repo_zf1/documentation/manual/en/module_specs/Zend_Feed-ConsumingRss.xml

<?xml version="1.0" encoding="UTF-8"?>
<!-- Reviewed: no -->
<sect1 id="zend.feed.consuming-rss">
    <title>Consuming an RSS Feed</title>
    <para>
        Reading an RSS feed is as simple as instantiating a <classname>Zend_Feed_Rss</classname> object with the URL
        of the feed:
    </para>
    <programlisting role="php"><![CDATA[
$channel = new Zend_Feed_Rss('http://rss.example.com/channelName');
]]></programlisting>
    <para>
        If any errors occur fetching the feed, a <classname>Zend_Feed_Exception</classname> will be thrown.
    </para>

    <para>
        Once you have a feed object, you can access any of the standard RSS "channel" properties directly
        on the object:
    </para>
    <programlisting role="php"><![CDATA[
echo $channel->title();
]]></programlisting>
    <para>
        Note the function syntax. <classname>Zend_Feed</classname> uses a convention of treating properties as XML
        object if they are requested with variable "getter" syntax (<code>$obj->property</code>) and as
        strings if they are access with method syntax (<code>$obj->property()</code>). This enables access
        to the full text of any individual node while still allowing full access to all children.
    </para>

    <para>
        If channel properties have attributes, they are accessible using PHP's array syntax:
    </para>
    <programlisting role="php"><![CDATA[
echo $channel->category['domain'];
]]></programlisting>
    <para>
        Since XML attributes cannot have children, method syntax is not necessary for accessing attribute
        values.
    </para>

    <para>
        Most commonly you'll want to loop through the feed and do something with its entries.
        <classname>Zend_Feed_Abstract</classname> implements PHP's <code>Iterator</code> interface, so printing all
        titles of articles in a channel is just a matter of:
    </para>
    <programlisting role="php"><![CDATA[
foreach ($channel as $item) {
    echo $item->title() . "\n";
}
]]></programlisting>
    <para>
        If you are not familiar with RSS, here are the standard elements you can expect to be available in
        an RSS channel and in individual RSS items (entries).
    </para>

    <para>
        Required channel elements:
    </para>

    <para>
        <itemizedlist>
            <listitem>
                <para><code>title</code> - The name of the channel</para>
            </listitem>
            <listitem>
                <para><code>link</code> - The URL of the web site corresponding to the channel</para>
            </listitem>
            <listitem>
                <para><code>description</code> - A sentence or several describing the channel</para>
            </listitem>
        </itemizedlist>
    </para>

    <para>
        Common optional channel elements:
    </para>

    <para>
        <itemizedlist>
            <listitem>
                <para><code>pubDate</code> - The publication date of this set of content, in RFC 822 date
                format</para>
            </listitem>
            <listitem>
                <para><code>language</code> - The language the channel is written in</para>
            </listitem>
            <listitem>
                <para><code>category</code> - One or more (specified by multiple tags) categories the
                channel belongs to</para>
            </listitem>
        </itemizedlist>
    </para>

    <para>
        RSS <code>&lt;item&gt;</code> elements do not have any strictly required elements. However, either
        <code>title</code> or <code>description</code> must be present.
    </para>

    <para>
        Common item elements:
    </para>

    <para>
        <itemizedlist>
            <listitem>
                <para><code>title</code> - The title of the item</para>
            </listitem>
            <listitem>
                <para><code>link</code> - The URL of the item</para>
            </listitem>
            <listitem>
                <para><code>description</code> - A synopsis of the item</para>
            </listitem>
            <listitem>
                <para><code>author</code> - The author's email address</para>
            </listitem>
            <listitem>
                <para><code>category</code> - One more more categories that the item belongs to</para>
            </listitem>
            <listitem>
                <para><code>comments</code> - URL of comments relating to this item</para>
            </listitem>
            <listitem>
                <para><code>pubDate</code> - The date the item was published, in RFC 822 date format</para>
            </listitem>
        </itemizedlist>
    </para>

    <para>
        In your code you can always test to see if an element is non-empty with:
    </para>
    <programlisting role="php"><![CDATA[
if ($item->propname()) {
    // ... proceed.
}
]]></programlisting>

    <para>
        If you use <code>$item->propname</code> instead, you will always get an empty object which will
        evaluate to <code>TRUE</code>, so your check will fail.
    </para>

    <para>
        For further information, the official RSS 2.0 specification is available at:
        <ulink url="http://blogs.law.harvard.edu/tech/rss">http://blogs.law.harvard.edu/tech/rss</ulink>
    </para>
</sect1>
<!--
vim:se ts=4 sw=4 et:
-->