Apache HTTP Server Version 2.3
Available Languages: en
Description: | Provides Lua hooks into various portions of the httpd request processing |
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Status: | Experimental |
Module Identifier: | lua_module |
Source File: | mod_lua.c |
Compatibility: | 2.3 and later |
Someone needs to write this. Include a link to the Lua website.
The basic module loading directive is
LoadModule lua_module modules/mod_lua.so
mod_lua
provides a handler named lua-script
,
which can be used with an AddHandler
directive:
AddHandler lua-script .lua
This will cause mod_lua
to handle requests for files
ending in .lua
by invoking that file's
handle
function.
For more flexibility, see LuaMapHandler
.
mod_lua
always looks to invoke a function for the handler, rather than
just evaluating a script body CGI style. A handler function looks
something like this:
-- example handler require "string" function handle_something(r) r.content_type = "text/plain" r:puts("Hello Lua World!\n") if r.method == 'GET' then for k, v in pairs( r:parseargs() ) do r:puts( string.format("%s: %s", k, v) ) end elseif r.method == 'POST' then for k, v in pairs( r:parsebody() ) do r:puts( string.format("%s: %s", k, v) ) end else r:puts("unknown HTTP method " .. r.method) end end
This handler function just prints out the uri or form encoded arguments to a plaintext page.
This means (and in fact encourages) that you can have multiple handlers (or hooks, or filters) in the same script.
Hook functions are passed the request object as their only argument.
They can return any value, depending on the hook, but most commonly
they'll return OK, DONE, or DECLINED, which you can write in lua as
apache2.OK
, apache2.DONE
, or
apache2.DECLINED
, or else an HTTP status code.
-- example hook require 'apache2' function translate_name(r) if r.uri == "/translate-name" then r.uri = "/find_me.txt" return apache2.DECLINED end return apache2.DECLINED end
The request_rec is mapped in as a userdata. It has a metatable which lets you do useful things with it. For the most part it has the same fields as the request_rec struct (see httpd.h until we get better docs here) many of which are writeable as well as readable. (The table fields' content can be changed, but the fields themselves cannot be set to different tables.)
Name | Lua type | Writable |
---|---|---|
ap_auth_type |
string | no |
args |
string | no |
assbackwards |
boolean | no |
canonical_filename |
string | no |
content_encoding |
string | no |
content_type |
string | yes |
document_root |
string | no |
err_headers_out |
table | no |
filename |
string | yes |
headers_in |
table | yes |
headers_out |
table | yes |
hostname |
string | no |
method |
string | no |
notes |
table | yes |
path_info |
string | no |
protocol |
string | no |
range |
string | no |
status |
number | yes |
the_request |
string | no |
unparsed_uri |
string | no |
uri |
string | yes |
user |
string | yes |
The request_rec has (at least) the following methods:
r:addoutputfilter(name|function) -- add an output filter
r:parseargs() -- returns a lua table containing the request's
query string arguments
r:parsebody() -- parse the request body as a POST and return
a lua table
r:puts("hello", " world", "!") -- print to response body
r:write("a single string") -- print to response body
-- examples of logging messages
r:debug("This is a debug log message")
r:info("This is an info log message")
r:notice("This is an notice log message")
r:warn("This is an warn log message")
r:err("This is an err log message")
r:alert("This is an alert log message")
r:crit("This is an crit log message")
r:emerg("This is an emerg log message")
A package named apache2
is available with (at least) the following contents.
(Other HTTP status codes are not yet implemented.)
Description: | Configure the compiled code cache. |
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Syntax: | LuaCodeCache stat|forever|never |
Default: | LuaCodeCache stat |
Context: | server config, virtual host, directory, .htaccess |
Override: | All |
Status: | Experimental |
Module: | mod_lua |
Specify the behavior of the in-memory code cache. The default is stat, which stats the top level script (not any included ones) each time that file is needed, and reloads it if the modified time indicates it is newer than the one it has already loaded. The other values cause it to keep the file cached forever (don't stat and replace) or to never cache the file.
In general stat or forever is good for production, and stat or never for development.
LuaCodeCache stat
LuaCodeCache forever
LuaCodeCache never
Description: | Provide a hook for the access_checker phase of request processing |
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Syntax: | LuaHookAccessChecker /path/to/lua/script.lua hook_function_name |
Context: | server config, virtual host, directory, .htaccess |
Override: | All |
Status: | Experimental |
Module: | mod_lua |
Add your hook to the access_checker phase. An access checker hook function usually returns OK, DECLINED, or HTTP_FORBIDDEN.
Description: | Provide a hook for the auth_checker phase of request processing |
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Syntax: | LuaHookAuthChecker /path/to/lua/script.lua hook_function_name |
Context: | server config, virtual host, directory, .htaccess |
Override: | All |
Status: | Experimental |
Module: | mod_lua |
Invoke a lua function in the auth_checker phase of processing a request. This can be used to implement arbitrary authentication and authorization checking. A very simple example:
require 'apache2' -- fake authcheck hook -- If request has no auth info, set the response header and -- return a 401 to ask the browser for basic auth info. -- If request has auth info, don't actually look at it, just -- pretend we got userid 'foo' and validated it. -- Then check if the userid is 'foo' and accept the request. function authcheck_hook(r) -- look for auth info auth = r.headers_in['Authorization'] if auth ~= nil then -- fake the user r.user = 'foo' end if r.user == nil then r:debug("authcheck: user is nil, returning 401") r.err_headers_out['WWW-Authenticate'] = 'Basic realm="WallyWorld"' return 401 elseif r.user == "foo" then r:debug('user foo: OK') else r:debug("authcheck: user='" .. r.user .. "'") r.err_headers_out['WWW-Authenticate'] = 'Basic realm="WallyWorld"' return 401 end return apache2.OK end
Description: | Provide a hook for the check_user_id phase of request processing |
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Syntax: | LuaHookCheckUserID /path/to/lua/script.lua hook_function_name |
Context: | server config, virtual host, directory, .htaccess |
Override: | All |
Status: | Experimental |
Module: | mod_lua |
...
Description: | Provide a hook for the fixups phase of request processing |
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Syntax: | LuaHookFixups /path/to/lua/script.lua hook_function_name |
Context: | server config, virtual host, directory, .htaccess |
Override: | All |
Status: | Experimental |
Module: | mod_lua |
Just like LuaHookTranslateName, but executed at the fixups phase
Description: | Provide a hook for the insert_filter phase of request processing |
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Syntax: | LuaHookInsertFilter /path/to/lua/script.lua hook_function_name |
Context: | server config, virtual host, directory, .htaccess |
Override: | All |
Status: | Experimental |
Module: | mod_lua |
Not Yet Implemented
Description: | Provide a hook for the map_to_storage phase of request processing |
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Syntax: | LuaHookMapToStorage /path/to/lua/script.lua hook_function_name |
Context: | server config, virtual host, directory, .htaccess |
Override: | All |
Status: | Experimental |
Module: | mod_lua |
...
Description: | Provide a hook for the translate name phase of request processing |
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Syntax: | LuaHookTranslateName /path/to/lua/script.lua hook_function_name |
Context: | server config, virtual host, directory, .htaccess |
Override: | All |
Status: | Experimental |
Module: | mod_lua |
Add a hook (at APR_HOOK_MIDDLE) to the translate name phase of request processing. The hook function receives a single argument, the request_rec, and should return a status code, which is either an HTTP error code, or the constants defined in the apache2 module: apache2.OK, apache2.DECLINED, or apache2.DONE.
For those new to hooks, basically each hook will be invoked until one of them returns apache2.OK. If your hook doesn't want to do the translation it should just return apache2.DECLINED. If the request should stop processing, then return apache2.DONE.
Example:
# httpd.conf LuaHookTranslateName /scripts/conf/hooks.lua silly_mapper -- /scripts/conf/hooks.lua -- require "apache2" function silly_mapper(r) if r.uri == "/" then r.file = "/var/www/home.lua" return apache2.OK else return apache2.DECLINED end end
Description: | Provide a hook for the type_checker phase of request processing |
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Syntax: | LuaHookTypeChecker /path/to/lua/script.lua hook_function_name |
Context: | server config, virtual host, directory, .htaccess |
Override: | All |
Status: | Experimental |
Module: | mod_lua |
...
Description: | Map a path to a lua handler |
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Syntax: | LuaMapHandler uri-pattern /path/to/lua/script.lua [function-name] |
Context: | server config, virtual host, directory, .htaccess |
Override: | All |
Status: | Experimental |
Module: | mod_lua |
This directive matches a uri pattern to invoke a specific handler function in a specific file. It uses PCRE regular expressions to match the uri, and supports interpolating match groups into both the file path and the function name be careful writing your regular expressions to avoid security issues.
LuaMapHandler /(\w+)/(/w+) /scripts/$1.lua handle_$2
This would match uri's such as /photos/show?id=9 to the file /scripts/photos.lua and invoke the handler function handle_show on the lua vm after loading that file.
LuaMapHandler /bingo /scripts/wombat.lua
This would invoke the "handle" function, which is the default if no specific function name is provided.
Description: | Add a directory to lua's package.cpath |
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Syntax: | LuaPackageCPath /path/to/include/?.soa |
Context: | server config, virtual host, directory, .htaccess |
Override: | All |
Status: | Experimental |
Module: | mod_lua |
Add a path to lua's shared library search path. Follows the same conventions as lua. This just munges the package.cpath in the lua vms.
Description: | Add a directory to lua's package.path |
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Syntax: | LuaPackagePath /path/to/include/?.lua |
Context: | server config, virtual host, directory, .htaccess |
Override: | All |
Status: | Experimental |
Module: | mod_lua |
Add a path to lua's module search path. Follows the same conventions as lua. This just munges the package.path in the lua vms.
LuaPackagePath /scripts/lib/?.lua
LuaPackagePath /scripts/lib/?/init.lua
Description: | Provide a hook for the quick handler of request processing |
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Syntax: |
|
Context: | server config, virtual host, directory, .htaccess |
Override: | All |
Status: | Experimental |
Module: | mod_lua |
...
Description: | Specify the base path for resolving relative paths for mod_lua directives |
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Syntax: | LuaRoot /path/to/a/directory |
Context: | server config, virtual host, directory, .htaccess |
Override: | All |
Status: | Experimental |
Module: | mod_lua |
Specify the base path which will be used to evaluate all relative paths within mod_lua. If not specified they will be resolved relative to the current working directory, which may not always work well for a server.
Description: | One of once, request, conn, server -- default is once |
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Syntax: | LuaScope once|request|conn|server [max|min max] |
Default: | LuaScope once |
Context: | server config, virtual host, directory, .htaccess |
Override: | All |
Status: | Experimental |
Module: | mod_lua |
Specify the lifecycle scope of the Lua interpreter which will be used by handlers in this "Directory." The default is "once"
Available Languages: en