LuaSocket: Network support for the Lua language

What is LuaSocket?

LuaSocket is a Lua extension library that is composed by two parts: a C core that provides support for the TCP and UDP transport layers, and a set of Lua modules that add support for functionality commonly needed by applications that deal with the Internet.

The core support has been implemented so that it is both efficient and simple to use. It is available to any Lua application once it has been properly initialized by the interpreter in use. The code has been tested and runs well on several Windows and Unix platforms.

Among the support modules, the most commonly used implement the SMTP (sending e-mails), HTTP (WWW access) and FTP (uploading and downloading files) client protocols. These provide a very natural and generic interface to the functionality defined by each protocol. In addition, you will find that the MIME (common encodings), URL (anything you could possible want to do with one) and LTN12 (filters, sinks, sources and pumps) modules can be very handy.

The library is available under the same terms and conditions as the Lua language, the MIT license. The idea is that if you can use Lua in a project, you should also be able to use LuaSocket.

Download

LuaSocket version 2.0 (beta3) is now available for download! It is compatible with Lua 5.0 and has been tested on Windows XP, Linux, and Mac OS X.

The library can be downloaded in source code from the following links:

luasocket-2.0-beta3.tar.gz
luasocket-2.0-beta3.zip

Besides the full C and Lua source code for the library, the distribution contains several examples, this user's manual and basic test procedures.

I am also providing PC Win32 binaries for those that want to give LuaSocket a try (Those on Unix or Mac OS X can just type make):

luasocket-2.0-beta3-win32.zip

The quick and dirty way to use these binaries is to unpack everything into a directory, say c:\luasocket, then set LUA_INIT to load the compat-5.1.lua and set LUA_PATH and LUA_CPATH to look for files in the current directory:

c:\luasocket\> set LUA_INIT=@c:\luasocket\compat-5.1.lua
c:\luasocket\> set LUA_CPATH=?.dll
c:\luasocket\> set LUA_PATH=?.lua

From that directory, you can then run the interpreter and it should find all files it needs. To download this manual page from the Internet, for example, do the following:

c:\luasocket\> lua
Lua 5.0.2  Copyright (C) 1994-2004 Tecgraf, PUC-Rio
> http = require"socket.http"
> print(http.request"http://www.tecgraf.puc-rio.br/luasocket/")
--> the source to this web page gets dumped to terminal

When you are done playing, take a look at the installation section of the manual to find out how to properly install the library.

Special thanks

Throughout LuaSocket's history, many people gave suggestions that helped improve it. For that, I thank the Lua community. Special thanks go to David Burgess, who has helped push the library to a new level of quality and from whom I have learned a lot of stuff that doesn't show up in RFCs. Special thanks also to Carlos Cassino, who played a big part in the extensible design seen in the C core of LuaSocket 2.0. Recently, Mike Pall has been helping a lot too! Thanks to you all!

What's New

The big change for the 2.0 (beta3) release was the adoption of the Lua 5.1 package proposal. Naturally, there were a few bug fixes (a beta is a beta, is a beta).

New compat-5.1 distribution:
- Installation uses new directory structure;
- Namespace hierarchy is in now back in use (ex. socket.url instead of url);
- All modules call require even for standard libraries;
socket.select wasn't calling tm_markstart;
LTN12 avoids coroutines (so you can go wild on the C side);
Kludge on wsocket.c:sock_send for windows timeout issue moved to buffer.c:sendraw so it's not a kludge anymore;
socket.protect only catches errors thrown by socket.try;
Fixed udp:sendto to call sock_sendto instead of sock_send;
close wasn't returning 1!
socket.gettime returns time since Unix Epoch 1/1/1970 (UTC);
socket.sleep is robust to interrupts;
http.PROXY wasn't working;
url.escape escapes only dangerous characters.

Incompatibilities with previous versions

Namespaces are hierarchical again. This means that whoever used to call require("url") should update their code to require("socket.url").

Old Versions

All previous versions of the LuaSocket library can be downloaded here. Although these versions are no longer supported, they are still available for those that have compatibility issues.