Nov 29, 2013 · Nov 28, 2013 · Nov 29, 2013 · Nov 28, 2013 · Nov 28, 2013 · Nov 28, 2013
diff --git a/book/includes/_service_container_my_mailer.rst.inc b/book/includes/_service_container_my_mailer.rst.inc
 .. configuration-block::

    .. code-block:: yaml

        # app/config/config.yml
        services:
            my_mailer:
                class:        Acme\HelloBundle\Mailer
                arguments:    [sendmail]

    .. code-block:: xml

        <!-- app/config/config.xml -->
        <?xml version="1.0" encoding="UTF-8" ?>
        <container xmlns="http://symfony.com/schema/dic/services"
            xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
            xsi:schemaLocation="http://symfony.com/schema/dic/services
                http://symfony.com/schema/dic/services/services-1.0.xsd"
            >

            <services>
                <service id="my_mailer" class="Acme\HelloBundle\Mailer">
                    <argument>sendmail</argument>
                </service>
            </services>
        </container>

    .. code-block:: php

        // app/config/config.php
        use Symfony\Component\DependencyInjection\Definition;

        $container->setDefinition('my_mailer', new Definition(
            'Acme\HelloBundle\Mailer',
            array('sendmail')
        ));
diff --git a/book/service_container.rst b/book/service_container.rst
 create the ``Mailer`` service. This is done via configuration, which can
 be specified in YAML, XML or PHP:

 .. configuration-block::

    .. code-block:: yaml

        # app/config/config.yml
        services:
            my_mailer:
                class:        Acme\HelloBundle\Mailer
                arguments:    [sendmail]

    .. code-block:: xml

        <!-- app/config/config.xml -->
        <?xml version="1.0" encoding="UTF-8" ?>
        <container xmlns="http://symfony.com/schema/dic/services"
            xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
            xsi:schemaLocation="http://symfony.com/schema/dic/services http://symfony.com/schema/dic/services/services-1.0.xsd">

            <services>
                <service id="my_mailer" class="Acme\HelloBundle\Mailer">
                    <argument>sendmail</argument>
                </service>
            </services>
        </container>

    .. code-block:: php

        // app/config/config.php
        use Symfony\Component\DependencyInjection\Definition;

        $container->setDefinition('my_mailer', new Definition(
            'Acme\HelloBundle\Mailer',
            array('sendmail')
        ));
 .. include includes/_service_container_my_mailer.rst.inc

 .. note::

 this dependency in the service container, the container takes care of all
 the work of instantiating the classes.

 Using the Expression Language
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

 .. versionadded:: 2.4
    The Expression Language functionality was introduced in Symfony 2.4.

 The service container also supports an "expression" that allows you to inject
 very specific values into a service.

 For example, suppose you have a third service (not shown here), called ``mailer_configuration``,
 which has a ``getMailerMethod()`` method on it, which will return a string
 like ``sendmail`` based on some configuration. Remember that the first argument
 to the ``my_mailer`` service is the simple string ``sendmail``:

 .. include includes/_service_container_my_mailer.rst.inc

 But instead of hardcoding this, how could we get this value from the ``getMailerMethod()``
 of the new ``mailer_configuration`` service? One way is to use an expression:

 .. configuration-block::

    .. code-block:: yaml

        # app/config/config.yml
        services:
            my_mailer:
                class:        Acme\HelloBundle\Mailer
                arguments:    ["@=service('mailer_configuration').getMailerMethod()"]

    .. code-block:: xml

        <!-- app/config/config.xml -->
        <?xml version="1.0" encoding="UTF-8" ?>
        <container xmlns="http://symfony.com/schema/dic/services"
            xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
            xsi:schemaLocation="http://symfony.com/schema/dic/services
                http://symfony.com/schema/dic/services/services-1.0.xsd"
            >

            <services>
                <service id="my_mailer" class="Acme\HelloBundle\Mailer">
                    <argument type="expression">service('mailer_configuration').getMailerMethod()</argument>
                </service>
            </services>
        </container>

    .. code-block:: php

        // app/config/config.php
        use Symfony\Component\DependencyInjection\Definition;
        use Symfony\Component\ExpressionLanguage\Expression;

        $container->setDefinition('my_mailer', new Definition(
            'Acme\HelloBundle\Mailer',
            array(new Expression('service("mailer_configuration").getMailerMethod()'))
        ));

 To learn more about the expression language syntax, see :doc:`/components/expression_language/syntax`.

 In this context, you have access to 2 functions:

 * ``service`` - returns a given service (see the example above);
 * ``parameter`` - returns a specific parameter value (syntax is just like ``service``)

 You also have access to the :class:`Symfony\\Component\\DependencyInjection\\ContainerBuilder`
 via a ``container`` variable. Here's another example:

 .. configuration-block::

    .. code-block:: yaml

        services:
            my_mailer:
                class:     Acme\HelloBundle\Mailer
                arguments: ["@=container.hasParameter('some_param') ? parameter('some_param') : 'default_value'"]

    .. code-block:: xml

        <?xml version="1.0" encoding="UTF-8" ?>
        <container xmlns="http://symfony.com/schema/dic/services"
            xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
            xsi:schemaLocation="http://symfony.com/schema/dic/services
                http://symfony.com/schema/dic/services/services-1.0.xsd"
            >

            <services>
                <service id="my_mailer" class="Acme\HelloBundle\Mailer">
                    <argument type="expression">@=container.hasParameter('some_param') ? parameter('some_param') : 'default_value'</argument>
                </service>
            </services>
        </container>

    .. code-block:: php

        use Symfony\Component\DependencyInjection\Definition;
        use Symfony\Component\ExpressionLanguage\Expression;

        $container->setDefinition('my_mailer', new Definition(
            'Acme\HelloBundle\Mailer',
            array(new Expression(
                "@=container.hasParameter('some_param') ? parameter('some_param') : 'default_value'"
            ))
        ));

 Expressions can be used in ``parameters``, ``arguments``, ``properties``,
 as arguments with ``configurator`` and as arguments to ``calls`` (method calls).

 Optional Dependencies: Setter Injection
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1,36 @@
		.. configuration-block::

		.. code-block:: yaml

		# app/config/config.yml
		services:
		my_mailer:
		class: Acme\HelloBundle\Mailer
		arguments: [sendmail]

		.. code-block:: xml

		<!-- app/config/config.xml -->
		<?xml version="1.0" encoding="UTF-8" ?>
		<container xmlns="http://symfony.com/schema/dic/services"
		xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
		xsi:schemaLocation="http://symfony.com/schema/dic/services
		http://symfony.com/schema/dic/services/services-1.0.xsd"
		>

Copy link Member xabbuhNov 28, 2013 Choose a reason for hiding this comment The reason will be displayed to describe this comment to others.Learn more. I prefer <containerxmlns="http://symfony.com/schema/dic/services"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://symfony.com/schema/dic/services http://symfony.com/schema/dic/services/services-1.0.xsd">
		<services>
		<service id="my_mailer" class="Acme\HelloBundle\Mailer">
		<argument>sendmail</argument>
		</service>
		</services>
		</container>

		.. code-block:: php

		// app/config/config.php
		use Symfony\Component\DependencyInjection\Definition;

		$container->setDefinition('my_mailer', new Definition(
		'Acme\HelloBundle\Mailer',
		array('sendmail')
		));
Copy link Member wouterjNov 28, 2013 Choose a reason for hiding this comment The reason will be displayed to describe this comment to others.Learn more. always add a new line at the end Copy link Member wouterjNov 28, 2013 Choose a reason for hiding this comment The reason will be displayed to describe this comment to others.Learn more. hmm, no. This can cause problems when including :) Copy link Member xabbuhNov 28, 2013 Choose a reason for hiding this comment The reason will be displayed to describe this comment to others.Learn more. Don't think so. Why should this cause problems?
Original file line number	Diff line number	Diff line change
Expand Up		@@ -103,40 +103,7 @@ for you. In order for this to work, you must teach the container how to
		create the ``Mailer`` service. This is done via configuration, which can
		be specified in YAML, XML or PHP:

		.. configuration-block::

		.. code-block:: yaml

		# app/config/config.yml
		services:
		my_mailer:
		class: Acme\HelloBundle\Mailer
		arguments: [sendmail]

		.. code-block:: xml

		<!-- app/config/config.xml -->
		<?xml version="1.0" encoding="UTF-8" ?>
		<container xmlns="http://symfony.com/schema/dic/services"
		xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
		xsi:schemaLocation="http://symfony.com/schema/dic/services http://symfony.com/schema/dic/services/services-1.0.xsd">

		<services>
		<service id="my_mailer" class="Acme\HelloBundle\Mailer">
		<argument>sendmail</argument>
		</service>
		</services>
		</container>

		.. code-block:: php

		// app/config/config.php
		use Symfony\Component\DependencyInjection\Definition;

		$container->setDefinition('my_mailer', new Definition(
		'Acme\HelloBundle\Mailer',
		array('sendmail')
		));
		.. include includes/_service_container_my_mailer.rst.inc

		.. note::

Expand DownExpand Up		@@ -660,6 +627,113 @@ service needs the ``my_mailer`` service in order to function. When you define
		this dependency in the service container, the container takes care of all
		the work of instantiating the classes.

		Using the Expression Language
		~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Copy link Member wouterjNov 28, 2013 Choose a reason for hiding this comment The reason will be displayed to describe this comment to others.Learn more. missing versionadded directive Copy link MemberAuthor weaverryanNov 29, 2013 Choose a reason for hiding this comment The reason will be displayed to describe this comment to others.Learn more. ah, good catch :)
		.. versionadded:: 2.4
		The Expression Language functionality was introduced in Symfony 2.4.

		The service container also supports an "expression" that allows you to inject
		very specific values into a service.

		For example, suppose you have a third service (not shown here), called ``mailer_configuration``,
		which has a ``getMailerMethod()`` method on it, which will return a string
		like ``sendmail`` based on some configuration. Remember that the first argument
		to the ``my_mailer`` service is the simple string ``sendmail``:

		.. include includes/_service_container_my_mailer.rst.inc
Copy link Member wouterjNov 28, 2013 Choose a reason for hiding this comment The reason will be displayed to describe this comment to others.Learn more. why did you include the config again, instead of adding a reference in case they forgot? Copy link MemberAuthor weaverryanNov 29, 2013 Choose a reason for hiding this comment The reason will be displayed to describe this comment to others.Learn more. I think seeing the 2 examples side-by-side will be much more clear

		But instead of hardcoding this, how could we get this value from the ``getMailerMethod()``
		of the new ``mailer_configuration`` service? One way is to use an expression:
Copy link Member wouterjNov 28, 2013 Choose a reason for hiding this comment The reason will be displayed to describe this comment to others.Learn more. one way? You mean, "the only way" (besides using parameters, which is already explained) Copy link MemberAuthor weaverryanNov 29, 2013 Choose a reason for hiding this comment The reason will be displayed to describe this comment to others.Learn more. The other way would be to inject`mailer_configuration` and then fetch the value. And depending on what you're doing in the mailer (what you need exactly), this might make sense. Copy link Member stofNov 29, 2013 Choose a reason for hiding this comment The reason will be displayed to describe this comment to others.Learn more. it also depends whether your configuration is mutable at runtime or no (getting it with an expression will not allow you to get an updated setting, while you can when injecting the configuration if you fetch the value each time you need it)

		.. configuration-block::

		.. code-block:: yaml

		# app/config/config.yml
		services:
		my_mailer:
		class: Acme\HelloBundle\Mailer
		arguments: ["@=service('mailer_configuration').getMailerMethod()"]

		.. code-block:: xml

		<!-- app/config/config.xml -->
		<?xml version="1.0" encoding="UTF-8" ?>
		<container xmlns="http://symfony.com/schema/dic/services"
		xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
		xsi:schemaLocation="http://symfony.com/schema/dic/services
		http://symfony.com/schema/dic/services/services-1.0.xsd"
		>

Copy link Member xabbuhNov 28, 2013 Choose a reason for hiding this comment The reason will be displayed to describe this comment to others.Learn more. see my comment in the example above
		<services>
		<service id="my_mailer" class="Acme\HelloBundle\Mailer">
		<argument type="expression">service('mailer_configuration').getMailerMethod()</argument>
		</service>
		</services>
		</container>

		.. code-block:: php

		// app/config/config.php
		use Symfony\Component\DependencyInjection\Definition;
		use Symfony\Component\ExpressionLanguage\Expression;

		$container->setDefinition('my_mailer', new Definition(
		'Acme\HelloBundle\Mailer',
		array(new Expression('service("mailer_configuration").getMailerMethod()'))
		));

		To learn more about the expression language syntax, see :doc:`/components/expression_language/syntax`.

		In this context, you have access to 2 functions:

		* ``service`` - returns a given service (see the example above);
		* ``parameter`` - returns a specific parameter value (syntax is just like ``service``)

		You also have access to the :class:`Symfony\\Component\\DependencyInjection\\ContainerBuilder`
		via a ``container`` variable. Here's another example:

		.. configuration-block::

		.. code-block:: yaml

		services:
		my_mailer:
		class: Acme\HelloBundle\Mailer
		arguments: ["@=container.hasParameter('some_param') ? parameter('some_param') : 'default_value'"]

		.. code-block:: xml

		<?xml version="1.0" encoding="UTF-8" ?>
		<container xmlns="http://symfony.com/schema/dic/services"
		xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
		xsi:schemaLocation="http://symfony.com/schema/dic/services
		http://symfony.com/schema/dic/services/services-1.0.xsd"
		>

		<services>
		<service id="my_mailer" class="Acme\HelloBundle\Mailer">
		<argument type="expression">@=container.hasParameter('some_param') ? parameter('some_param') : 'default_value'</argument>
		</service>
		</services>
		</container>

		.. code-block:: php

		use Symfony\Component\DependencyInjection\Definition;
		use Symfony\Component\ExpressionLanguage\Expression;

		$container->setDefinition('my_mailer', new Definition(
		'Acme\HelloBundle\Mailer',
		array(new Expression(
		"@=container.hasParameter('some_param') ? parameter('some_param') : 'default_value'"
		))
		));

		Expressions can be used in ``parameters``, ``arguments``, ``properties``,
Copy link Member wouterjNov 30, 2013 Choose a reason for hiding this comment The reason will be displayed to describe this comment to others.Learn more. expressions cannot be used in parameters (seesymfony/symfony#9658 ) Copy link mvrhovNov 30, 2013 Choose a reason for hiding this comment The reason will be displayed to describe this comment to others.Learn more. It would really be nice if they could be! AS I said in the issue it works just as advertised if I remove the expression from the parameters array in dumped container. Copy link MemberAuthor weaverryanDec 1, 2013 Choose a reason for hiding this comment The reason will be displayed to describe this comment to others.Learn more. @wouterj good catch - italmost looks like it's supported in YamlFileLoader, but not actually :). Fixed at sha:`4738c75`
		as arguments with ``configurator`` and as arguments to ``calls`` (method calls).

		Optional Dependencies: Setter Injection
		~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Expand Down