Analyze http rest request before in reaches server

Question

sorry for a newbie question, but..

when I send the REST request to a localhost via http is there any chance to check what exactly this request consist of/ modify it before it reaches server.

No debugging is available.

if it was just web-client i'd simply use fiddler or somethings, what is the way to see the requests coming to a certain host from a mobile device?

UPDATE: currently ... I just need to see what is the format of JSON is coming out of application

Answer 1

when I send the REST request to a localhost via http is there any chance to check what exactly this request consist of/ modify it before it reaches server.

I can think of a number of possibilities:

• If you simply want to see what is sent to the server, then you could use a packet monitor / sniffer such as Wireshark. This is probably the simplest approach ... if it does what you want. http://blogs.technet.com/b/yongrhee/archive/2012/12/01/network-tracing-packet-sniffing-built-in-to-windows-server-2008-r2-and-windows-server-2012.aspx

• If you want to intercept and (potentially) modify the request, then you could use a web proxy service. (The snag is that you need to configure your client to send requests destined for the server via that proxy.)

• In theory, if you are running on a system that uses packet filtering, you could route the TCP/IP stream through a local "service" that captured and maybe even rewrote the data.

Packet sniffer references:

• https://superuser.com/questions/23180/whats-the-easiest-way-to-sniff-tcp-traffic-data-on-linux
• Wireshark - http://www.wireshark.org/
• Nirsoft Smartsniff - http://www.nirsoft.net/utils/smsniff.html
• Builtin packet sniffing on Windows Server - http://blogs.technet.com/b/yongrhee/archive/2012/12/01/network-tracing-packet-sniffing-built-in-to-windows-server-2008-r2-and-windows-server-2012.aspx

Answer 2

You need to use a proxy server (a program that runs an HTTP server on some port, but instead of having Web pages of its own, it then goes and loads pages from another server). The choice of whether to use an existing server or to write a complete one (maybe in Ruby) depends on what you mean by "modifying" the requests and responses.

Answer 3

Make use of Logcat

You can log messages by using Log.d("tag", "msg");

You can also use Log.i("tag", "message"), Log.warn("tag", "message")