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  • What might cause the big overhead of making a HttpWebRequest call?

    - by Dimitri C.
    When I send/receive data using HttpWebRequest (on Silverlight, using the HTTP POST method) in small blocks, I measure the very small throughput of 500 bytes/s over a "localhost" connection. When sending the data in large blocks, I get 2 MB/s, which is some 5000 times faster. Does anyone know what could cause this incredibly big overhead? Update: I did the performance measurement on both Firefox 3.6 and Internet Explorer 7. Both showed similar results. Update: The Silverlight client-side code I use is essentially my own implementation of the WebClient class. The reason I wrote it is because I noticed the same performance problem with WebClient, and I thought that the HttpWebRequest would allow to tweak the performance issue. Regrettably, this did not work. The implementation is as follows: public class HttpCommChannel { public delegate void ResponseArrivedCallback(object requestContext, BinaryDataBuffer response); public HttpCommChannel(ResponseArrivedCallback responseArrivedCallback) { this.responseArrivedCallback = responseArrivedCallback; this.requestSentEvent = new ManualResetEvent(false); this.responseArrivedEvent = new ManualResetEvent(true); } public void MakeRequest(object requestContext, string url, BinaryDataBuffer requestPacket) { responseArrivedEvent.WaitOne(); responseArrivedEvent.Reset(); this.requestMsg = requestPacket; this.requestContext = requestContext; this.webRequest = WebRequest.Create(url) as HttpWebRequest; this.webRequest.AllowReadStreamBuffering = true; this.webRequest.ContentType = "text/plain"; this.webRequest.Method = "POST"; this.webRequest.BeginGetRequestStream(new AsyncCallback(this.GetRequestStreamCallback), null); this.requestSentEvent.WaitOne(); } void GetRequestStreamCallback(IAsyncResult asynchronousResult) { System.IO.Stream postStream = webRequest.EndGetRequestStream(asynchronousResult); postStream.Write(requestMsg.Data, 0, (int)requestMsg.Size); postStream.Close(); requestSentEvent.Set(); webRequest.BeginGetResponse(new AsyncCallback(this.GetResponseCallback), null); } void GetResponseCallback(IAsyncResult asynchronousResult) { HttpWebResponse response = (HttpWebResponse)webRequest.EndGetResponse(asynchronousResult); Stream streamResponse = response.GetResponseStream(); Dim.Ensure(streamResponse.CanRead); byte[] readData = new byte[streamResponse.Length]; Dim.Ensure(streamResponse.Read(readData, 0, (int)streamResponse.Length) == streamResponse.Length); streamResponse.Close(); response.Close(); webRequest = null; responseArrivedEvent.Set(); responseArrivedCallback(requestContext, new BinaryDataBuffer(readData)); } HttpWebRequest webRequest; ManualResetEvent requestSentEvent; BinaryDataBuffer requestMsg; object requestContext; ManualResetEvent responseArrivedEvent; ResponseArrivedCallback responseArrivedCallback; } I use this code to send data back and forth to an HTTP server.

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  • Is there a library or other way to do 128-bit math operations?

    - by samoz
    I am writing a cryptography application and need to work with 128 bit numbers. In addition to standard add, subtract, multiply, divide, and comparisons, I also need a power and modulo function as well. Does anyone know of a library or other implementation that can do this? If not 128-bit, is there a 64-bit option available?

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  • UrlRewriter.net Expression Examples

    - by Tarik
    Hello, I need some web.config examples for each expression types below : $number The last substring matched by group number number. $<name> The last substring matched by group named name matched by (?< name ). ${property} The value of the property when the expression is evaluated. ${transform(value)} The result of calling the transform on the specified value. ${map:value} The result of mapping the specified value using the map. Replaced with empty string if no mapping exists. ${map:value|default} The result of mapping the specified value using the map. Replaced with the default if no mapping exists. Sample: <rewriter> <if url="/tags/(.+)" rewrite="/tagcloud.aspx?tag=$1" /> <!-- same thing as <rewrite url="/tags/(.+)" to="/tagcloud.aspx?tag=$1" /> --> </rewriter> Thank you very much !

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  • C++ templates - matrix class

    - by lastOfMohicans
    Hi I'm learning templates in C++ so I decied to write matrix class which would be a template class. In Matrix.h file I wrote #pragma once #include "stdafx.h" #include <vector> using namespace std; template<class T> class Matrix { public: Matrix(); ~Matrix(); GetDataVector(); SetDataVector(vector<vector<T>> dataVector); bool operator == (Matrix* matrix); bool operator < (Matrix* matrix); bool operator <= (Matrix* matrix); bool operator > (Matrix* matrix); bool operator >= (Matrix* matrix); Matrix* operator + (Matrix* matrix); Matrix* operator - (Matrix* matrix); Matrix* operator * (Matrix* matrix); private: vector<vector<T>> datavector; int columns,rows; }; In Matrix cpp Visual Stuio automaticlly generated code for default constructors #include "StdAfx.h" #include "Matrix.h" Matrix::Matrix() { } Matrix::~Matrix() { } However if I want to compile this I get an error 'Matrix' : use of class template requires template argument list The error are in file Matrix.cpp in default constructors What may be the problem ??

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  • Python performance: iteration and operations on nested lists

    - by J.J.
    Problem Hey folks. I'm looking for some advice on python performance. Some background on my problem: Given: A mesh of nodes of size (x,y) each with a value (0...255) starting at 0 A list of N input coordinates each at a specified location within the range (0...x, 0...y) Increment the value of the node at the input coordinate and the node's neighbors within range Z up to a maximum of 255. Neighbors beyond the mesh edge are ignored. (No wrapping) BASE CASE: A mesh of size 1024x1024 nodes, with 400 input coordinates and a range Z of 75 nodes. Processing should be O(x*y*Z*N). I expect x, y and Z to remain roughly around the values in the base case, but the number of input coordinates N could increase up to 100,000. My goal is to minimize processing time. Current results I have 2 current implementations: f1, f2 Running speed on my 2.26 GHz Intel Core 2 Duo with Python 2.6.1: f1: 2.9s f2: 1.8s f1 is the initial naive implementation: three nested for loops. f2 is replaces the inner for loop with a list comprehension. Code is included below for your perusal. Question How can I further reduce the processing time? I'd prefer sub-1.0s for the test parameters. Please, keep the recommendations to native Python. I know I can move to a third-party package such as numpy, but I'm trying to avoid any third party packages. Also, I've generated random input coordinates, and simplified the definition of the node value updates to keep our discussion simple. The specifics have to change slightly and are outside the scope of my question. thanks much! f1 is the initial naive implementation: three nested for loops. 2.9s def f1(x,y,n,z): rows = [] for i in range(x): rows.append([0 for i in xrange(y)]) for i in range(n): inputX, inputY = (int(x*random.random()), int(y*random.random())) topleft = (inputX - z, inputY - z) for i in xrange(max(0, topleft[0]), min(topleft[0]+(z*2), x)): for j in xrange(max(0, topleft[1]), min(topleft[1]+(z*2), y)): if rows[i][j] <= 255: rows[i][j] += 1 f2 is replaces the inner for loop with a list comprehension. 1.8s def f2(x,y,n,z): rows = [] for i in range(x): rows.append([0 for i in xrange(y)]) for i in range(n): inputX, inputY = (int(x*random.random()), int(y*random.random())) topleft = (inputX - z, inputY - z) for i in xrange(max(0, topleft[0]), min(topleft[0]+(z*2), x)): l = max(0, topleft[1]) r = min(topleft[1]+(z*2), y) rows[i][l:r] = [j+1 for j in rows[i][l:r] if j < 255]

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  • Application Interface between a PC and an embedded device

    - by sasayins
    Hi, How can I make an application interface so that a PC application can communicate to an embedded device like a POS terminal? Like for example, an embedded device like POS terminal that has an embedded linux as an OS. Then I want a PC application to communicate in that POS terminal and access its module hardware like for example its magnetic stripe reader. What implementation should I create in the device, should I use CORBA or something related in that technology so that a PC application can communicate in the POS terminal? Many thanks.

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  • Find Port Number and Domain Name to connect to Hive Table

    - by user1419563
    I am new to Hive, MapReduce and Hadoop. I am using Putty to connect to hive table and access records in the tables. So what I did is- I opened Putty and in the host name I typed- ares-ingest.vip.host.com and then I click Open. And then I entered my username and password and then few commands to get to Hive sql. Below is the list what I did $ bash bash-3.00$ hive Hive history file=/tmp/rjamal/hive_job_log_rjamal_201207010451_1212680168.txt hive> set mapred.job.queue.name=hdmi-technology; hive> select * from table LIMIT 1; So my question is- I was trying to connect to Hive Tables using Squirrel SQL Client, so in that my Connection URL is- jdbc:hive://ares-ingest.vip.host.com:10000/default. So whenever I try to connect with these attributes, I always get Hive: Could not establish connection to ares-ingest.vip.host.com:10000/default: java.net.ConnectException: Connection timed out: connect. It might be possible I am using wrong port number or domain name here. Is there any way from the command prompt I can find out these two things, like what Domain Name and Port Number(where Hive server is running) should I use to connect to Hive table from Squirrel SQL Client. As I know host and port are determined by where the hive server is running

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  • entity set expansion python

    - by Nicolas M.
    Do you know of any existing implementation in any language (preferably python) of any entity set expansion algorithms, such that the one from Google sets ? ( http://labs.google.com/sets ) I couldn't find any library implementing such algorithms and I'd like to play with some of those to see how they would perform on some specific task I would like to implement. Any help is welcome ! Thanks a lot for your help, Regards, Nicolas.

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  • jQuery UI ThemeRoller - Installing themes

    - by CJM
    I'm trying to install jQuery UI with a ThemeRoller theme for the first time. I've downloaded jquery 1.4.2... I've downloaded jQuery UI with a couple of themes. I've tried to follow the instructions but they seem contradictory and don't seem to related to the downloaded files. When I try to use a datepicker... the datepicker functionality works, but it has the default (grey) style. This page refers to a folder/sub-folder/css files that don't exist. This page refers to a ui.theme.css file that doesn't exist. The downloads I received included the following: --demos --docs --external --themes ----base ----[theme name] --ui ----i8n ----minified --js So what do you put where? I've copied the js to the appropriate directory and linked it into my page. And I copied the themes/base folder as well, and linked into the jquery.ui.all.css file. Even the included demos only display the default (grey) styling. Where am I going wrong? The head section: <script type="text/javascript" src="/scripts/jquery-1.4.2.min.js"></script> <script type="text/javascript" src="/scripts/jquery-ui-1.8.custom.min.js"></script> <link rel="Stylesheet" href="/css/smoothness/jquery.ui.all.css" /> The body section: <script type="text/javascript"> $(function() { $("#datepicker").datepicker(); }); </script> <div> <p>Date: <input type="text" id="datepicker" /></p> </div>

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  • How to detect running on WebSphere

    - by Pedro Guedes
    Hi, I'm building a webapp that should run on both Tomcat and WebSphere and I've managed to make almost all the differences into properties with default values that I can override for deployment on the Tomcat server. I need to do yet another override for the authentication provider bean... public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException { if(isWebSphere()){ LOG.warn("Running on WebSphere... not overriding default authentication mechanism."); return; } LOG.info("Running on Tomcat... overriding authentication provider bean ("+AUTHENTICATION_PROVIDER_BEAN+")"); if (beanFactory.containsBean(AUTHENTICATOR_BEAN) && beanFactory.containsBean(POPULATOR_BEAN) && beanFactory.containsBean(USERDETAIL_PROVIDER_BEAN)){ LdapAuthenticator authenticator = (LdapAuthenticator) beanFactory.getBean(AUTHENTICATOR_BEAN); LdapAuthoritiesPopulator populator = (LdapAuthoritiesPopulator) beanFactory.getBean(POPULATOR_BEAN); UserDetailProvider userDetailProvider = (UserDetailProvider) beanFactory.getBean(USERDETAIL_PROVIDER_BEAN); ExtendedLdapAuthenticationProvider override = new ExtendedLdapAuthenticationProvider(authenticator, populator); override.setUserDetailProvider(userDetailProvider); beanFactory.registerSingleton(AUTHENTICATION_PROVIDER_BEAN, override); } else { throw new BeanCreationException("Could not find required beans to assemble overriding object for authentication..."); } } Now my problem is how to implement the isWebSphere() method. I was thinking Class.forName("someWebSphereSpecific"), but is there a better way?

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  • ATL CString or_bstr_t?

    - by Gopalakrishnan Subramani
    In our COM project, we need to choose between best string class implementation so that BSTR (used for COM interfaces) and elegant string class like CString provides many string manipulation APIs. Are there any better way to handle the strings and string operations so that it can be BSTR complaints as well as we can have naive CString operations?

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  • LINQ to XML vs. XmlReader

    - by Vadim
    In my Silverlight application I'm using mostly XmlReader but I'm playing with idea to replace XmlReader implementation with LINQ to XML. What are pros and cons between LINQ to XML and XmlReader in Silverlight?

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  • Javascript to convert Markdown/Textile to HTML (and, ideally, back to Markdown/Textile)

    - by Horace Loeb
    There are several good Javascript editors for Markdown / Textile (e.g.: http://attacklab.net/showdown/, the one I'm using right now), but all I need is a Javascript function that converts a string from Markdown / Textile - HTML and back. What's the best way to do this? (Ideally it would be jQuery-friendly -- e.g., $("#editor").markdown_to_html()) Edit: Another way to put it is that I'm looking for a Javascript implementation of Rails' textilize() and markdown() text helpers

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  • Maintaining ISAPI Rewrite Path with the ASP.NET tilde (~)

    - by Adam
    My team is upgrading from ASP.NET 3.5 to ASP.NET 4.0. We are currently using Helicon ISAPI Rewrite to map http://localhost/<account-name>/default.aspx to http://localhost/<virtual-directory>/default.aspx?AccountName=<account-name> where <account-name> is a query string variable and <virtual-directory> is a virtual directory (naturally). Before the upgrade the tilde (~) resolved to http://localhost/<account-name>/... (which I want it to do) and after the upgrade the tilde resolves to http://localhost/<virtual-directory>/... which results in an error because the <account-name> query string is required. I'd like to avoid going down the road of replacing everything with relative paths because there are several features in our system that use the entire URL instead of just the relative path. For what it's worth I'm using IIS7 in Windows 7, Visual Studio 2010 with ASP.NET 4.0 and the 64 bit Helicon ISAPI Rewrite. If I switch back to the ASP.NET 3.5 version then it still works fine (leading me to believe nothing changed in IIS unless it's within the 4.0 app pool - when I switch back and forth between 3.5 and 4.0 I have to change the app pool in IIS). Any ideas? Thanks in advance!

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  • How to use Scala in IntelliJ IDEA (or: why is it so difficult to get a working IDE for Scala)?

    - by Alex R
    I recently gave up trying to use Scala in Eclipse (basic stuff like completion doesn't work). So now I'm trying IntelliJ. I'm not getting very far. I've been able to edit programs (within syntax highlighting and completion... yay!). But I'm unable to run even the simplest "Hello World". This was the original error: Scala signature Predef has wrong version Expected 5.0 found: 4.1 in .... scala-library.jar But that was yesterday with IDEA 9.0.1. See below... UPDATE Today I uninstalled IntelliJ 9.0.1, and installed 9.0.2 Early Availability, with the 4/14 stable version of the Scala plug-in. Then I setup a project from scratch through the wizards: new project from scratch JDK is 1.6.u20 accept the default (project) instead of global / module accept the download of Scala 2.8.0beta1 into project's lib folder Created a new class: object hello { def main(args: Array[String]) { println("hello: " + args); } } For my efforts, I now have a brand-new error :) Here it is: Scalac internal error: class java.lang.ClassNotFoundException [java.net.URLClassLoader$1.run(URLClassLoader.java:202), java.security.AccessController.doPrivileged(Native Method), java.net.URLClassLoader.findClass(URLClassLoader.java:190), java.lang.ClassLoader.loadClass(ClassLoader.java:307), sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301), java.lang.ClassLoader.loadClass(ClassLoader.java:248), java.lang.Class.forName0(Native Method), java.lang.Class.forName(Class.java:169), org.jetbrains.plugins.scala.compiler.rt.ScalacRunner.main(ScalacRunner.java:72)] FINAL UPDATE I uninstalled 9.0.2 EA and reinstalled 9.0.1, but this time went with the 2.7.3 version of Scala rather than the default 2.7.6, because 2.7.3 is the one shown in the screen-shots at the IntelliJ website (I guess the screen-shots prove that they actually tested this version!). Now everything works!!!

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  • UITabBarController rotation problem with popViewControllerAnimated and selectedIndex (iPhone SDK)

    - by rjobidon
    Hi! This is a very important auto rotate issue and easy to reproduce. My application has a UITabBarController. Each tab is a UINavigationController. Auto rotation is handled with normal calls to shouldAutorotateToInterfaceOrientation and didRotateFromInterfaceOrientation. The interface rotates normally until I call UIViewController.popViewControllerAnimated and change UITabBarController.selectedIndex. Steps to reproduce: Create a demo Tab Bar Application. Add the following code to the App Delegate .h file: #import <UIKit/UIKit.h> @interface TestRotationAppDelegate : NSObject { UIWindow *window; UITabBarController *tabBarController; } @property (nonatomic, retain) IBOutlet UIWindow *window; @property (nonatomic, retain) IBOutlet UITabBarController *tabBarController; -(void)doAction; @end // Redefine the interface to cach rotation messages @interface UITabBarController (TestRotation1AppDelegate) @end Add the following code to the App Delegate .m file: #import "TestRotationAppDelegate.h" @implementation TestRotationAppDelegate @synthesize window; @synthesize tabBarController; -(BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions { [window addSubview:tabBarController.view]; [window makeKeyAndVisible]; return YES; } -(BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation { return YES; } -(void)dealloc { [tabBarController release]; [window release]; [super dealloc]; } @end @implementation UITabBarController (TestRotation1AppDelegate) -(void)viewDidLoad { [super viewDidLoad]; // Add a third tab and push a view UIViewController *view1 = [[UIViewController alloc] init]; view1.title = @"Third"; UINavigationController *nav = [[UINavigationController alloc] initWithRootViewController:view1]; NSMutableArray *array = [[NSMutableArray alloc] init]; [array addObjectsFromArray:self.viewControllers]; [array addObject:nav]; self.viewControllers = array; // Push view2 inside the third tab UIViewController *view2 = [[UIViewController alloc] init]; [nav pushViewController:view2 animated:YES]; // Create a button to pop view2 UIButton *button = [UIButton buttonWithType:UIButtonTypeRoundedRect]; button.frame = CGRectMake(50, 50, 220, 38); [button setTitle:@"Pop this view" forState:UIControlStateNormal]; [button addTarget:self action:@selector(doAction) forControlEvents:UIControlEventTouchUpInside]; [view2.view addSubview:button]; } -(void) doAction { // ROTATION PROBLEM BEGINS HERE // Remove one line of code and the problem doesn't occur. [self.selectedViewController popViewControllerAnimated:YES]; self.selectedIndex = 0; } -(BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation { return YES; } @end The interface auto rotates normally until you tap the button on tab #3. Your help will be geatly appreciated!

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  • Rails PDF Generation with Prawn in IE7

    - by fluid_chelsea
    I'm using Prawn and Prawnto to generate a PDF in a Ruby on Rails app (Rails version 2.2.2) which works great and generates PDFs happily and sends them to the user to download in Firefox. The problem is in IE7. I have a route set up like so: map.invoice_pdf '/invoices.pdf', :controller => 'invoices', :action => 'index', :format => 'pdf' Which I then have a link like so to call: invoice_pdf_path(:year => params[:year], :month => params[:month], :unpaid_only => params[:unpaid_only]) And the following in my controller: def index params[:year] = default params[:year] params[:month] = default params[:month] params[:page] ||= 1 @invoices = Arobl.find_invoices_for_customer(current_customer.strCustomerID, params) respond_to do |format| format.html{ render :action => 'index' } format.pdf{ prawnto :inline => false, :filename => "#{current_customer.strCustomerID}_invoice.pdf" end In FF this works as expected, when the link is clicked the show action is invoked with a format of .pdf, and responds with the correctly named PDF. When it's hit with IE7 it says that the file or website could not be found, and references "invoices.pdf" instead of the expected customer_id_invoice.pdf filename. Any idea what could be causing this behaviour? Thanks!

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  • JavaBeans and DSLs

    - by Aaron Digulla
    It's 2009 and we still all hold on the JavaBeans despite all their flaws, mostly because of the tooling support which we wrote in our own blood. But now we have method chaining and internal DSLs and some pressure to replace or extend JavaBeans with DSL classes. Has anyone an implementation that implements PropertyDescriptor for a DSL (where the getters and setter use the exact same name as the property) and a way to hook that into the Java RT so I don't need to create them all by myself?

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  • "Chunked" MemoryStream

    - by Karol Kolenda
    I'm looking for the implementation of MemoryStream which does not allocate memory as one big block, but rather a collection of chunks. I want to store a few GB of data in memory (64 bit) and avoid limitation of memory fragmentation.

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  • appstats broken filename in callstack

    - by Ray Yun
    When I visit appstats page and expand callstack, the file path has <path[N]> prefix. So click the file link then emit no such file or directory error. Stack: /google/appengine/datastore/datastore_rpc.py:951 make_rpc_call() /google/appengine/datastore/datastore_query.py:993 _make_query_result_rpc_call() /google/appengine/datastore/datastore_query.py:714 run_async() /google/appengine/datastore/datastore_query.py:685 run() /google/appengine/api/datastore.py:1281 GetBatcher() /google/appengine/api/datastore.py:1351 Get() /google/appengine/ext/db/init.py:1831 fetch() /google/appengine/ext/db/init.py:1778 get() /apps/fbapp/fbutil.py:232 oauth_load_fb_user() /apps/fbapp/fbutil.py:84 require_account() the error message for appengine source: [Errno 2] No such file or directory: u'/Applications/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/lib/ipaddr/google/appengine/datastore/datastore_rpc.py' the error message for my source: IOError [Errno 2] No such file or directory: u'/Applications/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/lib/antlr3/apps/fbapp/fbutil.py' I guess this was path problem and found some official comment from google. If your request handlers modify sys.path, you must make the same modifications to sys.path in appengine_config.py so the Appstats web interface can see all files. Actually I'm using appengine_django and two path was inserted to sys.path. I did it same again at appengine_django.py but also failed. Maybe some custom setting with appengine_config.py can solve this problem but doesn't figure out how to fix it. What can I do?

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  • Why does text from Assembly.GetManifestResourceStream() start with three junk characters?

    - by flipdoubt
    I have a SQL file added to my VS.NET 2008 project as an embedded resource. Whenever I use the following code to read the file's content, the string returned always starts with three junk characters and then the text I expect. I assume this has something to do with the Encoding.Default I am using, but that is just a guess. Why does this text keep showing up? Should I just trim off the first three characters or is there a more informed approach? public string GetUpdateRestoreSchemaScript() { var type = GetType(); var a = Assembly.GetAssembly(type); var script = "UpdateRestoreSchema.sql"; var resourceName = String.Concat(type.Namespace, ".", script); using(Stream stream = a.GetManifestResourceStream(resourceName)) { byte[] buffer = new byte[stream.Length]; stream.Read(buffer, 0, buffer.Length); // UPDATE: Should be Encoding.UTF8 return Encoding.Default.GetString(buffer); } } Update: I now know that my code works as expected if I simply change the last line to return a UTF-8 encoded string. It will always be true for this embedded file, but will it always be true? Is there a way to test any buffer to determine its encoding?

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  • Can I select 0 columns in SQL Server?

    - by Woody Zenfell III
    I am hoping this question fares a little better than the similar Create a table without columns. Yes, I am asking about something that will strike most as pointlessly academic. It is easy to produce a SELECT result with 0 rows (but with columns), e.g. SELECT a = 1 WHERE 1 = 0. Is it possible to produce a SELECT result with 0 columns (but with rows)? e.g. something like SELECT NO COLUMNS FROM Foo. (This is not valid T-SQL.) I came across this because I wanted to insert several rows without specifying any column data for any of them. e.g. (SQL Server 2005) CREATE TABLE Bar (id INT NOT NULL IDENTITY PRIMARY KEY) INSERT INTO Bar SELECT NO COLUMNS FROM Foo -- Invalid column name 'NO'. -- An explicit value for the identity column in table 'Bar' can only be specified when a column list is used and IDENTITY_INSERT is ON. One can insert a single row without specifying any column data, e.g. INSERT INTO Foo DEFAULT VALUES. One can query for a count of rows (without retrieving actual column data from the table), e.g. SELECT COUNT(*) FROM Foo. (But that result set, of course, has a column.) I tried things like INSERT INTO Bar () SELECT * FROM Foo -- Parameters supplied for object 'Bar' which is not a function. -- If the parameters are intended as a table hint, a WITH keyword is required. and INSERT INTO Bar DEFAULT VALUES SELECT * FROM Foo -- which is a standalone INSERT statement followed by a standalone SELECT statement. I can do what I need to do a different way, but the apparent lack of consistency in support for degenerate cases surprises me. I read through the relevant sections of BOL and didn't see anything. I was surprised to come up with nothing via Google either.

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  • EJB3 - @Column(insertable="false") question

    - by WhiteTigerK
    Hi All, I'm building a J2SE application with EJB3 and an Oracle Express Edition DB. My problem is like that - I set an EntityBean in my project which matches a table in the DB. The table contains a column which is not nullable and has a default value. All I want is that when persisting a new data to this table using the EJB, the column's value will get its default value. This is how I set it in the project: //holds user's first name @Basic(optional = true) @Column(name = "FIRST_NAME", insertable = false, updatable = true, nullable = false) private String m_firstName; I also set it in the ORM.XML file: <basic name="firstName"> <column name="FIRST_NAME" insertable="false" updatable="true" nullable="false"/> </basic> But for some reason, when creating a new EntityBean and not setting the first name field, and then trying to persist it, i get the following exception: Exception [TOPLINK-4002] (Oracle TopLink Essentials - 2.1 (Build b60e-fcs (12/23/2008))): oracle.toplink.essentials.exceptions.DatabaseException Internal Exception: java.sql.SQLException: ORA-01400: cannot insert NULL into ("TSDB"."USERS"."FIRST_NAME") Which means that the persistence manager tries to insert the first name field although I told it not to. Am I doing something wrong here ? Thanks!

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