mirror of
https://github.com/lunarmodules/luasocket.git
synced 2024-11-14 01:08:21 +01:00
480 lines
14 KiB
HTML
480 lines
14 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
|
|
"http://www.w3.org/TR/html4/strict.dtd">
|
|
<html>
|
|
|
|
<head>
|
|
<meta name="description" content="LuaSocket: The core namespace">
|
|
<meta name="keywords" content="Lua, LuaSocket, Socket, Network, Library, Support">
|
|
<title>LuaSocket: The socket namespace</title>
|
|
<link rel="stylesheet" href="reference.css" type="text/css">
|
|
</head>
|
|
|
|
<body>
|
|
|
|
<!-- header +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ -->
|
|
|
|
<div class=header>
|
|
<hr>
|
|
<center>
|
|
<table summary="LuaSocket logo">
|
|
<tr><td align=center><a href="http://www.lua.org">
|
|
<img width=128 height=128 border=0 alt="LuaSocket" src="luasocket.png">
|
|
</a></td></tr>
|
|
<tr><td align=center valign=top>Network support for the Lua language
|
|
</td></tr>
|
|
</table>
|
|
<p class=bar>
|
|
<a href="index.html">home</a> ·
|
|
<a href="index.html#download">download</a> ·
|
|
<a href="installation.html">installation</a> ·
|
|
<a href="introduction.html">introduction</a> ·
|
|
<a href="reference.html">reference</a>
|
|
</p>
|
|
</center>
|
|
<hr>
|
|
</div>
|
|
|
|
<!-- socket +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ -->
|
|
|
|
<h2 id=socket>The socket namespace</h2>
|
|
|
|
<p>
|
|
The <tt>socket</tt> namespace contains the core functionality of LuaSocket.
|
|
</p>
|
|
|
|
<p>
|
|
To obtain the <tt>socket</tt> namespace, run:
|
|
</p>
|
|
|
|
<pre class=example>
|
|
-- loads the socket module
|
|
local socket = require("socket")
|
|
</pre>
|
|
|
|
<!-- headers.canonic ++++++++++++++++++++++++++++++++++++++++++++++++++++++ -->
|
|
|
|
<p class=name id="headers.canonic">
|
|
socket.headers.<b>canonic</b></p>
|
|
|
|
<p> The <tt>socket.headers.canonic</tt> table
|
|
is used by the HTTP and SMTP modules to translate from
|
|
lowercase field names back into their canonic
|
|
capitalization. When a lowercase field name exists as a key
|
|
in this table, the associated value is substituted in
|
|
whenever the field name is sent out.
|
|
</p>
|
|
|
|
<p>
|
|
You can obtain the <tt>headers</tt> namespace if case run-time
|
|
modifications are required by running:
|
|
</p>
|
|
|
|
<pre class=example>
|
|
-- loads the headers module
|
|
local headers = require("headers")
|
|
</pre>
|
|
|
|
|
|
<!-- bind ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ -->
|
|
|
|
<p class=name id=bind>
|
|
socket.<b>bind(</b>address, port [, backlog]<b>)</b>
|
|
</p>
|
|
|
|
<p class=description>
|
|
This function is a shortcut that creates and returns a TCP server object
|
|
bound to a local <tt>address</tt> and <tt>port</tt>, ready to
|
|
accept client connections. Optionally,
|
|
user can also specify the <tt>backlog</tt> argument to the
|
|
<a href=tcp.html#listen><tt>listen</tt></a> method (defaults to 32).
|
|
</p>
|
|
|
|
<p class=note>
|
|
Note: The server object returned will have the option "<tt>reuseaddr</tt>"
|
|
set to <tt><b>true</b></tt>.
|
|
</p>
|
|
|
|
<!-- connect ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ -->
|
|
|
|
<p class=name id=connect>
|
|
socket.<b>connect[46](</b>address, port [, locaddr] [, locport] [, family]<b>)</b>
|
|
</p>
|
|
|
|
<p class=description>
|
|
This function is a shortcut that creates and returns a TCP client object
|
|
connected to a remote <tt>address</tt> at a given <tt>port</tt>. Optionally,
|
|
the user can also specify the local address and port to bind
|
|
(<tt>locaddr</tt> and <tt>locport</tt>), or restrict the socket family
|
|
to "<tt>inet</tt>" or "<tt>inet6</tt>".
|
|
Without specifying <tt>family</tt> to <tt>connect</tt>, whether a tcp or tcp6
|
|
connection is created depends on your system configuration. Two variations
|
|
of connect are defined as simple helper functions that restrict the
|
|
<tt>family</tt>, <tt>socket.connect4</tt> and <tt>socket.connect6</tt>.
|
|
</p>
|
|
|
|
<!-- debug ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ -->
|
|
|
|
<p class=name id=debug>
|
|
socket.<b>_DEBUG</b>
|
|
</p>
|
|
|
|
<p class=description>
|
|
This constant is set to <tt><b>true</b></tt> if the library was compiled
|
|
with debug support.
|
|
</p>
|
|
|
|
<!-- datagramsize +++++++++++++++++++++++++++++++++++++++++++++++++++++++ -->
|
|
|
|
<p class=name id=debug>
|
|
socket.<b>_DATAGRAMSIZE</b>
|
|
</p>
|
|
|
|
<p class=description>
|
|
Default datagram size used by calls to
|
|
<a href="udp.html#receive"<tt>receive</tt></a> and
|
|
<a href="udp.html#receivefrom"><tt>receivefrom</tt></a>.
|
|
(Unless changed in compile time, the value is 8192.)
|
|
</p>
|
|
|
|
<!-- get time +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ -->
|
|
|
|
<p class=name id=gettime>
|
|
socket.<b>gettime()</b>
|
|
</p>
|
|
|
|
<p class=description>
|
|
Returns the UNIX time in seconds. You should subtract the values returned by this function
|
|
to get meaningful values.
|
|
</p>
|
|
|
|
<pre class=example>
|
|
t = socket.gettime()
|
|
-- do stuff
|
|
print(socket.gettime() - t .. " seconds elapsed")
|
|
</pre>
|
|
|
|
<!-- newtry +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ -->
|
|
|
|
<p class=name id=newtry>
|
|
socket.<b>newtry(</b>finalizer<b>)</b>
|
|
</p>
|
|
|
|
<p class=description>
|
|
Creates and returns a <em>clean</em>
|
|
<a href="#try"><tt>try</tt></a>
|
|
function that allows for cleanup before the exception
|
|
is raised.
|
|
</p>
|
|
|
|
<p class=parameters>
|
|
<tt>Finalizer</tt> is a function that will be called before
|
|
<tt>try</tt> throws the exception.
|
|
</p>
|
|
|
|
<p class=return>
|
|
The function returns your customized <tt>try</tt> function.
|
|
</p>
|
|
|
|
<p class=note>
|
|
Note: This idea saved a <em>lot</em> of work with the
|
|
implementation of protocols in LuaSocket:
|
|
</p>
|
|
|
|
<pre class=example>
|
|
foo = socket.protect(function()
|
|
-- connect somewhere
|
|
local c = socket.try(socket.connect("somewhere", 42))
|
|
-- create a try function that closes 'c' on error
|
|
local try = socket.newtry(function() c:close() end)
|
|
-- do everything reassured c will be closed
|
|
try(c:send("hello there?\r\n"))
|
|
local answer = try(c:receive())
|
|
...
|
|
try(c:send("good bye\r\n"))
|
|
c:close()
|
|
end)
|
|
</pre>
|
|
|
|
|
|
<!-- protect +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ -->
|
|
|
|
<p class=name id=protect>
|
|
socket.<b>protect(</b>func<b>)</b>
|
|
</p>
|
|
|
|
<p class=description>
|
|
Converts a function that throws exceptions into a safe function. This
|
|
function only catches exceptions thrown by the <a href=#try><tt>try</tt></a>
|
|
and <a href=#newtry><tt>newtry</tt></a> functions. It does not catch normal
|
|
Lua errors.
|
|
</p>
|
|
|
|
<p class=parameters>
|
|
<tt>Func</tt> is a function that calls
|
|
<a href=#try><tt>try</tt></a> (or <tt>assert</tt>, or <tt>error</tt>)
|
|
to throw exceptions.
|
|
</p>
|
|
|
|
<p class=return>
|
|
Returns an equivalent function that instead of throwing exceptions in case of
|
|
a failed <a href=#try><tt>try</tt></a> call, returns <tt><b>nil</b></tt>
|
|
followed by an error message.
|
|
</p>
|
|
|
|
<!-- select +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ -->
|
|
|
|
<p class=name id=select>
|
|
socket.<b>select(</b>recvt, sendt [, timeout]<b>)</b>
|
|
</p>
|
|
|
|
<p class=description>
|
|
Waits for a number of sockets to change status.
|
|
</p>
|
|
|
|
<p class=parameters>
|
|
<tt>Recvt</tt> is an array with the sockets to test for characters
|
|
available for reading. Sockets in the <tt>sendt</tt> array are watched to
|
|
see if it is OK to immediately write on them. <tt>Timeout</tt> is the
|
|
maximum amount of time (in seconds) to wait for a change in status. A
|
|
<tt><b>nil</b></tt>, negative or omitted <tt>timeout</tt> value allows the
|
|
function to block indefinitely. <tt>Recvt</tt> and <tt>sendt</tt> can also
|
|
be empty tables or <tt><b>nil</b></tt>. Non-socket values (or values with
|
|
non-numeric indices) in the arrays will be silently ignored.
|
|
</p>
|
|
|
|
<p class=return> The function returns a list with the sockets ready for
|
|
reading, a list with the sockets ready for writing and an error message.
|
|
The error message is "<tt>timeout</tt>" if a timeout
|
|
condition was met, "<tt>select failed</tt>" if the call
|
|
to <tt>select</tt> failed, and
|
|
<tt><b>nil</b></tt> otherwise. The returned tables are
|
|
doubly keyed both by integers and also by the sockets
|
|
themselves, to simplify the test if a specific socket has
|
|
changed status.
|
|
</p>
|
|
|
|
<p class=note>
|
|
<b>Note:</b> <tt>select</tt> can monitor a limited number
|
|
of sockets, as defined by the constant <tt>socket._SETSIZE</tt>. This
|
|
number may be as high as 1024 or as low as 64 by default,
|
|
depending on the system. It is usually possible to change this
|
|
at compile time. Invoking <tt>select</tt> with a larger
|
|
number of sockets will raise an error.
|
|
</p>
|
|
|
|
<p class=note>
|
|
<b>Important note</b>: a known bug in WinSock causes <tt>select</tt> to fail
|
|
on non-blocking TCP sockets. The function may return a socket as
|
|
writable even though the socket is <em>not</em> ready for sending.
|
|
</p>
|
|
|
|
<p class=note>
|
|
<b>Another important note</b>: calling select with a server socket in the receive parameter before a call to accept does <em>not</em> guarantee
|
|
<a href=tcp.html#accept><tt>accept</tt></a> will return immediately.
|
|
Use the <a href=tcp.html#settimeout><tt>settimeout</tt></a>
|
|
method or <tt>accept</tt> might block forever.
|
|
</p>
|
|
|
|
<p class=note>
|
|
<b>Yet another note</b>: If you close a socket and pass
|
|
it to <tt>select</tt>, it will be ignored.
|
|
</p>
|
|
|
|
<p class=note>
|
|
<b>Using select with non-socket objects</b>: Any object that implements <tt>getfd</tt> and <tt>dirty</tt> can be used with <tt>select</tt>, allowing objects from other libraries to be used within a <tt>socket.select</tt> driven loop.
|
|
</p>
|
|
|
|
<!-- setsize ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ -->
|
|
|
|
<p class=name id=setsize>
|
|
socket.<b>_SETSIZE</b>
|
|
</p>
|
|
|
|
<p class=description>
|
|
The maximum number of sockets that the <a
|
|
href=#select><tt>select</tt></a> function can handle.
|
|
</p>
|
|
|
|
|
|
<!-- sink ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ -->
|
|
|
|
<p class=name id=sink>
|
|
socket.<b>sink(</b>mode, socket<b>)</b>
|
|
</p>
|
|
|
|
<p class=description>
|
|
Creates an
|
|
<a href="http://lua-users.org/wiki/FiltersSourcesAndSinks">LTN12</a>
|
|
sink from a stream socket object.
|
|
</p>
|
|
|
|
<p class=parameters>
|
|
<tt>Mode</tt> defines the behavior of the sink. The following
|
|
options are available:
|
|
</p>
|
|
<ul>
|
|
<li> <tt>"http-chunked"</tt>: sends data through socket after applying the
|
|
<em>chunked transfer coding</em>, closing the socket when done;
|
|
<li> <tt>"close-when-done"</tt>: sends all received data through the
|
|
socket, closing the socket when done;
|
|
<li> <tt>"keep-open"</tt>: sends all received data through the
|
|
socket, leaving it open when done.
|
|
</ul>
|
|
<p>
|
|
<tt>Socket</tt> is the stream socket object used to send the data.
|
|
</p>
|
|
|
|
<p class=return>
|
|
The function returns a sink with the appropriate behavior.
|
|
</p>
|
|
|
|
<!-- skip ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ -->
|
|
|
|
<p class=name id=skip>
|
|
socket.<b>skip(</b>d [, ret<sub>1</sub>, ret<sub>2</sub> ... ret<sub>N</sub>]<b>)</b>
|
|
</p>
|
|
|
|
<p class=description>
|
|
Drops a number of arguments and returns the remaining.
|
|
</p>
|
|
|
|
<p class=parameters>
|
|
<tt>D</tt> is the number of arguments to drop. <tt>Ret<sub>1</sub></tt> to
|
|
<tt>ret<sub>N</sub></tt> are the arguments.
|
|
</p>
|
|
|
|
<p class=return>
|
|
The function returns <tt>ret<sub>d+1</sub></tt> to <tt>ret<sub>N</sub></tt>.
|
|
</p>
|
|
|
|
<p class=note>
|
|
Note: This function is useful to avoid creation of dummy variables:
|
|
</p>
|
|
|
|
<pre class=example>
|
|
-- get the status code and separator from SMTP server reply
|
|
local code, sep = socket.skip(2, string.find(line, "^(%d%d%d)(.?)"))
|
|
</pre>
|
|
|
|
<!-- sleep ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ -->
|
|
|
|
<p class=name id=sleep>
|
|
socket.<b>sleep(</b>time<b>)</b>
|
|
</p>
|
|
|
|
<p class=description>
|
|
Freezes the program execution during a given amount of time.
|
|
</p>
|
|
|
|
<p class=parameters>
|
|
<tt>Time</tt> is the number of seconds to sleep for. If
|
|
<tt>time</tt> is negative, the function returns immediately.
|
|
</p>
|
|
|
|
<!-- source +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ -->
|
|
|
|
<p class=name id=source>
|
|
socket.<b>source(</b>mode, socket [, length]<b>)</b>
|
|
</p>
|
|
|
|
<p class=description>
|
|
Creates an
|
|
<a href="http://lua-users.org/wiki/FiltersSourcesAndSinks">LTN12</a>
|
|
source from a stream socket object.
|
|
</p>
|
|
|
|
<p class=parameters>
|
|
<tt>Mode</tt> defines the behavior of the source. The following
|
|
options are available:
|
|
</p>
|
|
<ul>
|
|
<li> <tt>"http-chunked"</tt>: receives data from socket and removes the
|
|
<em>chunked transfer coding</em> before returning the data;
|
|
<li> <tt>"by-length"</tt>: receives a fixed number of bytes from the
|
|
socket. This mode requires the extra argument <tt>length</tt>;
|
|
<li> <tt>"until-closed"</tt>: receives data from a socket until the other
|
|
side closes the connection.
|
|
</ul>
|
|
<p>
|
|
<tt>Socket</tt> is the stream socket object used to receive the data.
|
|
</p>
|
|
|
|
<p class=return>
|
|
The function returns a source with the appropriate behavior.
|
|
</p>
|
|
|
|
<!-- socketinvalid ++++++++++++++++++++++++++++++++++++++++++++++++++++++ -->
|
|
|
|
<p class=name id=socketinvalid>
|
|
socket.<b>_SOCKETINVALID</b>
|
|
</p>
|
|
|
|
<p class=description>
|
|
The OS value for an invalid socket.
|
|
</p>
|
|
|
|
<!-- try ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ -->
|
|
|
|
<p class=name id=try>
|
|
socket.<b>try(</b>ret<sub>1</sub> [, ret<sub>2</sub> ... ret<sub>N</sub>]<b>)</b>
|
|
</p>
|
|
|
|
<p class=description>
|
|
Throws an exception in case <tt>ret<sub>1</sub></tt> is falsy, using
|
|
<tt>ret<sub>2</sub></tt> as the error message. The exception is supposed to be caught
|
|
by a <a href=#protect><tt>protect</tt></a>ed function only.
|
|
</p>
|
|
|
|
<p class=parameters>
|
|
<tt>Ret<sub>1</sub></tt> to <tt>ret<sub>N</sub></tt> can be arbitrary
|
|
arguments, but are usually the return values of a function call
|
|
nested with <tt>try</tt>.
|
|
</p>
|
|
|
|
<p class=return>
|
|
The function returns <tt>ret</tt><sub>1</sub> to <tt>ret</tt><sub>N</sub> if
|
|
<tt>ret</tt><sub>1</sub> is not <tt><b>nil</b></tt> or <tt><b>false</b></tt>.
|
|
Otherwise, it calls <tt>error</tt> passing <tt>ret</tt><sub>2</sub> wrapped
|
|
in a table with metatable used by <a href=#protect><tt>protect</tt></a> to
|
|
distinguish exceptions from runtime errors.
|
|
</p>
|
|
|
|
<pre class=example>
|
|
-- connects or throws an exception with the appropriate error message
|
|
c = socket.try(socket.connect("localhost", 80))
|
|
</pre>
|
|
|
|
<!-- version ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ -->
|
|
|
|
<p class=name id=version>
|
|
socket.<b>_VERSION</b>
|
|
</p>
|
|
|
|
<p class=description>
|
|
This constant has a string describing the current LuaSocket version.
|
|
</p>
|
|
|
|
<!-- footer +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ -->
|
|
|
|
<div class=footer>
|
|
<hr>
|
|
<center>
|
|
<p class=bar>
|
|
<a href="index.html">home</a> ·
|
|
<a href="index.html#down">download</a> ·
|
|
<a href="installation.html">installation</a> ·
|
|
<a href="introduction.html">introduction</a> ·
|
|
<a href="reference.html">reference</a>
|
|
</p>
|
|
<p>
|
|
<small>
|
|
Last modified by Diego Nehab on <br>
|
|
Thu Apr 20 00:25:54 EDT 2006
|
|
</small>
|
|
</p>
|
|
</center>
|
|
</div>
|
|
|
|
</body>
|
|
</html>
|