Create custom-fields-permalink.php

Author: athlan

custom-fields-permalink.php

@@ -0,0 +1,91 @@
+<?php
+/*
+Plugin Name: Custom Fields Permalink 2
+Plugin URI: http://athlan.pl/custom-fields-permalink
+Description: This plugin enable to make a permalink from custom field's value.
+Author: Piotr Pelczar
+Version: 2.0
+Author URI: http://athlan.pl/
+*/
+
+class CustomFieldsPermalink {
+
+	const PARAM_CUSTOMFIELD_KEY = 'custom_field_key';
+	const PARAM_CUSTOMFIELD_VALUE = 'custom_field_value';
+	
+	public static function linkPost($permalink, $post, $leavename) {
+		return self::linkRewriteFields($permalink, $post);
+	}
+	
+	public static function linkPostType($permalink, $post, $leavename, $sample) {
+		return self::linkRewriteFields($permalink, $post);
+	}
+	
+	protected static function linkRewriteFields($permalink, $post) {
+		return preg_replace('#(%field_(.*?)%)#e', 'CustomFieldsPermalink::linkRewriteFieldsExtract($post, "\\2")', $permalink);
+	}
+	
+	public static function linkRewriteFieldsExtract($post, $fieldName) {
+		$postMeta = get_post_meta($post->ID);
+		
+		if(!isset($postMeta[$fieldName]))
+			return '';
+		
+		return implode('', $postMeta[$fieldName]);
+	}
+	
+	public static function registerExtraQueryVars($value) {
+		array_push($value, self::PARAM_CUSTOMFIELD_KEY, self::PARAM_CUSTOMFIELD_VALUE);
+		return $value;
+	}
+	
+	public static function processRequest($value) {
+		// additional parameters added to Wordpress
+		// Main Loop query
+		$value['meta_key'] = $value[self::PARAM_CUSTOMFIELD_KEY];
+		$value['meta_value'] = $value[self::PARAM_CUSTOMFIELD_VALUE];
+		
+		// remove temporary injected parameters
+		unset($value[self::PARAM_CUSTOMFIELD_KEY], $value[self::PARAM_CUSTOMFIELD_VALUE]);
+		
+		return $value;
+	}
+	
+	public static function rewriteRulesArrayFilter($rules) {
+		$keys = array_keys($rules);
+		$tmp = $rules;
+		$rules = array();
+		
+		for($i = 0, $j = sizeof($keys); $i < $j; ++$i) {
+			$key = $keys[$i];
+			
+			if (preg_match('/%field_([^%]*?)%/', $key)) {
+				$keyNew = preg_replace(
+					'/%field_([^%]*?)%/',
+					'([^/]+)',
+					// you can simply add next group to the url, because WordPress
+					// detect them automatically and add next $matches indiceis
+					$key
+				);
+				$rules[$keyNew] = preg_replace(
+					'/%field_([^%]*?)%/',
+					sprintf('%s=$1&%s=', self::PARAM_CUSTOMFIELD_KEY, self::PARAM_CUSTOMFIELD_VALUE),
+					// here on the end will be pasted $matches[$i] from $keyNew, so we can
+					// grab it it the future in self::PARAM_CUSTOMFIELD_VALUE parameter
+					$tmp[$key]
+				);
+			}
+			else {
+				$rules[$key] = $tmp[$key];
+			}
+		}
+		
+		return $rules;
+	}
+}
+
+add_filter('pre_post_link', array('CustomFieldsPermalink', 'linkPost'), 100, 3);
+add_filter('post_type_link', array('CustomFieldsPermalink', 'linkPostType'), 100, 4);
+add_filter('rewrite_rules_array', array('CustomFieldsPermalink', 'rewriteRulesArrayFilter'));
+add_filter('query_vars', array('CustomFieldsPermalink', 'registerExtraQueryVars'), 10, 1);
+add_filter('request', array('CustomFieldsPermalink', 'processRequest'), 10, 1);