lua.html.en revision d374d0c14a2cf6582e3c9825a9b0acba0d7c736a
<?xml version="1.0" encoding="ISO-8859-1"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
This file is generated from xml source: DO NOT EDIT
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
-->
<title>Creating hooks and scripts with mod_lua - Apache HTTP Server</title>
<link href="/style/css/manual.css" rel="stylesheet" media="all" type="text/css" title="Main stylesheet" />
<link href="/style/css/manual-loose-100pc.css" rel="alternate stylesheet" media="all" type="text/css" title="No Sidebar - Default font size" />
<link href="/style/css/manual-print.css" rel="stylesheet" media="print" type="text/css" /><link rel="stylesheet" type="text/css" href="/style/css/prettify.css" />
</script>
<body id="manual-page"><div id="page-header">
<p class="menu"><a href="/mod/">Modules</a> | <a href="/mod/directives.html">Directives</a> | <a href="http://wiki.apache.org/httpd/FAQ">FAQ</a> | <a href="/glossary.html">Glossary</a> | <a href="/sitemap.html">Sitemap</a></p>
<p class="apache">Apache HTTP Server Version 2.5</p>
<div id="path">
<a href="http://www.apache.org/">Apache</a> > <a href="http://httpd.apache.org/">HTTP Server</a> > <a href="http://httpd.apache.org/docs/">Documentation</a> > <a href="../">Version 2.5</a> > <a href="./">Developer</a></div><div id="page-content"><div id="preamble"><h1>Creating hooks and scripts with mod_lua</h1>
<div class="toplang">
<p><span>Available Languages: </span><a href="/en/developer/lua.html" title="English"> en </a></p>
</div>
<p>This document expands on the <code class="module"><a href="/mod/mod_lua.html">mod_lua</a></code> documentation and explores
additional ways of using mod_lua for writing hooks and scripts.</p>
</div>
<div id="quickview"><ul id="toc"><li><img alt="" src="/images/down.gif" /> <a href="#introduction">Introduction</a></li>
<li><img alt="" src="/images/down.gif" /> <a href="#enabling">Optimizing mod_lua for production servers</a></li>
<li><img alt="" src="/images/down.gif" /> <a href="#basic_remap">Example 1: A basic remapping module</a></li>
<li><img alt="" src="/images/down.gif" /> <a href="#mass_vhost">Example 2: Mass virtual hosting</a></li>
<li><img alt="" src="/images/down.gif" /> <a href="#basic_auth">Example 3: A basic authorization hook</a></li>
<li><img alt="" src="/images/down.gif" /> <a href="#authz">Example 4: Authorization using LuaAuthzProvider</a></li>
<li><img alt="" src="/images/down.gif" /> <a href="#map_handler">Example 5: Overlays using LuaMapHandler</a></li>
<li><img alt="" src="/images/down.gif" /> <a href="#mod_status_lua">Example 6: Basic Lua scripts</a></li>
<li><img alt="" src="/images/down.gif" /> <a href="#String_manipulation">HTTPd bindings: String manipulation</a></li>
<li><img alt="" src="/images/down.gif" /> <a href="#Request_handling">HTTPd bindings: Request handling</a></li>
<li><img alt="" src="/images/down.gif" /> <a href="#Parser_functions">HTTPd bindings: Parser functions</a></li>
<li><img alt="" src="/images/down.gif" /> <a href="#Server_settings">HTTPd bindings: Server settings</a></li>
<li><img alt="" src="/images/down.gif" /> <a href="#Database_connectivity">HTTPd bindings: Database connectivity</a></li>
<li><img alt="" src="/images/down.gif" /> <a href="#Miscellaneous">HTTPd bindings: Miscellaneous</a></li>
</ul><h3>See also</h3><ul class="seealso"><li><a href="/mod/mod_lua.html">mod_lua</a></li><li><a href="modguide.html">Developing modules for Apache 2.4</a></li><li><a href="request.html">Request Processing in Apache 2.4</a></li><li><a href="hooks.html">Apache 2.x Hook Functions</a></li></ul><ul class="seealso"><li><a href="#comments_section">Comments</a></li></ul></div>
<div class="section">
<h2><a name="introduction" id="introduction">Introduction</a></h2>
<h3><a name="what" id="what">What is mod_lua</a></h3>
<p>
</p>
<h3><a name="contents" id="contents">What we will be discussing in this document</a></h3>
<p>
This document will discuss several cases where <code class="module"><a href="/mod/mod_lua.html">mod_lua</a></code> can be used
to either ease up a phase of the request processing or create more transparency in
the logic behind a decision made in a phase.
</p>
<h3><a name="prerequisites" id="prerequisites">Prerequisites</a></h3>
<p>
First and foremost, you are expected to have a basic knowledge of how the Lua
programming language works. In most cases, we will try to be as pedagogical
as possible and link to documents describing the functions used in the
examples, but there are also many cases where it is necessary to either
just assume that "it works" or do some digging yourself into what the hows
and whys of various function calls.
</p>
<div class="section">
<h2><a name="enabling" id="enabling">Optimizing mod_lua for production servers</a></h2>
<h3>Setting a scope for Lua states</h3>
<p>
Setting the right <code class="directive"><a href="/mod/mod_lua.html#luascope">LuaScope</a></code> setting
for your Lua scripts can be essential to your server's
performance. By default, the scope is set to <code>once</code>, which means
that every call to a Lua script will spawn a new Lua state that handles that
script and is destroyed immediately after. This option keeps the memory
footprint of mod_lua low, but also affects the processing speed of a request.
If you have the memory to spare, you can set the scope to <code>thread</code>,
which will make mod_lua spawn a Lua state that lasts the entirity of a thread's
lifetime, speeding up request processing by 2-3 times. Since mod_lua will create
a state for each script, this may be an expensive move, memory-wise, so to
compromise between speed and memory usage, you can choose the <code>server</code>
option to create a pool of Lua states to be used. Each request for a Lua script or
a hook function will then acquire a state from the pool and release it back when it's
done using it, allowing you to still gain a significant performance increase, while
keeping your memory footprint low. Some examples of possible settings are:
</p>
<pre class="prettyprint lang-config">
LuaScope once
LuaScope thread
LuaScope server 5 40
</pre>
<p>
As a general rule of thumb: If your server has none to low usage, use <code>once</code>
or <code>request</code>, if your server has low to medium usage, use the <code>server</code>
pool, and if it has high usage, use the <code>thread</code> setting. As your server's
load increases, so will the number of states being actively used, and having your scope
</p>
<p>
<strong>Note:</strong> The <code>min</code> and <code>max</code> settings for the
<code>server</code> scope denotes the minimum and maximum states to keep in a pool per
server <em>process</em>, so keep this below your <code>ThreadsPerChild</code> limit.
</p>
<h3>Using code caching</h3>
<p>
By default, <code class="module"><a href="/mod/mod_lua.html">mod_lua</a></code> stats each Lua script to determine whether a reload
(and thus, a re-interpretation and re-compilation) of a script is required. This is managed
through the <code class="directive"><a href="/mod/mod_lua.html#luacodecache">LuaCodeCache</a></code> directive. If you are running
your scripts on a production server, and you do not need to update them regularly, it may be
advantageous to set this directive to the <code>forever</code> value, which will cause mod_lua
to skip the stat process and always reuse the compiled byte-code from the first access to the
script, thus speeding up the processing. For Lua hooks, this can prove to increase peformance,
while for scripts handled by the <code>lua-script</code> handler, the increase in performance
may be negligible, as files httpd will stat the files regardless.
</p>
<h3>Keeping the scope clean</h3>
<p>
For maximum performance, it is generally recommended that any initialization of libraries,
constants and master tables be kept outside the handle's scope:
</p>
<pre class="prettyprint lang-lua">
--[[ This is good practice ]]--
require "string"
require "someLibrary"
local masterTable = {}
local constant = "Foo bar baz"
function handle(r)
do_stuff()
end
</pre>
<pre class="prettyprint lang-lua">
--[[ This is bad practice ]]--
require "string"
function handle(r)
require "someLibrary"
local masterTable = {}
local constant = "Foo bar baz"
do_stuff()
end
</pre>
<div class="section">
<h2><a name="basic_remap" id="basic_remap">Example 1: A basic remapping module</a></h2>
<p>
These first examples show how mod_lua can be used to rewrite URIs in the same
way that one could do using <code class="directive"><a href="/mod/mod_alias.html#alias">Alias</a></code> or
<code class="directive"><a href="/mod/mod_rewrite.html#rewriterule">RewriteRule</a></code>, but with more clarity
on how the decision-making takes place, as well as allowing for more complex
decisions than would otherwise be allowed with said directives.
</p>
<pre class="prettyprint lang-config">
</pre>
<pre class="prettyprint lang-lua">
--[[
Simple remap example.
]]--
function remap(r)
-- Test if the URI matches our criteria
local barFile = r.uri:match("/foo/([a-zA-Z0-9]+)%.bar")
if barFile then
r.filename = "/internal/" .. barFile
end
return apache2.OK
end
</pre>
<pre class="prettyprint lang-lua">
--[[
Advanced remap example.
This example will evaluate some conditions, and based on that,
remap a file to one of two destinations, using a rewrite map.
This is similar to mixing AliasMatch and ProxyPass, but
without them clashing in any way. Assuming we are on example.com, then:
http://example.com/ext/foo.html will be proxied to http://www.external.com/foo.html
URIs that do not match, will be served by their respective default handlers
]]--
local map = {
photos = {
source = [[^/photos/(.+)\.png$]],
proxy = false
},
externals = {
source = [[^/ext/(.*)$]],
destination = [[http://www.external.com/$1]],
proxy = true
}
}
function interpolateString(s,v)
return s:gsub("%$(%d+)", function(a) return v[tonumber(a)] end)
end
function remap(r)
-- browse through the rewrite map
for key, entry in pairs(map) do
-- Match source regex against URI
if match and match[0] then
r.filename = interpolateString(entry.destination, match)
-- Is this a proxied remap?
if entry.proxy then
r.handler = "proxy-server" -- tell mod_proxy to handle this
r.proxyreq = apache2.PROXYREQ_REVERSE -- We'll want to do a reverse proxy
r.filename = "proxy:" .. r.filename -- Add the proxy scheme to the destination
end
return apache2.OK
end
end
return apache2.DECLINED
end
</pre>
<p>
bla bla
</p>
<div class="section">
<h2><a name="mass_vhost" id="mass_vhost">Example 2: Mass virtual hosting</a></h2>
<p>
As with simple and advanced rewriting, you can use mod_lua for dynamically
assigning a hostname to a specific document root, much like
<code class="module"><a href="/mod/mod_vhost_alias.html">mod_vhost_alias</a></code> does, but with more control over what goes
where. This could be as simple as a table holding the information about which
host goes into which folder, or more advanced, using a database holding the
document roots of each hostname.
</p>
<pre class="prettyprint lang-config">
</pre>
<pre class="prettyprint lang-lua">
--[[
Simple mass vhost script
This example will check a map for a virtual host and rewrite filename and
document root accordingly.
]]--
local vhosts = {
}
function mass_vhost(r)
-- Match against our hostname
for key, entry in pairs(vhosts) do
-- match against either host or *.host:
-- If it matches, rewrite filename and set document root
local filename = r.filename:sub(r.document_root:len()+1)
r.filename = entry.home .. filename
return apache2.OK
end
end
return apache2.DECLINED
end
</pre>
<pre class="prettyprint lang-lua">
--[[
Advanced mass virtual hosting
This example will query a database for vhost entries and save them for
60 seconds before checking for updates. For best performance, such scripts
should generally be run with LuaScope set to 'thread' or 'server'
]]--
local cached_vhosts = {}
local timeout = 60
-- Function for querying the database for saved vhost entries
function query_vhosts(r)
local host = r.hostname
if not cached_vhosts[host] or (cached_vhosts[host] and cached_vhosts[host].updated < os.time() - timeout) then
local db,err = ap.dbopen(r,"mod_dbd")
local _host = db:escape(r,host)
local res, err = db:query(r, ("SELECT `destination` FROM `vhosts` WHERE `hostname` = '%s' LIMIT 1"):format(_host) )
if res and #res == 1 then
cached_vhosts[host] = { updated = os.time(), destination = res[1][1] }
else
cached_vhosts[host] = { updated = os.time(), destination = nil } -- don't re-query whenever there's no result, wait a while.
end
db:close()
end
if cached_vhosts[host] then
return cached_vhosts[host].destination
else
return nil
end
end
function mass_vhost(r)
-- Check whether the hostname is in our database
local destination = query_vhosts(r)
if destination then
-- If found, rewrite and change document root
local filename = r.filename:sub(r.document_root:len()+1)
r.filename = destination .. filename
ap.set_document_root(r,destination)
return apache2.OK
end
return apache2.DECLINED
end
</pre>
<p>
</p>
<div class="section">
<h2><a name="basic_auth" id="basic_auth">Example 3: A basic authorization hook</a></h2>
<p>
With the authorization hooks, you can add custom auth phases to your request
processing, allowing you to either add new requirements that were not previously
supported by httpd, or tweaking existing ones to accommodate your needs.
</p>
<pre class="prettyprint lang-config">
</pre>
<pre class="prettyprint lang-lua">
--[[
A simple authentication hook that checks a table containing usernames and
passwords of two accounts.
]]--
local accounts = {
bob = 'somePassword',
jane = 'Iloveponies'
}
-- Function for parsing the Authorization header into a username and a password
function parse_auth(str)
local user,pass = nil, nil
if str and str:len() > 0 then
str = apache2.base64_decode(auth):sub(7));
user, pass = auth:match("([^:]+)%:([^:]+)")
end
return user, pass
end
-- The authentication hook
function check_auth(r)
local user, pass = parse_auth(r.headers_in['Authorization'])
local authenticated = false
if user and pass then
if accounts[user] and accounts[user] == pass then
authenticated = true
r.user = user
end
end
r.headers_out["WWW-Authenticate"] = 'Basic realm="Super secret zone"'
if not authenticated then
return 401
else
return apache2.OK
end
end
</pre>
<pre class="prettyprint lang-lua">
--[[
An advanced authentication checker with a database backend,
caching account entries for 1 minute
]]--
local timeout = 60 -- Set account info to be refreshed every minute
local accounts = {}
-- Function for parsing the Authorization header into a username and a password
function parse_auth(str)
local user,pass = nil, nil
if str and str:len() > 0 then
str = apache2.base64_decode(auth):sub(7));
user, pass = auth:match("([^:]+)%:([^:]+)")
end
return user, pass
end
-- Function for querying the database for the account's password (stored as a salted SHA-1 hash)
function fetch_password(user)
if not accounts[user] or (accounts[user] and accounts[user].updated < os.time() - timeout) then
local db = apache2.dbopen(r, "mod_dbd")
local usr = db:escape(user)
local res, err = db:query( ("SELECT `password` FROM `accounts` WHERE `user` = '%s' LIMIT 1"):format(usr) )
if res and #res == 1 then
accounts[user] = { updated = os.time(), password = res[1][1] }
else
accounts[user] = nil
end
db:close()
end
if accounts[user] then
return accounts[user].password
else
return nil
end
end
-- The authentication hook
function check_auth(r)
local user, pass = parse_auth(r.headers_in['Authorization'])
local authenticated = false
if user and pass then
pass = apache2.sha1("addSomeSalt" .. pass)
local stored_pass = fetch_password(user)
if stored_pass and pass == stored_pass then
authenticated = true
r.user = user
end
end
r.headers_out["WWW-Authenticate"] = 'Basic realm="Super secret zone"'
if not authenticated then
return 401
else
return apache2.OK
end
end
</pre>
<div class="section">
<h2><a name="authz" id="authz">Example 4: Authorization using LuaAuthzProvider</a></h2>
<p>
If you require even more advanced control over your authorization phases,
you can add custom authz providers to help you manage your server. The
example below shows you how you can split a single htpasswd file into
groups with different permissions:
</p>
<pre class="prettyprint lang-config">
Require rights member
</Directory>
Require rights admin
</Directory>
</pre>
<pre class="prettyprint lang-lua">
--[[
This script has two user groups; members and admins, and whichever
is refered to by the "Require rights" directive is checked to see
if the authenticated user belongs to this group.
]]--
local members = { "rbowen", "humbedooh", "igalic", "covener" }
local admins = { "humbedooh" }
function rights_handler(r, what)
if r.user == nil then
end
if what == "member" then
for k, v in pairs(members) do
if r.user == v then
return apache2.AUTHZ_GRANTED
end
end
elseif what == "admin" then
for k, v in pairs(admins) do
if r.user == v then
return apache2.AUTHZ_GRANTED
end
end
end
return apache2.AUTHZ_DENIED
end
</pre>
<div class="section">
<h2><a name="map_handler" id="map_handler">Example 5: Overlays using LuaMapHandler</a></h2>
<p>
Coming soon!
</p>
<pre class="prettyprint lang-config">
</pre>
<div class="section">
<h2><a name="mod_status_lua" id="mod_status_lua">Example 6: Basic Lua scripts</a></h2>
<p>
Also coming soon
</p>
<div class="section">
<h2><a name="String_manipulation" id="String_manipulation">HTTPd bindings: String manipulation</a></h2>
<p>
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
</p>
request_rec<em> r</em>, string<em> string</em>
)
</a></h3>
<p>
Decodes a base64-encoded string
</p>
<p>
<em>Arguments:</em>
</p>
<table class="bordered">
<tr>
<th>Argument</th>
<th>Description</th>
</tr>
<tr>
<td>r</td>
<td>The mod_lua request handle</td>
</tr>
<tr>
<td>string</td>
<td>The string to decode</td>
</tr>
</table>
<p>
<em>Return value(s):</em>
<br />
The base64-decoded string.
</p>
<p>
<em>Example:</em>
</p>
<pre class="prettyprint lang-lua">
local str = "This is a test"
local encoded = apache2.base64_encode(str)
local decoded = apache2.base64_decode(encoded)
</pre>
<p> </p>
request_rec<em> r</em>, string<em> string</em>
)
</a></h3>
<p>
Encodes a string using the base64 encoding scheme.
</p>
<p>
<em>Arguments:</em>
</p>
<table class="bordered">
<tr>
<th>Argument</th>
<th>Description</th>
</tr>
<tr>
<td>r</td>
<td>The mod_lua request handle</td>
</tr>
<tr>
<td>string</td>
<td>The string to encode</td>
</tr>
</table>
<p>
<em>Example:</em>
</p>
<pre class="prettyprint lang-lua">
local str = "This is a test"
local encoded = apache2.base64_encode(str)
local decoded = apache2.base64_decode(encoded)
</pre>
<p> </p>
request_rec<em> r</em>, string<em> string</em>
)
</a></h3>
<p>
url-escapes a string
</p>
<p>
<em>Arguments:</em>
</p>
<table class="bordered">
<tr>
<th>Argument</th>
<th>Description</th>
</tr>
<tr>
<td>r</td>
<td>The mod_lua request handle</td>
</tr>
<tr>
<td>string</td>
<td>The string to escape</td>
</tr>
</table>
<p>
<em>Return value(s):</em>
<br />
The URL-escaped string.
</p>
<p>
<em>Example:</em>
</p>
<pre class="prettyprint lang-lua">
local str = "This is a test"
local escaped = apache2.escape(str)
print(escaped) -- prints "This+is+a+test"
</pre>
<p> </p>
request_rec<em> r</em>, string<em> path</em>
)
</a></h3>
<p>
Escape a string for logging
</p>
<p>
<em>Arguments:</em>
</p>
<table class="bordered">
<tr>
<th>Argument</th>
<th>Description</th>
</tr>
<tr>
<td>r</td>
<td>The mod_lua request handle</td>
</tr>
<tr>
<td>path</td>
<td>The string to escape</td>
</tr>
</table>
<p>
<em>Return value(s):</em>
<br />
The converted string
</p>
<p> </p>
request_rec<em> r</em>, string<em> html</em>, boolean<em> toasc</em>
)
</a></h3>
<p>
Escapes HTML entities.
</p>
<p>
<em>Arguments:</em>
</p>
<table class="bordered">
<tr>
<th>Argument</th>
<th>Description</th>
</tr>
<tr>
<td>r</td>
<td>The mod_lua request handle</td>
</tr>
<tr>
<td>html</td>
<td>The HTML code to escape</td>
</tr>
<tr>
<td>toasc</td>
<td>Whether to escape all non-ASCI characters as &#nnn;</td>
</tr>
</table>
<p>
<em>Return value(s):</em>
<br />
The escaped HTML code.
</p>
<p>
<em>Example:</em>
</p>
<pre class="prettyprint lang-lua">
local html = "<b>Testing!</b>"
local escaped = apache2.escapehtml(html)
r:puts(escaped) -- prints "&lt;b&gt;Testing!&lt;/b&gt;"
</pre>
<p> </p>
request_rec<em> r</em>, string<em> string</em>
)
</a></h3>
<p>
Computes an MD5 digest sum based on a string (binary safe)
</p>
<p>
<em>Arguments:</em>
</p>
<table class="bordered">
<tr>
<th>Argument</th>
<th>Description</th>
</tr>
<tr>
<td>r</td>
<td>The mod_lua request handle</td>
</tr>
<tr>
<td>string</td>
<td>The (binary) string to digest</td>
</tr>
</table>
<p>
<em>Return value(s):</em>
<br />
The MD5 digest sum of the data provided
</p>
<p>
<em>Example:</em>
</p>
<pre class="prettyprint lang-lua">
local text = "The quick brown fox jumps over the lazy dog"
local md5 = apache2.md51(text)
r:puts(md5) -- prints out "9e107d9d372bb6826bd81d3542a419d6"
</pre>
<p> </p>
request_rec<em> r</em>, string<em> path</em>, boolean<em> partial</em>
)
</a></h3>
<p>
convert an OS path to a URL in an OS dependent way.
</p>
<p>
<em>Arguments:</em>
</p>
<table class="bordered">
<tr>
<th>Argument</th>
<th>Description</th>
</tr>
<tr>
<td>r</td>
<td>The mod_lua request handle</td>
</tr>
<tr>
<td>path</td>
<td>The path to convert</td>
</tr>
<tr>
<td>partial</td>
<td>partial if set, assume that the path will be appended to something with a '/' in it (and thus does not prefix "./")</td>
</tr>
</table>
<p>
<em>Return value(s):</em>
<br />
The converted URL
</p>
<p>
<em>Example:</em>
</p>
<pre class="prettyprint lang-lua">
</pre>
<p> </p>
request_rec<em> r</em>, string<em> string</em>
)
</a></h3>
<p>
Computes an SHA-1 digest sum based on a string (binary safe)
</p>
<p>
<em>Arguments:</em>
</p>
<table class="bordered">
<tr>
<th>Argument</th>
<th>Description</th>
</tr>
<tr>
<td>r</td>
<td>The mod_lua request handle</td>
</tr>
<tr>
<td>string</td>
<td>The (binary) string to digest</td>
</tr>
</table>
<p>
<em>Return value(s):</em>
<br />
The SHA-1 digest sum of the data provided
</p>
<p>
<em>Example:</em>
</p>
<pre class="prettyprint lang-lua">
local text = "The quick brown fox jumps over the lazy dog"
local sha1 = apache2.sha1(text)
r:puts(sha1) -- prints out "2fd4e1c67a2d28fced849ee1bb76e7391b93eb12"
</pre>
<p> </p>
request_rec<em> r</em>, string<em> string</em>
)
</a></h3>
<p>
unescapes an URL-escaped string
</p>
<p>
<em>Arguments:</em>
</p>
<table class="bordered">
<tr>
<th>Argument</th>
<th>Description</th>
</tr>
<tr>
<td>r</td>
<td>The mod_lua request handle</td>
</tr>
<tr>
<td>string</td>
<td>The string to unescape</td>
</tr>
</table>
<p>
<em>Return value(s):</em>
<br />
The URL-unescaped string
</p>
<p>
<em>Example:</em>
</p>
<pre class="prettyprint lang-lua">
local str = "This+is+a+test"
local unescaped = apache2.unescape(str)
print(unescaped) -- prints "This is a test"
</pre>
<p> </p>
<div class="section">
<h2><a name="Request_handling" id="Request_handling">HTTPd bindings: Request handling</a></h2>
<p>
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
</p>
request_rec<em> r</em>, string<em> filter</em>
)
</a></h3>
<p>
Adds an input filter to the request
</p>
<p>
<em>Arguments:</em>
</p>
<table class="bordered">
<tr>
<th>Argument</th>
<th>Description</th>
</tr>
<tr>
<td>r</td>
<td>The mod_lua request handle</td>
</tr>
<tr>
<td>filter</td>
<td>The name of the filter handler to add</td>
</tr>
</table>
<p>
<em>Example:</em>
</p>
<pre class="prettyprint lang-lua">
apache2.add_input_filter(r, "SPAM_FILTER") -- Check input for spam..?
</pre>
<p> </p>
request_rec<em> r</em>
)
</a></h3>
<p>
Returns the password from a basic authorization request or nil if none was supplied
</p>
<p>
<em>Arguments:</em>
</p>
<table class="bordered">
<tr>
<th>Argument</th>
<th>Description</th>
</tr>
<tr>
<td>r</td>
<td>The mod_lua request handle</td>
</tr>
</table>
<p>
<em>Return value(s):</em>
<br />
The password from a basic authorization request or nil if none was supplied
</p>
<p> </p>
<h3><a name="apache2.get_server_name_for_url" id="apache2.get_server_name_for_url">apache2.get_server_name_for_url(
request_rec<em> r</em>
)
</a></h3>
<p>
Get the current server name from the request for the purposes of using in a URL.
If the server name is an IPv6 literal address, it will be returned in URL format (e.g., "[fe80::1]").
</p>
<p>
<em>Arguments:</em>
</p>
<table class="bordered">
<tr>
<th>Argument</th>
<th>Description</th>
</tr>
<tr>
<td>r</td>
<td>The mod_lua request handle</td>
</tr>
</table>
<p> </p>
request_rec<em> r</em>, boolean<em> force_weak</em>
)
</a></h3>
<p>
Constructs an entity tag from the resource information. If it's a real file, build in some of the file characteristics.
</p>
<p>
<em>Arguments:</em>
</p>
<table class="bordered">
<tr>
<th>Argument</th>
<th>Description</th>
</tr>
<tr>
<td>r</td>
<td>The mod_lua request handle</td>
</tr>
<tr>
<td>force_weak</td>
<td>force_weak Force the entity tag to be weak - it could be modified again in as short an interval.</td>
</tr>
</table>
<p>
<em>Return value(s):</em>
<br />
The entity tag
</p>
<p> </p>
request_rec<em> r</em>, number<em> size</em>, string<em> filename</em>
)
</a></h3>
<p>
Reads the request body. If a filename is specified, the request body will be written to that file and the number of bytes written returned, otherwise, the full request body will be returned as a string.
</p>
<p>
<em>Arguments:</em>
</p>
<table class="bordered">
<tr>
<th>Argument</th>
<th>Description</th>
</tr>
<tr>
<td>r</td>
<td>The mod_lua request handle</td>
</tr>
<tr>
<td>size</td>
</tr>
<tr>
<td>filename</td>
<td>The file to save the output to, or nil to return it as a string</td>
</tr>
</table>
<p>
<em>Return value(s):</em>
<br />
The number of bytes written if a filename was specified, otherwise it returns the entire request body as a string.
</p>
<p>
<em>Example:</em>
</p>
<pre class="prettyprint lang-lua">
if tonumber(r.headers_in['Content-Length'] or 0) < 10000 then
local smallfile = apache2.requestbody(r, 10000) -- fetch a small file into memory
r:puts("I saved the uploaded file in memory")
else
r:puts("I saved the uploaded file in a temp directory. Total bytes written was: ", read)
end
</pre>
<p> </p>
<h3><a name="apache2.send_interim_response" id="apache2.send_interim_response">apache2.send_interim_response(
request_rec<em> r</em>, boolean<em> send_headers</em>
)
</a></h3>
<p>
Sends an interim (HTTP 1xx) response immediately.
</p>
<p>
<em>Arguments:</em>
</p>
<table class="bordered">
<tr>
<th>Argument</th>
<th>Description</th>
</tr>
<tr>
<td>r</td>
<td>The mod_lua request handle</td>
</tr>
<tr>
<td>send_headers</td>
<td>send_headers Whether to send&clear headers in r->headers_out</td>
</tr>
</table>
<p>
<em>Example:</em>
</p>
<pre class="prettyprint lang-lua">
apache2.send_interim_response(r, false)
</pre>
<p> </p>
<h3><a name="apache2.set_context_prefix" id="apache2.set_context_prefix">apache2.set_context_prefix(
request_rec<em> r</em>, string<em> prefix</em>, string<em> document</em>
)
</a></h3>
<p>
Set context_prefix and context_document_root for a request.
</p>
<p>
<em>Arguments:</em>
</p>
<table class="bordered">
<tr>
<th>Argument</th>
<th>Description</th>
</tr>
<tr>
<td>r</td>
<td>The mod_lua request handle</td>
</tr>
<tr>
<td>prefix</td>
<td>The URI prefix, without trailing slash</td>
</tr>
<tr>
<td>document</td>
<td>The corresponding directory on disk, without trailing slash</td>
</tr>
</table>
<p> </p>
request_rec<em> r</em>, string<em> root</em>
)
</a></h3>
<p>
Sets the document root of the request.
</p>
<p>
<em>Arguments:</em>
</p>
<table class="bordered">
<tr>
<th>Argument</th>
<th>Description</th>
</tr>
<tr>
<td>r</td>
<td>The mod_lua request handle</td>
</tr>
<tr>
<td>root</td>
<td>root</td>
</tr>
</table>
<p>
<em>Example:</em>
</p>
<pre class="prettyprint lang-lua">
if r.hostname == "www.foo.com" then
end
</pre>
<p> </p>
request_rec<em> r</em>
)
</a></h3>
<p>
Sets the keepalive status for this request
</p>
<p>
<em>Arguments:</em>
</p>
<table class="bordered">
<tr>
<th>Argument</th>
<th>Description</th>
</tr>
<tr>
<td>r</td>
<td>The mod_lua request handle</td>
</tr>
</table>
<p>
<em>Return value(s):</em>
<br />
True if keepalive can be set, false otherwise
</p>
<p> </p>
<div class="section">
<h2><a name="Parser_functions" id="Parser_functions">HTTPd bindings: Parser functions</a></h2>
<p>
<br />
<br />
<br />
</p>
request_rec<em> r</em>, string<em> expression</em>
)
</a></h3>
<p>
Evaluates an ap_expr (think <If ...>) expression and returns true if the expression is true, false otherwise. A second value containing an error string is returned if the expression is invalid.
</p>
<p>
<em>Arguments:</em>
</p>
<table class="bordered">
<tr>
<th>Argument</th>
<th>Description</th>
</tr>
<tr>
<td>r</td>
<td>The mod_lua request handle</td>
</tr>
<tr>
<td>expression</td>
<td>expression</td>
</tr>
</table>
<p>
<em>Return value(s):</em>
<br />
True if the expression evaluates as true, false if the expression doesn't evaluate as true or if an error occurred. If an error occurred during parsing, a second value will be returned, containng the error string.
</p>
<p>
<em>Example:</em>
</p>
<pre class="prettyprint lang-lua">
if apache2.expr("%{REQUEST_URI} =~ /force-gzip") then
r:addoutputfilter("DEFLATE")
end
</pre>
<p> </p>
request_rec<em> r</em>, string<em> expression</em>, string<em> source</em>
)
</a></h3>
<p>
Evaluates a regular expression and, if it matches the source string, captures the variables and returns the matches as a table. On error, it returns nil.
</p>
<p>
<em>Arguments:</em>
</p>
<table class="bordered">
<tr>
<th>Argument</th>
<th>Description</th>
</tr>
<tr>
<td>r</td>
<td>The mod_lua request handle</td>
</tr>
<tr>
<td>expression</td>
<td>expression to match for</td>
</tr>
<tr>
<td>source</td>
<td>the source string to capture from</td>
</tr>
</table>
<p>
<em>Return value(s):</em>
<br />
True if the expression evaluates as true, false if the expression doesn't evaluate as true or if an error occurred. If an error occurred during parsing, a second value will be returned, containng the error string.
</p>
<p>
<em>Example:</em>
</p>
<pre class="prettyprint lang-lua">
local matches = apache2.regex(r, [[(\S+) kitty]], "Hello kitty")
if matches and matches[1] then
r:puts("You said ", matches[1], " to kitty")
end
</pre>
<p> </p>
string<em> str</em>, string<em> expexted</em>, boolean<em> ignoreCase</em>
)
</a></h3>
<p>
Determines if a string matches a pattern containing the wildcards '?' or '*'
</p>
<p>
<em>Arguments:</em>
</p>
<table class="bordered">
<tr>
<th>Argument</th>
<th>Description</th>
</tr>
<tr>
<td>str</td>
<td>The string to check</td>
</tr>
<tr>
<td>expexted</td>
<td>The pattern to match against</td>
</tr>
<tr>
<td>ignoreCase</td>
<td>Whether to ignore case when matching</td>
</tr>
</table>
<p>
<em>Return value(s):</em>
<br />
True if the two strings match, false otherwise.
</p>
<p>
<em>Example:</em>
</p>
<pre class="prettyprint lang-lua">
if apache2.strcmp_match("foo.bar", "foo.*") then
r:puts("It matches!")
end
</pre>
<p> </p>
<div class="section">
<h2><a name="Server_settings" id="Server_settings">HTTPd bindings: Server settings</a></h2>
<p>
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
</p>
<h3><a name="apache2.add_version_component" id="apache2.add_version_component">apache2.add_version_component(
request_rec<em> r</em>, string<em> component</em>
)
</a></h3>
<p>
Adds a component to the server description and banner strings
</p>
<p>
<em>Arguments:</em>
</p>
<table class="bordered">
<tr>
<th>Argument</th>
<th>Description</th>
</tr>
<tr>
<td>r</td>
<td>The mod_lua request handle</td>
</tr>
<tr>
<td>component</td>
<td>The component to add</td>
</tr>
</table>
<p>
<em>Example:</em>
</p>
<pre class="prettyprint lang-lua">
if not apache2.banner():match("FooModule") then -- Make sure we haven't added it already
end
</pre>
<p> </p>
request_rec<em> r</em>, number<em> status</em>, string<em> string</em>
)
</a></h3>
<p>
Install a custom response handler for a given status
</p>
<p>
<em>Arguments:</em>
</p>
<table class="bordered">
<tr>
<th>Argument</th>
<th>Description</th>
</tr>
<tr>
<td>r</td>
<td>The mod_lua request handle</td>
</tr>
<tr>
<td>status</td>
<td>The status for which the custom response should be used</td>
</tr>
<tr>
<td>string</td>
<td>The custom response. This can be a static string, a file or a URL</td>
</tr>
</table>
<p>
<em>Example:</em>
</p>
<pre class="prettyprint lang-lua">
apache2.custom_response(r, 404, "Not found!!")
</pre>
<p> </p>
<h3><a name="apache2.exists_config_define" id="apache2.exists_config_define">apache2.exists_config_define(
string<em> name</em>
)
</a></h3>
<p>
Checks for a definition from the server command line
</p>
<p>
<em>Arguments:</em>
</p>
<table class="bordered">
<tr>
<th>Argument</th>
<th>Description</th>
</tr>
<tr>
<td>name</td>
<td>The define to check for</td>
</tr>
</table>
<p>
<em>Example:</em>
</p>
<pre class="prettyprint lang-lua">
if apache2.exists_config_define("FOO") then
r:puts("This server was started with -DFOO")
end
</pre>
<p> </p>
)
</a></h3>
<p>
Returns a table containing the name (c filename) of all loaded modules
</p>
<p>
<em>Arguments:</em>
</p>
<p>None</p>
<p>
<em>Return value(s):</em>
<br />
A table containing the name (c filename) of all loaded modules
</p>
<p> </p>
string<em> c</em>, string<em> file</em>
)
</a></h3>
<p>
Returns information about a specific module (if loaded)
</p>
<p>
<em>Arguments:</em>
</p>
<table class="bordered">
<tr>
<th>Argument</th>
<th>Description</th>
</tr>
<tr>
<td>c</td>
<td>c</td>
</tr>
<tr>
<td>file</td>
<td>file</td>
</tr>
</table>
<p>
<em>Return value(s):</em>
<br />
The various commands available to this module as a table, or nil if the module wasn't found.
</p>
<p> </p>
number<em> i</em>
)
</a></h3>
<p>
Queries the MPM for a specific value
</p>
<p>
<em>Arguments:</em>
</p>
<table class="bordered">
<tr>
<th>Argument</th>
<th>Description</th>
</tr>
<tr>
<td>i</td>
<td>i</td>
</tr>
</table>
<p>
<em>Return value(s):</em>
<br />
The queried value
</p>
<p> </p>
<h3><a name="apache2.runtime_dir_relative" id="apache2.runtime_dir_relative">apache2.runtime_dir_relative(
request_rec<em> r</em>, string<em> file</em>
)
</a></h3>
<p>
Returns the path of a file relative to the default runtime directory
</p>
<p>
<em>Arguments:</em>
</p>
<table class="bordered">
<tr>
<th>Argument</th>
<th>Description</th>
</tr>
<tr>
<td>r</td>
<td>The mod_lua request handle</td>
</tr>
<tr>
<td>file</td>
<td>file</td>
</tr>
</table>
<p>
<em>Return value(s):</em>
<br />
The path of a file relative to the default runtime directory
</p>
<p> </p>
<h3><a name="apache2.scoreboard_process" id="apache2.scoreboard_process">apache2.scoreboard_process(
request_rec<em> r</em>, number<em> child</em>
)
</a></h3>
<p>
Returns the scoreboard for a server daemon as a table
</p>
<p>
<em>Arguments:</em>
</p>
<table class="bordered">
<tr>
<th>Argument</th>
<th>Description</th>
</tr>
<tr>
<td>r</td>
<td>The mod_lua request handle</td>
</tr>
<tr>
<td>child</td>
<td>The server child to query</td>
</tr>
</table>
<p>
<em>Return value(s):</em>
<br />
The scoreboard for a server daemon as a table
</p>
<p> </p>
request_rec<em> r</em>, number<em> child</em>, number<em> thread</em>
)
</a></h3>
<p>
Returns the scoreboard for a single thread as a table
</p>
<p>
<em>Arguments:</em>
</p>
<table class="bordered">
<tr>
<th>Argument</th>
<th>Description</th>
</tr>
<tr>
<td>r</td>
<td>The mod_lua request handle</td>
</tr>
<tr>
<td>child</td>
<td>The server child to query</td>
</tr>
<tr>
<td>thread</td>
<td>The thread to query</td>
</tr>
</table>
<p>
<em>Return value(s):</em>
<br />
The scoreboard for a single thread as a table
</p>
<p> </p>
)
</a></h3>
<p>
Returns a table with information about the server program
</p>
<p>
<em>Arguments:</em>
</p>
<p>None</p>
<p>
<em>Return value(s):</em>
<br />
A table with information about the server program
</p>
<p> </p>
number<em> field</em>
)
</a></h3>
<p>
Query the server for some state information
</p>
<p>
<em>Arguments:</em>
</p>
<table class="bordered">
<tr>
<th>Argument</th>
<th>Description</th>
</tr>
<tr>
<td>field</td>
<td>Which information is requested</td>
</tr>
</table>
<p>
<em>Example:</em>
</p>
<pre class="prettyprint lang-lua">
local gen = apache2.state_query(2)
r:puts("This is generation no. " .. gen .. " of the top-level parent")
</pre>
<p> </p>
)
</a></h3>
<p>
Kills off a server process. This has no other use than to show how dangerous mod_lua can be ;)
</p>
<p>
<em>Arguments:</em>
</p>
<p>None</p>
<p> </p>
<div class="section">
<h2><a name="Database_connectivity" id="Database_connectivity">HTTPd bindings: Database connectivity</a></h2>
<p>
<br />
<a href="#db:query">db:query</a>
<br />
<a href="#db:do">db:do</a>
<br />
<a href="#db:close">db:close</a>
<br />
</p>
request_rec<em> r</em>, string<em> dbtype</em>, string<em> conn_string</em>
)
</a></h3>
<p>
Opens up a new database connection. See the DB functions for mod_pLua for more info on this.
</p>
<p>
<em>Arguments:</em>
</p>
<table class="bordered">
<tr>
<th>Argument</th>
<th>Description</th>
</tr>
<tr>
<td>r</td>
<td>The mod_lua request handle</td>
</tr>
<tr>
<td>dbtype</td>
<td>dbtype</td>
</tr>
<tr>
<td>conn_string</td>
<td>connection string</td>
</tr>
</table>
<p>
<em>Return value(s):</em>
<br />
The database connection as a table with functions, or nil if the connection failed. If a connection failed, a second argument (string) with the error code is returned.
</p>
<p>
<em>Example:</em>
</p>
<pre class="prettyprint lang-lua">
local db, error = apache2.dbopen(r, "mod_dbd")
if error then
r:puts("DB error: ", error)
else
-- DB stuff here
end
</pre>
<p> </p>
<h3><a name="db:close" id="db:close">db:close(
request_rec<em> r</em>
)
</a></h3>
<p>
Closes a database connection
</p>
<p>
<em>Arguments:</em>
</p>
<table class="bordered">
<tr>
<th>Argument</th>
<th>Description</th>
</tr>
<tr>
<td>r</td>
<td>The mod_lua request handle</td>
</tr>
</table>
<p>
<em>Example:</em>
</p>
<pre class="prettyprint lang-lua">
local db = apache2.dbopen(r, "mod_dbd") -- open a db connection
db:close() -- close it down
</pre>
<p> </p>
<h3><a name="db:do" id="db:do">db:do(
request_rec<em> r</em>, string<em> query</em>
)
</a></h3>
<p>
Executes a statement that doesn't return a result set
</p>
<p>
<em>Arguments:</em>
</p>
<table class="bordered">
<tr>
<th>Argument</th>
<th>Description</th>
</tr>
<tr>
<td>r</td>
<td>The mod_lua request handle</td>
</tr>
<tr>
<td>query</td>
<td>The SQL statement to execute</td>
</tr>
</table>
<p>
<em>Return value(s):</em>
<br />
If the statement is valid, a table of results are returned. If an error occurred, the first return value is false and the second return value is a string containing an error message.
</p>
<p>
<em>Example:</em>
</p>
<pre class="prettyprint lang-lua">
local db = apache2.dbopen(r, "mod_dbd")
local affected = db:do("DELETE FROM `table` WHERE 1")
if affected then
r:puts("Affected ", affected, " rows")
end
</pre>
<p> </p>
<h3><a name="db:query" id="db:query">db:query(
request_rec<em> r</em>, string<em> query</em>
)
</a></h3>
<p>
Queries the database for information using the specified statement.
</p>
<p>
<em>Arguments:</em>
</p>
<table class="bordered">
<tr>
<th>Argument</th>
<th>Description</th>
</tr>
<tr>
<td>r</td>
<td>The mod_lua request handle</td>
</tr>
<tr>
<td>query</td>
<td>The SQL statement to execute</td>
</tr>
</table>
<p>
<em>Return value(s):</em>
<br />
If the statement is valid, a table of results are returned. If an error occurred, the first return value is false and the second return value is a string containing an error message.
</p>
<p>
<em>Example:</em>
</p>
<pre class="prettyprint lang-lua">
local db = apache2.dbopen(r, "mod_dbd")
local result, error = db:query("SELECT * FROM `table` WHERE 1")
if result then
for key, value in pairs(result)
r:puts( ("row %s: %s\n"):format(key, table.concat(value, ", ")) )
end
end
</pre>
<p> </p>
<div class="section">
<h2><a name="Miscellaneous" id="Miscellaneous">HTTPd bindings: Miscellaneous</a></h2>
<p>
<br />
<br />
</p>
)
</a></h3>
<p>
Returns the current time in microseconds.
</p>
<p>
<em>Arguments:</em>
</p>
<p>None</p>
<p>
<em>Return value(s):</em>
<br />
The current time in microseconds.
</p>
<p> </p>
number<em> seconds</em>
)
</a></h3>
<p>
Sleeps for a while. Floating point values can be used to sleep for less than a second.
</p>
<p>
<em>Arguments:</em>
</p>
<table class="bordered">
<tr>
<th>Argument</th>
<th>Description</th>
</tr>
<tr>
<td>seconds</td>
<td>The number of seconds to sleep.</td>
</tr>
</table>
<p>
<em>Example:</em>
</p>
<pre class="prettyprint lang-lua">
r:puts("this is ")
apache2.sleep(0.25) -- sleep for a quarter second.
r:puts("delayed")
</pre>
<p> </p>
</div></div>
<div class="bottomlang">
<p><span>Available Languages: </span><a href="/en/developer/lua.html" title="English"> en </a></p>
</div><div class="top"><a href="#page-header"><img src="/images/up.gif" alt="top" /></a></div><div class="section"><h2><a id="comments_section" name="comments_section">Comments</a></h2><div class="warning"><strong>Notice:</strong><br />This is not a Q&A section. Comments placed here should be pointed towards suggestions on improving the documentation or server, and may be removed again by our moderators if they are either implemented or considered invalid/off-topic. Questions on how to manage the Apache HTTP Server should be directed at either our IRC channel, #httpd, on Freenode, or sent to our <a href="http://httpd.apache.org/lists.html">mailing lists</a>.</div>
var comments_shortname = 'httpd';
var comments_identifier = 'http://httpd.apache.org/docs/trunk/developer/lua.html';
(function(w, d) {
if (w.location.hostname.toLowerCase() == "httpd.apache.org") {
d.write('<div id="comments_thread"><\/div>');
var s = d.createElement('script');
s.type = 'text/javascript';
s.async = true;
s.src = 'https://comments.apache.org/show_comments.lua?site=' + comments_shortname + '&page=' + comments_identifier;
(d.getElementsByTagName('head')[0] || d.getElementsByTagName('body')[0]).appendChild(s);
}
else {
d.write('<div id="comments_thread">Comments are disabled for this page at the moment.<\/div>');
}
})(window, document);
//--><!]]></script></div><div id="footer">
<p class="apache">Copyright 2012 The Apache Software Foundation.<br />Licensed under the <a href="http://www.apache.org/licenses/LICENSE-2.0">Apache License, Version 2.0</a>.</p>
<p class="menu"><a href="/mod/">Modules</a> | <a href="/mod/directives.html">Directives</a> | <a href="http://wiki.apache.org/httpd/FAQ">FAQ</a> | <a href="/glossary.html">Glossary</a> | <a href="/sitemap.html">Sitemap</a></p></div><script type="text/javascript"><!--//--><![CDATA[//><!--
if (typeof(prettyPrint) !== 'undefined') {
prettyPrint();
}
//--><!]]></script>
</body></html>