php-doc-en/reference/sam/reference.xml

<?xml version='1.0' encoding='iso-8859-1'?>
<!-- $Revision: 1.5 $ -->
 <reference id="ref.sam">
  <title>SAM - Simple Asynchronous Messaging</title>
  <titleabbrev>SAM</titleabbrev>

  <partintro>
   <section id="sam.intro">
    &reftitle.intro;
    <para>
     This extension provides access to the functionality of messaging and
     queueing systems, such as the IBM WebSphere MQSeries family of products,
     from PHP scripts. The interface is designed to make it extremely simple
     to do the more commonly required tasks such as deliver simple text
     messages to queues while still allowing skilled users to do more complex
     messaging operations. For many users the complexities of setting up
     numerous options can be simply ignored.
    </para>
   </section>

   <section id='sam.installation'>
    &reftitle.install;
    <section id='sam.installation.prerequisites'>
     <title>Prerequisites</title>
      <para>
       The SAM extension interfaces to the IBM Messaging and Queuing
       middleware products using a set of libraries and some client side code
       referred to as XMS. This package is available as a free download in
       the guise of IBM support pack IA94. There is a description of this
       package and download links in the article <ulink url="&url.ibm.ia94;">
       Introducing XMS - The IBM Message Service API</ulink>.
      </para>
      <para>
       If you intend to use SAM to access the Messaging and Queuing
       infrastructure within WebSphere MQ then you will also need to have
       installed a local MQ queue manager or installed the WebSphere MQ
       clients package. The clients package is freely available as a support
       pack (<ulink url="&url.ibm.mqc6;">MQC6</ulink>).
      </para>
      <para>
       If you are only aiming to experiment with sending messages to and from
       WebSphere Application Server queues using the WebSphere Platform
       Messaging protocol (WPM) then you do not need to install the MQC6
       package.
      </para>
      <para>
       After installing these packages you will need to ensure the XMS binary
       and, if you are using it, the MQ client bin directory are included in
       the PATH environment variable so that Apache and PHP can find the
       dependent .DLLs/libraries.
      </para>
     </section>
     <section id='sam.installation.linux'>
      <title>Linux installation steps</title>
      <para>
       The sam extension is supplied as a PECL module, which
       you should be able to download and install in one step as follows:
       <screen>
<![CDATA[
pear install sam
]]>
       </screen>
       (Depending on your php environment, you will probably need to be root
       to do this.)
      </para>
      <para>
       Make sure that the module is loaded by PHP, by adding following line
       to &php.ini;:
       <screen>
<![CDATA[
extension=sam.so
]]>
       </screen>
      </para>
      <para>
       If you cannot use the PEAR installer, you can download the extension
       and build it manually:
      <screen>
<![CDATA[
pear download sam          #downloads sam-<version>.tgz
tar -xzf sam-<version>.tgz
cd sam-<version>
phpize
./configure
make
make install               #you may need to be root for this step
]]>
      </screen>
      </para>
      <para>
       To work with the very latest source, you'll need to extract it from
       cvs and build manually as above.
      </para>
     </section>
     <section id='sam.installation.windows'>
     <title>Windows installation steps</title>
      <para>
       Currently you will need to build the sam extension for Windows as
       there are no pre-built binaries. The extension can be built using the
       standard Windows extension build procedures.
      </para>
      <para>
       You will need the PHP source tree for the version of PHP you wish to
       build the SAM extension against which you can obtain from php.net. 
       This should be unpacked into a working directory of your choice.
      </para>
      <para>
       You will also need the libraries and headers used by PHP extensions
       available from http://www.php.net/extra/win32build.zip and this
       should be unzipped so that is in your working directory.
      </para>
      <para>
       You should have something like:
       <screen>
<![CDATA[
c:\php-build\-
              |
              |---php-5.0.5--|---build
              |              |---ext
              |              |--- ...
              |
              |---win32build--|---bin
                              |---include
                              |---lib
]]>
       </screen>
      </para>
      <para>
       You will need a compiler such as the free version of Visual Studio C++
       Express from the Microsoft web site. Also you need the Microsoft
       Windows Platform SDK which again can be downloaded from the Microsoft web site.
      </para>
      <para>
       Obtain the SAM extension source using pear (pear download sam) or by
       using CVS and copy the files to a new "sam" directory under the "ext"
       directory in your PHP source tree.
      </para>
      <para>
       To build the extension open a build environment window by going to the
       start menu->all programs->microsoft platform SDK for windows->
       open build environment window->windows 200 build environment->
       set windows 2000 build environment (retail)
      </para>
      <para>
       This should open a command prompt with all the environment variables
       set up to access the platform SDK etc. You then need to set the
       environment variables for Visual Studio by issuing the command
       "vcvars32.bat" in the window.
      </para>
      <para>
       Change directory to your working directory e.g. cd c:\php-build. Then
       make sure the win32build tools are accessible by adding them to the
       PATH environment variable:
       <screen>
<![CDATA[
set PATH=..\win32build\bin;%PATH%
]]>
       </screen>
      </para>
      <para> 
       Run the buildconf.bat command. This should rebuild the configure.js
       file.
      </para>
      <para>
       Run the cscript command:
       <screen>
<![CDATA[
cscript /nologo configure.js --with-sam="c:\program files\ibm\xms"
]]>
       </screen>
      </para>
      <para>
       The additional parameter passed for sam is the installation path to
       the XMS libraries and runtime that were installed as described under
       prerequisites at the top of this file.
      </para>
      <para>
       You can specify whatever other cscript parameters you require to
       include or exclude items from the php build or select options.
      </para>
      <para>
       Assuming all has gone well so far you can now finally run a make!
       <screen>
<![CDATA[
nmake php_sam.dll
]]>
      </screen>
      </para>
     </section>
     <section id='sam.installation.VS2005'>
      <title>Additional steps for Visual Studio 2005</title>
      <para>
       If you build the SAM extension with the Microsoft Visual Studio 2005
       compiler and tools you need to perform an additional step in the build
       process to ensure the <filename>php_sam.dll</filename> is able to link
       with the C runtime libraries at runtime. This step includes the
       dependancy manifest into the DLL. Switch to the directory where the
       <filename>php_sam.dll</filename> has been generated (usually 
       Release_TS or Debug_TS below the php source directory) and issue the
       following magic incantation:
       <screen>
<![CDATA[
mt.exe -manifest php_sam.dll.manifest -outputresource:php_sam.dll;2
]]>
       </screen>
      </para>
      <para>
       If you build the SAM extension using the compiler and libaries from
       Microsoft Visual Studio 2005 you will also need to ensure that the
       runtime components are installed on the system on which you intend to
       use SAM. This can be accomplished by installing Visual Studio 2005 or
       by using the freely distributable 
       <ulink url="&url.ms.crt;">runtime package</ulink>.
      </para>
     </section>
   </section>  <!-- id=sam.installation -->

   <section id='sam.usage'>
    <title>API Usage</title>

    <section id='sam.connections'>
     <title>Connections</title>
      <para>
       In order to perform any messaging and queueing functions a connection
       must be established with a messaging server by creating a SAMConnection
       object and calling its "connect" method, with a set of connection
       properties, to connect the PHP script to the messaging server.  Until
       such time as the SAMConnection object is destroyed the connection
       will be maintained and available for use. All SAMConnection objects
       are destroyed when the PHP script exits.
     </para>
     <para>
       A set of default properties may be used in connecting to a messaging
       server but as a minimum the PHP script must specify a protocol to be
       used.
     </para>
     <para>
      <example>
       <title>Creating a connection and connecting to a remote WebSphere MQSeries Messaging Server</title>
       <programlisting role='php'>
<![CDATA[
<?php
$conn = new SAMConnection();
$conn->connect(SAM_WMQ, array(SAM_HOST => myhost.mycompany.com,
                              SAM_PORT => 1506,
                              SAM_BROKER => mybroker));
?>
]]>
       </programlisting>
      </example>
     </para>
     <para>
      <example>
       <title>Creating a connection and connecting to a remote WebSphere Application Server</title>
       <programlisting role='php'>
<![CDATA[
<?php
$conn = new SAMConnection();
$conn->connect(SAM_WMQ, array(SAM_ENDPOINTS => 'localhost:7278:BootstrapBasicMessaging',
                              SAM_BUS => 'Bus1',
                              SAM_TARGETCHAIN => 'InboundBasicMessaging'));
?>
]]>
       </programlisting>
      </example>
     </para>
    </section>  <!-- id=sam.connections -->

    <section id='sam.messages'>
     <title>Messages</title>
     <para>
      Messages sent to and received from queues are represented by the
      SAMMessage object. The SAMMessage object encapsulates the body of
      the message (if one exists) and the header properties associated with
      the message. A SAMMessage object is either supplied as a parameter to
      a messaging operation or returned as a result.
     </para>
     <para>
      <example>
       <title>Creating a message with a simple text body</title>
       <programlisting role="php">
<![CDATA[
<?php
$msg = new SAMMessage('This is a simple text message');
?>
]]>
       </programlisting>
      </example>
     </para>
     <para>
      Messages may have header properties associated with them that provide
      control over the transport of the message or further information to the
      receiving application. By default message properties are delivered to
      the underlying messaging system as strings and in this case they may be
      set with the following simple syntax:
     </para>
     <para>
      <example>
       <title>Setting a text format property using the default syntax</title>
       <programlisting role="php">
<![CDATA[
<?php
   $msg->header->myPropertyName = 'textData';
?>
]]>
       </programlisting>
      </example>
     </para>
     <para>
      If it is desired to pass type information an alternative syntax may be
      used where the value and the type hint are passed in an associative
      array:
     </para>
     <para>
      <example>
       <title>Setting a property using a type hint</title>
       <programlisting role="php">
<![CDATA[
<?php
   $msg->header->myPropertyName = array(3.14159, SAM_FLOAT);
?>
]]>
       </programlisting>
      </example>
     </para>
     <para>
      Properties may also be extracted from the header of a message.
     </para>
     <para>
      <example>
       <title>Retrieving a property from a message header</title>
       <programlisting role="php">
<![CDATA[
<?php
   $myProperty = $msg->header->myPropertyName;
?>
]]>
       </programlisting>
      </example>
     </para>
    </section>  <!-- id=sam.messages -->

    <section id='sam.operations'>
     <title>Messaging operations</title>
     <para>
      All messaging operations are performed through calls to methods on the
      connection object.
      To add a message to a queue the "send" method is used, to obtain a
      message from a queue the "receive" method is used. Other methods
      provide publish and subscribe functionality and control of transaction
      boundaries.
     </para>
     <para>
      <example>
       <title>Adding a message to a queue and receiving a response</title>
       <programlisting role="php">
<![CDATA[
<?php
$msg = new SAMMessage('This is a simple text message');
$msg->header->SAM_REPLY_TO = 'queue://receive/test';
$correlid = $conn->send('queue://send/test', $msg);

if (!$correlid) {
  // The Send failed!
  echo "Send failed ($conn->errno) $conn->error";
} else {
  $resp = $conn->receive('queue://receive/test', array(SAM_CORRELID => $correlid));
}
?>
]]>
       </programlisting>
      </example>
     </para>
    </section>  <!-- id=sam.operations -->
    <section id='sam.pubsub'>
     <title>Publish/Subscribe and suscriptions to topics</title>
     <para>
      SAM allows messages to be sent either to queues or, for WebSphere MQ
      and WPM, to publish/subscribe topics.
      A topic desintation is specified to SAM in the usual way, i.e. in the
      form 'topic://fred', rather than the form 'queue://AQUEUE' used for
      point to point operation. To use publish/subscribe it is simply
      necessary to specify the correct broker name on the SAMConnect
      "connect" call and the desired topic in the destination argument to
      the SAMConnect "send" and "receive" calls. The PHP interface is
      otherwise identical to the point to point model.
     </para>
     <para>
      By default, SAM creates non-durable subscriptions when using 
      publish/subscribe. This means that if a client application is 
      inactive when messages are published to a topic, then it will not
      receive them when it subsequently restarted. SAM does also allow
      durable subscriptions to be made to topics when using WPM or WebSphere
      MQ publish/subscribe. The purpose of these subscriptions is to allow
      data to be received by a client application even if that client was not
      active at the time the data was published.
     </para>
     <para>
      Durable subscriptions are specified by using the SAMConnect "subscribe"
      call. This method takes the destination topic as an input parameter and
      returns a subscription identifier that may be used on subsequent 
      "receive" calls. When the subscription is no longer required the
      SAMConnection "unsubscribe" method should be used to delete the 
      subscription.
     </para>
     <para>
      <example>
       <title>Creating a durable subscription to a topic</title>
       <programlisting role="php">
<![CDATA[
<?php

$subName = $conn->subscribe('topic://A');

if (!$subName) {
   echo "Subscribe failed";
} else {
   # Subscribe was OK
   // ...
}
?>
]]>
       </programlisting>
      </example>
     </para>
     <para>
      <example>
       <title>Subscribing to a topic using a WebSphere Platform Messaging (WPM) server</title>
       <programlisting role="php">
<![CDATA[
<?php
$conn = new SAMConnection();
// Note: For pub/sub on WPM, when connecting the name of a messaging engine
//   to hold the durable subscription (SAM_WPM_DUR_SUB_HOME) must be specified.
$conn->connect(SAM_WMQ, array(SAM_ENDPOINTS => 'localhost:7278:BootstrapBasicMessaging',
                              SAM_BUS => 'Bus1',
                              SAM_TARGETCHAIN => 'InboundBasicMessaging'
                              SAM_WPM_DUR_SUB_HOME => 'MyMachineNode01.server1-Bus1'));

$subName = $conn->subscribe('topic://A');

if (!$subName) {
   echo "Subscribe failed";
} else {
   # Subscribe was OK
   // ...
}
?>
]]>
       </programlisting>
      </example>
     </para>
     <para>
      <example>
       <title>Receiving published data using a durable subscription</title>
       <programlisting role="php">
<![CDATA[
<?php

$msg = $conn->receive($subName);
if ($msg) {
   echo "Received a message OK";
} else {
   echo "The receive failed";
}

?>
]]>
       </programlisting>
      </example>
     </para>
     <para>
      <example>
       <title>Deleting a durable subscription to a topic</title>
       <programlisting role="php">
<![CDATA[
<?php

if (!$conn->unsubscribe($subName)) {
   echo "Unsubscribe failed";
}

?>
]]>
       </programlisting>
      </example>
     </para>
    </section>  <!-- id=sam.pubsub -->
    <section id='sam.errors'>
     <title>Error handling</title>
     <para>
      All SAMConnection methods that provide access to messaging operations
      return &false; if an error occurred in processing the request. 
      In addition the SAMConnection object has two properties, "errno"
      and "error", that provide respectively the error number and
      text description of the last error to occur on the connection.
     </para>
     <para>
      <example>
       <title>Handling an error from a method that returns no result</title>
       <programlisting role="php">
        <![CDATA[
<?php
   if (!$conn->commit()) {
     // The commit failed!
     echo "Commit failed ($conn->errno) $conn->error";
   }
?>
        ]]>
       </programlisting>
      </example>
     </para>
     <para>
      <example>
       <title>Handling an error from a method that returns a result</title>
       <programlisting role="php">
<![CDATA[
<?php
$correlid = $conn->send('queue://send/test', $msg);

if (!$correlid) {
  // The Send failed!
  echo "Send failed ($conn->errno) $conn->error";
} else {
  ...
}
?>
]]>
       </programlisting>
      </example>
     </para>
    </section>  <!-- id=sam.errors -->
   </section>  <!-- id=sam.usage -->

   <!-- class definition section -->
   <section id='sam.classes'>
    &reftitle.classes;

<!-- Connection class  -->
    <section id='sam.class.Connection'>
     <title><classname>SAMConnection</classname></title>
     <para>
      Object representing a connection to a Messaging Server
     </para>

     <section id='sam.class.Connection.constructor'>
      &reftitle.constructor;
      <itemizedlist>
       <listitem>
        <para>
         <link linkend='function.samconnection-constructor'>new SAMConnection</link> - construct a new connection object to allow connection to a messaging infrastructure.
        </para>
       </listitem>
      </itemizedlist>
     </section>  <!-- id=sam.class.Connection.constructor -->

     <section id='sam.class.Connection.methods'>
      &reftitle.methods;
      <itemizedlist>
       <listitem>
        <para>
         <link linkend='function.samconnection-commit'>commit</link>
         - a method that commits (successfully completes) an in-flight unit
         of work.
        </para>
       </listitem>
       <listitem>
        <para>
         <link linkend='function.samconnection-connect'>connect</link>
         - a method that connects a PHP script to a messaging server.
        </para>
       </listitem>
       <listitem>
        <para>
         <link linkend='function.samconnection-disconnect'>disconnect</link>
         - a method that disconnects a PHP script from a messaging server.
        </para>
       </listitem>
       <listitem>
        <para>
         <link linkend='function.samconnection-isconnected'>isConnected</link>
         - a method that checks whether a PHP script is connected to a
          messaging server.
        </para>
       </listitem>
       <listitem>
        <para>
         <link linkend='function.samconnection-peek'>peek</link>
         - a method that receives a message from a queue without removing it
          from the queue.
        </para>
       </listitem>
       <listitem>
        <para>
         <link linkend='function.samconnection-peekall'>peekAll</link>
         - a method that receives one or messages from a queue without 
         removing them from the queue.
        </para>
       </listitem>       
       <listitem>
        <para>
         <link linkend='function.samconnection-receive'>receive</link>
         - a method that receives a message from a queue or subscription.
        </para>
       </listitem>
       <listitem>
        <para>
         <link linkend='function.samconnection-remove'>remove</link>
         - a method that removes a message from a queue.
        </para>
       </listitem>
       <listitem>
        <para>
         <link linkend='function.samconnection-rollback'>rollback</link>
         - a method that cancels (rolls back) an in-flight unit of work.
        </para>
       </listitem>
       <listitem>
        <para>
         <link linkend='function.samconnection-send'>send</link>
         - a method that sends a message to a queue or posts to a topic
        </para>
       </listitem>
       <listitem>
        <para>
         <link linkend='function.samconnection-subscribe'>subscribe</link>
         - a method that creates a subscription to one or more topics
        </para>
       </listitem>
       <listitem>
        <para>
         <link linkend='function.samconnection-unsubscribe'>unsubscribe</link>
         - a method that destroys a subscription to one or more topics
        </para>
       </listitem>
      </itemizedlist>
     </section>  <!-- id=sam.class.Connection.methods -->

     <section id='sam.class.Connection.properties'>
      &reftitle.properties;
      <itemizedlist>
       <listitem>
        <para>
         <link linkend='function.samconnection-errno'>errno</link> - the
         numeric error code for the last encountered error on this
         connection. This property is set to 0 if the last operation was
         successful.
        </para>
       </listitem>
       <listitem>
        <para>
         <link linkend='function.samconnection-error'>error</link> - the
         text description for the last encountered error on this connection
        </para>
       </listitem>
      </itemizedlist>
     </section>    <!-- id=sam.class.Connection.properties -->
    </section>   <!-- id=sam.class.Connection -->

<!-- Message class    *************************************************** -->
    <section id='sam.class.Message'>
     <title><classname>SAMMessage</classname></title>
     <para>
      Object representing a message to be sent or received
     </para>

     <section id='sam.class.Message.constructor'>
      &reftitle.constructor;
      <itemizedlist>
       <listitem>
        <para>
         <link linkend='function.sammessage-constructor'>new SAMMessage</link> - construct a
         new message.
        </para>
       </listitem>
      </itemizedlist>
     </section>  <!-- id=sam.class.Message.constructor -->

     <section id='sam.class.Message.properties'>
      &reftitle.properties;
      <itemizedlist>
       <listitem>
        <para>
         <link linkend='function.sammessage-body'>body</link> - the body of
         the message.
        </para>
       </listitem>
       <listitem>
        <para>
         <link linkend='function.sammessage-header'>header</link> - the
         header properties of the message.
        </para>
       </listitem>
      </itemizedlist>
     </section>  <!-- id=sam.class.Message.methods -->
    </section>   <!-- id=sam.class.Message -->

   </section>    <!-- id=sam.classes -->


   <!-- Include the stuff from constants.xml? -->
  &reference.sam.constants;

  </partintro>

  <!-- This seems to create the table of contents -->
 &reference.sam.functions;

 </reference>
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