Jelix - PHP5 Framework

General informations

Jelix is a framework for PHP5, whose objective is to ease the development of applications or Web sites of any kind.

Here is what is proposed to developers:

• API dealing with numbers of technical aspects: data access, MVC model, templates, output format generators (HTML, XUL,…), Web services (xml-RPC, json-RPC), forms generator, CRUD, authentication, rights management, localization, etc…
• a modular structure and an organization of the files of the project, imposing a framework and some developing standards.
• a “layer” organization of the project: presentation, coordination, service, business, persistence.

These characteristics allow a better re-use of the code, a capitalization of know-how, a better organization in the development, leading to a better productivity.

Jelix uses to the maximum of specificities of PHP5, in order to be the lightest and most powerful possible. This is why a project based on Jelix is 100% object oriented.

Features

Original functions and characteristics

• Modular architecture : an application can be cut out in several reusable modules.
• Minimal guarantee on the data exchange : Jelix controls the generation of output formats according to the type of request. For example, if we have a request for a XML-RPC web service, we cannot generate HTML, the answer will be obligatorily in XML-RPC. Si it offers a certain robustness of the application in client/server communication. (Unless the developer does not use objects from Jelix, because indeed nothing prevents from making an echo of anything anywhere).
• Generation of technical errors in specified format : thanks to the Jelix system described before, all the technical errors are returned in the format awaited by the client. For example: no HTML formatted error when client is awaiting XML-RPC or RDF response.
• Light and evolutionary template engine (jTpl), with a syntax halfway between Smarty and PHP. A plugin system like in Smarty is also available.
• jDao, object-relational mapping, based on the DAO design pattern (Data Access Object). Declared in XML files, automatic generation of its SQL requests , handling of security problems (SQL injection etc…).
• Designation of files and resources by selectors, and not by physical ways, then bringing a certain independence to a module towards the installation.
• Event system allowing module-to-module communication.
• Overload file : it is possible to redefine some files of a module without changing the originals (DAO, templates, properties). Useful when a module is used by several applications at the same time, or to facilitate the update of a third module.

Modern functions and characteristics

Functions that we don’t find so often in frameworks:

• Web Services : Jelix deals with analysis of the content of requests, and the generation of the response. XML-RPC and JSON-RPC are handled. Other types of services Web are completely possible (SOAP,…).
• Handling of RESTfull : by simple implementation of an interface: one can easily define what is done after HTTP GET/POST/PUT/DELETE requests.
• Themes system: it is possible to define several templates, each one redefining the template of modules.
• Automatic system for URL generation and mapping : no complete URL in Jelix. The framework has the responsibility to generate urls in the templates or elsewhere, according to the configuration of URL mapping defined on actions (mod_rewrite & co).
• PHP scripts for code generation to execute in command liner, allowing fast creation of various files of a project (module, DAO, template, controller, etc)
• Technical cache system : almost all non PHP files of a Jelix project “are compiled” in PHP in order to improve the performances (templates, DAO, events etc.).
• UTF-8 compliant: it's the default encoding of the framework
• Module dedicated to unit tests: unit tests are essentials to create a reliable application. So Jelix provide a module which has an interface to launch unit tests and a simple way to create unit tests (using simpleTest)

Traditional functions and characteristics

Functions which one finds in many frameworks:

• The architecture of the core is MVC type (Model-View-Controller). A coordinator handles the execution of an action according to the parameters in the URL. The possible actions are implemented in classes of jController type (controllers).
• Jelix provide several output generators (jResponse objects): XHTML, CSS, ATOM, RSS, XML, RDF, XUL, XUL overlay, ZIP, PDF (from Latex source files or with TCPDF). Others formats are also possible.
• Database access abstraction layer: jDb relies on PDO or its own classes (when PDO is not available) to access to the databases.
• Localization: you can have your application translated in several languages. Storage of localized string is done in properties files.
• System of authentication and rights management.
• Use of XML: declaration of the events, DAOs etc, … That makes it possible to facilitate writing, generation and modifying these parts of a project by third-party tools (for example with JelixEclipse, an eclipse plugin), and thus to increase productivity.

How does Jelix work

1. an HTTP request calls Jelix. Jelix creates an instance of a jRequest object which contains datas of the request. It then create an instance of your controller which corresponds to the asked action.
2. A method in the controller is executed. It retrieves request parameters in order to know which process to run.
3. Then the method execute business processes and retrieves eventually some results which will be used for the response
4. The method of the controller create an instance of a jResponse object which is setup with datas or else (initialization of templates etc..).
5. Jelix gets this jResponse object, launch the generation of the final document (html page, pdf..) and then sends it to the browser.