Upgrading Instructions for Yii Framework v2
===========================================

!!!IMPORTANT!!!

The following upgrading instructions are cumulative. That is,
if you want to upgrade from version A to version C and there is
version B between A and C, you need to following the instructions
for both A and B.

Upgrade from Yii 2.0 RC
-----------------------

* If you've implemented `yii\rbac\ManagerInterface` you need to add implementation for new method `removeChildren()`.

* The input dates for datetime formatting are now assumed to be in UTC unless a timezone is explicitly given.
  Before, the timezone assumed for input dates was the default timezone set by PHP which is the same as `Yii::$app->timeZone`.
  This causes trouble because the formatter uses `Yii::$app->timeZone` as the default values for output so no timezone conversion
  was possible. If your timestamps are stored in the database without a timezone identifier you have to ensure they are in UTC or
  add a timezone identifier explicitly.
  
* `yii\bootstrap\Collapse` is now encoding labels by default. `encode` item option and global `encodeLabels` property were
 introduced to disable it. Keys are no longer used as labels. You need to remove keys and use `label` item option instead.


Upgrade from Yii 2.0 Beta
-------------------------

* If you are using Composer to upgrade Yii, you should run the following command first (once for all) to install
  the composer-asset-plugin, *before* you update your project:

  ```
  php composer.phar global require "fxp/composer-asset-plugin:1.0.0-beta2"
  ```

  You also need to add the following code to your project's `composer.json` file:

  ```json
  "extra": {
      "asset-installer-paths": {
          "npm-asset-library": "vendor/npm",
          "bower-asset-library": "vendor/bower"
      }
  }
  ```
  
  It is also a good idea to upgrade composer itself to the latest version if you see any problems:
  
  ```
  php composer.phar self-update
  ```

* If you used `clearAll()` or `clearAllAssignments()` of `yii\rbac\DbManager`, you should replace
  them with `removeAll()` and `removeAllAssignments()` respectively.

* If you created RBAC rule classes, you should modify their `execute()` method by adding `$user`
  as the first parameter: `execute($user, $item, $params)`. The `$user` parameter represents
  the ID of the user currently being access checked. Previously, this is passed via `$params['user']`.

* If you override `yii\grid\DataColumn::getDataCellValue()` with visibility `protected` you have
  to change visibility to `public` as visibility of the base method has changed.

* If you have classes implementing `yii\web\IdentityInterface` (very common), you should modify
  the signature of `findIdentityByAccessToken()` as
  `public static function findIdentityByAccessToken($token, $type = null)`. The new `$type` parameter
  will contain the type information about the access token. For example, if you use
  `yii\filters\auth\HttpBearerAuth` authentication method, the value of this parameter will be
  `yii\filters\auth\HttpBearerAuth`. This allows you to differentiate access tokens taken by
  different authentication methods.

* If you are sharing the same cache across different applications, you should configure
  the `keyPrefix` property of the cache component to use some unique string.
  Previously, this property was automatically assigned with a unique string.

* If you are using `dropDownList()`, `listBox()`, `activeDropDownList()`, or `activeListBox()`
  of `yii\helpers\Html`, and your list options use multiple blank spaces to format and align
  option label texts, you need to specify the option `encodeSpaces` to be true.

* If you are using `yii\grid\GridView` and have configured a data column to use a PHP callable
  to return cell values (via `yii\grid\DataColumn::value`), you may need to adjust the signature
  of the callable to be `function ($model, $key, $index, $widget)`. The `$key` parameter was newly added
  in this release.

* `yii\console\controllers\AssetController` is now using hashes instead of timestamps. Replace all `{ts}` with `{hash}`.

* The database table of the `yii\log\DbTarget` now needs a `prefix` column to store context information.
  You can add it with `ALTER TABLE log ADD COLUMN prefix TEXT AFTER log_time;`.

* The `fileinfo` PHP extension is now required by Yii. If you use  `yii\helpers\FileHelper::getMimeType()`, make sure
  you have enabled this extension. This extension is [builtin](http://www.php.net/manual/en/fileinfo.installation.php) in php above `5.3`.

* Please update your main layout file by adding this line in the `<head>` section: `<?= Html::csrfMetaTags() ?>`.
  This change is needed because `yii\web\View` no longer automatically generates CSRF meta tags due to issue #3358.

* If your model code is using the `file` validation rule, you should rename its `types` option to `extensions`.

* `MailEvent` class has been moved to the `yii\mail` namespace. You have to adjust all references that may exist in your code.

* The behavior and signature of `ActiveRecord::afterSave()` has changed. `ActiveRecord::$isNewRecord` will now always be
  false in afterSave and also dirty attributes are not available. This change has been made to have a more consistent and
  expected behavior. The changed attributes are now available in the new parameter of afterSave() `$changedAttributes`.
  `$changedAttributes` contains the old values of attributes that had changed and were saved.

* `ActiveRecord::updateAttributes()` has been changed to not trigger events and not respect optimistic locking anymore to
  differentiate it more from calling `update(false)` and to ensure it can be used in `afterSave()` without triggering infinite
  loops.

* If you are developing RESTful APIs and using an authentication method such as `yii\filters\auth\HttpBasicAuth`,
  you should explicitly configure `yii\web\User::enableSession` in the application configuration to be false to avoid
  starting a session when authentication is performed. Previously this was done automatically by authentication method.

* `mail` component was renamed to `mailer`, `yii\log\EmailTarget::$mail` was renamed to `yii\log\EmailTarget::$mailer`.
  Please update all references in the code and config files.

* `yii\caching\GroupDependency` was renamed to `TagDependency`. You should create such a dependency using the code
  `new \yii\caching\TagDependency(['tags' => 'TagName'])`, where `TagName` is similar to the group name that you
  previously used.

* If you are using the constant `YII_PATH` in your code, you should rename it to `YII2_PATH` now.

* You must explicitly configure `yii\web\Request::cookieValidationKey` with a secret key. Previously this is done automatically.
  To do so, modify your application configuration like the following:

  ```php
  return [
      // ...
      'components' => [
          'request' => [
              'cookieValidationKey' => 'your secret key here',
          ],
      ],
  ];
  ```

  > Note: If you are using the `Advanced Application Template` you should not add this configuration to `common/config`
  or `console/config` because the console application doesn't have to deal with CSRF and uses its own request that
  doesn't have `cookieValidationKey` property.

* `yii\rbac\PhpManager` now stores data in three separate files instead of one. In order to convert old file to
new ones save the following code as `convert.php` that should be placed in the same directory your `rbac.php` is in: 

  ```php
  <?php
  $oldFile = 'rbac.php';
  $itemsFile = 'items.php';
  $assignmentsFile = 'assignments.php';
  $rulesFile = 'rules.php';
  
  $oldData = include $oldFile;
  
  function saveToFile($data, $fileName) {
      $out = var_export($data, true);
      $out = "<?php\nreturn " . $out . ";";
      $out = str_replace(['array (', ')'], ['[', ']'], $out);
      file_put_contents($fileName, $out);
  }
  
  $items = [];
  $assignments = [];
  if (isset($oldData['items'])) {
      foreach ($oldData['items'] as $name => $data) {
          if (isset($data['assignments'])) {
              foreach ($data['assignments'] as $userId => $assignmentData) {
                  $assignments[$userId][] = $assignmentData['roleName'];
              }
              unset($data['assignments']);
          }
          $items[$name] = $data;
      }
  }
  
  $rules = [];
  if (isset($oldData['rules'])) {
      $rules = $oldData['rules'];
  }
  
  saveToFile($items, $itemsFile);
  saveToFile($assignments, $assignmentsFile);
  saveToFile($rules, $rulesFile);
  
  echo "Done!\n";
  ```

  Run it once, delete `rbac.php`. If you've configured `authFile` property, remove the line from config and instead
  configure `itemFile`, `assignmentFile` and `ruleFile`.

* Static helper `yii\helpers\Security` has been converted into an application component. You should change all usage of
  its methods to a new syntax, for example: instead of `yii\helpers\Security::hashData()` use `Yii::$app->getSecurity()->hashData()`.
  Default encryption and hash parameters has been upgraded. If you need to decrypt/validate data that was encrypted/hashed
  before, use the following configuration of the 'security' component:

  ```php
  return [
      'components' => [
          'security' => [
              'cryptBlockSize' => 16,
              'cryptKeySize' => 24,
              'derivationIterations' => 1000,
              'deriveKeyStrategy' => 'hmac', // for PHP version < 5.5.0
              //'deriveKeyStrategy' => 'pbkdf2', // for PHP version >= 5.5.0
              'useDeriveKeyUniqueSalt' => false,
          ],
          // ...
      ],
      // ...
  ];
  ```

* If you are using query caching, you should modify your relevant code as follows, as `beginCache()` and `endCache()` are
  replaced by `cache()`:

  ```php
  $db->cache(function ($db) {

     // ... SQL queries that need to use query caching

  }, $duration, $dependency);
  ```
  
* Due to significant changes to security you need to upgrade your code to use `\yii\base\Security` component instead of
  helper. If you have any data encrypted it should be re-encrypted. In order to do so you can use old security helper
  [as explained by @docsolver at github](https://github.com/yiisoft/yii2/issues/4461#issuecomment-50237807).

* [[yii\helpers\Url::to()]] will no longer prefix base URL to relative URLs. For example, `Url::to('images/logo.png')`
  will return `images/logo.png` directly. If you want a relative URL to be prefix with base URL, you should make use
  of the alias `@web`. For example, `Url::to('@web/images/logo.png')` will return `/BaseUrl/images/logo.png`.

* The following properties are now taking `false` instead of `null` for "don't use" case:
  - `yii\bootstrap\NavBar::$brandLabel`.
  - `yii\bootstrap\NavBar::$brandUrl`.
  - `yii\bootstrap\Modal::$closeButton`.
  - `yii\bootstrap\Modal::$toggleButton`.
  - `yii\bootstrap\Alert::$closeButton`.
  - `yii\widgets\LinkPager::$nextPageLabel`.
  - `yii\widgets\LinkPager::$prevPageLabel`.
  - `yii\widgets\LinkPager::$firstPageLabel`.
  - `yii\widgets\LinkPager::$lastPageLabel`.

* The format of the Faker fixture template is changed. For an example, please refer to the file
  `apps/advanced/common/tests/templates/fixtures/user.php`.

* The signature of all file downloading methods in `yii\web\Response` is changed, as summarized below:
  - `sendFile($filePath, $attachmentName = null, $options = [])`
  - `sendContentAsFile($content, $attachmentName, $options = [])`
  - `sendStreamAsFile($handle, $attachmentName, $options = [])`
  - `xSendFile($filePath, $attachmentName = null, $options = [])`

* The signature of callbacks used in `yii\base\ArrayableTrait::fields()` is changed from `function ($field, $model) {`
  to `function ($model, $field) {`.

* `Html::radio()`, `Html::checkbox()`, `Html::radioList()`, `Html::checkboxList()` no longer generate the container
  tag around each radio/checkbox when you specify labels for them. You should manually render such container tags,
  or set the `item` option for `Html::radioList()`, `Html::checkboxList()` to generate the container tags.

* The formatter class has been refactored to have only one class regardless whether PHP intl extension is installed or not.
  Functionality of `yii\base\Formatter` has been merged into `yii\i18n\Formatter` and `yii\base\Formatter` has been
  removed so you have to replace all usage of `yii\base\Formatter` with `yii\i18n\Formatter` in your code.
  Also the API of the Formatter class has changed in many ways.
  The signature of the following Methods has changed:

  - `asDate`
  - `asTime`
  - `asDateTime`
  - `asSize` has been split up into `asSize` and `asShortSize`
  - `asCurrency`
  - `asDecimal`
  - `asPercent`
  - `asScientific`

  The following methods have been removed, this also means that the corresponding format which may be used by a
  GridView or DetailView is not available anymore:

  - `asNumber`
  - `asDouble`

  Also due to these changes some formatting defaults have changes so you have to check all your GridView and DetailView
  configuration and make sure the formatting is displayed correctly.

  The configuration for `asSize()` has changed. It now uses the configuration for the number formatting from intl
  and only the base is configured using `$sizeFormatBase`.

  The specification of the date and time formats is now using the ICU pattern format even if PHP intl extension is not installed.
  You can prefix a date format with `php:` to use the old format of the PHP `date()`-function.

* The DateValidator has been refactored to use the same format as the Formatter class now (see previous change).
  When you use the DateValidator and did not specify a format it will now be what is configured in the formatter class instead of 'Y-m-d'.
  To get the old behavior of the DateValidator you have to set the format explicitly in your validation rule:

  ```php
  ['attributeName', 'date', 'format' => 'php:Y-m-d'],
  ```

* `beforeValidate()`, `beforeValidateAll()`, `afterValidate()`, `afterValidateAll()`, `ajaxBeforeSend()` and `ajaxComplete()`
  are removed from `ActiveForm`. The same functionality is now achieved via JavaScript event mechanism like the following:

  ```js
  $('#myform').on('beforeValidate', function (event, messages, deferreds) {
      // called when the validation is triggered by submitting the form
      // return false if you want to cancel the validation for the whole form
  }).on('beforeValidateAttribute', function (event, attribute, messages, deferreds) {
      // before validating an attribute
      // return false if you want to cancel the validation for the attribute
  }).on('afterValidateAttribute', function (event, attribute, messages) {
      // ...
  }).on('afterValidate', function (event, messages) {
      // ...
  }).on('beforeSubmit', function () {
      // after all validations have passed
      // you can do ajax form submission here
      // return false if you want to stop form submission
  });
  ```

* The signature of `View::registerJsFile()` and `View::registerCssFile()` has changed. The `$depends` and `$position`
  paramaters have been merged into `$options`. The new signatures are as follows:
  
  - `registerJsFile($url, $options = [], $key = null)`
  - `registerCssFile($url, $options = [], $key = null)`
