Hooks - Extending the Framework Core

revIgniter's hooks feature provides a means to tap into and modify the inner workings of the framework without hacking the core files. When revIgniter runs it follows a specific execution process, diagramed in the Application Flow page. There may be instances, however, where you'd like to cause some action to take place at a particular stage in the execution process. For example, you might want to run a script right before your controllers get loaded, or right after, or you might want to trigger one of your own scripts in some other location.

Enabling Hooks

The hooks feature can be globally enabled/disabled by setting the following item in the application/config/config.lc file:

put TRUE into gConfig["enableHooks"]

Defining a Hook

Hooks are defined in the application/config/hooks.lc file. Each hook is specified as an array with this prototype:

	put "MyHandler" into gHooks["preController"]["handler"]
	put "MyScript.lc" into gHooks["preController"]["filename"]
	put "hooks" into gHooks["preController"]["filepath"]
	put "beer" into gHooks["preController"]["params"][1]
	put "wine" into gHooks["preController"]["params"][2]
	put "snacks" into gHooks["preController"]["params"][3]

The array index correlates to the name of the particular hook point you want to use. In the above example the hook point is preController. A list of hook points is found below. The following items should be defined in your associative hook array:

Multiple Calls to the Same Hook

If you want to use the same hook point with more then one script, simply make your array declaration multidimensional, like this:

	put "MyHandler" into gHooks["preController"][1]["handler"]
	put "MyScript.lc" into gHooks["preController"][1]["filename"]
	put "hooks" into gHooks["preController"][1]["filepath"]
	put "beer" into gHooks["preController"][1]["params"][1]
	put "wine" into gHooks["preController"][1]["params"][2]
	put "snacks" into gHooks["preController"][1]["params"][3]

	put "MyOtherHandler" into gHooks["preController"][2]["handler"]
	put "MyOtherScript.lc" into gHooks["preController"][2]["filename"]
	put "hooks" into gHooks["preController"][2]["filepath"]
	put "red" into gHooks["preController"][2]["params"][1]
	put "yellow" into gHooks["preController"][2]["params"][2]
	put "blue" into gHooks["preController"][2]["params"][3]

This permits you to have the same hook point with multiple scripts. The order you define your array will be the execution order.

Hook Points

The following is a list of available hook points.

Hook Example Using displayOverride as Hook Point to Minify Output

Let's say you want revIgniter to automatically minify the HTML output just before it is displayed. This can easily be accomplished with the help of revIgniter's hooks feature.

First you need a script which removes all comments and whitespace from the output. Here is the script which is included since version 1.3.21b and is located in system/application/hooks for your convenience:


if gBASEPATH is "gBASEPATH" then
	put "No direct script access allowed."
	exit to top
end if

--| COMMAND rigMinifyOutput
--| Author: rabit
--| Version:  1.1
--| Created: 13-05-2011
--| Last Mod: 29-06-2011
--| Requires: rigGetOutput(), rigPregReplace(), rigSetOutput, _rigDisplay
--| Summary: Minifies HTML output.
--| Format:  rigMinifyOutput	
--| Parameters: --
--| Return: void

command rigMinifyOutput
	put rigGetOutput() into tRawHTML

	put "(?s)(\<!--\s*[^\s\[\>\<].*?--\>)" into tRegEx
	put " " into tReplacement
	put rigPregReplace(tRawHTML, tRegEx, , tReplacement) into tMinifiedHTML

	put "(?s)(\>\s+\<)" into tRegEx
	put "><" into tReplacement
	put rigPregReplace(tMinifiedHTML, tRegEx, , tReplacement) into tMinifiedHTML

	put "(?s)((\s)+)" into tRegEx
	put " " into tReplacement
	put rigPregReplace(tMinifiedHTML, tRegEx, , tReplacement) into tMinifiedHTML

	rigSetOutput tMinifiedHTML
end rigMinifyOutput

--| END OF overrideOutput.lc
--| Location:  ./system/application/hooks/overrideOutput.lc

The next step is to add the following lines to your hooks.lc file in system/application/config:

put "rigMinifyOutput" into gHooks["displayOverride"]["handler"]
put "overrideOutput.lc" into gHooks["displayOverride"]["filename"]
put "hooks" into gHooks["displayOverride"]["filepath"]

Now enable hooks in system/application/config/config.lc and your are done. You don't need to care anymore about how much overhead there is due to comments and whitespace in your view files as revIgniter, by using this hook, sends solely relevant data to the client. This works with cached output too.