repo_zf1/documentation/manual/en/module_specs/Zend_Amf-Server.xml

<?xml version="1.0" encoding="UTF-8"?>
<!-- Reviewed: no -->
<sect1 id="zend.amf.server">
    <title>Zend_Amf_Server</title>

    <para>
        <classname>Zend_Amf_Server</classname> provides an <acronym>RPC</acronym>-style server for
        handling requests made from the Adobe Flash Player using the <acronym>AMF</acronym>
        protocol. Like all Zend Framework server classes, it follows the SoapServer
        <acronym>API</acronym>, providing an easy to remember interface for creating servers.
    </para>

    <example id="zend.amf.server.basic">
        <title>Basic AMF Server</title>

        <para>
            Let's assume that you have created a class <classname>Foo</classname> with a
            variety of public methods. You may create an <acronym>AMF</acronym> server using the
            following code:
        </para>

        <programlisting language="php"><![CDATA[
$server = new Zend_Amf_Server();
$server->setClass('Foo');
$response = $server->handle();
echo $response;
]]></programlisting>

        <para>
            Alternately, you may choose to attach a simple function as a
            callback instead:
        </para>

        <programlisting language="php"><![CDATA[
$server = new Zend_Amf_Server();
$server->addFunction('myUberCoolFunction');
$response = $server->handle();
echo $response;
]]></programlisting>

        <para>
            You could also mix and match multiple classes and functions. When
            doing so, we suggest namespacing each to ensure that no method name
            collisions occur; this can be done by simply passing a second string
            argument to either <methodname>addFunction()</methodname> or
            <methodname>setClass()</methodname>:
        </para>

        <programlisting language="php"><![CDATA[
$server = new Zend_Amf_Server();
$server->addFunction('myUberCoolFunction', 'my')
       ->setClass('Foo', 'foo')
       ->setClass('Bar', 'bar');
$response = $server->handle();
echo $response;
]]></programlisting>

        <para>
            The <classname>Zend_Amf_Server</classname> also allows services to be dynamically
            loaded based on a supplied directory path. You may add as many directories as you wish
            to the server. The order that you add the directories to the server will be the
            order that the <acronym>LIFO</acronym> search will be performed on the directories to
            match the class. Adding directories is completed with the
            <methodname>addDirectory()</methodname> method.
        </para>

        <programlisting language="php"><![CDATA[
$server->addDirectory(dirname(__FILE__) .'/../services/');
$server->addDirectory(dirname(__FILE__) .'/../package/');
]]></programlisting>

        <para>
            When calling remote services your source name can have underscore ("_") and dot (".")
            directory delimiters. When an underscore is used <acronym>PEAR</acronym> and Zend
            Framework class naming conventions will be respected. This means that if you call the
            service com_Foo_Bar the server will look for the file
            <filename>Bar.php</filename> in the each of the included paths at
            <filename>com/Foo/Bar.php</filename>. If the dot notation is used for your remote
            service such as <filename>com.Foo.Bar</filename> each included path will have
            <filename>com/Foo/Bar.php</filename> append to the end to autoload
            <filename>Bar.php</filename>
        </para>

        <para>
            All <acronym>AMF</acronym> requests sent to the script will then be handled by the
            server, and an <acronym>AMF</acronym> response will be returned.
        </para>
    </example>

    <note>
        <title>All Attached Methods and Functions Need Docblocks</title>

        <para>
            Like all other server components in Zend Framework, you must document your class
            methods using <acronym>PHP</acronym> docblocks. At the minimum, you
            need to provide annotations for each required argument as well as
            the return value. As examples:
        </para>

        <programlisting language="php"><![CDATA[
// Function to attach:

/**
 * @param  string $name
 * @param  string $greeting
 * @return string
 */
function helloWorld($name, $greeting = 'Hello')
{
    return $greeting . ', ' . $name;
}
]]></programlisting>

        <programlisting language="php"><![CDATA[
// Attached class

class World
{
    /**
     * @param  string $name
     * @param  string $greeting
     * @return string
     */
    public function hello($name, $greeting = 'Hello')
    {
        return $greeting . ', ' . $name;
    }
}
]]></programlisting>

        <para>
            Other annotations may be used, but will be ignored.
        </para>
    </note>

    <sect2 id="zend.amf.server.flex">
        <title>Connecting to the Server from Flex</title>

        <para>
            Connecting to your <classname>Zend_Amf_Server</classname> from your Flex
            project is quite simple; you simply need to point your endpoint <acronym>URI</acronym>
            to your <classname>Zend_Amf_Server</classname> script.
        </para>

        <para>
            Say, for instance, you have created your server and placed it in the
            <filename>server.php</filename> file in your application root, and thus the
            <acronym>URI</acronym> is <filename>http://example.com/server.php</filename>. In this
            case, you would modify your <filename>services-config.xml</filename> file to set the
            channel endpoint uri attribute to this value.
        </para>

        <para>
            If you have never created a <filename>service-config.xml</filename> file you can do so
            by opening your project in your Navigator window. Right click on the project name and
            select 'properties'. In the Project properties dialog go into 'Flex Build Path' menu,
            'Library path' tab and be sure the '<filename>rpc.swc</filename>' file is added to your
            projects path and Press Ok to close the window.
        </para>

        <para>
            You will also need to tell the compiler to use the
            <filename>service-config.xml</filename> to find the RemoteObject endpoint. To do this
            open your project properties panel again by right clicking on the project folder from
            your Navigator and selecting properties. From the properties popup select 'Flex
            Compiler' and add the string: <command>-services "services-config.xml"</command>. Press
            Apply then OK to return to update the option. What you have just done is told the Flex
            compiler to look to the <filename>services-config.xml</filename> file for runtime
            variables that will be used by the RemotingObject class.
        </para>

        <para>
            We now need to tell Flex which services configuration file to use for connecting to
            our remote methods. For this reason create a new
            '<filename>services-config.xml</filename>' file into your Flex project src folder. To
            do this right click on the project folder and select 'new' 'File' which will popup a
            new window. Select the project folder and then name the file
            '<filename>services-config.xml</filename>' and press finish.
        </para>

        <para>
            Flex has created the new <filename>services-config.xml</filename> and has it open. Use
            the following example text for your <filename>services-config.xml</filename> file. Make
            sure that you update your endpoint to match that of your testing server. Make sure you
            save the file.
        </para>

        <programlisting language="xml"><![CDATA[
<?xml version="1.0" encoding="UTF-8"?>
<services-config>
    <services>
        <service id="zend-service"
            class="flex.messaging.services.RemotingService"
            messageTypes="flex.messaging.messages.RemotingMessage">
            <destination id="zend">
                <channels>
                    <channel ref="zend-endpoint"/>
                </channels>
                <properties>
                    <source>*</source>
                </properties>
            </destination>
        </service>
    </services>
    <channels>
        <channel-definition id="zend-endpoint"
            class="mx.messaging.channels.AMFChannel">
            <endpoint uri="http://example.com/server.php"
                class="flex.messaging.endpoints.AMFEndpoint"/>
        </channel-definition>
    </channels>
</services-config>
]]></programlisting>

        <para>
            There are two key points in the example. First, but last in the
            listing, we create an <acronym>AMF</acronym> channel, and specify the endpoint as the
            <acronym>URL</acronym> to our <classname>Zend_Amf_Server</classname>:
        </para>

        <programlisting language="xml"><![CDATA[
<channel-definition id="zend-endpoint"
    <endpoint uri="http://example.com/server.php"
        class="flex.messaging.endpoints.AMFEndpoint"/>
</channel-definition>
]]></programlisting>

        <para>
            Notice that we've given this channel an identifier, "zend-endpoint".
            The example create a service destination that refers to this channel,
            assigning it an ID as well -- in this case "zend".
        </para>

        <para>
            Within our Flex <acronym>MXML</acronym> files, we need to bind a RemoteObject to the
            service. In <acronym>MXML</acronym>, this might be done as follows:
        </para>

        <programlisting language="xml"><![CDATA[
<mx:RemoteObject id="myservice"
    fault="faultHandler(event)"
    showBusyCursor="true"
    destination="zend">
]]></programlisting>

        <para>
            Here, we've defined a new remote object identified by "myservice"
            bound to the service destination "zend" we defined in the
            <filename>services-config.xml</filename> file. We then call methods on it
            in our ActionScript by simply calling "myservice.&lt;method&gt;".
            As an example:
        </para>

        <programlisting language="ActionScript"><![CDATA[
myservice.hello("Wade");
]]></programlisting>

        <para>
            When namespacing, you would use
            "myservice.&lt;namespace&gt;.&lt;method&gt;":
        </para>

        <programlisting language="ActionScript"><![CDATA[
myservice.world.hello("Wade");
]]></programlisting>

        <para>
            For more information on Flex RemoteObject invocation, <ulink
            url="http://livedocs.adobe.com/flex/3/html/help.html?content=data_access_4.html">
            visit the Adobe Flex 3 Help site</ulink>.
        </para>
    </sect2>

    <sect2 id="zend.amf.server.errors">
        <title>Error Handling</title>

        <para>
            By default, all exceptions thrown in your attached classes or
            functions will be caught and returned as <acronym>AMF</acronym> ErrorMessages. However,
            the content of these ErrorMessage objects will vary based on whether
            or not the server is in "production" mode (the default state).
        </para>

        <para>
            When in production mode, only the exception code will be returned.
            If you disable production mode -- something that should be done for
            testing only -- most exception details will be returned: the
            exception message, line, and backtrace will all be attached.
        </para>

        <para>
            To disable production mode, do the following:
        </para>

        <programlisting language="php"><![CDATA[
$server->setProduction(false);
]]></programlisting>

        <para>
            To re-enable it, pass a <constant>TRUE</constant> boolean value instead:
        </para>

        <programlisting language="php"><![CDATA[
$server->setProduction(true);
]]></programlisting>

        <note>
            <title>Disable production mode sparingly!</title>

            <para>
                We recommend disabling production mode only when in development.
                Exception messages and backtraces can contain sensitive system
                information that you may not wish for outside parties to access.
                Even though <acronym>AMF</acronym> is a binary format, the specification is now
                open, meaning anybody can potentially deserialize the payload.
            </para>
        </note>

        <para>
            One area to be especially careful with is <acronym>PHP</acronym> errors themselves.
            When the <property>display_errors</property> <acronym>INI</acronym> directive is
            enabled, any <acronym>PHP</acronym> errors for the current error reporting level are
            rendered directly in the output -- potentially disrupting the <acronym>AMF</acronym>
            response payload. We suggest turning off the <property>display_errors</property>
            directive in production to prevent such problems
        </para>
    </sect2>

    <sect2 id="zend.amf.server.response">
        <title>AMF Responses</title>

        <para>
            Occasionally you may desire to manipulate the response object
            slightly, typically to return extra message headers. The
            <methodname>handle()</methodname> method of the server returns the response
            object, allowing you to do so.
        </para>

        <example id="zend.amf.server.response.messageHeaderExample">
            <title>Adding Message Headers to the AMF Response</title>

            <para>
                In this example, we add a 'foo' MessageHeader with the value
                'bar' to the response prior to returning it.
            </para>

            <programlisting language="php"><![CDATA[
$response = $server->handle();
$response->addAmfHeader(new Zend_Amf_Value_MessageHeader('foo', true, 'bar'))
echo $response;
]]></programlisting>
        </example>
    </sect2>

    <sect2 id="zend.amf.server.typedobjects">
        <title>Typed Objects</title>

        <para>
            Similar to <acronym>SOAP</acronym>, <acronym>AMF</acronym> allows passing objects
            between the client and server. This allows a great amount of flexibility and
            coherence between the two environments.
        </para>

        <para>
            <classname>Zend_Amf</classname> provides three methods for mapping
            ActionScript and <acronym>PHP</acronym> objects.
        </para>

        <itemizedlist>
            <listitem>
                <para>
                    First, you may create explicit bindings at the server level,
                    using the <methodname>setClassMap()</methodname> method. The first
                    argument is the ActionScript class name, the second the <acronym>PHP</acronym>
                    class name it maps to:
                </para>

                <programlisting language="php"><![CDATA[
// Map the ActionScript class 'ContactVO' to the PHP class 'Contact':
$server->setClassMap('ContactVO', 'Contact');
]]></programlisting>
            </listitem>

            <listitem>
                <para>
                    Second, you can set the public property <varname>$_explicitType</varname>
                    in your <acronym>PHP</acronym> class, with the
                    value representing the ActionScript class to map to:
                </para>

                <programlisting language="php"><![CDATA[
class Contact
{
    public $_explicitType = 'ContactVO';
}
]]></programlisting>
            </listitem>

            <listitem>
                <para>
                    Third, in a similar vein, you may define the public method
                    <methodname>getASClassName()</methodname> in your <acronym>PHP</acronym> class;
                    this method should return the appropriate ActionScript class:
                </para>

                <programlisting language="php"><![CDATA[
class Contact
{
    public function getASClassName()
    {
        return 'ContactVO';
    }
}
]]></programlisting>
            </listitem>
        </itemizedlist>

        <para>
            Although we have created the ContactVO on the server we now need to make its
            corresponding class in <acronym>AS3</acronym> for the server object to be mapped to.
        </para>

        <para>
            Right click on the src folder of the Flex project and select New -> ActionScript
            File. Name the file ContactVO and press finish to see the new file. Copy the
            following code into the file to finish creating the class.
        </para>

        <programlisting language="as"><![CDATA[
package
{
    [Bindable]
    [RemoteClass(alias="ContactVO")]
    public class ContactVO
    {
        public var id:int;
        public var firstname:String;
        public var lastname:String;
        public var email:String;
        public var mobile:String;
        public function ProductVO():void {
        }
    }
}
]]></programlisting>

        <para>
            The class is syntactically equivalent to the <acronym>PHP</acronym> of the same name.
            The variable names are exactly the same and need to be in the same case
            to work properly. There are two unique <acronym>AS3</acronym> meta tags in this class.
            The first is bindable which makes fire a change event when it is updated.
            The second tag is the RemoteClass tag which defines that this class can
            have a remote object mapped with the alias name in this case
            <emphasis>ContactVO</emphasis>. It is mandatory that this tag the value that was set
            is the <acronym>PHP</acronym> class are strictly equivalent.
        </para>

        <programlisting language="as"><![CDATA[
[Bindable]
private var myContact:ContactVO;

private function getContactHandler(event:ResultEvent):void {
    myContact = ContactVO(event.result);
}
]]></programlisting>

        <para>
            The following result event from the service call is cast instantly onto the Flex
            ContactVO. Anything that is bound to myContact will be updated with the returned
            ContactVO data.
        </para>
    </sect2>

    <sect2 id="zend.amf.server.resources">
        <title>Resources</title>

        <para>
            <classname>Zend_Amf</classname> provides tools for mapping resource types
            returned by service classes into data consumable by ActionScript.
        </para>

        <para>
            In order to handle specific resource type, the user needs to create a plugin class named
            after the resource name, with words capitalized and spaces removed (so, resource
            type "mysql result" becomes MysqlResult), with some prefix, e.g.
            <classname>My_MysqlResult</classname>. This class should implement one method,
            <methodname>parse()</methodname>, receiving one argument - the resource - and returning
            the value that should be sent to ActionScript. The class should be located in the file
            named after the last component of the name, e.g. <filename>MysqlResult.php</filename>.
        </para>

        <para>
            The directory containing the resource handling plugins should be registered with
            <classname>Zend_Amf</classname> type loader:
        </para>

        <programlisting language="php"><![CDATA[
Zend_Amf_Parse_TypeLoader::addResourceDirectory(
    "My",
    "application/library/resources/My"
);
]]></programlisting>

        <para>
            For detailed discussion of loading plugins, please see
            the <link linkend="zend.loader.pluginloader">plugin loader</link> section.
        </para>

        <para>
            Default directory for <classname>Zend_Amf</classname> resources is registered
            automatically and currently contains handlers for "mysql result" and "stream"
            resources.
        </para>

        <programlisting language="php"><![CDATA[
// Example class implementing handling resources of type mysql result
class Zend_Amf_Parse_Resource_MysqlResult
{
    /**
     * Parse resource into array
     *
     * @param resource $resource
     * @return array
     */
    public function parse($resource) {
        $result = array();
        while($row = mysql_fetch_assoc($resource)) {
            $result[] = $row;
        }
        return $result;
    }
}
]]></programlisting>

        <para>
            Trying to return unknown resource type (i.e., one for which no handler plugin exists)
            will result in an exception.
        </para>
    </sect2>

    <sect2 id="zend.amf.server.flash">
        <title>Connecting to the Server from Flash</title>

        <para>
            Connecting to your <classname>Zend_Amf_Server</classname> from your Flash project is
            slightly different than from Flex. However once the connection Flash functions with
            <classname>Zend_Amf_Server</classname> the same way is flex. The following example can
            also be used from a Flex <acronym>AS3</acronym> file. We will reuse the same
            <classname>Zend_Amf_Server</classname> configuration along with the World class for our
            connection.
        </para>

        <para>
            Open Flash CS and create and new Flash File (ActionScript 3). Name the document
            <filename>ZendExample.fla</filename> and save the document into a folder that you will
            use for this example. Create a new <acronym>AS3</acronym> file in the same directory
            and call the file <filename>Main.as</filename>. Have both files open in your editor. We
            are now going to connect the two files via the document class. Select ZendExample and
            click on the stage. From the stage properties panel change the Document class to Main.
            This links the <filename>Main.as</filename> ActionScript file with the user interface
            in <filename>ZendExample.fla</filename>. When you run the Flash file ZendExample the
            <filename>Main.as</filename> class will now be run. Next we will add ActionScript to
            make the <acronym>AMF</acronym> call.
        </para>

        <para>
            We now are going to make a Main class so that we can send the data to the server and
            display the result. Copy the following code into your <filename>Main.as</filename> file
            and then we will walk through the code to describe what each element's role is.
        </para>

        <programlisting language="as"><![CDATA[
package {
  import flash.display.MovieClip;
  import flash.events.*;
  import flash.net.NetConnection;
  import flash.net.Responder;

  public class Main extends MovieClip {
    private var gateway:String = "http://example.com/server.php";
    private var connection:NetConnection;
    private var responder:Responder;

    public function Main() {
      responder = new Responder(onResult, onFault);
      connection = new NetConnection;
      connection.connect(gateway);
    }

    public function onComplete( e:Event ):void{
      var params = "Sent to Server";
      connection.call("World.hello", responder, params);
    }

    private function onResult(result:Object):void {
      // Display the returned data
      trace(String(result));
    }
    private function onFault(fault:Object):void {
      trace(String(fault.description));
    }
  }
}
]]></programlisting>

        <para>
            We first need to import two ActionScript libraries that perform the bulk of the work.
            The first is NetConnection which acts like a by directional pipe between the client and
            the server. The second is a Responder object which handles the return values from the
            server related to the success or failure of the call.
        </para>

        <programlisting language="as"><![CDATA[
import flash.net.NetConnection;
import flash.net.Responder;
]]></programlisting>

        <para>
            In the class we need three variables to represent the NetConnection, Responder, and
            the gateway <acronym>URL</acronym> to our <classname>Zend_Amf_Server</classname>
            installation.
        </para>

        <programlisting language="as"><![CDATA[
private var gateway:String = "http://example.com/server.php";
private var connection:NetConnection;
private var responder:Responder;
]]></programlisting>

        <para>
            In the Main constructor we create a responder and a new connection to the
            <classname>Zend_Amf_Server</classname> endpoint. The responder defines two different
            methods for handling the response from the server. For simplicity I have called these
            onResult and onFault.
        </para>

        <programlisting language="as"><![CDATA[
responder = new Responder(onResult, onFault);
connection = new NetConnection;
connection.connect(gateway);
]]></programlisting>

        <para>
            In the onComplete function which is run as soon as the construct has completed we send
            the data to the server. We need to add one more line that makes a call to the
            <classname>Zend_Amf_Server</classname> World->hello function.
        </para>

        <programlisting language="as"><![CDATA[
connection.call("World.hello", responder, params);
]]></programlisting>

        <para>
            When we created the responder variable we defined an onResult and onFault function to
            handle the response from the server. We added this function for the successful result
            from the server. A successful event handler is run every time the connection is handled
            properly to the server.
        </para>

        <programlisting language="as"><![CDATA[
private function onResult(result:Object):void {
    // Display the returned data
    trace(String(result));
}
]]></programlisting>

        <para>
            The onFault function, is called if there was an invalid response from the server. This
            happens when there is an error on the server, the <acronym>URL</acronym> to the server
            is invalid, the remote service or method does not exist, and any other connection
            related issues.
        </para>

        <programlisting language="as"><![CDATA[
private function onFault(fault:Object):void {
    trace(String(fault.description));
}
]]></programlisting>

        <para>
            Adding in the ActionScript to make the remoting connection is now complete. Running the
            ZendExample file now makes a connection to <classname>Zend_Amf</classname>. In review
            you have added the required variables to open a connection to the remote server, defined
            what methods should be used when your application receives a response from the server,
            and finally displayed the returned data to output via <methodname>trace()</methodname>.
        </para>
    </sect2>

    <sect2 id="zend.amf.server.auth">
        <title>Authentication</title>

        <para>
            <classname>Zend_Amf_Server</classname> allows you to specify authentication and
            authorization hooks to control access to the services. It is using the infrastructure
            provided by <link linkend="zend.auth"><classname>Zend_Auth</classname></link> and
            <link linkend="zend.acl"><classname>Zend_Acl</classname></link> components.
        </para>

        <para>
            In order to define authentication, the user provides authentication adapter extening
            <classname>Zend_Amf_Auth_Abstract</classname> abstract class. The adapter should
            implement the <methodname>authenticate()</methodname> method just like regular
            <link linkend="zend.auth.introduction.adapters">authentication adapter</link>.
        </para>

        <para>
            The adapter should use properties <emphasis>_username</emphasis> and
            <emphasis>_password</emphasis> from the parent
            <classname>Zend_Amf_Auth_Abstract</classname> class in order to authenticate. These
            values are set by the server using <methodname>setCredentials()</methodname> method
            before call to <methodname>authenticate()</methodname> if the credentials are received
            in the <acronym>AMF</acronym> request headers.
        </para>

        <para>
            The identity returned by the adapter should be an object containing property
            <property>role</property> for the <acronym>ACL</acronym> access control to work.
        </para>

        <para>
            If the authentication result is not successful, the request is not proceseed further
            and failure message is returned with the reasons for failure taken from the result.
        </para>

        <para>
            The adapter is connected to the server using <methodname>setAuth()</methodname> method:
        </para>

        <programlisting language="php"><![CDATA[
$server->setAuth(new My_Amf_Auth());
]]></programlisting>

        <para>
            Access control is performed by using <classname>Zend_Acl</classname> object set by
            <methodname>setAcl()</methodname> method:
        </para>

        <programlisting language="php"><![CDATA[
$acl = new Zend_Acl();
createPermissions($acl); // create permission structure
$server->setAcl($acl);
]]></programlisting>

        <para>
            If the <acronym>ACL</acronym> object is set, and the class being called defines
            <methodname>initAcl()</methodname> method, this method will be called with the
            <acronym>ACL</acronym> object as an argument. The class then can create additional
            <acronym>ACL</acronym> rules and return <constant>TRUE</constant>, or return
            <constant>FALSE</constant> if no access control is required for this class.
        </para>

        <para>
            After <acronym>ACL</acronym> have been set up, the server will check if access is
            allowed with role set by the authentication, resource being the class name (or
            <constant>NULL</constant> for
            function calls) and privilege being the function name. If no authentication was
            provided, then if the <emphasis>anonymous</emphasis> role was defined, it will be used,
            otherwise the access will be denied.
        </para>

        <programlisting language="php"><![CDATA[
if($this->_acl->isAllowed($role, $class, $function)) {
    return true;
} else {
    require_once 'Zend/Amf/Server/Exception.php';
    throw new Zend_Amf_Server_Exception("Access not allowed");
}
]]></programlisting>
    </sect2>
</sect1>
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