How to Build a simple HTTP server in C

Question

I need to build a simple HTTP server in C. Any guidance? Links? Samples? Thanks!

Answer 1

How simple?

Answer 2

I'd suggest looking at the source to something like lighthttpd.

Answer 3

Open a TCP socket on port 80, start listening for new connections, implement this. Depending on your purposes, you can ignore almost everything. At the easiest, you can send the same response for every request, which just involves writing text to the socket.

Answer 4

I have written my own that you can use. This one works has sqlite, is thread safe and is in C++ for UNIX.

You should be able to pick it apart and use the C compatible code.

http://code.google.com/p/mountain-cms/

Answer 5

Use platform specific socket functions to encapsulate the HTTP protocol, just like guys behind Apache did.

Answer 6

I suggest you take a look at tiny httpd. If you want to write it from scratch, then you'll want to thoroughly read RFC 2616. Use BSD sockets to access the network at a really low level.

Answer 7

An HTTP server is conceptually simple:

• Open port 80 for listening
• When contact is made, gather a little information (get mainly - you can ignore the rest for now)
• Translate the request into a file request
• Open the file and spit it back at the client

It gets more difficult depending on how much of HTTP you want to support - POST is a little more complicated, scripts, handling multiple requests, etc.

But the base is very simple.

Answer 8

Simple HTTP Daemon (SHTTPD) is pretty good. In particular, it's embeddable and compiles under Windows, Windows CE, and UNIX.

Answer 9

I'd recommend that you take a look at: A Practical Guide to Writing Clients and Servers

What you have to implement in incremental steps is:

1. Get your basic TCP sockets layer running (listen on port/ports, accept client connections and send/receive data).
2. Implement a buffered reader so that you can read requests one line (delimited by CRLF) at a time.
3. Read the very first line. Parse out the method, the request version and the path.
4. Implement generic header reader for the "Header: value" syntax. Don't forget unfolding folded headers.
5. Check the request method, content type and content size to determine how/if the body will be read.
6. Implement decoding of content based on content-type.
7. If you're going to support HTTP 1.1, implement things like "100 Continue", keep-alive, chunked transfer.
8. Add robustness/security measures like detecting incomplete requests, limiting max number of clients etc.
9. Shrink wrap your code and open-source it :)

Answer 10

The HTTP spec and Firebug were very useful for me when I had to do it for my homework.

Good luck with yours. :)

Answer 11

http://www.manning.com/hethmon/ -- "Illustrated Guide to HTTP by Paul S. Hethmon" from Manning is a very good book to learn HTTP protocol and will be very useful to someone implementing it /extending it.

Answer 12

There is a duplicate with more responses.

One candidate not mentioned yet is spserver.