Do HTTP Stream + Namespace Example

Author: jakejackson1

examples/at_a_glance.php

@@ -0,0 +1,77 @@
+<?php
+/**
+ * Example of grabbing and parsing Linked Data from DBPedia.
+ *
+ * This example illustrates how QueryPath can be used to do the following:
+ *
+ * - Make a robust HTTP connection to a remote server to fetch data.
+ * - Using context to control the underlying stream.
+ * - Working with Linked Data.
+ * - Work with XML Namespaces in documents.
+ *   * Using namespaces to access elements in selectors
+ *   * Using namespaces to access attributes in selectors
+ *   * Using namespaces to access attributes in XML methods.
+ *
+ * The code here connects to the DBPedia server and looks up the Linked
+ * Data stored there for a particular Wikipedia entry (any Wikipedia
+ * wiki name should work here).
+ *
+ *
+ * @author  M Butcher <[email protected]>
+ * @license LGPL The GNU Lesser GPL (LGPL) or an MIT-like license.
+ * @see     http://www.w3.org/DesignIssues/LinkedData.html
+ * @see     http://dbpedia.org
+ * @see     sparql.php
+ * @see     musicbrainz.php
+ */
+
+require_once __DIR__ . '/../../vendor/autoload.php';
+
+// The URL to look up:
+$url = 'https://dbpedia.org/resource/Ben_Sealey';
+
+// HTTP headers:
+$headers = [
+	'Accept: application/rdf,application/rdf+xml;q=0.9,*/*;q=0.8',
+	'Accept-Language: en-us,en',
+	'Accept-Charset: ISO-8859-1,utf-8',
+	'User-Agent: QueryPath/1.2',
+];
+
+// The context options:
+$options = [
+	'http' => [
+		'method' => 'GET',
+		'protocol_version' => 1.1,
+		'header' => implode("\r\n", $headers),
+	],
+];
+
+// Create a stream context that will tell QueryPath how to load the file.
+$context = stream_context_create($options);
+
+// Fetch the URL and select all rdf:Description elements.
+// (Note that | is the CSS 3 equiv of colons for namespacing.)
+// To add the context, we pass it in as an option to QueryPath.
+$qp = qp($url, 'rdf|Description', ['context' => $context]);
+
+printf('There are %d descriptions in this record.<br>' . PHP_EOL, $qp->count());
+
+// Here, we use foaf|* to select all elements in the FOAF namespace.
+printf('There are %d DBO items in this record.<br><br>' . PHP_EOL, $qp->top()->find('dbo|*')->count());
+
+// Standard pseudo-classes that are not HTML specific can be used on namespaced elements, too.
+echo 'About (RDFS): ' . $qp->top()->find('rdfs|label:first-of-type')->text() . '<br>' . PHP_EOL;
+echo 'About (FOAF): ' . $qp->top()->find('foaf|name:first-of-type')->text() . '<br>' . PHP_EOL;
+
+// Namespaced attributes can be retrieved using the same sort of delimiting.
+echo PHP_EOL . '<br>Comment:<br>' . PHP_EOL;
+echo $qp->top()->find('rdfs|comment[xml|lang="en"]')->text();
+echo '<br>' . PHP_EOL;
+
+$qp->top();
+
+echo PHP_EOL . '<br>Other Sites:<br>' . PHP_EOL;
+foreach ($qp as $item) {
+	echo $item->attr('rdf:about') . '<br>' . PHP_EOL;
+}