From 74b222230da8a3dadc4d03e1a3e000c1ca09e12a Mon Sep 17 00:00:00 2001
From: =?utf8?q?Bartosz=20Dziewo=C5=84ski?= <matma.rex@gmail.com>
Date: Fri, 7 Mar 2014 18:39:51 +0100
Subject: [PATCH] Check validity and availability of usernames during signup
 via AJAX
MIME-Version: 1.0
Content-Type: text/plain; charset=utf8
Content-Transfer-Encoding: 8bit

This is done in addition to the server-side checks. Users who have
disabled JavaScript will not notice any difference.

The way this is done (via action=query&list=users API) means that we
can't check for all possible error conditions, both for the username
(e.g. these enforced by extensions like AntiSpoof) and other parts of
the form (e-mail, password…) – these are still handled server-side
only. Thus we intentionally never say that whatever the user typed in
is valid – we only warn when we know it's not.

Doing this "properly" would require some reworking of the internals of
the signup process and this way is already a huge improvement.

(Split off from the reverted a0c72523.)

Bug: 34447
Change-Id: I42c00b54651fd4e7217a862b3116c6113935f5ae
---
 RELEASE-NOTES-1.23                            |   2 +
 includes/templates/Usercreate.php             |  12 +-
 resources/Resources.php                       |   9 +-
 .../mediawiki.special.userlogin.signup.js     | 112 +++++++++++++++++-
 4 files changed, 129 insertions(+), 6 deletions(-)

diff --git a/RELEASE-NOTES-1.23 b/RELEASE-NOTES-1.23
index 2b91f88f88..b24442056e 100644
--- a/RELEASE-NOTES-1.23
+++ b/RELEASE-NOTES-1.23
@@ -116,6 +116,8 @@ production.
   creations, similar to the topOnly option.
 * Add mediawiki.ui.button styling to all pages so wiki content can use styled
   buttons.
+* Special:UserLogin/signup now does AJAX checks for invalid and taken usernames,
+  displaying the error live.
 
 === Bug fixes in 1.23 ===
 * (bug 41759) The "updated since last visit" markers (on history pages, recent
diff --git a/includes/templates/Usercreate.php b/includes/templates/Usercreate.php
index 0cb83d555e..aba0d2767c 100644
--- a/includes/templates/Usercreate.php
+++ b/includes/templates/Usercreate.php
@@ -58,15 +58,23 @@ class UsercreateTemplate extends BaseTemplate {
 			<section class="mw-form-header">
 				<?php $this->html( 'header' ); /* extensions such as ConfirmEdit add form HTML here */ ?>
 			</section>
+			<!-- This element is used by the mediawiki.special.userlogin.signup.js module. -->
+			<div
+				id="mw-createacct-status-area"
+				<?php if ( $this->data['message'] ) { ?>
+					class="<?php echo $this->data['messagetype']; ?>box"
+				<?php } else { ?>
+					style="display: none;"
+				<?php } ?>
+			>
 			<?php if ( $this->data['message'] ) { ?>
-				<div class="<?php $this->text( 'messagetype' ); ?>box">
 					<?php if ( $this->data['messagetype'] == 'error' ) { ?>
 						<strong><?php $this->msg( 'createacct-error' ); ?></strong>
 						<br />
 					<?php } ?>
 					<?php $this->html( 'message' ); ?>
-				</div>
 			<?php } ?>
+			</div>
 
 			<div>
 				<label for='wpName2'>
diff --git a/resources/Resources.php b/resources/Resources.php
index 5ceda32142..207e689cad 100644
--- a/resources/Resources.php
+++ b/resources/Resources.php
@@ -1249,9 +1249,16 @@ return array(
 	'mediawiki.special.userlogin.signup.js' => array(
 		'scripts' => 'resources/mediawiki.special/mediawiki.special.userlogin.signup.js',
 		'messages' => array(
+			'createacct-error',
 			'createacct-emailrequired',
+			'noname',
+			'userexists',
+		),
+		'dependencies' => array(
+			'mediawiki.api',
+			'mediawiki.jqueryMsg',
+			'jquery.throttle-debounce',
 		),
-		'dependencies' => 'mediawiki.jqueryMsg',
 	),
 	'mediawiki.special.javaScriptTest' => array(
 		'scripts' => 'resources/mediawiki.special/mediawiki.special.javaScriptTest.js',
diff --git a/resources/mediawiki.special/mediawiki.special.userlogin.signup.js b/resources/mediawiki.special/mediawiki.special.userlogin.signup.js
index c293f655ff..0615932fe3 100644
--- a/resources/mediawiki.special/mediawiki.special.userlogin.signup.js
+++ b/resources/mediawiki.special/mediawiki.special.userlogin.signup.js
@@ -3,7 +3,7 @@
  */
 ( function ( mw, $ ) {
 	// When sending password by email, hide the password input fields.
-	function hidePasswordOnEmail() {
+	$( function () {
 		// Always required if checked, otherwise it depends, so we use the original
 		var $emailLabel = $( 'label[for="wpEmail"]' ),
 			originalText = $emailLabel.text(),
@@ -28,7 +28,113 @@
 
 		$createByMailCheckbox.on( 'change', updateForCheckbox );
 		updateForCheckbox();
-	}
+	} );
 
-	$( hidePasswordOnEmail );
+	// Check if the username is invalid or already taken
+	$( function () {
+		var
+			// We need to hook to all of these events to be sure we are notified of all changes to the
+			// value of an <input type=text> field.
+			events = 'keyup keydown change mouseup cut paste focus blur',
+			$input = $( '#wpName2' ),
+			$statusContainer = $( '#mw-createacct-status-area' ),
+			api = new mw.Api(),
+			currentRequest;
+
+		// Hide any present status messages.
+		function clearStatus() {
+			$statusContainer.slideUp( function () {
+				$statusContainer
+					.removeAttr( 'class' )
+					.empty();
+			} );
+		}
+
+		// Returns a promise receiving a { state:, username: } object, where:
+		// * 'state' is one of 'invalid', 'taken', 'ok'
+		// * 'username' is the validated username if 'state' is 'ok', null otherwise (if it's not
+		//   possible to register such an account)
+		function checkUsername( username ) {
+			// We could just use .then() if we didn't have to pass on .abort()…
+			var d, apiPromise;
+
+			d = $.Deferred();
+			apiPromise = api.get( {
+				action: 'query',
+				list: 'users',
+				ususers: username // '|' in usernames is handled below
+			} )
+				.done( function ( resp ) {
+					var userinfo = resp.query.users[0];
+
+					if ( resp.query.users.length !== 1 ) {
+						// Happens if the user types '|' into the field
+						d.resolve( { state: 'invalid', username: null } );
+					} else if ( userinfo.invalid !== undefined ) {
+						d.resolve( { state: 'invalid', username: null } );
+					} else if ( userinfo.userid !== undefined ) {
+						d.resolve( { state: 'taken', username: null } );
+					} else {
+						d.resolve( { state: 'ok', username: username } );
+					}
+				} )
+				.fail( d.reject );
+
+			return d.promise( { abort: apiPromise.abort } );
+		}
+
+		function updateUsernameStatus() {
+			var
+				username = $.trim( $input.val() ),
+				currentRequestInternal;
+
+			// Abort any pending requests.
+			if ( currentRequest ) {
+				currentRequest.abort();
+			}
+
+			if ( username === '' ) {
+				clearStatus();
+				return;
+			}
+
+			currentRequest = currentRequestInternal = checkUsername( username ).done( function ( info ) {
+				var message;
+
+				// Another request was fired in the meantime, the result we got here is no longer current.
+				// This shouldn't happen as we abort pending requests, but you never know.
+				if ( currentRequest !== currentRequestInternal ) {
+					return;
+				}
+				// If we're here, then the current request has finished, avoid calling .abort() needlessly.
+				currentRequest = undefined;
+
+				if ( info.state === 'ok' ) {
+					clearStatus();
+				} else {
+					if ( info.state === 'invalid' ) {
+						message = mw.message( 'noname' ).text();
+					} else if ( info.state === 'taken' ) {
+						message = mw.message( 'userexists' ).text();
+					}
+
+					$statusContainer
+						.attr( 'class', 'errorbox' )
+						.empty()
+						.append(
+							// Ugh…
+							// @todo Change the HTML structure in includes/templates/Usercreate.php
+							$( '<strong>' ).text( mw.message( 'createacct-error' ).text() ),
+							$( '<br>' ),
+							document.createTextNode( message )
+						)
+						.slideDown();
+				}
+			} ).fail( function () {
+				clearStatus();
+			} );
+		}
+
+		$input.on( events, $.debounce( 250, updateUsernameStatus ) );
+	} );
 }( mediaWiki, jQuery ) );
-- 
2.20.1