PHP XML Generating XML as a String

PHP XML

Generating XML as a String

Problem

You want to generate XML. For instance, you want to provide an XML version of your data for another program to parse.

Solution

Loop through your data and print it out surrounded by the correct XML tags:

       header('Content-Type: text/xml');
       print '<?xml version="1.0"?>' . "\n";
       print "<shows>\n";

       $shows = array(array('name'      => 'Modern Family',
                                               'channel'   => 'ABC',
                                               'start'         => '9:00 PM',
                                               'duration' => '30'),
           
                                    array('name'      => 'Law & Order: SVU',
                                               'channel'  => 'NBC',
                                               'start'        => '9:00 PM',
                                               'duration' => '60'));

       foreach ($shows as $show) {
             print " <show>\n";
             foreach($show as $tag => $data) {
                    print  "             <$tag>" . htmlspecialchars($data) . "</$tag>\n";
             }
             print " </show>\n";
       }

       print "</shows>\n";

Discussion

Printing out XML manually mostly involves lots of foreach loops as you iterate through arrays. However, there are a few tricky details. First, you need to call header() to set the correct Content-Type header for the document. Because you’re sending XML instead of HTML, it should be text/xml.

Next, depending on your settings for the short_open_tag configuration directive, trying to print the XML declaration may accidentally turn on PHP processing. Because the <? of <?xml version="1.0"?> is the short PHP open tag, to print the declaration to the browser you need to either disable the directive or print the line from within PHP. We do the latter in the Solution.

Last, entities must be escaped. For example, the & in the show Law & Order needs to be &amp;. Call htmlspecialchars() to escape your data.

Example  Tonight’s TV listings

       <?xml version="1.0"?>
       <shows>
              <show>
                     <name>Modern Family</name>
                     <channel>ABC</channel>
                     <start>9:00 PM</start>
                     <duration>30</duration>
              </show>
              <show>
                     <name>Law &amp; Order: SVU</name>
                     <channel>NBC</channel>
                     <start>9:00 PM</start>
                     <duration>60</duration>
              </show>
       </shows>