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Best Practices when Creating Modules

When creating a ZF2 module, there are some best practices you should keep in mind.

  • Keep the init() method lightweight. Be conservative with the actions you perform in the init() method of your Module class. This method is run for every page request, and should not perform anything heavy. As a rule of thumb, registering event listeners is an appropriate task to perform in the init() method. Such lightweight tasks will generally not have a measurable impact on the performance of your application, even with many modules enabled. It is considered bad practice to utilize the init() method for setting up or configuring instances of application resources such as a database connection, application logger, or mailer. Tasks such as these are better served through the dependency injection capabilities of Zend Framework 2.

  • Do not perform writes within a module. You should never code your module to perform or expect any writes within the module's directory. Once installed, the files within a module's directory should always match the distribution verbatim. Any user-provided configuration should be performed via overrides in the Application module or via application-level configuration files. Any other required filesystem writes should be performed in some writeable path that is outside of the module's directory.

    There are two primary advantages to following this rule. First, any modules which attempt to write within themselves will not be compatible with phar packaging. Second, by keeping the module in sync with the upstream distribution, updates via mechanisms such as Git will be simple and trouble-free. Of course, the Application module is a special exception to this rule, as there is typically no upstream distribution for this module, and it's unlikely you would want to run this package from within a phar archive.

  • Utilize a vendor prefix for module names. To avoid module naming conflicts, you are encouraged to prefix your module namespace with a vendor prefix. As an example, the (incomplete) developer tools module distributed by Zend is named "ZendDeveloperTools" instead of simply "DeveloperTools".

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