# HTTP Concatenation module for Nginx ## Introduction This is a module that is distributed with [tengine](http://tengine.taobao.org) which is a distribution of [Nginx](http://nginx.org) that is used by the e-commerce/auction site [Taobao.com](http://en.wikipedia.org/wiki/Taobao). This distribution contains some modules that are new on the Nginx scene. The `ngx_http_concat` module is one of them. The module is inspired by Apache's [`modconcat`](http://code.google.com/p/modconcat). It follows the same pattern for enabling the concatenation. It uses two `?`, like this: http://example.com/??style1.css,style2.css,foo/style3.css If a **third** `?` is present it's treated as **version string**. Like this: http://example.com/??style1.css,style2.css,foo/style3.css?v=102234 ## Configuration example location ^~ /static { location ~* /static/css/css_[[:alnum:]]+\.css$ { concat on; concat_max_files 20; } location ~* /static/js/js_[[:alnum:]]+\.js$ { concat on; concat_max_files 30; } } ## Module directives **concat** `on` | `off` **default:** `concat off` **context:** `http, server, location` It enables the concatenation in a given context.

**concat_types** `MIME types` **default:** `concat_types: text/css application/x-javascript` **context:** `http, server, location` Defines the [MIME types](http://en.wikipedia.org/wiki/MIME_type) which can be concatenated in a given context.

**concat_unique** `on` | `off` **default:** `concat_unique on` **context:** `http, server, location` Defines if only files of a given MIME type can concatenated or if several MIME types can be concatenated. For example if set to `off` then in a given context you can concatenate Javascript and CSS files. Note that the default value is `on`, meaning that only files with same MIME type are concatenated in a given context. So if you have CSS and JS you cannot do something like this: http://example.com/static/??foo.css,bar/foobaz.js In order to do that you **must** set `concat_unique off`. This applies to any other type of files that you decide to concatenate by adding the respective MIME type via `concat_types`,

**concat\_max\_files** `number`p **default:** `concat_max_files 10` **context:** `http, server, location` Defines the **maximum** number of files that can be concatenated in a given context. Note that a given URI cannot be bigger than the page size of your platform. On Linux you can get the page size issuing: getconf PAGESIZE Usually is 4k. So if you try to concatenate a lot of files together in a given context you might hit this barrier. To overcome that OS defined limitation you must use the [`large_client_header_buffers`](http://wiki.nginx.org/NginxHttpCoreModule#large_client_header_buffers) directive. Set it to the value you need. ## Installation 1. Clone the git repo. git clone git://github.com/perusio/nginx-http-concat.git 2. Add the module to the build configuration by adding `--add-module=/path/to/nginx-http-concat`. 3. Build the nginx binary. 4. Install the nginx binary. 5. Configure contexts where concat is enabled. 6. Build your links such that the above format, i.e., all URIs that have files that are to be concatenated have a `??` prefix. The HTML produced would have something like this inside the `` element for concatenating CSS files. Similarly for Javascript files you should have: