Allow wikis to be redirected when deleting

Fixes #54

Author: edg2s

404.php

@@ -4,9 +4,41 @@
 
 include "header.php";
 
-echo new \OOUI\MessageWidget( [
-	'type' => 'error',
-	'label' => 'Page not found. The wiki you are looking for may have been deleted.'
-] );
+$redirect = false;
+
+// Check for redirect
+$uri = $_SERVER['REQUEST_URI'];
+if ( preg_match( '`/wikis/([0-9a-f]{10,32})/`', $uri, $matches, PREG_OFFSET_CAPTURE ) !== false ) {
+	$wiki = $matches[1][0];
+	$offset = $matches[1][1];
+	$wikiData = get_wiki_data( $wiki );
+	// Follow up to 10 redirect steps
+	$i = 0;
+	while ( $wikiData['redirect'] && $i < 10 ) {
+		$redirect = $wikiData['redirect'];
+		$wikiData = get_wiki_data( $redirect );
+		$i++;
+	}
+	$redirectUri =
+		substr( $uri, 0, $offset ) .
+		$redirect .
+		substr( $uri, $offset + strlen( $wiki ) );
+}
+
+if ( $redirect ) {
+	echo new \OOUI\MessageWidget( [
+		'type' => 'info',
+		'icon' => 'articleRedirect',
+		'label' => new \OOUI\HtmlSnippet(
+			'This wiki has been deleted and the following wiki was selected as a direct replacement: ' .
+			'<a href="' . htmlspecialchars( $redirectUri ) . '" class="wiki">' . substr( $redirect, 0, 10 ) . '</a>'
+		)
+	] );
+} else {
+	echo new \OOUI\MessageWidget( [
+		'type' => 'error',
+		'label' => 'Page not found. The wiki you are looking for may have been deleted.'
+	] );
+}
 
 include "footer.html";

delete.php

@@ -34,6 +34,25 @@
 			'</tr>' .
 		'</table>';
 
+		$wikilist = [
+			[
+				'data' => '',
+				'label' => 'None',
+			]
+		];
+		$results = $mysqli->query( 'SELECT wiki, creator, UNIX_TIMESTAMP( created ) created FROM wikis WHERE !deleted ORDER BY created DESC' );
+		if ( !$results ) {
+			die( $mysqli->error );
+		}
+		while ( $data = $results->fetch_assoc() ) {
+			if ( $data[ 'wiki' ] === $wiki ) {
+				continue;
+			}
+			$wikilist[] = [
+				'data' => $data[ 'wiki' ],
+				'label' => substr( $data[ 'wiki' ], 0, 10 ) . ' - ' . $data[ 'creator' ] . ' (' . date( 'Y-m-d H:i:s', $data[ 'created' ] ) . ')',
+			];
+		}
 		echo new OOUI\FormLayout( [
 			'method' => 'POST',
 			'items' => [
@@ -42,6 +61,18 @@
 						'<br>Are you sure you want to delete this wiki? This cannot be undone.'
 					),
 					'items' => array_filter( [
+						count( $wikilist ) > 1 ?
+							new OOUI\FieldLayout(
+								new OOUI\DropdownInputWidget( [
+									'name' => 'redirect',
+									'options' => $wikilist,
+								] ),
+								[
+									'label' => 'Leave a redirect to another wiki (optional):',
+									'align' => 'left',
+								]
+							) :
+							null,
 						new OOUI\FieldLayout(
 							new OOUI\ButtonInputWidget( [
 								'type' => 'submit',
@@ -51,7 +82,7 @@
 							] ),
 							[
 								'label' => ' ',
-								'align' => 'inline',
+								'align' => 'left',
 							]
 						),
 						new OOUI\FieldLayout(
@@ -70,10 +101,12 @@
 			die( "Invalid session." );
 		}
 
+		$redirect = $_POST['redirect'] ?: null;
+
 		ob_implicit_flush( true );
 
 		echo '<div class="consoleLog">';
-		$error = delete_wiki( $wiki );
+		$error = delete_wiki( $wiki, $redirect );
 		echo '</div>';
 
 		if ( $error ) {
@@ -88,3 +121,7 @@
 if ( $wikiData['deleted'] ) {
 	echo '<p>Wiki deleted.</p>';
 }
+
+if ( $wikiData['redirect'] ) {
+	echo '<p>Redirected to <a href="wikis/' . $wikiData['redirect'] . '/w">' . $wikiData['redirect'] . '</a>.</p>';
+}

includes.php

@@ -77,7 +77,7 @@ function get_wiki_data( string $wiki ): array {
 	global $mysqli;
 
 	$stmt = $mysqli->prepare( '
-		SELECT wiki, creator, UNIX_TIMESTAMP( created ) created, patches, branch, announcedTasks, timeToCreate, deleted
+		SELECT wiki, creator, UNIX_TIMESTAMP( created ) created, patches, branch, announcedTasks, timeToCreate, deleted, redirect
 		FROM wikis WHERE wiki = ?
 	' );
 	if ( !$stmt ) {
@@ -316,7 +316,11 @@ function shell( $cmd, array $env = [] ): ?string {
 	return $error ? null : $process->getOutput();
 }
 
-function delete_wiki( string $wiki ): ?string {
+function is_valid_hash( string $hash ): bool {
+	return preg_match( '/^[0-9a-f]{10,32}$/', $hash ) !== false;
+}
+
+function delete_wiki( string $wiki, ?string $redirect = null ): ?string {
 	global $mysqli;
 
 	$wikiData = get_wiki_data( $wiki );
@@ -346,12 +350,16 @@ function delete_wiki( string $wiki ): ?string {
 		);
 	}
 
+	if ( $redirect && !is_valid_hash( $redirect ) ) {
+		$redirect = null;
+	}
+
 	$stmt = $mysqli->prepare( '
 		UPDATE wikis
-		SET deleted = 1
+		SET deleted = 1, redirect = ?
 		WHERE wiki = ?
 	' );
-	$stmt->bind_param( 's', $wiki );
+	$stmt->bind_param( 'ss', $redirect, $wiki );
 	$stmt->execute();
 	$stmt->close();
 

sql/patchdemo.sql

@@ -42,3 +42,6 @@ ALTER TABLE `tasks`
 
 ALTER TABLE `wikis`
 	ADD COLUMN IF NOT EXISTS `branch` VARCHAR(64) NOT NULL AFTER `patches`;
+
+ALTER TABLE `wikis`
+	ADD COLUMN IF NOT EXISTS `redirect` VARCHAR(32) NULL AFTER `deleted`;