From a49698b0f775c195131eac1f8e887af41e42d872 Mon Sep 17 00:00:00 2001
From: Domas Mituzas <midom@users.mediawiki.org>
Date: Mon, 18 Apr 2005 17:21:27 +0000
Subject: [PATCH] Add external repositories support for Revision, would follow
 url if flag on text set, allows pluggable storage modules and migration from
 databases to somewhere else (huh, other databases ;-)

---
 includes/DefaultSettings.php   | 12 ++++++++++
 includes/ExternalStore.php     | 44 ++++++++++++++++++++++++++++++++++
 includes/ExternalStoreHttp.php | 23 ++++++++++++++++++
 includes/Revision.php          | 14 ++++++++++-
 4 files changed, 92 insertions(+), 1 deletion(-)
 create mode 100644 includes/ExternalStore.php
 create mode 100644 includes/ExternalStoreHttp.php

diff --git a/includes/DefaultSettings.php b/includes/DefaultSettings.php
index e4a7067f48..549f2aaeb5 100644
--- a/includes/DefaultSettings.php
+++ b/includes/DefaultSettings.php
@@ -1278,6 +1278,18 @@ $wgEnableSorbs = true;
  */
 $wgCountCategorizedImagesAsUsed = false;
 
+/** 
+ * External stores allow including content 
+ * from non database sources following URL links
+ * 
+ * Short names of ExternalStore classes may be specified in an array here:
+ * $wgExternalStores = array("http","file","custom")...
+ * 
+ * CAUTION: Access to database might lead to code execution
+ */
+$wgExternalStores = false;
+
+
 } else {
 	die();
 }
diff --git a/includes/ExternalStore.php b/includes/ExternalStore.php
new file mode 100644
index 0000000000..78e1b84d6e
--- /dev/null
+++ b/includes/ExternalStore.php
@@ -0,0 +1,44 @@
+<?php
+/**
+ * 
+ * @package MediaWiki
+ *
+ * Constructor class for data kept in external repositories
+ *
+ * External repositories might be populated by maintenance/async 
+ * scripts, thus partial moving of data may be possible, as well 
+ * as possibility to have any storage format (i.e. for archives)
+ *
+ */
+ 
+class ExternalStore {
+	/* Fetch data from given URL */
+	function fetchFromURL($url) {
+		global $wgExternalStores;
+
+		if (!$wgExternalStores) 
+			return false;
+
+		@list($proto,$path)=explode('://',$url,2);
+		/* Bad URL */
+		if ($path=="") 
+			return false;
+		/* Protocol not enabled */
+		if (!in_array( $proto, $wgExternalStores ))
+			return false;
+
+		$class='ExternalStore'.ucfirst($proto);
+		/* Preloaded modules might exist, especially ones serving multiple protocols */
+		if (!class_exists($class)) {
+			if (!include_once($class.'.php'))
+				return false;	
+		}
+		$store=new $class();
+		return $store->fetchFromURL($url);
+	}
+
+	/* XXX: may require other methods, for store, delete, 
+	 * whatever, for initial ext storage  
+	 */
+}
+?>
diff --git a/includes/ExternalStoreHttp.php b/includes/ExternalStoreHttp.php
new file mode 100644
index 0000000000..d7c1cc818d
--- /dev/null
+++ b/includes/ExternalStoreHttp.php
@@ -0,0 +1,23 @@
+<?php
+/**
+ * 
+ * @package MediaWiki
+ *
+ * Example class for HTTP accessable external objects
+ *
+ */
+ 
+class ExternalStoreHttp {
+	/* Fetch data from given URL */
+	function fetchFromURL($url) {
+        ini_set( "allow_url_fopen", true );
+        $ret = file_get_contents( $url );
+        ini_set( "allow_url_fopen", false );
+		return $ret;
+	}
+
+	/* XXX: may require other methods, for store, delete, 
+	 * whatever, for initial ext storage  
+	 */
+}
+?>
diff --git a/includes/Revision.php b/includes/Revision.php
index d6418e3508..67eb4be6fc 100644
--- a/includes/Revision.php
+++ b/includes/Revision.php
@@ -378,6 +378,18 @@ class Revision {
 			return false;
 		}
 
+		# Use external methods for external objects, text in table is URL-only then
+		if ( in_array( 'external', $flags ) ) {
+			$url=$text;
+			@list($proto,$path)=explode('://',$url,2);
+			if ($path=="") {
+				wfProfileOut( $fname );
+				return false;
+			}
+			require_once('ExternalStore.php');
+			$text=ExternalStore::fetchFromURL($url);
+		}
+
 		if( in_array( 'gzip', $flags ) ) {
 			# Deal with optional compression of archived pages.
 			# This can be done periodically via maintenance/compressOld.php, and
@@ -555,4 +567,4 @@ class Revision {
 	}
 	
 }
-?>
\ No newline at end of file
+?>
-- 
2.20.1