|
| Network support for the Lua language |
|
|
| Network support for the Lua language |
LuaSocket 2.0 uses the new package proposal for Lua 5.1. All Lua library developers are encouraged to update their libraries so that all libraries can coexist peacefully and users can benefit from the standardization and flexibility of the standard.
The proposal was considered important enough by some of us to justify early adoption, even before release of Lua 5.1. Thus, a compability module compat-5.1 has been released in conjunction with Roberto Ierusalimschy and The Kepler Project team. It implements the Lua 5.1 package proposal on top of Lua 5.0.
As far as LuaSocket is concerned, this means that whoever is deploying a non-standard distribution of LuaSocket will probably have no problems customizing it. Here we will only describe the standard distribution. If the standard doesn't meet your needs, we refer you to the Lua discussion list, where any question about the package scheme will likely already have been answered.
On Unix systems, the standard distribution uses two base directories, one for system dependent files, and another for system independent files. Let's call these directories <LIB> and <SHARE>, respectively. For instance, in my laptop, I use '/usr/local/lib/lua/5.0' for <LIB> and '/usr/local/share/lua/5.0' for <SHARE>. On Windows, only one directory is used, say 'c:\program files\lua\5.0'. Here is the standard LuaSocket distribution directory structure:
<SHARE>/compat-5.1.lua <SHARE>/ltn12.lua <SHARE>/mime/init.lua (originally mime.lua) <LIB>/mime/core.dll <SHARE>/socket/init.lua (originally socket.lua) <LIB>/socket/core.dll <SHARE>/socket/http.lua <SHARE>/socket/tp.lua <SHARE>/socket/ftp.lua <SHARE>/socket/smtp.lua <SHARE>/socket/url.lua
Naturally, on Unix systems, core.dll would be replaced by core.so. Notice that in the instalation, socket.lua becomes socket/init.lua, and the same happens with mime.lua, which becomes mime/init.lua.
In order for the interpreter to find all LuaSocket components, three environment variables need to be set. The first environment variable tells the interpreter to load the compat-5.1.lua module at startup:
LUA_INIT=@<SHARE>/compat-5.1.lua
The other two environment variables instruct the compatibility module to look for dynamic libraries and extension modules in the appropriate directories and with the appropriate filename extensions.
LUA_PATH=<SHARE>/?.lua;?.lua LUA_CPATH=<LIB>/?.dll;?.dll
Again, naturally, on Unix systmems the shared library extension would be .so instead of .dll.
With the above setup, and an interpreter with shared library support, it should be easy to use LuaSocket. Just fire the interpreter and use the require function to gain access to whatever module you need:
Lua 5.0.2 Copyright (C) 1994-2004 Tecgraf, PUC-Rio
> socket = require("socket")
> print(socket._VERSION)
--> LuaSocket 2.0
Each module loads their dependencies automatically, so you only need to load the modues you directly depend upon:
Lua 5.0.2 Copyright (C) 1994-2004 Tecgraf, PUC-Rio
> http = require("socket.http")
>
print(http.request("http://www.cs.princeton.edu/~diego/professional/luasocket"))
--> homepage gets dumped to terminal