luasocket/doc/url.html
Diego Nehab 58096449c6 Manual is almost done. HTTP is missing.
Implemented new distribution scheme.
Select is now purely C.
HTTP reimplemented seems faster dunno why.
LTN12 functions that coroutines fail gracefully.
2004-06-15 06:24:00 +00:00

316 lines
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
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<html>
<head>
<title>LuaSocket: Network support for the Lua language</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 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="home.html">home</a> &middot;
<a href="home.html#download">download</a> &middot;
<a href="introduction.html">introduction</a> &middot;
<a href="reference.html">reference</a>
</p>
</center>
<hr>
</div>
<!-- url ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ -->
<h2 id=url>URL</h2>
<p>
The module <tt>url.lua</tt> provides functions to parse, protect,
and build URLs, as well as functions to compose absolute URLs
from base and relative URLs, according to
<a href="http://www.cs.princeton.edu/~diego/rfc/rfc2396.txt">RFC
2396</a>.
</p>
<p>
An URL is defined by the following grammar:
</p>
<blockquote>
<tt>
&lt;url&gt; ::= [&lt;scheme&gt;:][//&lt;authority&gt;][/&lt;path&gt;][;&lt;params&gt;][?&lt;query&gt;][#&lt;fragment&gt;]<br>
&lt;authority&gt; ::= [&lt;userinfo&gt;@]&lt;host&gt;[:&lt;port&gt;]<br>
&lt;userinfo&gt; ::= &lt;user&gt;[:&lt;password&gt;]<br>
&lt;path&gt; ::= {&lt;segment&gt;/}&lt;segment&gt;<br>
</tt>
</blockquote>
<!-- absolute +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ -->
<p class=name id=absolute>
url.<b>absolute(</b>base, relative<b>)</b>
</p>
<p class=description>
Builds an absolute URL from a base URL and a relative URL.
</p>
<p class=parameters>
<tt>Base</tt> is a string with the base URL and <tt>relative</tt> is a
string with the relative URL.
</p>
<p class=return>
The function returns a string with the absolute URL.
</p>
<p class=note>
Note: The rules that
govern the composition are fairly complex, and are described in detail in
<a href="http://www.cs.princeton.edu/~diego/rfc/rfc2396.txt">RFC 2396</a>.
The example bellow should give an idea of what the rules are.
</p>
<pre class=example>
http://a/b/c/d;p?q
+
g:h = g:h
g = http://a/b/c/g
./g = http://a/b/c/g
g/ = http://a/b/c/g/
/g = http://a/g
//g = http://g
?y = http://a/b/c/?y
g?y = http://a/b/c/g?y
#s = http://a/b/c/d;p?q#s
g#s = http://a/b/c/g#s
g?y#s = http://a/b/c/g?y#s
;x = http://a/b/c/;x
g;x = http://a/b/c/g;x
g;x?y#s = http://a/b/c/g;x?y#s
. = http://a/b/c/
./ = http://a/b/c/
.. = http://a/b/
../ = http://a/b/
../g = http://a/b/g
../.. = http://a/
../../ = http://a/
../../g = http://a/g
</pre>
<!-- build ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ -->
<p class=name id=build>
url.<b>build(</b>parsed_url<b>)</b>
</p>
<p class=description>
Rebuilds an URL from its parts.
</p>
<p class=parameters>
<tt>Parsed_url</tt> is a table with same components returned by
<a href="#parse"><tt>parse</tt></a>.
Lower level components, if specified,
take precedence over hight level components of the URL grammar.
</p>
<p class=return>
The function returns a string with the built URL.
</p>
<!-- build_path +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ -->
<p class=name id=build_path>
url.<b>build_path(</b>segments, unsafe<b>)</b>
</p>
<p class=description>
Builds a <tt>&lt;path&gt;</tt> component from a list of
<tt>&lt;segment&gt;</tt> parts.
Before composition, any reserved characters found in a segment are escaped into
their protected form, so that the resulting path is a valid URL path
component.
</p>
<p class=parameters>
<tt>Segments</tt> is a list of strings with the <tt>&lt;segment&gt;</tt>
parts. If <tt>unsafe</tt> is anything but <b><tt>nil</tt></b>, reserved
characters are left untouched.
</p>
<p class=return>
The function returns a string with the
built <tt>&lt;path&gt;</tt> component.
</p>
<!-- escape +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ -->
<p class=name id="escape">
url.<b>escape(</b>content<b>)</b>
</p>
<p class=description>
Applies the URL escaping content coding to a string
Each byte is encoded as a percent character followed
by the two byte hexadecimal representation of its integer
value.
</p>
<p class=parameters>
<tt>Content</tt> is the string to be encoded.
</p>
<p class=result>
The function returns the encoded string.
</p>
<pre class=example>
-- load url module
url = require("url")
code = url.escape("/#?;")
-- code = "%2f%23%3f%3b"
</pre>
<!-- parse ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ -->
<p class=name id=parse>
url.<b>parse(</b>url, default<b>)</b>
</p>
<p class=description>
Parses an URL given as a string into a Lua table with its components.
</p>
<p class=parameters>
<tt>Url</tt> is the URL to be parsed. If the <tt>default</tt> table is
present, it is used to store the parsed fields. Only fields present in the
URL are overwritten. Therefore, this table can be used to pass default
values for each field.
</p>
<p class=return>
The function returns a table with all the URL components:
</p>
<blockquote><tt>
parsed_url = {<br>
&nbsp;&nbsp;url = <i>string</i>,<br>
&nbsp;&nbsp;scheme = <i>string</i>,<br>
&nbsp;&nbsp;authority = <i>string</i>,<br>
&nbsp;&nbsp;path = <i>string</i>,<br>
&nbsp;&nbsp;params = <i>string</i>,<br>
&nbsp;&nbsp;query = <i>string</i>,<br>
&nbsp;&nbsp;fragment = <i>string</i>,<br>
&nbsp;&nbsp;userinfo = <i>string</i>,<br>
&nbsp;&nbsp;host = <i>string</i>,<br>
&nbsp;&nbsp;port = <i>string</i>,<br>
&nbsp;&nbsp;user = <i>string</i>,<br>
&nbsp;&nbsp;password = <i>string</i><br>
}
</tt></blockquote>
<pre class=example>
-- load url module
url = require("url")
parsed_url = url.parse("http://www.puc-rio.br/~diego/index.lua?a=2#there")
-- parsed_url = {
-- scheme = "http",
-- authority = "www.puc-rio.br",
-- path = "/~diego/index.lua"
-- query = "a=2",
-- fragment = "there",
-- host = "www.puc-rio.br",
-- }
parsed_url = url.parse("ftp://root:passwd@unsafe.org/pub/virus.exe;type=i")
-- parsed_url = {
-- scheme = "ftp",
-- authority = "root:passwd@unsafe.org",
-- path = "/pub/virus.exe",
-- params = "type=i",
-- userinfo = "root:passwd",
-- host = "unsafe.org",
-- user = "root",
-- password = "passwd",
-- }
</pre>
<!-- parse_path +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ -->
<p class=name id=parse_path>
url.<b>parse_path(</b>path<b>)</b>
</p>
<p class=description>
Breaks a <tt>&lt;path&gt;</tt> URL component into all its
<tt>&lt;segment&gt;</tt> parts.
</p>
<p class=description>
<tt>Path</tt> is a string with the path to be parsed.
</p>
<p class=return>
Since some characters are reserved in URLs, they must be escaped
whenever present in a <tt>&lt;path&gt;</tt> component. Therefore, before
returning a list with all the parsed segments, the function unescapes all
of them.
</p>
<!-- unescape +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ -->
<p class=name id="unescape">
url.<b>unescape(</b>content<b>)</b>
</p>
<p class=description>
Removes the URL escaping content coding from a string.
</p>
<p class=parameters>
<tt>Content</tt> is the string to be decoded.
</p>
<p class=return>
The function returns the decoded string.
</p>
<!-- footer +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ -->
<div class=footer>
<hr>
<center>
<p class=bar>
<a href="home.html">home</a> &middot;
<a href="home.html#down">download</a> &middot;
<a href="introduction.html">introduction</a> &middot;
<a href="reference.html">reference</a>
</p>
<p>
<small>
Last modified by Diego Nehab on <br>
Sat Aug 9 01:00:41 PDT 2003
</small>
</p>
</center>
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