How to Use the ashx File

When we mention the ashx file, we will think of HTTP handler and image loading (we used aspx or WebService before). The general practice is as follows:

 

Handler. ashx:
<% @ Webhandler Language = "C #" class = "handler" %>
Using system;
Using system. IO;
Using system. Web;
Public class handler: ihttphandler {

 

Public bool isreusable {
Get {
Return true;
}
}
Public void processrequest (httpcontext context ){
Context. response. contenttype = "image/JPEG ";
Context. response. cache. setcacheability (httpcacheability. Public );
Context. response. bufferoutput = false;
Photosize size;
Switch (context. Request. querystring ["size"]) {
Case "S ":
Size = photosize. Small;
Break;
Case "M ":
Size = photosize. medium;
Break;
Case "L ":
Size = photosize. Large;
Break;
Default:
Size = photosize. Original;
Break;
}
Int32 id =-1;
Stream stream = NULL;
If (context. Request. querystring ["photoid"]! = NULL & context. Request. querystring ["photoid"]! = ""){
Id = convert. toint32 (context. Request. querystring ["photoid"]);
Stream = photomanager. getphoto (ID, size );
} Else {
Id = convert. toint32 (context. Request. querystring ["albumid"]);
Stream = photomanager. getfirstphoto (ID, size );
}
If (Stream = NULL) stream = photomanager. getphoto (size );
Const int buffersize = 1024*16;
Byte [] buffer = new byte [buffersize];
Int COUNT = stream. Read (buffer, 0, buffersize );
While (count> 0 ){
Context. response. outputstream. Write (buffer, 0, count );
Count = stream. Read (buffer, 0, buffersize );
}
}
}

 

*. Aspx:

 

We can work with the following changes and find that in addition to outputting images, we can also output text:
Handler. ashx:
<% @ Webhandler Language = "C #" class = "handler" %>
Using system;
Using system. Web;
Public class handler: ihttphandler {

Public void processrequest (httpcontext context ){
Context. response. contenttype = "text/plain ";
Context. response. Write ("alert ('Hi ')");
}

Public bool isreusable {
Get {
Return false;
}
}
}

 

*. Aspx:
Alert pop-up
<SCRIPT src = "handler. ashx"> </SCRIPT>
You can also use. ashx as a CSS file.
<Link href = "CSS/handler. ashx" rel = "stylesheet" type = "text/CSS">
XML file
Orderdoc. Load ("handler. ashx ");

 

You can also embed text:
Handler. ashx:
<% @ Webhandler Language = "C #" class = "testhandler" %>
Using system;
Using system. Web;
Public class testhandler: ihttphandler {

Public void processrequest (httpcontext context ){
Context. response. contenttype = "text/plain ";
Context. response. Write ("document. Write (\" Hello world \");");
}

 

Public bool isreusable {
Get {
Return false;
}
}
}
*. Aspx:
<SCRIPT type = "text/JavaScript" src = "testhandler. ashx"/>

 

 

When you want to access your session from ashx or httphandler, you must implement the ireadonlysessionstate interface.

Code:

Using system;
Using system. Web;
Using system. Web. sessionstate;

Public class downloadhandler: ihttphandler, ireadonlysessionstate
{
Public bool isreusable {get {return true ;}}

Public void processrequest (httpcontext CTX)
{
CTX. response. Write (CTX. session ["Fred"]);
}
}