Download REPACK File Using Ashx Handler C
Malvina Mcneely
I am replacing a Project built using ASP.NET WebForms and I need to replace the .ashx Generic Handlers - but I need to keep the page names so an app that has these URIs hardcoded does not require updating.
I know how to deal with the logic, that is not the problem. The problem is that these pages are referenced by an app that I do not want to update, so I need to be able to use URIs that point to pages ending in .ashx.
I figured it out. I am using the Middleware Pattern, and it turns out that this will execute early in the pipeline and allow me to inspect the URL for the .ashx extension and then route accordingly. I should be able to return a response from this point - I still have to implement that code, but it is not directly germane to this question so I will not cover it here.
I am pretty sure I can just return a Response from here and after implementing the code that does the work based on the incoming legacy page name, I should have a replacement for my .ashx Generic Handlers.
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I have an ASP.net C# 4.0 website project. I am calling an ASHX handler using a jQuery AJAX postback. Normally when I debug C#, I use this method Debug > Attach to Process > select w3wp.exe and start debugging.
When I do this with my ASHX handler Visual Studio says "The breakpoint will not be hit. No symbols have been loaded for this document." Sure enough, when I run the AJAX call to the handler, the breakpoint is not hit.
It turns out that Visual Studio will not actually load symbols for debugging until it actually tries to run the ASHX handler. My problem turned out to be elsewhere - a bug in the jQuery code that called the handler.
I didn't see this bug at first so assumed the handler was being hit. Once the handler is called, VS will then allow you to debug it. I didn't realise that ASHX handlers behaved this way, I thought they would work just like a regular C# file.
I am storing images in a database and I am using an image handler to display the images using the file path + id. The problem I have is when I update the image through the page, the image doesn't change. Wierd thing is I don't have this problem with firefox or chrome.
What I ended up doing is using a guid as my image id in my Image handler. But in my SQL, when I update an image I use sql servers in-built newid() function so everytime an update is made that images guid will change. By doing this IE recognises that its not the same ID and doesn't use the cached image.
This example takes advantage of the generic handler, which has all the flexibility of a web page but none of the overhead of the web page life cycle. While I am returning text/xml this could be any of your defined MIME types.
I want to access some value(which is already set in.aspx file) in .ashx file. I tried to get that value using querystring, session etc but each time it failed. Can anyone suggest me how can we access session value in .ashx file?
I've been trying to figure out how to convert my site to .NET 5 or 6 for a long while. The pages are written in PHP (because that was the only thing available to me on my web host at the time) but there are many .ashx handlers that were added when I originally decided to move to ASP.NET but never got round to completing the job. But the .NET Framework isn't going to be improved or added to in the future so moving to .NET 5/6 needs to happen at some point. It's not a simple process, the differences are fairly major, but I think I've finally figured out a path to making the move.
I configured that assembly to target .NET 4.8 and .NET 5, since there would have to be differences between them. At this point, the .NET 4.8 assembly compiled fine (although with many warnings about using things from System.Web even though that's perfectly fine in .NET 4.8!) and the .NET 5 assembly failed with a gazillion errors.
The next step was to build the .NET 5 assembly without errors. I decided the simplest way to do that was to build .NET 5 only versions of all the things the compiler was complaining about. This meant things like HttpContext, HttpRequest, HttpResponse and IHttpHandler. The properties and methods didn't do anything except throw an exception, I didn't want the code to run, just compile. I'd figure out the details of how to implement those methods as I went through each handler and got them working in .NET 5.
Now I could call my handlers and start to fix up the methods in my dummy classes. Which is where I am currently, going through each handler fixing issues as I find them, whilst still being able to work on my live website. Once that is done and has gone live, I may try to figure out how to finally move my PHP code to proper .NET
In GetSpaceImage.ashx, i am dynamically generating images. But the problem is, for the first time it works good. But, second time and so on it never generate the new images. Debugger hits hanlder only for the first time(when the application loads). I have tried using: "context.Response.Cache.SetCacheability(HttpCacheability.NoCache);"
I want to be able to ping the external websites to let them know the data has changed so they can referesh their cache. I figure I can setup an ASHX handler that receives a parameter telling them what data has changed, so they can both delete that data and refresh it.
This application is intended for individual people to create one-off data points. As-is, it would be trivial for someone to write a script to create 1000s of rows in our database using this publicly available handler.
Can I prevent users from seeing the handler url and the format of the data it accepts? The data itself is not secret, but I don't want it to be easy to reverse-engineer the API call that writes to the database.
Having the code in a .cs file in App_Code resulted in it working as you expected. I suspect that this is something to do with the fact that code inside .ashx files gets compiled slightly differently to account for the fact that it's responding to a specific URL (URLHandler.ashx) as it's a physical file, rather than being a class that's referenced from web.config which may be sufficient to mangle the name/location of the type so IIS can't find it when referenced in config.
A handler is responsible for fulfilling requests from a browser. Requests that a browser manages
are either handled by file extension (or lack thereof) or by calling the handler directly. Only
one handler can be called per request. A handler does not have any HTML static text like .aspx
or .ascx files. A handler is a class that implements the IHttpHandler interface. If you need
to interact with any Session information, you will also need to implement IRequiresSessionState.
If you want to make an asynchronus handler, you will need to implement the IHttpAsyncHandler
interface instead of the IHttpHandler interface.
An example of a handler that is invoked by file extension is the Trace.axd file used for debugging.
In order to invoke the Trace.axd handler, you configure the website for tracing by adding a trace
section to web.config:
Invoking handlers by file extension or no extension gives you flexibility about what is called and when.
There are many articles on the web about file extension handlers so this article will focus on the handler
that is called directly.
At this point, build the project and set the handler.ashx file as the startup file.
Start debugging. You will be prompted to allow the process to change your web.config to allow
debug. Unless you want to type in the change to allow debugging yourself
(""), accept this change.
When you use a debug build, you have the full resources of the Visual Studio debugger, all .NET
Framework namespaces, and any system utilities and applications. The Visual Studio Debugger allows
you to view the call stack, local variables, any watch variables, etc. You are probably familiar
with using these features to some degree. However, with a HTTP Hander, debugging is much more
important because the only visual indication of a bug is whatever you code into the content.
The release build is different from the debug build in both features and performance. When you are
using a release build, it is probably in a production environment. As such, you will need to use a
different set of tools to find your issues.
This blog post is about custom Asp.Net Web API and it is not like standard Web API using Web Api Controllers, Url routing etc.
I use general term or concept of Web API that is simply programming interface in a web. This can be done with many ways. Later on, the standard Microsoft Asp.Net Web API will be presented in this blog. API is just an additional layer in application usually to access data. Web API can be consumed by any device or method that support HTTP. With that concept, I use Handler .ASHX to make an Web API. This post shows custom Web API used by Client script with JQuery also by Asp.Net Server Control. I give those examples in below list. Steps for creating custom Web API using .ASHX:
Using ASHX handlers and MVC Controllers for to get JSON data for Ext.NET Stores via an AjaxProxy are demonstrated both in my book and on the Ext.NET Examples Explorer and Ext.NET MVC Examples Explorer.
In the case of Ext.NET using MVC Controllers for Store/Ajax Proxies, Ext.NET provides extension methods to return StoreResult, which is a JSON object containing data for the stores, the total record count, success, or failure message, etc.
Another weird thing is that I've another 2 visual web parts with the same structure and an http handler that works just fine with every user. So there's something in this particular handler that's causing the access denied problem.
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