（Python）通过网络发送结构化数据包

Question

i want to build a chat application which supports text messaging, group messaging, file transfer(like netmeeting). when i send it over TCP socket i saw that data is not structured all the data send as string over TCP. I want to send it in a structured way with few headers like name:,ip:,data:,data_type_flag:(file or text message) etc... one stackoverflow member told me to use TELEPATHY but i can't get a simple tutorial to understand. how can i send structured data over socket? or can any one suggest me a good tutorial to implement telepathy properly. i want to communicate over network as peer-to-peer rather than dedicated server.. Thanks

Answer 1

Try google protcol buffers or apache thrift . There are many examples for how to use them.

As for your comment about "peer to peer", please realize that even in peer-to-peer one of the peers is always acting as a server (sometimes both are).

Answer 2

TCP is a transport layer protocol, as opposed to application layer. This means that TCP is not responsible for the types of data you send, only the raw bits. HTTP has headers and other metadata because it is application level.

For a project like the one you're talking about, you will want to implement your own application layer protocol, but this is not exactly a trivial task. I would look at the python source code in the httplib module for an example of how to implement such a protocol, but note that this is likely fairly different still from what you want, as you will want persistent socket connections to be a first-class citizen in a peer-to-peer chat protocol like the one you're describing.

Another option is to use one of the various RPC libraries, eg xmlrpclib , which will handle a decent amount of the required low-level network things for you (although not file transfer; there are other libraries like the ftplib that can do this).

Answer 3

Pickle your data before you send it, and unpickle it on the other end? http://docs.python.org/library/pickle.html