An application is an instance of TApplication or its derived class. It manages modules that provide different functionalities and are loaded when needed. It provides services to end-users. It is the central place to store various parameters used in an application. In a PRADO application, the application instance is the only object that is globally accessible via Prado::getApplication() function call.
Applications are configured via application configurations. They are usually created in entry scripts like the following,
$application = new TApplication;
where the method run()
starts the application to handle user requests.
A minimal PRADO application contains two files: an entry file and a page template file. They must be organized as follows,
- wwwroot - Web document root or sub-directory.
- index.php - entry script of the PRADO application.
- assets - directory storing published private files. See assets section.
- protected - application base path storing application data and private script files. This directory should be configured inaccessible to Web-inaccessible, or it may be located outside of Web directories.
- runtime - application runtime storage path. This directory is used by PRADO to store application runtime information, such as application state, cached data, etc.
- pages - base path storing all PRADO pages. See services section.
- Home.page - default page returned when users do not explicitly specify the page requested. This is a page template file. The file name without suffix is the page name. The page class is TPage. If there is also a class file Home.php, the page class becomes Home.
A product PRADO application usually needs more files. It may include an application configuration file named application.xml under the application base path protected. The pages may be organized in directories, some of which may contain page configuration files named config.xml. Fore more details, please see configurations section.
Deploying a PRADO application mainly involves copying directories. For example, to deploy the above minimal application to another server, follow the following steps,
- Copy the content under wwwroot to a Web-accessible directory on the new server.
- Modify the entry script file index.php so that it includes correctly the prado.php file.
- Remove all content under assets and runtime directories and make sure both directories are writable by the Web server process.
Like page lifecycles, an application also has lifecycles. Application modules can register for the lifecycle events. When the application reaches a particular lifecycle and raises the corresponding event, the registered module methods are invoked automatically. Modules included in the PRADO release, such as TAuthManager, are using this way to accomplish their goals.
The application lifecycles can be depicted as follows,