It is allowing the cache to serve up different cached versions of the page depending on whether or not the browser requests GZIP encoding or not. The vary header instructs the cache to store a different version of the page if there is any variation in the indicated header. 

As things stand, there will be one (possibly compressed) copy of the page in cache. Say it is the compressed version: If somebody requests the resource but does not support gzip encoding, they&#39;ll be served the wrong content.

Vary: Accept-Encoding informs the behavior of the server with respect to caching the representation of the requested resource. If a new request for a previously cached resource is received, it will be served from the cache unless the Accept-Encoding header of the new request is different from the previously cached representation, at which point the request will be treated as a new request and will not be served from cache.

** EDIT **
As spender points out - if you&#39;re serving a compressed file from cache and the client doesn&#39;t accept your compression mechanism they&#39;ll get a page of junk, so yes, it&#39;s necessary.  You wouldn&#39;t necessarily notice the difference through normal testing, though.

See http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.44 and http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.3

In Python, if some methods of a class need a helper function, but the helper function itself doesn&#39;t use anything in the class, should I put the helper function inside or outside the class?

I tried putting it inside but PyLint was complaining that this function could have been put outside.

@Karl:

The class is a software upgrader and the helper function creates a new folder if the folder doesn&#39;t exist yet. The class is in a module having pretty much only the code for the class as of now. Other classes may be added later on.

Python - Should I put my helper functions inside or outside the class?

When I&#39;m using something like git reflog, I lose my ability to type in commands. I don&#39;t know what you look up, because I&#39;m relatively new to bash.

So, what&#39;s the terminology I can use to go back to running git commands after running a reflog?

Escaping git bash after reflog, or commit, etc

the google page speed addon informs me:

    The following publicly cacheable, compressible resources should have a &quot;Vary: Accept-Encoding&quot; header:
    //some .js and .css files

I don&#39;t understand what this means. I&#39;ve already compressed these files like so:

    if (encodings.Contains(&quot;gzip&quot;) || encodings == &quot;*&quot;)
    {
        app.Response.Filter = new GZipStream(baseStream, CompressionMode.Compress);
        app.Response.AppendHeader(&quot;Content-Encoding&quot;, &quot;gzip&quot;);
    }

And this all seems to work. Why is having `Vary: Accept-Encoding` necessary?

What does vary:accept-encoding mean?

the google page speed addon informs me:
<pre><code class="hljs language-less">The following publicly cacheable, compressible resources should have a "Vary: Accept-Encoding" header:
//some .js and .css files
</code></pre>
I don't understand what this means. I've already compressed these files like so:
<pre><code class="hljs language-ini">if (encodings.Contains("gzip") || encodings == "*")
{
 app.Response.Filter = new GZipStream(baseStream, CompressionMode.Compress);
 app.Response.AppendHeader("Content-Encoding", "gzip");
}
</code></pre>
And this all seems to work. Why is having <code>Vary: Accept-Encoding</code> necessary?

&lt;del&gt;&lt;img src=&quot;http://i.minus.com/i3xuoWZkpfxHn.png&quot; /&gt;&lt;/del&gt;

I don&#39;t see anything that would let me pick files from my computer... there has to be one, where is it? I&#39;m probably missing a reference?

---

**Edit:** What I had in mind was a textbox with a &quot;Browse&quot; button beside it. It occurs to me now that I probably have to place the textbox and browse button myself and add a click event to the button to open the dialog...

Where&#39;s the file-picker dialog in WPF?

I have directory that contains nearly 14,000,000 audio samples in *.wav format.

All plain storage, no subdirectories.

I want to loop through the files, but when I use `DirectoryInfo.GetFiles()` on that folder the whole application freezes for minutes!

Can this be done another way? Perhaps read 1000, process them, then take next 1000 and so on?

Retrieving files from directory that contains large amount of files

I have this string array:

    string[] stringArray = { &quot;text1&quot;, &quot;text2&quot;, &quot;text3&quot;, &quot;text4&quot; };
    string value = &quot;text3&quot;;
    
I would like to determine if `stringArray` contains `value`. If so, I want to locate its position in the array. 

I don&#39;t want to use loops. Can anyone suggest how I might do this?

Checking if a string array contains a value, and if so, getting its position

What is the best way for **checking empty** strings (I&#39;m not [asking about initializing!](https://stackoverflow.com/questions/263191/in-c-should-i-use-string-empty-or-string-empty-or)) in C# when considering **code performance**?(see code below)

    string a;

    // some code here.......

    
    if(a == string.Empty)

or

    if(string.IsNullOrEmpty(a))

or

    if(a == &quot;&quot;)

any help would be appreciated. :)




Most advisable way of checking empty strings in C#

So I am learning MSIL right now to learn to debug my C# .NET applications.

I&#39;ve always wondered: **what is the purpose of the stack?** 

*Just to put my question in context:&lt;br/&gt;
Why is there a transfer from memory to stack or &quot;loading?&quot; 
On the other hand, why is there a transfer from stack to memory or &quot;storing&quot;?
**Why not just have them all placed in the memory?***

- Is it because it&#39;s faster?
- Is it because it&#39;s RAM based?
- For efficiency?

I&#39;m trying to grasp this to help me understand [CIL][1] codes much more deeply.

  [1]: http://en.wikipedia.org/wiki/Common_Intermediate_Language


What is the purpose of a stack? Why do we need it?

I have an ASP.NET 4.0 application running atop IIS 7.5 on a 64-bit Windows Server 2008 R2 Enterprise machine with gobs of RAM, CPU, disk, etc.

With every web request, the ASP.NET application makes a connection to a backend web service (via raw sockets), which is running on the same machine.

**Problem:** There appears to be something limiting the # of simultaneous connections to the backend web service.  Suspiciously, the number of concurrent connections is topping out at 16.

I found this key article from Microsoft explaining how to tweak IIS&#39; settings to accomodate ASP.NET apps that make lots of web service requests: http://support.microsoft.com/?id=821268#tocHeadRef

I followed the article&#39;s recommendatinos, but still no luck.  The setting that is particularly interesting is the `maxconnection` setting, which I even bumped to 999.

**Any ideas what *else* could be throttling connections?**

**Note:** When I cut IIS out of the mix and have the clients connect directly to the backend web service, it will happily open as many connections as I need, so I&#39;m positive the backend is not the bottleneck.  It must be something in IIS/ASP.NET-land.

Here&#39;s the relevant section of the `machine.config` which I&#39;m sure is being read by the application (verified with `appcmd.exe`):

    &lt;system.web&gt;
        &lt;processModel autoConfig=&quot;false&quot; maxWorkerThreads=&quot;100&quot; maxIoThreads=&quot;100&quot; minWorkerThreads=&quot;50&quot; /&gt;
		&lt;httpRuntime minFreeThreads=&quot;176&quot; minLocalRequestFreeThreads=&quot;152&quot;/&gt;
		
        &lt;httpHandlers /&gt;

        &lt;membership&gt;
            &lt;providers&gt;
                &lt;add name=&quot;AspNetSqlMembershipProvider&quot;
                    type=&quot;System.Web.Security.SqlMembershipProvider, System.Web, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a&quot;
                    connectionStringName=&quot;LocalSqlServer&quot;
                    enablePasswordRetrieval=&quot;false&quot;
                    enablePasswordReset=&quot;true&quot;
                    requiresQuestionAndAnswer=&quot;true&quot;
                    applicationName=&quot;/&quot;
                    requiresUniqueEmail=&quot;false&quot;
                    passwordFormat=&quot;Hashed&quot;
                    maxInvalidPasswordAttempts=&quot;5&quot;
                    minRequiredPasswordLength=&quot;7&quot;
                    minRequiredNonalphanumericCharacters=&quot;1&quot;
                    passwordAttemptWindow=&quot;10&quot;
                    passwordStrengthRegularExpression=&quot;&quot; /&gt;
            &lt;/providers&gt;
        &lt;/membership&gt;

        &lt;profile&gt;
            &lt;providers&gt;
                &lt;add name=&quot;AspNetSqlProfileProvider&quot; connectionStringName=&quot;LocalSqlServer&quot; applicationName=&quot;/&quot;
                    type=&quot;System.Web.Profile.SqlProfileProvider, System.Web, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a&quot; /&gt;
            &lt;/providers&gt;
        &lt;/profile&gt;

        &lt;roleManager&gt;
            &lt;providers&gt;
                &lt;add name=&quot;AspNetSqlRoleProvider&quot; connectionStringName=&quot;LocalSqlServer&quot; applicationName=&quot;/&quot;
                    type=&quot;System.Web.Security.SqlRoleProvider, System.Web, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a&quot; /&gt;
                &lt;add name=&quot;AspNetWindowsTokenRoleProvider&quot; applicationName=&quot;/&quot;
                    type=&quot;System.Web.Security.WindowsTokenRoleProvider, System.Web, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a&quot; /&gt;
            &lt;/providers&gt;
        &lt;/roleManager&gt;
    &lt;/system.web&gt;
	&lt;system.net&gt;
		&lt;connectionManagement&gt;
			&lt;add address=&quot;*&quot; maxconnection=&quot;999&quot;/&gt;
		&lt;/connectionManagement&gt;
	&lt;/system.net&gt;

What is limiting the # of simultaneous connections my ASP.NET application can make to a web service?

I want to call specific client from server, and not broadcast to all of them. Problem is that I&#39;m in scope of some AJAX request (in .aspx codebehind let say), and not in Hub or PersistentConnection, so don&#39;t have Clients property - and client who made that ajax (jquery) call is not the client I want to send signalr message!   

Now, I have one hub that it&#39;s called on JS page load, which registers new client into server static list, so I have client Guids. But don&#39;t know how to use that to send message from server to specific client. 

Call specific client from SignalR

I have a REST and WCF service and want to send a custom status code based on the operation. 

For example when some validation fails then I want to send HTTP 444 and when authorization fails I want to send HTTP 455

The question is how do we have it validated for both SOAP and REST web services. 

On the client how does the error code act because when you send an HTTP 400/500 from a WCF Service (using SOAP) an exception is thrown on the client showing the status code? 

Now if I send a new custom status code how does the client handle this?

Can we create custom HTTP Status codes?

Previous working asp.net webforms app now throws this error:

&gt; System.MissingMethodException: Method not found

The `DoThis` method is on the same class and it should work.

I have a generic handler as such:

    public class MyHandler: IHttpHandler
    {
        public void Processrequest(HttpContext context)
        {
          // throws error now System.MissingMethodException: 
          // Method not found.
          this.DoThis(); 
        }
    
        public void DoThis(){ ... }
    }

System.MissingMethodException: Method not found?

I&#39;m reading about [how to set up windows authentication for my web application on IIS 7][1]. In the description they have Window Authentication as an option in IIS. 
![enter image description here][2]

I have windows authenication turned on for my machine(I&#39;m on Windows 7 Professional 64bit) and I  still don&#39;t see it as one of the authentication options for my web application. Why?  
![enter image description here][3]
![enter image description here][4]





  [1]: http://www.asp.net/mvc/tutorials/authenticating-users-with-windows-authentication-cs
  [2]: http://i.stack.imgur.com/GrCuS.jpg
  [3]: http://i.stack.imgur.com/gnGUx.png
  [4]: http://i.stack.imgur.com/j1KQd.png

In IIS, why doesn&#39;t Window Authentication show up as one of the options for my web application?

Create a web service on **http://www.a.com/service.asmx** and send a cross-domain ajax request to it from **http://www.b.com**. Check the headers in **Firebug**, or in **Live HTTP Headers**, or any other plugin you wish.

There is no trace of the **X-Requested-With** HTTP Header field among request headers. 

However, if you send an ajax request to the same service from the same domain (say for example **http://www.a.com/about**), you will see that header field. 

Why is the **X-Requested-With** header field omitted for cross-domain ajax requests? 

**Update:** I know that JSONP calls are not AJAX calls in nature. Thus you won&#39;t see any **X-Requested-With** header field, in JSONP calls.

Cross-Domain AJAX doesn&#39;t send X-Requested-With header

What is difference between HTTP and HTTPS header? 

 1. What are benefits of using HTTPS over HTTP? 
 2. What settings  needs to be done for making website HTTPS?
 3. Can we use HTTPS for only login purpose and then onwords HTTP?
 4. Is there any threat present in HTTPS?
 5. Is processing time required for HTTPS is greater than HTTP?
 6. Does HTTPS cost more than HTTP?

Difference between http and https

I need to authenticate a client when he sends a request to an API. The client has an API-token and I was thinking about using the standard `Authorization` header for sending the token to the server.

Normally this header is used for `Basic` and `Digest` authentication. But I don&#39;t know if I&#39;m allowed to customize the value of this header and use a custom authentication scheme, e.g:

    Authorization: Token 1af538baa9045a84c0e889f672baf83ff24

Would you recommend this or not? Or is there a better approach for sending the token?

Customize the Authorization HTTP header

I want the user to be able to download some files I have on my server, but when I try to use any of the many examples of this around the internet nothing seems to work for me. I&#39;ve tried code like this: 

    &lt;?php

    $size = filesize(&quot;Image.png&quot;);

    header(&#39;Content-Description: File Transfer&#39;);
    header(&#39;Content-Type: image/png&#39;);
    header(&#39;Content-Disposition: attachment; filename=&quot;Image.png&quot;&#39;);
    header(&#39;Content-Transfer-Encoding: binary&#39;);
    header(&#39;Expires: 0&#39;);
    header(&#39;Cache-Control: must-revalidate, post-check=0, pre-check=0&#39;);
    header(&#39;Pragma: public&#39;);
    header(&#39;Content-Length: &#39; . $size);
    readfile(&quot;Image.png&quot;);

I&#39;ve even tried to use the most basic example I could find, like this: 

    &lt;?php
    header(&#39;Content-type: image/png&#39;);
    header(&#39;Content-Disposition: attachment; filename=&quot;Image.png&quot;&#39;);
    readfile(&#39;Image.png&#39;);

When I&#39;ve tested this I have removed all the other code I have and used an empty file with just this code to remove any faults created by external sources.

When I look in the console the file gets sent with the right headers i.e

    &#39;Content-Disposition: attachment; filename=&quot;Image.png&quot;&#39;

But the save dialog isn&#39;t displayed.

I&#39;ve also tried with inline instead of attachment in the content disposition header but that didn&#39;t make a difference either, I&#39;ve tested this in Firefox 8.0.1 Chrome 15.0.874.121 and Safari 5.1.1.

Force file download with php using header()

I need to add some custom headers to the `HttpWebRequest` object. How can I add Custom Header to  `HttpWebRequest` object in Windows Phone 7.

Content Type	Original Author	Original Content on Stackoverflow
Question	Oliver	View Question on Stackoverflow
Solution 1 - C#	spender	View Answer on Stackoverflow
Solution 2 - C#	cori	View Answer on Stackoverflow

What does vary:accept-encoding mean?

C# Problem Overview

C# Solutions

Solution 1 - C#

Solution 2 - C#

Escaping git bash after reflog, or commit, etc

Python - Should I put my helper functions inside or outside the class?

Attributions