feat: add XPath module, to be used in querying and processing the feed

Author: Harrison Ifeanyichukwu

src/XPath.php

@@ -0,0 +1,76 @@
+<?php
+declare(strict_types = 1);
+
+namespace Forensic\FeedParser;
+
+use DOMDocument;
+use DOMXPath;
+use DOMNode;
+
+class XPath
+{
+    private $_dom_xpath = null;
+
+    public function __construct(DOMDocument $doc)
+    {
+        $this->_dom_xpath = new DOMXPath($doc);
+    }
+
+    /**
+     * registers namespace
+     *
+     *@return boolean
+    */
+    public function registerNamespace(string $prefix, string $namespacePrefix)
+    {
+        return $this->_dom_xpath->registerNamespace($prefix, $namespacePrefix);
+    }
+
+    /**
+     * registers namespaces
+    */
+    public function registerNamespaces(array $namespaces)
+    {
+        foreach($namespaces as $prefix => $namespacePrefix)
+            if (is_string($prefix) && is_string($namespacePrefix))
+                $this->registerNamespace($prefix, $namespacePrefix);
+    }
+
+    /**
+     * queries the document and returns a single result item or null
+     *
+     *@return DOMNode|null
+    */
+    public function selectNode(string $expression, DOMNode $context_node = null)
+    {
+        $result = $this->_dom_xpath->query($expression, $context_node);
+        if ($result === false || $result->length === 0)
+            return null;
+
+        return $result->item(0);
+    }
+
+    /**
+     * queries the document and returns a a DOMNodeList or null
+     *
+     *@return DOMNodeList|null
+    */
+    public function selectNodes(string $expression, DOMNode $context_node = null)
+    {
+        $result = $this->_dom_xpath->query($expression, $context_node);
+        if ($result === false)
+            return null;
+
+        return $result;
+    }
+
+    /**
+     * returns the dom xpath
+     *
+     *@return DOMXPath
+    */
+    public function get()
+    {
+        return $this->_dom_xpath;
+    }
+}