Make search mechanism pluggable

Currently, TinyTinyRSS can use raw SQL or the Sphinx search engine
for searching.  It would be nice if other search engines (such as
Xapian) could be used, or if features of the underlying SQL engine
(such as MySQL's FULLTEXT indexes) could be leveraged.  This commit
makes searching into a plugin hook, falling back to the builtin behavior
if no search plugin is active.  The Sphinx search behavior has been
broken out into a plugin.

8 files changed, 69 insertions, 55 deletions

diff --git a/classes/feeds.php b/classes/feeds.php
index ca470c032..89acb0d0b 100644
--- a/classes/feeds.php
+++ b/classes/feeds.php
@@ -1147,7 +1147,7 @@ class Feeds extends Handler_Protected {
 
 		print "<div class=\"dlgButtons\">";
 
-		if (!SPHINX_ENABLED) {
+		if (count(PluginHost::getInstance()->get_hooks(PluginHost::HOOK_SEARCH)) == 0) {
 			print "<div style=\"float : left\">
 				<a class=\"visibleLink\" target=\"_blank\" href=\"http://tt-rss.org/wiki/SearchSyntax\">".__("Search syntax")."</a>
 				</div>";
diff --git a/classes/pluginhost.php b/classes/pluginhost.php
index 19f8b563b..4582c314a 100644
--- a/classes/pluginhost.php
+++ b/classes/pluginhost.php
@@ -39,6 +39,7 @@ class PluginHost {
 	const HOOK_FETCH_FEED = 22;
 	const HOOK_QUERY_HEADLINES = 23;
 	const HOOK_HOUSE_KEEPING = 24;
+	const HOOK_SEARCH = 25;
 
 	const KIND_ALL = 1;
 	const KIND_SYSTEM = 2;
diff --git a/config.php-dist b/config.php-dist
index 999f00773..2d7a6d195 100644
--- a/config.php-dist
+++ b/config.php-dist
@@ -108,10 +108,6 @@
 	// *** Sphinx search ***
 	// *********************
 
-	define('SPHINX_ENABLED', false);
-	// Enable fulltext search using Sphinx (http://www.sphinxsearch.com)
-	// Please see http://tt-rss.org/wiki/SphinxSearch for more information.
-
 	define('SPHINX_SERVER', 'localhost:9312');
 	// Hostname:port combination for the Sphinx server.
 
diff --git a/include/functions2.php b/include/functions2.php
index ca58ea6c5..22c602362 100644
--- a/include/functions2.php
+++ b/include/functions2.php
@@ -397,20 +397,15 @@
 		$search_words = array();
 
 			if ($search) {
+				foreach (PluginHost::getInstance()->get_hooks(PluginHost::HOOK_SEARCH) as $plugin) {
+					list($search_query_part, $search_words) = $plugin->hook_search($search);
+				}
 
-				if (SPHINX_ENABLED) {
-					$ids = join(",", @sphinx_search($search, 0, 500));
-
-					if ($ids)
-						$search_query_part = "ref_id IN ($ids) AND ";
-					else
-						$search_query_part = "ref_id = -1 AND ";
-
-				} else {
+				// fall back in case of no plugins
+				if (!$search_query_part) {
 					list($search_query_part, $search_words) = search_to_sql($search);
-					$search_query_part .= " AND ";
 				}
-
+				$search_query_part .= " AND ";
 			} else {
 				$search_query_part = "";
 			}
@@ -1994,39 +1989,6 @@
 		}
 	}
 
-	function sphinx_search($query, $offset = 0, $limit = 30) {
-		require_once 'lib/sphinxapi.php';
-
-		$sphinxClient = new SphinxClient();
-
-		$sphinxpair = explode(":", SPHINX_SERVER, 2);
-
-		$sphinxClient->SetServer($sphinxpair[0], (int)$sphinxpair[1]);
-		$sphinxClient->SetConnectTimeout(1);
-
-		$sphinxClient->SetFieldWeights(array('title' => 70, 'content' => 30,
-			'feed_title' => 20));
-
-		$sphinxClient->SetMatchMode(SPH_MATCH_EXTENDED2);
-		$sphinxClient->SetRankingMode(SPH_RANK_PROXIMITY_BM25);
-		$sphinxClient->SetLimits($offset, $limit, 1000);
-		$sphinxClient->SetArrayResult(false);
-		$sphinxClient->SetFilter('owner_uid', array($_SESSION['uid']));
-
-		$result = $sphinxClient->Query($query, SPHINX_INDEX);
-
-		$ids = array();
-
-		if (is_array($result['matches'])) {
-			foreach (array_keys($result['matches']) as $int_id) {
-				$ref_id = $result['matches'][$int_id]['attrs']['ref_id'];
-				array_push($ids, $ref_id);
-			}
-		}
-
-		return $ids;
-	}
-
 	function cleanup_tags($days = 14, $limit = 1000) {
 
 		if (DB_TYPE == "pgsql") {
diff --git a/include/sanity_check.php b/include/sanity_check.php
index 1aa581bfc..6bec43051 100644
--- a/include/sanity_check.php
+++ b/include/sanity_check.php
@@ -146,11 +146,6 @@
 				array_push($errors, "PHP support for CURL is required for PubSubHubbub.");
 			}
 
-			if (SPHINX_ENABLED && class_exists("SphinxClient")) {
-				array_push($errors, "Your PHP has a separate systemwide Sphinx client installed which conflicts with the client library used by tt-rss. Either remove the system library or disable Sphinx support.");
-
-			}
-
 			if (!class_exists("DOMDocument")) {
 				array_push($errors, "PHP support for DOMDocument is required, but was not found.");
 			}
diff --git a/include/sanity_config.php b/include/sanity_config.php
index 99e83e0d9..76fba4b81 100644
--- a/include/sanity_config.php
+++ b/include/sanity_config.php
@@ -1,3 +1,3 @@
 <?php # This file has been generated at:  Fri Sep 27 13:42:37 MSK 2013
 define('GENERATED_CONFIG_CHECK', 26);
-$requred_defines = array( 'DB_TYPE', 'DB_HOST', 'DB_USER', 'DB_NAME', 'DB_PASS', 'MYSQL_CHARSET', 'SELF_URL_PATH', 'FEED_CRYPT_KEY', 'SINGLE_USER_MODE', 'SIMPLE_UPDATE_MODE', 'PHP_EXECUTABLE', 'LOCK_DIRECTORY', 'CACHE_DIR', 'ICONS_DIR', 'ICONS_URL', 'AUTH_AUTO_CREATE', 'AUTH_AUTO_LOGIN', 'FORCE_ARTICLE_PURGE', 'PUBSUBHUBBUB_HUB', 'PUBSUBHUBBUB_ENABLED', 'SPHINX_ENABLED', 'SPHINX_SERVER', 'SPHINX_INDEX', 'ENABLE_REGISTRATION', 'REG_NOTIFY_ADDRESS', 'REG_MAX_USERS', 'SESSION_COOKIE_LIFETIME', 'SESSION_CHECK_ADDRESS', 'SMTP_FROM_NAME', 'SMTP_FROM_ADDRESS', 'DIGEST_SUBJECT', 'SMTP_SERVER', 'SMTP_LOGIN', 'SMTP_PASSWORD', 'SMTP_SECURE', 'CHECK_FOR_NEW_VERSION', 'DETECT_ARTICLE_LANGUAGE', 'ENABLE_GZIP_OUTPUT', 'PLUGINS', 'LOG_DESTINATION', 'CONFIG_VERSION'); ?>
+$requred_defines = array( 'DB_TYPE', 'DB_HOST', 'DB_USER', 'DB_NAME', 'DB_PASS', 'MYSQL_CHARSET', 'SELF_URL_PATH', 'FEED_CRYPT_KEY', 'SINGLE_USER_MODE', 'SIMPLE_UPDATE_MODE', 'PHP_EXECUTABLE', 'LOCK_DIRECTORY', 'CACHE_DIR', 'ICONS_DIR', 'ICONS_URL', 'AUTH_AUTO_CREATE', 'AUTH_AUTO_LOGIN', 'FORCE_ARTICLE_PURGE', 'PUBSUBHUBBUB_HUB', 'PUBSUBHUBBUB_ENABLED', 'ENABLE_REGISTRATION', 'REG_NOTIFY_ADDRESS', 'REG_MAX_USERS', 'SESSION_COOKIE_LIFETIME', 'SESSION_CHECK_ADDRESS', 'SMTP_FROM_NAME', 'SMTP_FROM_ADDRESS', 'DIGEST_SUBJECT', 'SMTP_SERVER', 'SMTP_LOGIN', 'SMTP_PASSWORD', 'SMTP_SECURE', 'CHECK_FOR_NEW_VERSION', 'DETECT_ARTICLE_LANGUAGE', 'ENABLE_GZIP_OUTPUT', 'PLUGINS', 'LOG_DESTINATION', 'CONFIG_VERSION'); ?>
diff --git a/plugins/search_sphinx/init.php b/plugins/search_sphinx/init.php
new file mode 100644
index 000000000..f2877e44d
--- /dev/null
+++ b/plugins/search_sphinx/init.php
@@ -0,0 +1,60 @@
+<?php
+
+class Search_Sphinx extends Plugin {
+	function about() {
+		return array(1.0,
+			"Delegate searching for articles to Sphinx",
+			"hoelzro",
+			true);
+	}
+
+	function init($host) {
+		$host->add_hook($host::HOOK_SEARCH, $this);
+
+		require_once __DIR__ . "/sphinxapi.php";
+	}
+
+	function hook_search($search) {
+		$offset = 0;
+		$limit  = 500;
+
+		$sphinxClient = new SphinxClient();
+
+		$sphinxpair = explode(":", SPHINX_SERVER, 2);
+
+		$sphinxClient->SetServer($sphinxpair[0], (int)$sphinxpair[1]);
+		$sphinxClient->SetConnectTimeout(1);
+
+		$sphinxClient->SetFieldWeights(array('title' => 70, 'content' => 30,
+			'feed_title' => 20));
+
+		$sphinxClient->SetMatchMode(SPH_MATCH_EXTENDED2);
+		$sphinxClient->SetRankingMode(SPH_RANK_PROXIMITY_BM25);
+		$sphinxClient->SetLimits($offset, $limit, 1000);
+		$sphinxClient->SetArrayResult(false);
+		$sphinxClient->SetFilter('owner_uid', array($_SESSION['uid']));
+
+		$result = $sphinxClient->Query($search, SPHINX_INDEX);
+
+		$ids = array();
+
+		if (is_array($result['matches'])) {
+			foreach (array_keys($result['matches']) as $int_id) {
+				$ref_id = $result['matches'][$int_id]['attrs']['ref_id'];
+				array_push($ids, $ref_id);
+			}
+		}
+
+		$ids = join(",", $ids);
+
+		if ($ids)
+			return array("ref_id IN ($ids)", array());
+		else
+			return array("ref_id = -1", array());
+	}
+
+	function api_version() {
+		return 2;
+	}
+}
+?>
diff --git a/lib/sphinxapi.php b/plugins/search_sphinx/sphinxapi.php
index 90643d3c7..90643d3c7 100644
--- a/lib/sphinxapi.php
+++ b/plugins/search_sphinx/sphinxapi.php