Introduction To Development

Dependencies

X2EngineCRM is built using the following frameworks; see their respective documentation for information about their use.

Yii Framework

Yii Framework is a PHP framework based on the time-tested MVC (Model-View-Controller) design methodology, which is of particular importance in understanding how requests translate to the execution of class methods.

jQuery and jQuery UI

Most of the Javascript in the codebase, including Yii Framework itself, depends on jQuery in some way or another. Thus, for front-end design (especially design that involves asynchronous content loading via AJAX) it is essential to understand the usage of this library. In many cases, Yii Framework provides certain utilities for constructing HTML elements and jQuery-based scripts, and it is thus also important to first search for effort-saving devices available in Yii Framework before writing something from scratch. In particular, CHtml contains methods such as ajaxButton, and the subclasses of CJuiWidget can be used to easily construct most common jQuery UI elements and seamlessly integrate them with Yii as input fields.

MVC In a Nutshell

How a Request To The Web Application Translates To Code Executing

Relevant pages: Controller, Model and View in The Definitive Guide to Yii

A request to the server translates to the instantiation of a controller class. Which controller is instantiated depends upon the route, which contains the first part of the controller class's name with the first letter in lowercase. Then, the method of the class whose name begins with "action" is run based on the action ID of the request URL. As the action runs, it will retrieve data from the database using a model class. Actions which respond with content will then typically make a call to render or renderPartial, methods inherited from the CController class. The view file, specified by the first argument to that method, will then be used to display the content (contained in the model) that is then passed back to the client.

File Structure

Modifying the codebase requires an understanding of where the relevant files are located. All PHP files used in the web application, which don't belong to the framework, are under the protected/ directory. This directory is not accessible from the web per the access rules defined in the .htaccess file; rather, these files are executed by the framework as the application runs. Within protected are the following directories:

components/

Miscellaneous classes used throughout the application, especially those which are extended by other classes.

config/

Core configuration files for the web application.

controllers/

Base-level controller classes.

data/

(Currently unused) Miscellaneous data files, i.e. SQL scripts

extensions/

The designated folder for storing third-party classes.

messages/

Files containing translations of messages within the application (used by Yii::t)

models/

All core/base level model classes.

modules/

Self-contained modules. Most of the subdirectories here contain modules whose names appear in the main menu. Each subdirectory typically has the same structure as the base application; they each will have directories named controllers, models and views. See Fundamentals:Module in The Definitive Guide to Yii for more information.

runtime/

(For the application's use) Temporary files written to by the application

tests/

The designated directory for storing unit tests.

views/

View files corresponding to base-level controllers.