Catching HTTP request - 【StackMirror】|httpwebrequest

I'm trying to catch outgoing HTTP request and replace it with another. For example i have a application that initiate request to www.xxxxxxxxxx.com/something
I need to catch this request and instead of going to www.xxxxxxxxxx.com/something i have to redirect it to www.yyyyyyyyyyyy.com/somethingElse.

The request is made by application that i have no access to the source code so it have to be done outside the application.

Anyone may give me a hint how this may be done?

httpwebrequest

2012-04-04 08:13
by Jordan

you can use fiddler auto responder for this

Obviously this would only work if you have full access to the client machine. If this needs to be done from the server you can set up a proxy on the server to relay the request to a different web page.

check this blog entry for the details

http://blogs.msdn.com/b/fiddler/archive/2010/06/21/capturing-and-changing-websites-using-fiddler.aspx

This blog post describes how to modify requests, but you can just as easily forward them to a different domain.

It is also possible to use this technique over HTTPS using generated certificates http://www.fiddler2.com/fiddler/help/httpsdecryption.asp

Some people appear to be claiming that this answer will not work, i appreciate the fact that they are baffled by the capabilities of fiddler, but in the end they are wrong, do your research.

An even easier solution could be to override your local DNS, you can do this with the HOSTS file on windows, keep in mind that this will send the original host headers to the different domain, which you may not want.

2012-04-04 08:15
by Willem D'Haeseleer

How is it possible if it is https - Ramesh PVK 2012-04-04 09:06

@RameshPVK That is an excellent question, You can use a spoofed CA root certificate, comes with fiddler. It's pretty easy to set up really. more info here : http://www.fiddler2.com/fiddler/help/httpsdecryption.as - Willem D'Haeseleer 2012-04-04 09:15

Fidler is a testing tool which record the request and plays them again. While doing that, you can change the host address. That is not the solution for the question - Ramesh PVK 2012-04-04 09:18

Please check all the below responses given. exactly says that - Ramesh PVK 2012-04-04 09:19

@RameshPVK, with all due respect, i do not think you are completely informed off the capabilities of the fiddler auto responder. The OP wants to modify and/or redirect http requests form a process on his machine, the is perfectly possible using fiddler. Please inform your self before you downvote answers - Willem D'Haeseleer 2012-04-04 09:24

Use a smart proxy or rewrite the URL at the server end.

2012-04-04 08:22
by symcbean

The OP wants to capture outgoing requests, not incoming requests, this is not an answer - Willem D'Haeseleer 2012-04-04 09:25

@helmus: "and replace it with another" - this is the only way to solve the problem if the client applciation cannot be modified - symcbean 2012-04-04 10:29

fiddler can intercept the http(s) requests from the client application and "replace them with another" completely, to whatever you wan - Willem D'Haeseleer 2012-04-04 10:34

@helmus: this kind of application is what is called a "proxy - symcbean 2012-04-04 12:07

i understand that, fiddler is a proxy that runs on the client side, not the server side. The OP states that he wants to capture outgoing http requests, not incoming http requests - Willem D'Haeseleer 2012-04-04 12:10

If the request is initiated from the client side then you can't intercept that request and redirect user to some other address. However, you may add a HTTPModule in the HTTP Pipeline that will change the URL to some other address before sending response to the client browser.

2012-04-04 08:41
by Manish

"If the request is initiated from the client side then you can't intercept that request and redirect user to some other address." This is true if you want to intercept it from the server side, you can however intercept it from the client side, which is what ( i believe ) the OP want's to d - Willem D'Haeseleer 2012-04-04 09:39

No, you cannot do that on client side.

Instead, you should redirect to www.yyyyyyyyyyyy.com/somethingElse when any request comes to www.xxxxxxxxxx.com/something on the server side.
Or use LB or a Proxy.

2012-04-04 08:16
by Ramesh PVK

If you have root access on the client side then this is perfectly possible using fiddler - Willem D'Haeseleer 2012-04-04 08:20

how will you do it if it https - Ramesh PVK 2012-04-04 09:05

What kind of application is this! Normally if you have a webserver like apache, lighttpd, cherokee in front of it or the application is deployed on it, than you can use URL-Rewritting.

Apache can do it, even to a different Server. http://httpd.apache.org/docs/2.0/misc/rewriteguide.html

2012-04-04 08:22
by Adi