diff options
Diffstat (limited to 'doc/cml.txt')
| -rw-r--r-- | doc/cml.txt | 48 |
1 files changed, 24 insertions, 24 deletions
diff --git a/doc/cml.txt b/doc/cml.txt index 10fac70..ae69067 100644 --- a/doc/cml.txt +++ b/doc/cml.txt @@ -12,10 +12,10 @@ Module: mod_cml :abstract: CML is a Meta language to describe the dependencies of a page at one side and building a page from its fragments on the other side using LUA. - + .. meta:: :keywords: lighttpd, cml, lua - + .. contents:: Table of Contents Description @@ -31,7 +31,7 @@ CML (Cache Meta Language) wants to solves several problems: Cache Decision -------------- -A simple example should show how to a content caching the very simple way in PHP. +A simple example should show how to a content caching the very simple way in PHP. jan.kneschke.de has a very simple design: @@ -39,7 +39,7 @@ jan.kneschke.de has a very simple design: * the menu is generated from a menu.csv file * the content is coming from files on the local directory named content-1, content-2 and so on -The page content is static as long non of the those tree items changes. A change in the layout +The page content is static as long non of the those tree items changes. A change in the layout is affecting all pages, a change of menu.csv too, a change of content-x file only affects the cached page itself. @@ -58,7 +58,7 @@ If we model this in PHP we get: :: } foreach($content as $k => $v) { - if (isset($v["file"]) && + if (isset($v["file"]) && filemtime($v["file"]) > $cachemtime) { return 0; } @@ -71,7 +71,7 @@ If we model this in PHP we get: :: return 0; } } - + if (is_cachable(...), $cachefile) { readfile($cachefile); exit(); @@ -81,7 +81,7 @@ If we model this in PHP we get: :: ?> Quite simple. No magic involved. If the one of the files is new than the cached -content, the content is dirty and has to be regenerated. +content, the content is dirty and has to be regenerated. Now let take a look at the numbers: @@ -92,9 +92,9 @@ As you can see the increase is not as good as it could be. The main reason as th of the PHP interpreter to start up (a byte-code cache has been used here). Moving these decisions out of the PHP script into a server module will remove the need -to start PHP for a cache-hit. +to start PHP for a cache-hit. -To transform this example into a CML you need 'index.cml' in the list of indexfiles +To transform this example into a CML you need 'index.cml' in the list of indexfiles and the following index.cml file: :: output_contenttype = "text/html" @@ -110,7 +110,7 @@ and the following index.cml file: :: file_mtime(b .. "templates/jk.tmpl") > file_mtime(cwd .. "_cache.html") or file_mtime(b .. "content.html") > file_mtime(cwd .. "_cache.html") then return CACHE_MISS - else + else return CACHE_HIT end @@ -132,26 +132,26 @@ Sometimes the different fragment are already generated externally. You have to c readfile("spacer2.html"); readfile("news.html"); readfile("footer.html"); - ?> + ?> -We we can do the same several times faster directly in the webserver. +We we can do the same several times faster directly in the webserver. Don't forget: Webserver are built to send out static content, that is what they can do best. The index.cml for this looks like: :: output_contenttype = "text/html" - + cwd = request["CWD"] - - output_include = { cwd .. "head.html", + + output_include = { cwd .. "head.html", cwd .. "menu.html", cwd .. "spacer.html", cwd .. "db-content.html", cwd .. "spacer2.html", cwd .. "news.html", cwd .. "footer.html" } - + return CACHE_HIT Now we get about 10000 req/s instead of 600 req/s. @@ -161,7 +161,7 @@ Power Magnet Next to all the features about Cache Decisions CML can do more. Starting with lighttpd 1.4.9 a power-magnet was added which attracts each request -and allows you to manipulate the request for your needs. +and allows you to manipulate the request for your needs. We want to display a maintainance page by putting a file in a specified place: @@ -183,7 +183,7 @@ and create /home/www/power-magnet.cml with: :: For each requested file the /home/www/power-magnet.cml is executed which checks if maintainance.html exists in the docroot and displays it -instead of handling the usual request. +instead of handling the usual request. Another example, create thumbnail for requested image and serve it instead of sending the big image: :: @@ -196,7 +196,7 @@ of sending the big image: :: dr = request["DOCUMENT_ROOT"] sn = request["SCRIPT_NAME"] - ## to be continued :) ... + ## to be continued :) ... trigger_handler = '/gen_image.php' @@ -217,7 +217,7 @@ To use the plugin you have to load it: :: Options ======= -:cml.extension: +:cml.extension: the file extension that is bound to the cml-module :cml.memcache-hosts: hosts for the memcache.* functions @@ -229,7 +229,7 @@ Options Language ======== -The language used for CML is provided by `LUA <http://www.lua.org/>`_. +The language used for CML is provided by `LUA <http://www.lua.org/>`_. Additionally to the functions provided by lua mod_cml provides: :: @@ -252,10 +252,10 @@ Additionally to the functions provided by lua mod_cml provides: :: number file_mtime(string) string memcache_get_string(string) number memcache_get_long(string) - boolean memcache_exists(string) + boolean memcache_exists(string) -What ever your script does, it has to return either CACHE_HIT or CACHE_MISS. -It case a error occures check the error-log, the user will get a error 500. If you don't like +What ever your script does, it has to return either CACHE_HIT or CACHE_MISS. +It case a error occures check the error-log, the user will get a error 500. If you don't like the standard error-page use ``server.errorfile-prefix``. |