composer automatically loaded four ways

For automatic loading of a third party package, Composer provides support of four ways, namely PSR-0 and autoloaders PSR-4 generates class-map, and the files contained directly.

First introduced autoload.php, in the main index.php file.

require 'vendor/autoload.php';

PSR-4 (recommended)

In composer.json is carried out in the configuration:

{
  "autoload": {
    "psr-4": {
      "Foo\\": "src/"
    }
  }
}

Perform composer installupdates automatically load, update execution Composer dump-the autoload . According to the rules of the PSR-4, when trying to index.php new Foo\Bar\Bazwhen this class, composer will automatically look for "src / Bar / Baz.php" this file, if it exists, is loaded.

PSR-0 (not recommended)

In composer.json is carried out in the configuration:

{
  "autoload": {
    "psr-0": {
      "Foo\\": "src/"
    }
  }
}

Perform composer installupdates automatically load, update execution Composer dump-the autoload . Note that according to the rules PSR-0 when trying to index.php new Foo\Bar\Bazwhen this class, composer will look for "src / Foo / Bar / Baz.php " this file, if it exists, is loaded.

NOTE: Also note PSR-4 and is disposed in the PSR-0, "Foo \" end delimiter must be added to the namespace and escaped, to prevent "Foo" matched to such an accident "FooBar" occurs.

Class-map mode

{
  "autoload": {
    "classmap": ["src/", "lib/", "Something.php"]
  }
}

Perform composer installupdates automatically load, update execution Composer dump-the autoload . composer scans the specified directory to the file .php or .inc the end of the class, generate class to the specified file path mapping, and add the newly created vendor/composer/autoload_classmap.php file. For example, a src / the BaseControllerclass, then the autoload_classmap.phpfile, such a configuration will be generated:

'BaseController' => $baseDir . '/src/BaseController.php'

Examples of class manner There are two different situations.

• If you load the file has a namespace, press namespace instantiated.
• If no namespace, directly by the class name to instantiate.

Files mode

{
  "autoload": {
    "files": ["src/MyLibrary/functions.php"]
  }
}

Perform composer installupdates automatically load, update execution Composer dump-the autoload . Files way is to manually specify the file for immediate loading. For example, we have a series of global helper functions, can be placed in a helper file and then directly loaded, that is, when you use require 'vendor/autoload.php';the automatic loader class loader will automatically load the files in the file came in, you used directly on the line.

 

Turn: https: //blog.csdn.net/ltx06/article/details/78820127