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<tr><td align=center valign=top>Network support for the Lua language
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The <tt>url</tt> namespace 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.ietf.org/rfc/rfc2396.txt">RFC 2396</a>.

To obtain the <tt>url</tt> namespace, run:

<pre class=example>
-- loads the URL module 
local url = require("socket.url")
</pre>

An URL is defined by the following grammar:

<blockquote>
<tt>
&lt;url&gt; ::= [&lt;scheme&gt;:][//&lt;authority&gt;][/&lt;path&gt;][;&lt;params&gt;][?&lt;query&gt;][#&lt;fragment&gt;] 
&lt;authority&gt; ::= [&lt;userinfo&gt;@]&lt;host&gt;[:&lt;port&gt;] 
&lt;userinfo&gt; ::= &lt;user&gt;[:&lt;password&gt;] 
&lt;path&gt; ::= {&lt;segment&gt;/}&lt;segment&gt; 
</tt>
</blockquote>

url.absolute(base, relative)

Builds an absolute URL from a base URL and a relative URL.

<tt>Base</tt> is a string with the base URL or
a parsed URL table. <tt>Relative</tt> is a
string with the relative URL.

The function returns a string with the absolute URL.

Note: The rules that
govern the composition are fairly complex, and are described in detail in
<a href="http://www.ietf.org/rfc/rfc2396.txt">RFC 2396</a>.
The example bellow should give an idea of what the rules are.

<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>

url.build(parsed_url)

Rebuilds an URL from its parts.

<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 high level components of the URL grammar.

The function returns a string with the built URL.

url.build_path(segments, unsafe)

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.

<tt>Segments</tt> is a list of strings with the <tt>&lt;segment&gt;</tt>
parts. If <tt>unsafe</tt> is anything but <tt>nil</tt>, reserved
characters are left untouched.

The function returns a string with the 
built <tt>&lt;path&gt;</tt> component.

url.escape(content)

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.

<tt>Content</tt> is the string to be encoded.

The function returns the encoded string.

<pre class=example>
-- load url module
url = require("socket.url")

code = url.escape("/#?;")
-- code = "%2f%23%3f%3b"
</pre>

url.parse(url, default)

Parses an URL given as a string into a Lua table with its components.

<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.

The function returns a table with all the URL components:

<blockquote><tt>
parsed_url = { 
&nbsp;&nbsp;url = string, 
&nbsp;&nbsp;scheme = string, 
&nbsp;&nbsp;authority = string, 
&nbsp;&nbsp;path = string, 
&nbsp;&nbsp;params = string, 
&nbsp;&nbsp;query = string, 
&nbsp;&nbsp;fragment = string, 
&nbsp;&nbsp;userinfo = string, 
&nbsp;&nbsp;host = string, 
&nbsp;&nbsp;port = string, 
&nbsp;&nbsp;user = string, 
&nbsp;&nbsp;password = string 
}
</tt></blockquote>

<pre class=example>
-- load url module
url = require("socket.url")

parsed_url = url.parse("http://www.example.com/cgilua/index.lua?a=2#there")
-- parsed_url = {
--   scheme = "http",
--   authority = "www.example.com",
--   path = "/cgilua/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>

url.parse_path(path)

Breaks a <tt>&lt;path&gt;</tt> URL component into all its 
<tt>&lt;segment&gt;</tt> parts.

<tt>Path</tt> is a string with the path to be parsed.

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 removes
escaping from all of them.

url.unescape(content)

Removes the URL escaping content coding from a string.

<tt>Content</tt> is the string to be decoded.

The function returns the decoded string.

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Last modified by Diego Nehab on 
Thu Apr 20 00:26:05 EDT 2006


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