repo_zf1/documentation/manual/en/module_specs/Zend_Mail_Read.xml

<?xml version="1.0" encoding="UTF-8"?>
<!-- Reviewed: no -->
<sect1 id="zend.mail.read">
    <title>Reading Mail Messages</title>

    <para>
        <classname>Zend_Mail</classname> can read mail messages from several local or remote mail
        storages. All of them have the same basic <acronym>API</acronym> to count and fetch messages
        and some of them implement additional interfaces for not so common features. For a feature
        overview of the implemented storages, see the following table.
    </para>

    <table id="zend.mail.read.table-1">
        <title>Mail Read Feature Overview</title>

        <tgroup cols="5">
            <thead>
                <row>
                    <entry>Feature</entry>
                    <entry>Mbox</entry>
                    <entry>Maildir</entry>
                    <entry>Pop3</entry>
                    <entry><constant>IMAP</constant></entry>
                </row>
            </thead>

            <tbody>
                <row>
                    <entry>Storage type</entry>
                    <entry>local</entry>
                    <entry>local</entry>
                    <entry>remote</entry>
                    <entry>remote</entry>
                </row>

                <row>
                    <entry>Fetch message</entry>
                    <entry>Yes</entry>
                    <entry>Yes</entry>
                    <entry>Yes</entry>
                    <entry>Yes</entry>
                </row>

                <row>
                    <entry>Fetch <acronym>MIME</acronym>-part</entry>
                    <entry>emulated</entry>
                    <entry>emulated</entry>
                    <entry>emulated</entry>
                    <entry>emulated</entry>
                </row>

                <row>
                    <entry>Folders</entry>
                    <entry>Yes </entry>
                    <entry>Yes</entry>
                    <entry>No</entry>
                    <entry>Yes</entry>
                </row>

                <row>
                    <entry>Create message/folder</entry>
                    <entry>No</entry>
                    <entry>todo</entry>
                    <entry>No</entry>
                    <entry>todo</entry>
                </row>

                <row>
                    <entry>Flags</entry>
                    <entry>No</entry>
                    <entry>Yes</entry>
                    <entry>No</entry>
                    <entry>Yes</entry>
                </row>

                <row>
                    <entry>Quota</entry>
                    <entry>No</entry>
                    <entry>Yes</entry>
                    <entry>No</entry>
                    <entry>No</entry>
                </row>
            </tbody>
        </tgroup>
    </table>

    <sect2 id="zend.mail.read-example">
        <title>Simple example using Pop3</title>

        <programlisting language="php"><![CDATA[
$mail = new Zend_Mail_Storage_Pop3(array('host'     => 'localhost',
                                         'user'     => 'test',
                                         'password' => 'test'));

echo $mail->countMessages() . " messages found\n";
foreach ($mail as $message) {
    echo "Mail from '{$message->from}': {$message->subject}\n";
}
]]></programlisting>
    </sect2>

    <sect2 id="zend.mail.read-open-local">
        <title>Opening a local storage</title>

        <para>
            Mbox and Maildir are the two supported formats for local mail storages, both in their
            most simple formats.
        </para>

        <para>
            If you want to read from a Mbox file you only need to give the filename to the
            constructor of <classname>Zend_Mail_Storage_Mbox</classname>:
        </para>

        <programlisting language="php"><![CDATA[
$mail = new Zend_Mail_Storage_Mbox(array('filename' =>
                                             '/home/test/mail/inbox'));
]]></programlisting>

        <para>Maildir is very similar but needs a dirname:</para>

        <programlisting language="php"><![CDATA[
$mail = new Zend_Mail_Storage_Maildir(array('dirname' =>
                                                '/home/test/mail/'));
]]></programlisting>

        <para>
            Both constructors throw a <classname>Zend_Mail_Exception</classname> if the storage
            can't be read.
        </para>
    </sect2>

    <sect2 id="zend.mail.read-open-remote">
        <title>Opening a remote storage</title>

        <para>
            For remote storages the two most popular protocols are supported: Pop3 and Imap. Both
            need at least a host and a user to connect and login. The default password is an empty
            string, the default port as given in the protocol <acronym>RFC</acronym>.
        </para>

        <programlisting language="php"><![CDATA[
// connecting with Pop3
$mail = new Zend_Mail_Storage_Pop3(array('host'     => 'example.com',
                                         'user'     => 'test',
                                         'password' => 'test'));

// connecting with Imap
$mail = new Zend_Mail_Storage_Imap(array('host'     => 'example.com',
                                         'user'     => 'test',
                                         'password' => 'test'));

// example for a none standard port
$mail = new Zend_Mail_Storage_Pop3(array('host'     => 'example.com',
                                         'port'     => 1120
                                         'user'     => 'test',
                                         'password' => 'test'));
]]></programlisting>

        <para>
            For both storages <acronym>SSL</acronym> and TLS are supported. If you use
            <acronym>SSL</acronym> the default port changes as given in the <acronym>RFC</acronym>.
        </para>

        <programlisting language="php"><![CDATA[
// examples for Zend_Mail_Storage_Pop3, same works for Zend_Mail_Storage_Imap

// use SSL on different port (default is 995 for Pop3 and 993 for Imap)
$mail = new Zend_Mail_Storage_Pop3(array('host'     => 'example.com',
                                         'user'     => 'test',
                                         'password' => 'test',
                                         'ssl'      => 'SSL'));

// use TLS
$mail = new Zend_Mail_Storage_Pop3(array('host'     => 'example.com',
                                         'user'     => 'test',
                                         'password' => 'test',
                                         'ssl'      => 'TLS'));
]]></programlisting>

        <para>
            Both constructors can throw <classname>Zend_Mail_Exception</classname> or
            <classname>Zend_Mail_Protocol_Exception</classname> (extends
            <classname>Zend_Mail_Exception</classname>), depending on the type of error.
        </para>
    </sect2>

    <sect2 id="zend.mail.read-fetching">
        <title>Fetching messages and simple methods</title>

        <para>
            Messages can be fetched after you've opened the storage . You need the message number,
            which is a counter starting with 1 for the first message. To fetch the message, you use
            the method <methodname>getMessage()</methodname>:
        </para>

        <programlisting language="php"><![CDATA[
$message = $mail->getMessage($messageNum);
]]></programlisting>

        <para>
            Array access is also supported, but this access method won't supported any additional
            parameters that could be added to <methodname>getMessage()</methodname>. As long as you
            don't mind, and can live with the default values, you may use:
        </para>

        <programlisting language="php"><![CDATA[
$message = $mail[$messageNum];
]]></programlisting>

        <para>For iterating over all messages the Iterator interface is implemented:</para>

        <programlisting language="php"><![CDATA[
foreach ($mail as $messageNum => $message) {
    // do stuff ...
}
]]></programlisting>

        <para>
            To count the messages in the storage, you can either use the method
            <methodname>countMessages()</methodname> or use array access:
        </para>

        <programlisting language="php"><![CDATA[
// method
$maxMessage = $mail->countMessages();

// array access
$maxMessage = count($mail);
]]></programlisting>

        <para>
            To remove a mail, you use the method <methodname>removeMessage()</methodname> or again
            array access:
        </para>

        <programlisting language="php"><![CDATA[
// method
$mail->removeMessage($messageNum);

// array access
unset($mail[$messageNum]);
]]></programlisting>
    </sect2>

    <sect2 id="zend.mail.read-message">
        <title>Working with messages</title>

        <para>
            After you fetch the messages with <methodname>getMessage()</methodname> you want to
            fetch headers, the content or single parts of a multipart message. All headers can be
            accessed via properties or the method <methodname>getHeader()</methodname> if you want
            more control or have unusual header names. The header names are lower-cased internally,
            thus the case of the header name in the mail message doesn't matter. Also headers with a
            dash can be written in camel-case. If no header is found for both notations an exception
            is thrown. To encounter this the method <methodname>headerExists()</methodname> can be
            used to check the existence of a header.
        </para>

        <programlisting language="php"><![CDATA[
// get the message object
$message = $mail->getMessage(1);

// output subject of message
echo $message->subject . "\n";

// get content-type header
$type = $message->contentType;

// check if CC isset:
if( isset($message->cc) ) { // or $message->headerExists('cc');
    $cc = $message->cc;
}
]]></programlisting>

        <para>
            If you have multiple headers with the same name- i.e. the Received headers- you might
            want an array instead of a string. In this case, use the
            <methodname>getHeader()</methodname> method.
        </para>

        <programlisting language="php"><![CDATA[
// get header as property - the result is always a string,
// with new lines between the single occurrences in the message
$received = $message->received;

// the same via getHeader() method
$received = $message->getHeader('received', 'string');

// better an array with a single entry for every occurrences
$received = $message->getHeader('received', 'array');
foreach ($received as $line) {
    // do stuff
}

// if you don't define a format you'll get the internal representation
// (string for single headers, array for multiple)
$received = $message->getHeader('received');
if (is_string($received)) {
    // only one received header found in message
}
]]></programlisting>

        <para>
            The method <methodname>getHeaders()</methodname> returns all headers as array with the
            lower-cased name as key and the value as and array for multiple headers or as string for
            single headers.
        </para>

        <programlisting language="php"><![CDATA[
// dump all headers
foreach ($message->getHeaders() as $name => $value) {
    if (is_string($value)) {
        echo "$name: $value\n";
        continue;
    }
    foreach ($value as $entry) {
        echo "$name: $entry\n";
    }
}
]]></programlisting>

        <para>
            If you don't have a multipart message, fetching the content is easily done via
            <methodname>getContent()</methodname>. Unlike the headers, the content is only fetched
            when needed (aka late-fetch).
        </para>

        <programlisting language="php"><![CDATA[
// output message content for HTML
echo '<pre>';
echo $message->getContent();
echo '</pre>';
]]></programlisting>

        <para>
            Checking for multipart messages is done with the method
            <methodname>isMultipart()</methodname>. If you have multipart message you can get an
            instance of <classname>Zend_Mail_Part</classname> with the method
            <methodname>getPart()</methodname>. <classname>Zend_Mail_Part</classname> is the base
            class of <classname>Zend_Mail_Message</classname>, so you have the same methods:
            <methodname>getHeader()</methodname>, <methodname>getHeaders()</methodname>,
            <methodname>getContent()</methodname>, <methodname>getPart()</methodname>,
            <code>isMultipart</code> and the properties for headers.
        </para>

        <programlisting language="php"><![CDATA[
// get the first none multipart part
$part = $message;
while ($part->isMultipart()) {
    $part = $message->getPart(1);
}
echo 'Type of this part is ' . strtok($part->contentType, ';') . "\n";
echo "Content:\n";
echo $part->getContent();
]]></programlisting>

        <para>
            <classname>Zend_Mail_Part</classname> also implements <code>RecursiveIterator</code>,
            which makes it easy to scan through all parts. And for easy output, it also implements
            the magic method <methodname>__toString()</methodname>, which returns the content.
        </para>

        <programlisting language="php"><![CDATA[
// output first text/plain part
$foundPart = null;
foreach (new RecursiveIteratorIterator($mail->getMessage(1)) as $part) {
    try {
        if (strtok($part->contentType, ';') == 'text/plain') {
            $foundPart = $part;
            break;
        }
    } catch (Zend_Mail_Exception $e) {
        // ignore
    }
}
if (!$foundPart) {
    echo 'no plain text part found';
} else {
    echo "plain text part: \n" . $foundPart;
}
]]></programlisting>
    </sect2>

    <sect2 id="zend.mail.read-flags">
        <title>Checking for flags</title>

        <para>
            Maildir and IMAP support storing flags. The class
            <classname>Zend_Mail_Storage</classname> has constants for all known maildir and IMAP
            system flags, named <classname>Zend_Mail_Storage::FLAG_&lt;flagname&gt;</classname>. To
            check for flags <classname>Zend_Mail_Message</classname> has a method called
            <methodname>hasFlag()</methodname>. With <methodname>getFlags()</methodname> you'll get
            all set flags.
        </para>

        <programlisting language="php"><![CDATA[
// find unread messages
echo "Unread mails:\n";
foreach ($mail as $message) {
    if ($message->hasFlag(Zend_Mail_Storage::FLAG_SEEN)) {
        continue;
    }
    // mark recent/new mails
    if ($message->hasFlag(Zend_Mail_Storage::FLAG_RECENT)) {
        echo '! ';
    } else {
        echo '  ';
    }
    echo $message->subject . "\n";
}

// check for known flags
$flags = $message->getFlags();
echo "Message is flagged as: ";
foreach ($flags as $flag) {
    switch ($flag) {
        case Zend_Mail_Storage::FLAG_ANSWERED:
            echo 'Answered ';
            break;
        case Zend_Mail_Storage::FLAG_FLAGGED:
            echo 'Flagged ';
            break;

        // ...
        // check for other flags
        // ...

        default:
            echo $flag . '(unknown flag) ';
    }
}
]]></programlisting>

        <para>
            As IMAP allows user or client defined flags, you could get flags that don't have a
            constant in <classname>Zend_Mail_Storage</classname>. Instead, they are returned as
            strings and can be checked the same way with <methodname>hasFlag()</methodname>.
        </para>

        <programlisting language="php"><![CDATA[
// check message for client defined flags $IsSpam, $SpamTested
if (!$message->hasFlag('$SpamTested')) {
    echo 'message has not been tested for spam';
} else if ($message->hasFlag('$IsSpam')) {
    echo 'this message is spam';
} else {
    echo 'this message is ham';
}
]]></programlisting>
    </sect2>

    <sect2 id="zend.mail.read-folders">
        <title>Using folders</title>

        <para>
            All storages, except Pop3, support folders, also called mailboxes. The interface
            implemented by all storages supporting folders is called
            <classname>Zend_Mail_Storage_Folder_Interface</classname>. Also all of these classes
            have an additional optional parameter called <code>folder</code>, which is the folder
            selected after login, in the constructor.
        </para>

        <para>
            For the local storages you need to use separate classes called
            <classname>Zend_Mail_Storage_Folder_Mbox</classname> or
            <classname>Zend_Mail_Storage_Folder_Maildir</classname>. Both need one parameter called
            <code>dirname</code> with the name of the base dir. The format for maildir is as defined
            in maildir++ (with a dot as default delimiter), Mbox is a directory hierarchy with Mbox
            files. If you don't have a Mbox file called INBOX in your Mbox base dir you need to set
            another folder in the constructor.
        </para>

        <para>
            <classname>Zend_Mail_Storage_Imap</classname> already supports folders by default.
            Examples for opening these storages:
        </para>

        <programlisting language="php"><![CDATA[
// mbox with folders
$mail = new Zend_Mail_Storage_Folder_Mbox(array('dirname' =>
                                                    '/home/test/mail/'));

// mbox with a default folder not called INBOX, also works
// with Zend_Mail_Storage_Folder_Maildir and Zend_Mail_Storage_Imap
$mail = new Zend_Mail_Storage_Folder_Mbox(array('dirname' =>
                                                    '/home/test/mail/',
                                                'folder'  =>
                                                    'Archive'));

// maildir with folders
$mail = new Zend_Mail_Storage_Folder_Maildir(array('dirname' =>
                                                       '/home/test/mail/'));

// maildir with colon as delimiter, as suggested in Maildir++
$mail = new Zend_Mail_Storage_Folder_Maildir(array('dirname' =>
                                                       '/home/test/mail/',
                                                   'delim'   => ':'));

// imap is the same with and without folders
$mail = new Zend_Mail_Storage_Imap(array('host'     => 'example.com',
                                         'user'     => 'test',
                                         'password' => 'test'));
]]></programlisting>

        <para>
            With the method getFolders($root = null) you can get the folder hierarchy starting with
            the root folder or the given folder. It's returned as an instance of
            <classname>Zend_Mail_Storage_Folder</classname>, which implements
            <code>RecursiveIterator</code> and all children are also instances of
            <classname>Zend_Mail_Storage_Folder</classname>. Each of these instances has a local and
            a global name returned by the methods <methodname>getLocalName()</methodname> and
            <methodname>getGlobalName()</methodname>. The global name is the absolute name from the
            root folder (including delimiters), the local name is the name in the parent folder.
        </para>

        <table id="zend.mail.read-folders.table-1">
            <title>Mail Folder Names</title>

            <tgroup cols="2">
                <thead>
                    <row>
                        <entry>Global Name</entry>
                        <entry>Local Name</entry>
                    </row>
                </thead>

                <tbody>
                    <row>
                        <entry>/INBOX</entry>
                        <entry>INBOX</entry>
                    </row>

                    <row>
                        <entry>/Archive/2005</entry>
                        <entry>2005</entry>
                    </row>

                    <row>
                        <entry>List.ZF.General</entry>
                        <entry>General</entry>
                    </row>
                </tbody>
            </tgroup>
        </table>

        <para>
            If you use the iterator, the key of the current element is the local name. The global
            name is also returned by the magic method <methodname>__toString()</methodname>. Some
            folders may not be selectable, which means they can't store messages and selecting them
            results in an error. This can be checked with the method
            <methodname>isSelectable()</methodname>. So it's very easy to output the whole tree in a
            view:
        </para>

        <programlisting language="php"><![CDATA[
$folders = new RecursiveIteratorIterator($this->mail->getFolders(),
                                         RecursiveIteratorIterator::SELF_FIRST);
echo '<select name="folder">';
foreach ($folders as $localName => $folder) {
    $localName = str_pad('', $folders->getDepth(), '-', STR_PAD_LEFT) .
                 $localName;
    echo '<option';
    if (!$folder->isSelectable()) {
        echo ' disabled="disabled"';
    }
    echo ' value="' . htmlspecialchars($folder) . '">'
        . htmlspecialchars($localName) . '</option>';
}
echo '</select>';
]]></programlisting>

        <para>
            The current selected folder is returned by the method
            <methodname>getSelectedFolder()</methodname>. Changing the folder is done with the
            method <methodname>selectFolder()</methodname>, which needs the global name as
            parameter. If you want to avoid to write delimiters you can also use the properties of a
            <classname>Zend_Mail_Storage_Folder</classname> instance:
        </para>

        <programlisting language="php"><![CDATA[
// depending on your mail storage and its settings $rootFolder->Archive->2005
// is the same as:
//   /Archive/2005
//  Archive:2005
//  INBOX.Archive.2005
//  ...
$folder = $mail->getFolders()->Archive->2005;
echo 'Last folder was '
   . $mail->getSelectedFolder()
   . "new folder is $folder\n";
$mail->selectFolder($folder);
]]></programlisting>
    </sect2>

    <sect2 id="zend.mail.read-advanced">
        <title>Advanced Use</title>

        <sect3 id="zend.mail.read-advanced.noop">
            <title>Using NOOP</title>

            <para>
                If you're using a remote storage and have some long tasks you might need to keep
                the connection alive via noop:
            </para>

            <programlisting language="php"><![CDATA[
foreach ($mail as $message) {

    // do some calculations ...

    $mail->noop(); // keep alive

    // do something else ...

    $mail->noop(); // keep alive
}
]]></programlisting>
        </sect3>

        <sect3 id="zend.mail.read-advanced.caching">
            <title>Caching instances</title>

            <para>
                <classname>Zend_Mail_Storage_Mbox</classname>,
                <classname>Zend_Mail_Storage_Folder_Mbox</classname>,
                <classname>Zend_Mail_Storage_Maildir</classname> and
                <classname>Zend_Mail_Storage_Folder_Maildir</classname> implement the magic methods
                <methodname>__sleep()</methodname> and <methodname>__wakeup()</methodname>, which
                means they are serializable. This avoids parsing the files or directory tree more
                than once. The disadvantage is that your Mbox or Maildir storage should not change.
                Some easy checks may be done, like reparsing the current Mbox file if the
                modification time changes, or reparsing the folder structure if a folder has
                vanished (which still results in an error, but you can search for another folder
                afterwards). It's better if you have something like a signal file for changes and
                check it before using the cached instance.
            </para>

            <programlisting language="php"><![CDATA[
// there's no specific cache handler/class used here,
// change the code to match your cache handler
$signal_file = '/home/test/.mail.last_change';
$mbox_basedir = '/home/test/mail/';
$cache_id = 'example mail cache ' . $mbox_basedir . $signal_file;

$cache = new Your_Cache_Class();
if (!$cache->isCached($cache_id) ||
    filemtime($signal_file) > $cache->getMTime($cache_id)) {
    $mail = new Zend_Mail_Storage_Folder_Pop3(array('dirname' =>
                                                        $mbox_basedir));
} else {
    $mail = $cache->get($cache_id);
}

// do stuff ...

$cache->set($cache_id, $mail);
]]></programlisting>
        </sect3>

        <sect3 id="zend.mail.read-advanced.extending">
            <title>Extending Protocol Classes</title>

            <para>
                Remote storages use two classes:
                <classname>Zend_Mail_Storage_&lt;Name&gt;</classname> and
                <classname>Zend_Mail_Protocol_&lt;Name&gt;</classname>. The protocol class
                translates the protocol commands and responses from and to <acronym>PHP</acronym>,
                like methods for the commands or variables with different structures for data.
                The other/main class implements the common interface.
            </para>

            <para>
                If you need additional protocol features, you can extend the protocol class and use
                it in the constructor of the main class. As an example, assume we need to knock
                different ports before we can connect to POP3.
            </para>

            <programlisting language="php"><![CDATA[
class Example_Mail_Exception extends Zend_Mail_Exception
{
}

class Example_Mail_Protocol_Exception extends Zend_Mail_Protocol_Exception
{
}

class Example_Mail_Protocol_Pop3_Knock extends Zend_Mail_Protocol_Pop3
{
    private $host, $port;

    public function __construct($host, $port = null)
    {
        // no auto connect in this class
        $this->host = $host;
        $this->port = $port;
    }

    public function knock($port)
    {
        $sock = @fsockopen($this->host, $port);
        if ($sock) {
            fclose($sock);
        }
    }

    public function connect($host = null, $port = null, $ssl = false)
    {
        if ($host === null) {
            $host = $this->host;
        }
        if ($port === null) {
            $port = $this->port;
        }
        parent::connect($host, $port);
    }
}

class Example_Mail_Pop3_Knock extends Zend_Mail_Storage_Pop3
{
    public function __construct(array $params)
    {
        // ... check $params here! ...
        $protocol = new Example_Mail_Protocol_Pop3_Knock($params['host']);

        // do our "special" thing
        foreach ((array)$params['knock_ports'] as $port) {
            $protocol->knock($port);
        }

        // get to correct state
        $protocol->connect($params['host'], $params['port']);
        $protocol->login($params['user'], $params['password']);

        // initialize parent
        parent::__construct($protocol);
    }
}

$mail = new Example_Mail_Pop3_Knock(array('host'        => 'localhost',
                                          'user'        => 'test',
                                          'password'    => 'test',
                                          'knock_ports' =>
                                              array(1101, 1105, 1111)));
]]></programlisting>

            <para>
                As you see, we always assume we're connected, logged in and, if supported, a folder
                is selected in the constructor of the main class. Thus if you assign your own
                protocol class, you always need to make sure that's done or the next method will
                fail if the server doesn't allow it in the current state.
            </para>
        </sect3>

        <sect3 id="zend.mail.read-advanced.quota">
            <title>Using Quota (since 1.5)</title>

            <para>
                <classname>Zend_Mail_Storage_Writable_Maildir</classname> has support for Maildir++
                quotas. It's disabled by default, but it's possible to use it manually, if the
                automatic checks are not desired (this means
                <methodname>appendMessage()</methodname>, <methodname>removeMessage()</methodname>
                and <methodname>copyMessage()</methodname> do no checks and do not add entries to
                the maildirsize file). If enabled, an exception is thrown if you try to write to the
                maildir and it's already over quota.
            </para>

            <para>
                There are three methods used for quotas: <methodname>getQuota()</methodname>,
                <methodname>setQuota()</methodname> and <methodname>checkQuota()</methodname>:
            </para>

            <programlisting language="php"><![CDATA[
$mail = new Zend_Mail_Storage_Writable_Maildir(array('dirname' =>
                                                   '/home/test/mail/'));
$mail->setQuota(true); // true to enable, false to disable
echo 'Quota check is now ', $mail->getQuota() ? 'enabled' : 'disabled', "\n";
// check quota can be used even if quota checks are disabled
echo 'You are ', $mail->checkQuota() ? 'over quota' : 'not over quota', "\n";
]]></programlisting>

            <para>
                <methodname>checkQuota()</methodname> can also return a more detailed response:
            </para>

            <programlisting language="php"><![CDATA[
$quota = $mail->checkQuota(true);
echo 'You are ', $quota['over_quota'] ? 'over quota' : 'not over quota', "\n";
echo 'You have ',
     $quota['count'],
     ' of ',
     $quota['quota']['count'],
     ' messages and use ';
echo $quota['size'], ' of ', $quota['quota']['size'], ' octets';
]]></programlisting>

            <para>
                If you want to specify your own quota instead of using the one specified in the
                maildirsize file you can do with <methodname>setQuota()</methodname>:
            </para>

            <programlisting language="php"><![CDATA[
// message count and octet size supported, order does matter
$quota = $mail->setQuota(array('size' => 10000, 'count' => 100));
]]></programlisting>

            <para>
                To add your own quota checks use single letters as keys, and they will be preserved
                (but obviously not checked). It's also possible to extend
                <classname>Zend_Mail_Storage_Writable_Maildir</classname> to define your own quota
                only if the maildirsize file is missing (which can happen in Maildir++):
            </para>

            <programlisting language="php"><![CDATA[
class Example_Mail_Storage_Maildir extends Zend_Mail_Storage_Writable_Maildir {
    // getQuota is called with $fromStorage = true by quota checks
    public function getQuota($fromStorage = false) {
        try {
            return parent::getQuota($fromStorage);
        } catch (Zend_Mail_Storage_Exception $e) {
            if (!$fromStorage) {
                // unknown error:
                throw $e;
            }
            // maildirsize file must be missing

            list($count, $size) = get_quota_from_somewhere_else();
            return array('count' => $count, 'size' => $size);
        }
    }
}
]]></programlisting>
        </sect3>
    </sect2>
</sect1>
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