves the 'this-in-constructor' problem as well as a few others as well. What bothers me is that people using your code now must remember to call Init() every time they construct one of your objects. The only way I can think of to enforce this is by having an assertion that Init() has already been called at the top of every member function, but this is tedious to write and cumbersome to execute. Are there any idioms out there that solve this problem at any step along the way?

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Create static instances of a class inside said class in Python

- by Samir Talwar

Apologies if I've got the terminology wrong here—I can't think what this particular idiom would be called. I've been trying to create a Python 3 class that statically declares instances of itself inside itself—sort of like an enum would work. Here's a simplified version of the code I wrote: class Test: A = Test("A") B = Test("B") def __init__(self, value): self.value = value def __str__(self): return "Test: " + self.value print(str(Test.A)) print(str(Test.B)) Writing this, I got an exception on line 2 (A = Test("A")). I assume line 3 would also error if it had made it that far. Using __class__ instead of Test gives the same error. File "<stdin>", line 1, in <module> File "<stdin>", line 2, in Test NameError: name 'Test' is not defined Is there any way to refer to the current class in a static context in Python? I could declare these particular variables outside the class or in a separate class, but for clarity's sake, I'd rather not if I can help it. To better demonstrate what I'm trying to do, here's the same example in Java: public class Test { private static final Test A = new Test("A"); private static final Test B = new Test("B"); private final String value; public Test(String value) { this.value = value; } public String toString() { return "Test: " + value; } public static void main(String[] args) { System.out.println(A); System.out.println(B); } } This works as you would expect: it prints: Test: A Test: B How can I do the same thing in Python?

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How to Treat Race Condition of Session in Web Application?

- by Morgan Cheng

I was in a ASP.NET application has heavy traffic of AJAX requests. Once a user login our web application, a session is created to store information of this user's state. Currently, our solution to keep session data consistent is quite simple and brutal: each request needs to acquire a exclusive lock before being processed. This works fine for tradition web application. But, when the web application turns to support AJAX, it turns to not efficient. It is quite possible that multiple AJAX requests are sent to server at the same time without reloading the web page. If all AJAX requests are serialized by the exclusive lock, the response is not so quick. Anyway, many AJAX requests that doesn't access same session variables are blocked as well. If we don't have a exclusive lock for each requests, then we need to treat all race condition carefully to avoid dead lock. I'm afraid that would make the code complex and buggy. So, is there any best practice to keep session data consistent and keep code simple and clean?

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How do I build a filtered_streambuf based on basic_streambuf?

- by swestrup

I have a project that requires me to insert a filter into a stream so that outgoing data will be modified according to the filter. After some research, it seems that what I want to do is create a filtered_streambuf like this: template <class StreamBuf class filtered_streambuf: public StreamBuf { ... } And then insert a filtered_streambuf<> into whichever stream I need to be filtered. My problem is that I don't know what invariants I need to maintain while filtering a stream, in order to ensure that Derived classes can work as expected. In particular, I may find I have filtered_streambufs built over other filtered_streambufs. All the various stream inserters, extractors and manipulators work as expected. The trouble is that I just can't seem to work out what the minimal interface is that I need to supply in order to guarantee that an iostream will have what it needs to work correctly. In particular, do I need to fake the movement of the protected pointer variables, or not? Do I need a fake data buffer, or not? Can I just override the public functions, rewriting them in terms of the base streambuf, or is that too simplistic?

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VS2010 - Using <Import /> to share properties between setup projects?

- by arex1337

Why doesn't it work to <Import /> this file, when it works when I replace the statement with just copy-pasting the three properties? ../../Setup.Version.proj <Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003"> <PropertyGroup> <InstallerMajorVersion>7</InstallerMajorVersion> <InstallerMinorVersion>7</InstallerMinorVersion> <InstallerBuildNumber>7</InstallerBuildNumber> </PropertyGroup> </Project> Works: <?xml version="1.0" encoding="utf-8"?> <Project ToolsVersion="4.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003"> <PropertyGroup> <InstallerMajorVersion>7</InstallerMajorVersion> <InstallerMinorVersion>7</InstallerMinorVersion> <InstallerBuildNumber>7</InstallerBuildNumber> <OutputName>asdf-$(InstallerMajorVersion).$(InstallerMinorVersion).$(InstallerBuildNumber)</OutputName> <OutputType>Package</OutputType> Doesn't work: <?xml version="1.0" encoding="utf-8"?> <Project ToolsVersion="4.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003"> <Import Project="../../Setup.Version.proj" /> <PropertyGroup> <OutputName>asdf-$(InstallerMajorVersion).$(InstallerMinorVersion).$(InstallerBuildNumber)</OutputName> <OutputType>Package</OutputType> Here the variables just evaulate to empty strings... :( I'm certain the path to the imported project is correct.

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How best to deal with warning c4305 when type could change?

- by identitycrisisuk

I'm using both Ogre and NxOgre, which both have a Real typedef that is either float or double depending on a compiler flag. This has resulted in most of our compiler warnings now being: warning C4305: 'argument' : truncation from 'double' to 'Ogre::Real' When initialising variables with 0.1 for example. Normally I would use 0.1f but then if you change the compiler flag to double precision then you would get the reverse warning. I guess it's probably best to pick one and stick with it but I'd like to write these in a way that would work for either configuration if possible. One fix would be to use #pragma warning (disable : 4305) in files where it occurs, I don't know if there are any other more complex problems that can be hidden by not having this warning. I understand I would push and pop these in header files too so that they don't end up spreading across code. Another is to create some macro based on the accuracy compiler flag like: #if OGRE_DOUBLE_PRECISION #define INIT_REAL(x) (x) #else #define INIT_REAL(x) static_cast<float>( x ) #endif which would require changing all the variable initialisation done so far but at least it would be future proof. Any preferences or something I haven't thought of?

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SSRS code variable resetting on new page

- by edmicman

In SSRS 2008 I am trying to maintain a SUM of SUMs on a group using custom Code. The reason is that I have a table of data, grouped and returning SUMs of the data. I have a filter on the group to remove lines where group sums are zero. Everything works except I'm running into problems with the group totals - it should be summing the visible group totals but is instead summing the entire dataset. There's tons of articles about how to work around this, usually using custom code. I've made custom functions and variables to maintain a counter: Public Dim GroupMedTotal as Integer Public Dim GrandMedTotal as Integer Public Function CalcMedTotal(ThisValue as Integer) as Integer GroupMedTotal = GroupMedTotal + ThisValue GrandMedTotal = GrandMedTotal + ThisValue Return ThisValue End Function Public Function ReturnMedSubtotal() as Integer Dim ThisValue as Integer = GroupMedTotal GroupMedTotal = 0 Return ThisValue End Function Basically CalcMedTotal is fed a SUM of a group, and maintains a running total of that sum. Then in the group total line I output ReturnMedSubtotal which is supposed to give me the accumulated total and reset it for the next group. This actually works great, EXCEPT - it is resetting the GroupMedTotal value on each page break. I don't have page breaks explicitly set, it's just the natural break in the SSRS viewer. And if I export the results to Excel everything works and looks correctly. If I output Code.GroupMedTotal on each group row, I see it count correctly, and then if a group spans multiple pages on the next page GroupMedTotal is reset and begins counting from zero again. Any help in what's going on or how to work around this? Thanks!

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receive and pass values with XML, AS3

- by VideoDnd

My example imports XML and has an object rotating on stage. The rotating object is called enemy corresponds to ENEMY in the XML. How do I set the rotation variable to receive values from XML? REASON It seems more difficult to set up variables using external data. I want to understand it better. here's a link http://videodnd.weebly.com/ rotation.fla //LOAD XML var myXML:XML; var myLoader:URLLoader = new URLLoader(); myLoader.load(new URLRequest("enemy.xml")); myLoader.addEventListener(Event.COMPLETE, processXML); //PARSE XML function processXML(e:Event):void { myXML = new XML(e.target.data); trace(myXML.ROGUE.*); trace(myXML); //TEXT var text:TextField = new TextField(); text.text = myXML.ENEMY.*; addChild(text); } //ROTATION function enterFrameHandler(event:Event):void { //==>CODE I WANT TO CHANGE<== enemy.rotationY += 10; //enemy.rotationY = myXML.ENEMY.*; } addEventListener(Event.ENTER_FRAME, enterFrameHandler); enemy.xml ENEMY is set to -100, use what you like <?xml version="1.0" encoding="utf-8"?> <BADGUYS> <ENEMY TITLE="sticky">-100</ENEMY> <ROGUE TITLE="slimy">-1000</ROGUE> </BADGUYS>

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What does a WinForm application need to be designed for usability, and be robust, clean, and profess

- by msorens

One of the principal problems impeding productivity in software implementation is the classic conundrum of “reinventing the wheel”. Of late I am a .NET developer and even the wonderful wizardry of .NET and Visual Studio covers only a portion of this challenging issue. Below I present my initial thoughts both on what is available and what should be available from .NET on a WinForm, focusing on good usability. That is, aspects of an application exposed to the user and making the user experience easier and/or better. (I do include a couple items not visible to the user because I feel strongly about them, such as diagnostics.) I invite you to contribute to these lists. LIST A: Components provided by .NET These are substantially complete components provided by .NET, i.e. those requiring at most trivial coding to use. “About” dialog -- add it with a couple clicks then customize. Persist settings across invocations -- .NET has the support; just use a few lines of code to glue them together. Migrate settings with a new version -- a powerful one, available with one line of code. Tooltips (and infotips) -- .NET includes just plain text tooltips; third-party libraries provide richer ones. Diagnostic support -- TraceSources, TraceListeners, and more are built-in. Internationalization -- support for tailoring your app to languages other than your own. LIST B: Components not provided by .NET These are not supplied at all by .NET or supplied only as rudimentary elements requiring substantial work to be realized. Splash screen -- a small window present during program startup with your logo, loading messages, etc. Tip of the day -- a mini-tutorial presented one bit at a time each time the user starts your app. Check for available updates -- facility to query a server to see if the user is running the latest version of your app, then provide a simple way to upgrade if a new version is found. Maximize to multiple monitors -- the canonical window allows you to maximize to a single monitor only; in my apps I allow maximizing across multiple monitors with a click. Taskbar notifier -- flash the taskbar when your backgrounded app has new info for the user. Options dialogs -- multi-page dialogs letting the user customize the app settings to his/her own preferences. Progress indicator -- for long running operations give the user feedback on how far there is left to go. Memory gauge -- an indicator (either absolute or percentage) of how much memory is used by your app. LIST C: Stylistic and/or tiny bits of functionality This list includes bits of functionality that are too tiny to merit being called a component, along with stylistic concerns (that admittedly do overlap with the Windows User Experience Interaction Guidelines). Design a form for resizing -- unless you are restricting your form to be a fixed size, use anchors and docking so that it does what is reasonable when enlarged or shrunk by the user. Set tab order on a form -- repeated tab presses by the user should advance from field to field in a logical order rather than the default order in which you added fields. Adjust controls to be aware of operating modes -- When starting a background operation with, for example, a “Go” button, disable that “Go” button until the operation completes. Provide access keys for all menu items (per UXGuide). Provide shortcut keys for commonly used menu items (per UXGuide). Set up some (global or important or common) shortcut keys without associating to menu items. Allow some menu items to be invoked with or without modifier keys (shift, control, alt) where the modifier key is useful to vary the operation slightly. Hook up Escape and Enter on child forms to do what is reasonable. Decorate any library classes with documentation-comments and attributes -- this allows Visual Studio to leverage them for Intellisense and property descriptions. Spell check your code! What else would you include?

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Converting contents of a byte array to wchar_t*

- by Christopher MacKinnon

I seem to be having an issue converting a byte array (containing the text from a word document) to a LPTSTR (wchar_t *) object. Every time the code executes, I am getting a bunch of unwanted Unicode characters returned. I figure it is because I am not making the proper calls somewhere, or not using the variables properly, but not quite sure how to approach this. Hopefully someone here can guide me in the right direction. The first thing that happens in we call into C# code to open up Microsoft Word and convert the text in the document into a byte array. byte document __gc[]; document = word->ConvertToArray(filename); The contents of document are as follows: {84, 101, 115, 116, 32, 68, 111, 99, 117, 109, 101, 110, 116, 13, 10} Which ends up being the following string: "Test Document". Our next step is to allocate the memory to store the byte array into a LPTSTR variable, byte __pin * value; value = &document[0]; LPTSTR image; image = (LPTSTR)malloc( document->Length + 1 ); Once we execute the line where we start allocating the memory, our image variable gets filled with a bunch of unwanted Unicode characters: ????????????????? And then we do a memcpy to transfer over all of the data memcpy(image,value,document->Length); Which just causes more unwanted Unicode characters to appear: ????????????????? I figure the issue that we are having is either related to how we are storing the values in the byte array, or possibly when we are copying the data from the byte array to the LPTSTR variable. Any help with explaining what I'm doing wrong, or anything to point me in the right direction will be greatly appreciated.

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