Rewriting Binary Streams using Java

Question

I have been studying Netty and Mina but am confused as to the best way to rewrite binary streams. For example, I would like to create a proxy that will allow for replacement of XML and forward along.

Examples appreciated.

Answer 1

I think you're thinking at too low of a level. XML is not so much "binary" as it is an abstraction on top of binary. If you want to replace snippets of XML as they come across your line, you'll have to poke into the payload portion of the packets and look for patterns of XML.. a simple way is to use a regular expression after rebuilding the bytes into content temporarily.

Once you have this search and you have matched what you want, you can replace what you want to replace and re-send.

The hard part of this is that you will likely need to cache some input before it leaves your machine so that you are able to find the beginning and end of what it is you are searching for. What makes this difficult is that often times, you don't know what constitutes the "beginning" and the "end" of a data payload.