Add simplified storage API

Provide a standard mechanism for accessing localStorage.

It may seems simplistic right now, but to give an idea of the why:
* We already have jquery.jStorage.js which is a much more heavyweight
approach to storing non-essential values.
* We are repeating ourselves a lot in extensions by having
to do localStorage detection and then deal with full localStorage.
In MobileFrontend we have a settings module. This is one of the reasons Gather
depends on MobileFrontend and I'm keen to remove that dependency.
* We might want to move to indexdb in future. Having a single API makes moving
this easier - we don't have to update everywhere that uses localStorage
* Saving non-string support would be useful. The API could be adjusted to take a
mixed second parameter that stringifys JSON objects.
* Cookie fallbacks are a possible alternative when localStorage is not supported. This allows
us to be agnostic of the storage mechanism going forward.

Note:
This doesn't reuse the handling in mediawiki.js as at this point
I am not sure there is value. mw.loader.store.enabled is false when
$wgResourceLoaderStorageEnabled is not true and this should work even
without that case. We can review this at a latter point.

See:
Id5c32bb7a662dda8d153490f7c47e972cabc1efd
I3fd44b0ae6633a7053aee247bc3c4704ba987bc8

Bug: T96155
Change-Id: Idb37352acecd745beb53aa8d77ea050851448e0d

diff --git a/maintenance/jsduck/categories.json b/maintenance/jsduck/categories.json
index a338ff0..07e72bf 100644 (file)
--- a/maintenance/jsduck/categories.json
+++ b/maintenance/jsduck/categories.json
@@ -27,6 +27,7 @@
                                        "mw.messagePoster.*",
                                        "mw.notification",
                                        "mw.Notification_",
+                                       "mw.storage",
                                        "mw.user",
                                        "mw.util",
                                        "mw.plugin.*",

diff --git a/resources/Resources.php b/resources/Resources.php
index 1116b79..e1f27f7 100644 (file)
--- a/resources/Resources.php
+++ b/resources/Resources.php
@@ -1092,6 +1092,10 @@ return array(
                'styles' => 'resources/src/mediawiki/mediawiki.sectionAnchor.css',
                'targets' => array( 'desktop', 'mobile' ),
        ),
+       'mediawiki.storage' => array(
+               'scripts' => 'resources/src/mediawiki/mediawiki.storage.js',
+               'targets' => array( 'desktop', 'mobile' ),
+       ),
        'mediawiki.Title' => array(
                'scripts' => 'resources/src/mediawiki/mediawiki.Title.js',
                'dependencies' => array(

diff --git a/resources/src/mediawiki/mediawiki.storage.js b/resources/src/mediawiki/mediawiki.storage.js
new file mode 100644 (file)
index 0000000..e10b561
--- /dev/null
+++ b/resources/src/mediawiki/mediawiki.storage.js
@@ -0,0 +1,69 @@
+( function ( mw ) {
+       'use strict';
+       var storage;
+
+       /**
+        * Library for storing device specific information. It should be used for storing simple
+        * strings and is not suitable for storing large chunks of data.
+        * @class mw.storage
+        * @singleton
+        */
+       storage = {
+               isLocalStorageSupported: false,
+               /**
+                * Retrieve value from device storage.
+                *
+                * @param {String} key of item to retrieve
+                * @returns {String|Boolean} false when localStorage not available, otherwise string
+                */
+               get: function ( key ) {
+                       if ( this.isLocalStorageSupported ) {
+                               return localStorage.getItem( key );
+                       } else {
+                               return false;
+                       }
+               },
+
+               /**
+                * Set a value in device storage.
+                *
+                * @param {String} key key name to store under.
+                * @param {String} value to be stored.
+                * @returns {Boolean} whether the save succeeded or not.
+                */
+               set: function ( key, value ) {
+                       try {
+                               localStorage.setItem( key, value );
+                               return true;
+                       } catch ( e ) {
+                               return false;
+                       }
+               },
+
+               /**
+                * Remove a value from device storage.
+                *
+                * @param {String} key of item to remove.
+                * @returns {Boolean} whether the save succeeded or not.
+                */
+               remove: function ( key ) {
+                       if ( this.isLocalStorageSupported ) {
+                               localStorage.removeItem( key );
+                               return true;
+                       } else {
+                               return false;
+                       }
+               }
+       };
+
+       mw.storage = storage;
+       // See if local storage is supported
+       try {
+               localStorage.setItem( 'localStorageTest', 'localStorageTest' );
+               localStorage.removeItem( 'localStorageTest' );
+               storage.isLocalStorageSupported = true;
+       } catch ( e ) {
+               // Already set. No body needed.
+       }
+
+}( mediaWiki ) );

diff --git a/tests/qunit/QUnitTestResources.php b/tests/qunit/QUnitTestResources.php
index 3608a53..bcfdead 100644 (file)
--- a/tests/qunit/QUnitTestResources.php
+++ b/tests/qunit/QUnitTestResources.php
@@ -68,6 +68,7 @@ return array(
                        'tests/qunit/suites/resources/mediawiki/mediawiki.jscompat.test.js',
                        'tests/qunit/suites/resources/mediawiki/mediawiki.messagePoster.factory.test.js',
                        'tests/qunit/suites/resources/mediawiki/mediawiki.RegExp.test.js',
+                       'tests/qunit/suites/resources/mediawiki/mediawiki.storage.test.js',
                        'tests/qunit/suites/resources/mediawiki/mediawiki.template.test.js',
                        'tests/qunit/suites/resources/mediawiki/mediawiki.test.js',
                        'tests/qunit/suites/resources/mediawiki/mediawiki.Title.test.js',
@@ -113,6 +114,7 @@ return array(
                        'mediawiki.jqueryMsg',
                        'mediawiki.messagePoster',
                        'mediawiki.RegExp',
+                       'mediawiki.storage',
                        'mediawiki.Title',
                        'mediawiki.toc',
                        'mediawiki.Uri',

diff --git a/tests/qunit/suites/resources/mediawiki/mediawiki.storage.test.js b/tests/qunit/suites/resources/mediawiki/mediawiki.storage.test.js
new file mode 100644 (file)
index 0000000..c25641d
--- /dev/null
+++ b/tests/qunit/suites/resources/mediawiki/mediawiki.storage.test.js
@@ -0,0 +1,53 @@
+( function ( mw ) {
+       QUnit.module( 'mediawiki.storage: normal case.', {
+               setup: function () {
+                       this.sandbox.stub( mw.storage, 'isLocalStorageSupported', true );
+                       this.spy = this.sandbox.spy( localStorage, 'setItem' );
+                       this.sandbox.stub( localStorage, 'getItem' )
+                               .withArgs( 'foo' ).returns( 'test' )
+                               .withArgs( 'bar' ).returns( null );
+               }
+       } );
+
+       QUnit.test( 'set/get with localStorage', 4, function ( assert ) {
+               mw.storage.set( 'foo', 'test' );
+               assert.strictEqual( this.spy.calledOnce, true, 'Check localStorage called.' );
+               assert.strictEqual( this.spy.calledWith( 'foo', 'test' ), true,
+                       'Check prefixed.' );
+               assert.strictEqual( mw.storage.get( 'foo' ), 'test', 'Check value gets stored.' );
+               assert.strictEqual( mw.storage.get( 'bar' ), null, 'Unset values are null.' );
+       } );
+
+       QUnit.module( 'mediawiki.storage: localStorage does not exist', {
+               setup: function () {
+                       this.sandbox.stub( mw.storage, 'isLocalStorageSupported', false );
+                       this.sandbox.stub( localStorage, 'setItem' ).throws();
+               }
+       } );
+
+       QUnit.test( 'set/get without localStorage', 3, function ( assert ) {
+               assert.strictEqual( mw.storage.set( 'foo', 'test' ), false,
+                       'When localStorage not available save fails.' );
+
+               assert.strictEqual( mw.storage.remove( 'foo', 'test' ), false,
+                       'When localStorage not available remove fails.' );
+
+               assert.strictEqual( mw.storage.get( 'foo' ), false,
+                               'Inability to retrieve values return false to differentiate from null (not set).' );
+       } );
+
+       QUnit.module( 'mediawiki.storage: localStorage exhausted', {
+               setup: function () {
+                       this.sandbox.stub( mw.storage, 'isLocalStorageSupported', true );
+                       this.sandbox.stub( localStorage, 'setItem' ).throws();
+                       this.sandbox.stub( localStorage, 'getItem' ).returns( null );
+               }
+       } );
+
+       QUnit.test( 'set/get without localStorage', 2, function ( assert ) {
+               assert.strictEqual( mw.storage.set( 'foo', 'test' ), false,
+                       'When localStorage not available inform user with false.' );
+               assert.strictEqual( mw.storage.get( 'foo' ), null, 'No value registered.' );
+       } );
+
+}( mediaWiki ) );