luasocket/doc/ftp.html

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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"> <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>
<!-- ftp ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ -->
<h2 id=ftp>FTP</h2>
<p>
FTP (File Transfer Protocol) is a protocol used to transfer files
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between hosts. The <tt>ftp</tt> namespace offers thorough support
to FTP, under a simple interface. The implementation conforms to
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<a href="http://www.cs.princeton.edu/~diego/rfc/rfc0959.txt">RFC 959</a>.
</p>
<p>
High level functions are provided supporting the most common operations.
These high level functions are implemented on top of a lower level
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interface. Using the low-level interface, users can easily create their
own functions to access <em>any</em> operation supported by the FTP
protocol. For that, check the implementation.
</p>
<p>
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To really benefit from this module, a good understanding of
<a href="http://lua-users.org/wiki/FiltersSourcesAndSinks">
LTN012, Filters sources and sinks</a> is necessary.
</p>
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<p class=description> To obtain the <tt>ftp</tt> namespace, run:
</p>
<pre class=example>
-- loads the FTP module and any libraries it requires
local ftp = require("ftp")
</pre>
<p>
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URLs MUST conform to
<a href="http://www.cs.princeton.edu/~diego/rfc/rfc1738.txt">RFC
1738</a>, that is, an URL is a string in the form:
</p>
<blockquote>
<tt>
[ftp://][&lt;user&gt;[:&lt;password&gt;]@]&lt;host&gt;[:&lt;port&gt;][/&lt;path&gt;][<i>type</i>=a|i]</tt>
</blockquote>
<p>
The following constants in the namespace can be set to control the default behavior of
the FTP module:
</p>
<ul>
<li> <tt>PASSWORD</tt>: default anonymous password.
<li> <tt>PORT</tt>: default port used for the control connection;
<li> <tt>TIMEOUT</tt>: sets the timeout for all I/O operations;
<li> <tt>USER</tt>: default anonymous user;
</ul>
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<!-- ftp.get ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ -->
<p class=name id=get>
ftp.<b>get(</b>url<b>)</b><br>
ftp.<b>get{</b><br>
&nbsp;&nbsp;host = <i>string</i>,<br>
&nbsp;&nbsp;sink = <i>LTN12 sink</i>,<br>
&nbsp;&nbsp;argument <i>or</i> path = <i>string</i>,<br>
&nbsp;&nbsp;[user = <i>string</i>,]<br>
&nbsp;&nbsp;[password = <i>string</i>]<br>
&nbsp;&nbsp;[command = <i>string</i>,]<br>
&nbsp;&nbsp;[port = <i>number</i>,]<br>
&nbsp;&nbsp;[type = <i>string</i>,]<br>
&nbsp;&nbsp;[step = <i>LTN12 pump step</i>],<br>
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<b>}</b>
</p>
<p class=description>
The <tt>get</tt> function has two forms. The simple form has fixed
functionality: it downloads the contents of a URL and returns it as a
string. The generic form allows a <em>lot</em> more control, as explained
below.
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</p>
<p class=parameters>
If the argument of the <tt>get</tt> function is a table, the function
expects at least the fields <tt>host</tt>, <tt>sink</tt>, and one of
<tt>argument</tt> or <tt>path</tt> (<tt>argument</tt> takes
precedence). <tt>Host</tt> is the server to connect to. <tt>Sink</tt> is
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the <em>simple</em> LTN12 sink that will receive the downloaded data. <tt>Argument</tt> or
<tt>path</tt> give the target path to the resource in the server. The
optional arguments are the following:
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</p>
<ul>
<li><tt>user</tt>, <tt>password</tt>: User name and password used for
authentication. Defaults to "<tt>ftp:anonymous@anonymous.org</tt>";
<li><tt>command</tt>: The FTP command used to obtain data. Defaults to
"<tt>retr</tt>", but see example below;
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<li><tt>port</tt>: The port to used for the control connection. Defaults to 21;
<li><tt>type</tt>: The transfer mode. Can take values "<tt>i</tt>" or
"<tt>a</tt>". Defaults to whatever is the server default;
<li><tt>step</tt>: LTN12 pump step function used to pass data from the
server to the sink. Defaults to the LTN12 <tt>pump.step</tt> function.
</ul>
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<p class=return>
If successful, the simple version returns the URL contents as a
string, and the generic function returns 1. In case of error, both
functions return <b><tt>nil</tt></b> and an error message describing the
error.
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</p>
<pre class=example>
-- load the ftp support
local ftp = require("ftp")
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-- Log as user "anonymous" on server "ftp.tecgraf.puc-rio.br",
-- and get file "lua.tar.gz" from directory "pub/lua" as binary.
f, e = ftp.get("ftp://ftp.tecgraf.puc-rio.br/pub/lua/lua.tar.gz;type=i")
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</pre>
<pre class=example>
-- load needed modules
local ftp = require("ftp")
local ltn12 = require("ltn12")
local url = require("url")
-- a function that returns a directory listing
function ls(u)
local t = {}
local p = url.parse(u)
p.command = "nlst"
p.sink = ltn12.sink.table(t)
local r, e = ftp.get(p)
return r and table.concat(t), e
end
</pre>
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<!-- put ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ -->
<p class=name id=put>
ftp.<b>put(</b>url, content<b>)</b><br>
ftp.<b>put{</b><br>
&nbsp;&nbsp;host = <i>string</i>,<br>
&nbsp;&nbsp;source = <i>LTN12 sink</i>,<br>
&nbsp;&nbsp;argument <i>or</i> path = <i>string</i>,<br>
&nbsp;&nbsp;[user = <i>string</i>,]<br>
&nbsp;&nbsp;[password = <i>string</i>]<br>
&nbsp;&nbsp;[command = <i>string</i>,]<br>
&nbsp;&nbsp;[port = <i>number</i>,]<br>
&nbsp;&nbsp;[type = <i>string</i>,]<br>
&nbsp;&nbsp;[step = <i>LTN12 pump step</i>],<br>
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<b>}</b>
</p>
<p class=description>
The <tt>put</tt> function has two forms. The simple form has fixed
functionality: it uploads a string of content into a URL. The generic form
allows a <em>lot</em> more control, as explained below.
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</p>
<p class=parameters>
If the argument of the <tt>put</tt> function is a table, the function
expects at least the fields <tt>host</tt>, <tt>source</tt>, and one of
<tt>argument</tt> or <tt>path</tt> (<tt>argument</tt> takes
precedence). <tt>Host</tt> is the server to connect to. <tt>Source</tt> is
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the <em>simple</em> LTN12 source that will provide the contents to be uploaded.
<tt>Argument</tt> or
<tt>path</tt> give the target path to the resource in the server. The
optional arguments are the following:
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</p>
<ul>
<li><tt>user</tt>, <tt>password</tt>: User name and password used for
authentication. Defaults to "<tt>ftp:anonymous@anonymous.org</tt>";
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<li><tt>command</tt>: The FTP command used to send data. Defaults to
"<tt>stor</tt>", but see example below;
<li><tt>port</tt>: The port to used for the control connection. Defaults to 21;
<li><tt>type</tt>: The transfer mode. Can take values "<tt>i</tt>" or
"<tt>a</tt>". Defaults to whatever is the server default;
<li><tt>step</tt>: LTN12 pump step function used to pass data from the
server to the sink. Defaults to the LTN12 <tt>pump.step</tt> function.
</ul>
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<p class=return>
Both functions return 1 if successful, or <b><tt>nil</tt></b> and an error
message describing the reason for failure.
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</p>
<pre class=example>
-- load the ftp support
local ftp = require("ftp")
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-- Log as user "diego" on server "ftp.tecgraf.puc-rio.br",
-- using password "nehab", and store a file "README" with contents
-- "wrong password, of course"
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f, e = ftp.put("ftp://diego:nehab@ftp.tecgraf.puc-rio.br/README",
"wrong password, of course")
</pre>
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<pre class=example>
-- load the ftp support
local ftp = require("ftp")
local ltn12 = require("ltn12")
-- Log as user "diego" on server "ftp.tecgraf.puc-rio.br",
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-- using password "nehab", and append to the remote file "LOG", sending the
-- contents of the local file "LOCAL-LOG"
f, e = ftp.put{
host = "ftp.tecgraf.puc-rio.br",
user = "diego",
password = "nehab",
command = "appe",
argument = "LOG",
source = ltn12.source.file(io.open("LOCAL-LOG", "r"))
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}
</pre>
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<!-- footer +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ -->
<div class=footer>
<hr>
<center>
<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>
<p>
<small>
Last modified by Diego Nehab on <br>
Sat Aug 9 01:00:41 PDT 2003
</small>
</p>
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