CODEWITHSUNDEEP
c#asp.net-corehttprequestmiddlewaresystem.net.httpwebrequest
realPro
realPro

Reputation: 1846

ASP.NET Core Modify HTTP Request Headers using Middleware

All I need to do is to modify [Connection] HTTP Header from "Keep-alive" to lowercase "keep-alive".

I wrote the class, 

public class PreRequestModifications
{

    private readonly RequestDelegate _next;

    public PreRequestModifications(RequestDelegate next)
    {
        _next = next;
    }

    public async Task Invoke(HttpContext context)
    {
        // Does not get called when making an HTTPWebRequest.   
        await _next.Invoke(context);              
    }
}

and registered on startup, 

 public void Configure(IApplicationBuilder app, IHostingEnvironment env)
 {    
     app.UseMiddleware<PreRequestModifications>();
 }

but the Invoke method does not get called when I execute await httpWebRequest.GetResponseAsync();

Upvotes: 2

Views: 14841

Answers (2)

Saeed Ganji
Saeed Ganji

Reputation: 307

Have you registered your middleware in the DI system? You need to do so in your Startup class, ConfigureServices method: 

services.AddScoped<IMiddleware, SomeMiddleware>();

Upvotes: 1

Christopher Lake
Christopher Lake

Reputation: 378

So middleware gets hit when a request is made and when a response is sent back. Effectively this means you can move through the Invoke method twice like so:

public async Task Invoke(HttpContext context)
{
  ModifyRequest(context);
  await _next(context);
  ModifyResponse(context);
}

So you can modify the response in the ModifyResponse method.

Microsoft's documentation will make it clearer: https://learn.microsoft.com/en-us/aspnet/core/fundamentals/middleware/?view=aspnetcore-2.1

Hopefully this helps.

Upvotes: 1

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