Modules can interact among them in two ways: explicitly (by direct query) and inwardly (through event system).
Explicit interaction means:
- Module connection using the function
- Direct query of a class method or a module function.
Example of an explicit interaction:
// we connect the module mymodule
// we execute its method
Interaction through Events
Event - is an arbitrary action at the time of execution of which (before or after) all the handlers of such an event are collected and executed one by one.
The entity of an event permits making modules independent from one another to a maximum degree. The module “knows” nothing about the particulars of functioning of another module, but it can interact with it through the interface of events.
The events operating procedure is as follows. The module initializing an event must perform the following operations at the place within the code where this event occurs:
- Collect all the registered handlers using the function
- Perform them one by one using the function
ExecuteModuleEvent processing the values returned by the handlers accordingly.
In its turn, the module that “wants” to perform any actions to this event must:
- Register its handler using the function
RegisterModuleDependences at the time of installation.
- Accordingly, this handler function must be available, and you have to make sure that the script where this function is located is connected in the file /bitrix/modules/module ID/include.php.
Example of Interaction
The perfect example of such an interaction is the interaction of system modules with the Search module. This module has no information about the data of other modules, their storage and processing particulars. It only provides an interface for data indexing. Any system model to be indexed registers a handler for the event
OnReindex. upon installation. Each such handler, in its turn, returns data for the indexing to be used by the Search module for filling its base.
Sample codes of examples of interaction through events:
// handler registration:
// when the event OnSomeEvent occurs in the module init_module
// the method CMyModuleClass::Handler of the module handler_module will be called
"handler_module", "CMyModuleClass", "Handler"
// arbitrary function of the module init_module
// where the event is generated
// the arbitrary code is located here
// it represents the event
// after that, registered handlers are collected
$rsHandlers = GetModuleEvents("anothermodule", "OnSomeEvent");
while($arHandler = $rsHandlers->Fetch())
// and executed one by one
if(!ExecuteModuleEvent($arHandler, $param1, $param2))
// if the handler returns false,
// then, for example, we return the phrase "I can't do it..."
return "I can't do it...";
return "I have done it!";
function Handler($param1, $param2)