diff options
Diffstat (limited to 'guides/source')
29 files changed, 812 insertions, 206 deletions
diff --git a/guides/source/3_2_release_notes.md b/guides/source/3_2_release_notes.md index f6571544f9..ae6eb27f35 100644 --- a/guides/source/3_2_release_notes.md +++ b/guides/source/3_2_release_notes.md @@ -36,7 +36,7 @@ TIP: Note that Ruby 1.8.7 p248 and p249 have marshalling bugs that crash Rails. * `coffee-rails ~> 3.2.1` * `uglifier >= 1.0.3` -* Rails 3.2 deprecates `vendor/plugins` and Rails 4.0 will remove them completely. You can start replacing these plugins by extracting them as gems and adding them in your Gemfile. If you choose not to make them gems, you can move them into, say, `lib/my_plugin/*` and add an appropriate initializer in `config/initializers/my_plugin.rb`. +* Rails 3.2 deprecates `vendor/plugins` and Rails 4.0 will remove them completely. You can start replacing these plugins by extracting them as gems and adding them in your `Gemfile`. If you choose not to make them gems, you can move them into, say, `lib/my_plugin/*` and add an appropriate initializer in `config/initializers/my_plugin.rb`. * There are a couple of new configuration changes you'd want to add in `config/environments/development.rb`: @@ -156,7 +156,7 @@ Railties will create indexes for `title` and `author` with the latter being a unique index. Some types such as decimal accept custom options. In the example, `price` will be a decimal column with precision and scale set to 7 and 2 respectively. -* Turn gem has been removed from default Gemfile. +* Turn gem has been removed from default `Gemfile`. * Remove old plugin generator `rails generate plugin` in favor of `rails plugin new` command. diff --git a/guides/source/4_1_release_notes.md b/guides/source/4_1_release_notes.md index 6bf65757ec..2c5e665e33 100644 --- a/guides/source/4_1_release_notes.md +++ b/guides/source/4_1_release_notes.md @@ -274,7 +274,7 @@ for detailed changes. * The [Spring application preloader](https://github.com/rails/spring) is now installed by default for new applications. It uses the development group of - the Gemfile, so will not be installed in + the `Gemfile`, so will not be installed in production. ([Pull Request](https://github.com/rails/rails/pull/12958)) * `BACKTRACE` environment variable to show unfiltered backtraces for test diff --git a/guides/source/4_2_release_notes.md b/guides/source/4_2_release_notes.md index 036a310ac8..7105df5634 100644 --- a/guides/source/4_2_release_notes.md +++ b/guides/source/4_2_release_notes.md @@ -368,7 +368,7 @@ Please refer to the [Changelog][railties] for detailed changes. ### Notable changes -* Introduced `web-console` in the default application Gemfile. +* Introduced `web-console` in the default application `Gemfile`. ([Pull Request](https://github.com/rails/rails/pull/11667)) * Added a `required` option to the model generator for associations. diff --git a/guides/source/5_2_release_notes.md b/guides/source/5_2_release_notes.md new file mode 100644 index 0000000000..eb361e200a --- /dev/null +++ b/guides/source/5_2_release_notes.md @@ -0,0 +1,210 @@ +**DO NOT READ THIS FILE ON GITHUB, GUIDES ARE PUBLISHED ON http://guides.rubyonrails.org.** + +Ruby on Rails 5.2 Release Notes +=============================== + +Highlights in Rails 5.2: + +* Active Storage +* Redis Cache Store +* HTTP/2 Early hints support +* Credentials +* Default Content Security Policy + +These release notes cover only the major changes. To learn about various bug +fixes and changes, please refer to the change logs or check out the [list of +commits](https://github.com/rails/rails/commits/5-2-stable) in the main Rails +repository on GitHub. + +-------------------------------------------------------------------------------- + +Upgrading to Rails 5.2 +---------------------- + +If you're upgrading an existing application, it's a great idea to have good test +coverage before going in. You should also first upgrade to Rails 5.1 in case you +haven't and make sure your application still runs as expected before attempting +an update to Rails 5.2. + + +Major Features +-------------- + +### Active Storage + +[README](https://github.com/rails/rails/blob/d3893ec38ec61282c2598b01a298124356d6b35a/activestorage/README.md) + +### Redis Cache Store + +[Pull Request](https://github.com/rails/rails/pull/31134) + + +### HTTP/2 Early hints support + +[Pull Request](https://github.com/rails/rails/pull/30744) + + +### Credentials + +[Pull Request](https://github.com/rails/rails/pull/30067) + + +### Default Content Security Policy + +[Pull Request](https://github.com/rails/rails/pull/31162) + +Incompatibilities +----------------- + +ToDo + +Railties +-------- + +Please refer to the [Changelog][railties] for detailed changes. + +### Removals + +ToDo + +### Notable changes + +ToDo + +Action Cable +----------- + +Please refer to the [Changelog][action-cable] for detailed changes. + +### Notable changes + +ToDo + +Action Pack +----------- + +Please refer to the [Changelog][action-pack] for detailed changes. + +### Removals + +ToDo + +### Deprecations + +ToDo + +### Notable changes + +ToDo + +Action View +------------- + +Please refer to the [Changelog][action-view] for detailed changes. + +### Removals + +ToDo + +### Deprecations + +ToDo + +### Notable changes + +ToDo + +Action Mailer +------------- + +Please refer to the [Changelog][action-mailer] for detailed changes. + +### Notable changes + +ToDo + +Active Record +------------- + +Please refer to the [Changelog][active-record] for detailed changes. + +ToDo + +### Deprecations + +ToDo + +### Notable changes + +ToDo + +Active Model +------------ + +Please refer to the [Changelog][active-model] for detailed changes. + +### Removals + +ToDo + +### Notable changes + +ToDo + +Active Storage +-------------- + +Please refer to the [Changelog][active-support] for detailed changes. + +### Notable changes + +ToDo + +Active Support +-------------- + +Please refer to the [Changelog][active-support] for detailed changes. + +### Removals + +ToDo + +### Deprecations + +ToDo + +### Notable changes + +ToDo + +Active Job +----------- + +Please refer to the [Changelog][active-job] for detailed changes. + +### Removals + +ToDo + +### Notable changes + +ToDo + +Credits +------- + +See the +[full list of contributors to Rails](http://contributors.rubyonrails.org/) for +the many people who spent many hours making Rails, the stable and robust +framework it is. Kudos to all of them. + +[railties]: https://github.com/rails/rails/blob/5-2-stable/railties/CHANGELOG.md +[action-pack]: https://github.com/rails/rails/blob/5-2-stable/actionpack/CHANGELOG.md +[action-view]: https://github.com/rails/rails/blob/5-2-stable/actionview/CHANGELOG.md +[action-mailer]: https://github.com/rails/rails/blob/5-2-stable/actionmailer/CHANGELOG.md +[action-cable]: https://github.com/rails/rails/blob/5-2-stable/actioncable/CHANGELOG.md +[active-record]: https://github.com/rails/rails/blob/5-2-stable/activerecord/CHANGELOG.md +[active-model]: https://github.com/rails/rails/blob/5-2-stable/activemodel/CHANGELOG.md +[active-storage]: https://github.com/rails/rails/blob/5-2-stable/activestorage/CHANGELOG.md +[active-support]: https://github.com/rails/rails/blob/5-2-stable/activesupport/CHANGELOG.md +[active-job]: https://github.com/rails/rails/blob/5-2-stable/activejob/CHANGELOG.md diff --git a/guides/source/action_cable_overview.md b/guides/source/action_cable_overview.md index 57403a4bf9..1a86b1fcbb 100644 --- a/guides/source/action_cable_overview.md +++ b/guides/source/action_cable_overview.md @@ -1,12 +1,12 @@ Action Cable Overview ===================== -In this guide you will learn how Action Cable works and how to use WebSockets to +In this guide, you will learn how Action Cable works and how to use WebSockets to incorporate real-time features into your Rails application. After reading this guide, you will know: -* What Action Cable is and its integration on backend and frontend +* What Action Cable is and its integration backend and frontend * How to setup Action Cable * How to setup channels * Deployment and Architecture setup for running Action Cable @@ -129,7 +129,7 @@ subscriptions based on an identifier sent by the cable consumer. # app/channels/chat_channel.rb class ChatChannel < ApplicationCable::Channel # Called when the consumer has successfully - # become a subscriber of this channel. + # become a subscriber to this channel. def subscribed end end @@ -225,7 +225,7 @@ A *broadcasting* is a pub/sub link where anything transmitted by a publisher is routed directly to the channel subscribers who are streaming that named broadcasting. Each channel can be streaming zero or more broadcastings. -Broadcastings are purely an online queue and time dependent. If a consumer is +Broadcastings are purely an online queue and time-dependent. If a consumer is not streaming (subscribed to a given channel), they'll not get the broadcast should they connect later. @@ -515,8 +515,8 @@ user. For a user with an ID of 1, the broadcasting name would be The channel has been instructed to stream everything that arrives at `web_notifications:1` directly to the client by invoking the `received` callback. The data passed as argument is the hash sent as the second parameter -to the server-side broadcast call, JSON encoded for the trip across the wire, -and unpacked for the data argument arriving to `received`. +to the server-side broadcast call, JSON encoded for the trip across the wire +and unpacked for the data argument arriving as `received`. ### More Complete Examples @@ -569,7 +569,7 @@ This may change in the future. [#27214](https://github.com/rails/rails/issues/27 Action Cable will only accept requests from specified origins, which are passed to the server config as an array. The origins can be instances of -strings or regular expressions, against which a check for match will be performed. +strings or regular expressions, against which a check for the match will be performed. ```ruby config.action_cable.allowed_request_origins = ['http://rubyonrails.com', %r{http://ruby.*}] @@ -592,7 +592,7 @@ environment configuration files. ### Other Configurations -The other common option to configure, is the log tags applied to the +The other common option to configure is the log tags applied to the per-connection logger. Here's an example that uses the user account id if available, else "no-account" while tagging: @@ -607,7 +607,7 @@ config.action_cable.log_tags = [ For a full list of all configuration options, see the `ActionCable::Server::Configuration` class. -Also note that your server must provide at least the same number of database +Also, note that your server must provide at least the same number of database connections as you have workers. The default worker pool size is set to 4, so that means you have to make at least that available. You can change that in `config/database.yml` through the `pool` attribute. diff --git a/guides/source/action_controller_overview.md b/guides/source/action_controller_overview.md index 28f7246197..6ecfb57db3 100644 --- a/guides/source/action_controller_overview.md +++ b/guides/source/action_controller_overview.md @@ -21,7 +21,7 @@ After reading this guide, you will know: What Does a Controller Do? -------------------------- -Action Controller is the C in MVC. After the router has determined which controller to use for a request, the controller is responsible for making sense of the request and producing the appropriate output. Luckily, Action Controller does most of the groundwork for you and uses smart conventions to make this as straightforward as possible. +Action Controller is the C in [MVC](https://en.wikipedia.org/wiki/Model%E2%80%93view%E2%80%93controller). After the router has determined which controller to use for a request, the controller is responsible for making sense of the request, and producing the appropriate output. Luckily, Action Controller does most of the groundwork for you and uses smart conventions to make this as straightforward as possible. For most conventional [RESTful](https://en.wikipedia.org/wiki/Representational_state_transfer) applications, the controller will receive the request (this is invisible to you as the developer), fetch or save data from a model and use a view to create HTML output. If your controller needs to do things a little differently, that's not a problem, this is just the most common way for a controller to work. diff --git a/guides/source/action_view_overview.md b/guides/source/action_view_overview.md index c1e02745de..fde2040173 100644 --- a/guides/source/action_view_overview.md +++ b/guides/source/action_view_overview.md @@ -149,10 +149,10 @@ end #### Jbuilder [Jbuilder](https://github.com/rails/jbuilder) is a gem that's -maintained by the Rails team and included in the default Rails Gemfile. +maintained by the Rails team and included in the default Rails `Gemfile`. It's similar to Builder, but is used to generate JSON, instead of XML. -If you don't have it, you can add the following to your Gemfile: +If you don't have it, you can add the following to your `Gemfile`: ```ruby gem 'jbuilder' diff --git a/guides/source/active_record_callbacks.md b/guides/source/active_record_callbacks.md index 53417f012e..630dafe632 100644 --- a/guides/source/active_record_callbacks.md +++ b/guides/source/active_record_callbacks.md @@ -213,6 +213,7 @@ The following methods trigger callbacks: * `save!` * `save(validate: false)` * `toggle!` +* `touch` * `update_attribute` * `update` * `update!` @@ -245,7 +246,6 @@ Just as with validations, it is also possible to skip callbacks by using the fol * `increment` * `increment_counter` * `toggle` -* `touch` * `update_column` * `update_columns` * `update_all` diff --git a/guides/source/active_record_querying.md b/guides/source/active_record_querying.md index 3786343fc3..4e28e31a53 100644 --- a/guides/source/active_record_querying.md +++ b/guides/source/active_record_querying.md @@ -801,7 +801,7 @@ The SQL that would be executed: SELECT * FROM articles WHERE id > 10 ORDER BY id DESC # Original query without `only` -SELECT "articles".* FROM "articles" WHERE (id > 10) ORDER BY id desc LIMIT 20 +SELECT * FROM articles WHERE id > 10 ORDER BY id DESC LIMIT 20 ``` @@ -820,14 +820,14 @@ Article.find(10).comments.reorder('name') The SQL that would be executed: ```sql -SELECT * FROM articles WHERE id = 10 +SELECT * FROM articles WHERE id = 10 LIMIT 1 SELECT * FROM comments WHERE article_id = 10 ORDER BY name ``` In the case where the `reorder` clause is not used, the SQL executed would be: ```sql -SELECT * FROM articles WHERE id = 10 +SELECT * FROM articles WHERE id = 10 LIMIT 1 SELECT * FROM comments WHERE article_id = 10 ORDER BY posted_at DESC ``` @@ -1091,7 +1091,7 @@ This produces: ```sql SELECT articles.* FROM articles - INNER JOIN categories ON articles.category_id = categories.id + INNER JOIN categories ON categories.id = articles.category_id INNER JOIN comments ON comments.article_id = articles.id ``` @@ -1871,14 +1871,14 @@ All calculation methods work directly on a model: ```ruby Client.count -# SELECT count(*) AS count_all FROM clients +# SELECT COUNT(*) FROM clients ``` Or on a relation: ```ruby Client.where(first_name: 'Ryan').count -# SELECT count(*) AS count_all FROM clients WHERE (first_name = 'Ryan') +# SELECT COUNT(*) FROM clients WHERE (first_name = 'Ryan') ``` You can also use various finder methods on a relation for performing complex calculations: @@ -1890,9 +1890,9 @@ Client.includes("orders").where(first_name: 'Ryan', orders: { status: 'received' Which will execute: ```sql -SELECT count(DISTINCT clients.id) AS count_all FROM clients - LEFT OUTER JOIN orders ON orders.client_id = clients.id WHERE - (clients.first_name = 'Ryan' AND orders.status = 'received') +SELECT COUNT(DISTINCT clients.id) FROM clients + LEFT OUTER JOIN orders ON orders.client_id = clients.id + WHERE (clients.first_name = 'Ryan' AND orders.status = 'received') ``` ### Count diff --git a/guides/source/active_support_core_extensions.md b/guides/source/active_support_core_extensions.md index 54d3dec1c2..66d2fbd939 100644 --- a/guides/source/active_support_core_extensions.md +++ b/guides/source/active_support_core_extensions.md @@ -2970,6 +2970,32 @@ Extensions to `Date` NOTE: All the following methods are defined in `active_support/core_ext/date/calculations.rb`. +```ruby +yesterday +tomorrow +beginning_of_week (at_beginning_of_week) +end_of_week (at_end_of_week) +monday +sunday +weeks_ago +prev_week (last_week) +next_week +months_ago +months_since +beginning_of_month (at_beginning_of_month) +end_of_month (at_end_of_month) +last_month +beginning_of_quarter (at_beginning_of_quarter) +end_of_quarter (at_end_of_quarter) +beginning_of_year (at_beginning_of_year) +end_of_year (at_end_of_year) +years_ago +years_since +last_year +on_weekday? +on_weekend? +``` + INFO: The following calculation methods have edge cases in October 1582, since days 5..14 just do not exist. This guide does not document their behavior around those days for brevity, but it is enough to say that they do what you would expect. That is, `Date.new(1582, 10, 4).tomorrow` returns `Date.new(1582, 10, 15)` and so on. Please check `test/core_ext/date_ext_test.rb` in the Active Support test suite for expected behavior. #### `Date.current` @@ -2980,68 +3006,6 @@ When making Date comparisons using methods which honor the user time zone, make #### Named dates -##### `prev_year`, `next_year` - -In Ruby 1.9 `prev_year` and `next_year` return a date with the same day/month in the last or next year: - -```ruby -d = Date.new(2010, 5, 8) # => Sat, 08 May 2010 -d.prev_year # => Fri, 08 May 2009 -d.next_year # => Sun, 08 May 2011 -``` - -If date is the 29th of February of a leap year, you obtain the 28th: - -```ruby -d = Date.new(2000, 2, 29) # => Tue, 29 Feb 2000 -d.prev_year # => Sun, 28 Feb 1999 -d.next_year # => Wed, 28 Feb 2001 -``` - -`prev_year` is aliased to `last_year`. - -##### `prev_month`, `next_month` - -In Ruby 1.9 `prev_month` and `next_month` return the date with the same day in the last or next month: - -```ruby -d = Date.new(2010, 5, 8) # => Sat, 08 May 2010 -d.prev_month # => Thu, 08 Apr 2010 -d.next_month # => Tue, 08 Jun 2010 -``` - -If such a day does not exist, the last day of the corresponding month is returned: - -```ruby -Date.new(2000, 5, 31).prev_month # => Sun, 30 Apr 2000 -Date.new(2000, 3, 31).prev_month # => Tue, 29 Feb 2000 -Date.new(2000, 5, 31).next_month # => Fri, 30 Jun 2000 -Date.new(2000, 1, 31).next_month # => Tue, 29 Feb 2000 -``` - -`prev_month` is aliased to `last_month`. - -##### `prev_quarter`, `next_quarter` - -Same as `prev_month` and `next_month`. It returns the date with the same day in the previous or next quarter: - -```ruby -t = Time.local(2010, 5, 8) # => Sat, 08 May 2010 -t.prev_quarter # => Mon, 08 Feb 2010 -t.next_quarter # => Sun, 08 Aug 2010 -``` - -If such a day does not exist, the last day of the corresponding month is returned: - -```ruby -Time.local(2000, 7, 31).prev_quarter # => Sun, 30 Apr 2000 -Time.local(2000, 5, 31).prev_quarter # => Tue, 29 Feb 2000 -Time.local(2000, 10, 31).prev_quarter # => Mon, 30 Oct 2000 -Time.local(2000, 11, 31).next_quarter # => Wed, 28 Feb 2001 -``` - -`prev_quarter` is aliased to `last_quarter`. - ##### `beginning_of_week`, `end_of_week` The methods `beginning_of_week` and `end_of_week` return the dates for the @@ -3159,6 +3123,8 @@ Date.new(2012, 2, 29).years_ago(3) # => Sat, 28 Feb 2009 Date.new(2012, 2, 29).years_since(3) # => Sat, 28 Feb 2015 ``` +`last_year` is short-hand for `#years_ago(1)`. + ##### `months_ago`, `months_since` The methods `months_ago` and `months_since` work analogously for months: @@ -3175,6 +3141,8 @@ Date.new(2010, 4, 30).months_ago(2) # => Sun, 28 Feb 2010 Date.new(2009, 12, 31).months_since(2) # => Sun, 28 Feb 2010 ``` +`last_month` is short-hand for `#months_ago(1)`. + ##### `weeks_ago` The method `weeks_ago` works analogously for weeks: @@ -3337,35 +3305,7 @@ WARNING: `DateTime` is not aware of DST rules and so some of these methods have NOTE: All the following methods are defined in `active_support/core_ext/date_time/calculations.rb`. -The class `DateTime` is a subclass of `Date` so by loading `active_support/core_ext/date/calculations.rb` you inherit these methods and their aliases, except that they will always return datetimes: - -```ruby -yesterday -tomorrow -beginning_of_week (at_beginning_of_week) -end_of_week (at_end_of_week) -monday -sunday -weeks_ago -prev_week (last_week) -next_week -months_ago -months_since -beginning_of_month (at_beginning_of_month) -end_of_month (at_end_of_month) -prev_month (last_month) -next_month -beginning_of_quarter (at_beginning_of_quarter) -end_of_quarter (at_end_of_quarter) -beginning_of_year (at_beginning_of_year) -end_of_year (at_end_of_year) -years_ago -years_since -prev_year (last_year) -next_year -on_weekday? -on_weekend? -``` +The class `DateTime` is a subclass of `Date` so by loading `active_support/core_ext/date/calculations.rb` you inherit these methods and their aliases, except that they will always return datetimes. The following methods are reimplemented so you do **not** need to load `active_support/core_ext/date/calculations.rb` for these ones: @@ -3513,8 +3453,6 @@ Extensions to `Time` NOTE: All the following methods are defined in `active_support/core_ext/time/calculations.rb`. -Active Support adds to `Time` many of the methods available for `DateTime`: - ```ruby past? today? @@ -3526,6 +3464,8 @@ change advance ago since (in) +prev_day +next_day beginning_of_day (midnight, at_midnight, at_beginning_of_day) end_of_day beginning_of_hour (at_beginning_of_hour) @@ -3541,15 +3481,17 @@ months_ago months_since beginning_of_month (at_beginning_of_month) end_of_month (at_end_of_month) -prev_month (last_month) +prev_month next_month +last_month beginning_of_quarter (at_beginning_of_quarter) end_of_quarter (at_end_of_quarter) beginning_of_year (at_beginning_of_year) end_of_year (at_end_of_year) years_ago years_since -prev_year (last_year) +prev_year +last_year next_year on_weekday? on_weekend? @@ -3607,6 +3549,74 @@ now.all_year # => Fri, 01 Jan 2010 00:00:00 UTC +00:00..Fri, 31 Dec 2010 23:59:59 UTC +00:00 ``` +#### `prev_day`, `next_day` + +In Ruby 1.9 `prev_day` and `next_day` return the date in the last or next day: + +```ruby +d = Date.new(2010, 5, 8) # => Sat, 08 May 2010 +d.prev_day # => Fri, 07 May 2010 +d.next_day # => Sun, 09 May 2010 +``` + +#### `prev_month`, `next_month` + +In Ruby 1.9 `prev_month` and `next_month` return the date with the same day in the last or next month: + +```ruby +d = Date.new(2010, 5, 8) # => Sat, 08 May 2010 +d.prev_month # => Thu, 08 Apr 2010 +d.next_month # => Tue, 08 Jun 2010 +``` + +If such a day does not exist, the last day of the corresponding month is returned: + +```ruby +Date.new(2000, 5, 31).prev_month # => Sun, 30 Apr 2000 +Date.new(2000, 3, 31).prev_month # => Tue, 29 Feb 2000 +Date.new(2000, 5, 31).next_month # => Fri, 30 Jun 2000 +Date.new(2000, 1, 31).next_month # => Tue, 29 Feb 2000 +``` + +#### `prev_year`, `next_year` + +In Ruby 1.9 `prev_year` and `next_year` return a date with the same day/month in the last or next year: + +```ruby +d = Date.new(2010, 5, 8) # => Sat, 08 May 2010 +d.prev_year # => Fri, 08 May 2009 +d.next_year # => Sun, 08 May 2011 +``` + +If date is the 29th of February of a leap year, you obtain the 28th: + +```ruby +d = Date.new(2000, 2, 29) # => Tue, 29 Feb 2000 +d.prev_year # => Sun, 28 Feb 1999 +d.next_year # => Wed, 28 Feb 2001 +``` + +#### `prev_quarter`, `next_quarter` + +`prev_quarter` and `next_quarter` return the date with the same day in the previous or next quarter: + +```ruby +t = Time.local(2010, 5, 8) # => 2010-05-08 00:00:00 +0300 +t.prev_quarter # => 2010-02-08 00:00:00 +0200 +t.next_quarter # => 2010-08-08 00:00:00 +0300 +``` + +If such a day does not exist, the last day of the corresponding month is returned: + +```ruby +Time.local(2000, 7, 31).prev_quarter # => 2000-04-30 00:00:00 +0300 +Time.local(2000, 5, 31).prev_quarter # => 2000-02-29 00:00:00 +0200 +Time.local(2000, 10, 31).prev_quarter # => 2000-07-31 00:00:00 +0300 +Time.local(2000, 11, 31).next_quarter # => 2001-03-01 00:00:00 +0200 +``` + +`prev_quarter` is aliased to `last_quarter`. + ### Time Constructors Active Support defines `Time.current` to be `Time.zone.now` if there's a user time zone defined, with fallback to `Time.now`: diff --git a/guides/source/api_app.md b/guides/source/api_app.md index 43a7de88b0..b360f270d7 100644 --- a/guides/source/api_app.md +++ b/guides/source/api_app.md @@ -414,8 +414,10 @@ Some common modules you might want to add: - `AbstractController::Translation`: Support for the `l` and `t` localization and translation methods. -- `ActionController::HttpAuthentication::Basic` (or `Digest` or `Token`): Support - for basic, digest or token HTTP authentication. +- Support for basic, digest or token HTTP authentication: + * `ActionController::HttpAuthentication::Basic::ControllerMethods`, + * `ActionController::HttpAuthentication::Digest::ControllerMethods`, + * `ActionController::HttpAuthentication::Token::ControllerMethods` - `ActionView::Layouts`: Support for layouts when rendering. - `ActionController::MimeResponds`: Support for `respond_to`. - `ActionController::Cookies`: Support for `cookies`, which includes diff --git a/guides/source/api_documentation_guidelines.md b/guides/source/api_documentation_guidelines.md index 2c153d3783..10b89433e7 100644 --- a/guides/source/api_documentation_guidelines.md +++ b/guides/source/api_documentation_guidelines.md @@ -16,7 +16,7 @@ RDoc ---- The [Rails API documentation](http://api.rubyonrails.org) is generated with -[RDoc](http://docs.seattlerb.org/rdoc/). To generate it, make sure you are +[RDoc](https://ruby.github.io/rdoc/). To generate it, make sure you are in the rails root directory, run `bundle install` and execute: ```bash @@ -26,9 +26,9 @@ in the rails root directory, run `bundle install` and execute: Resulting HTML files can be found in the ./doc/rdoc directory. Please consult the RDoc documentation for help with the -[markup](http://docs.seattlerb.org/rdoc/RDoc/Markup.html), +[markup](https://ruby.github.io/rdoc/RDoc/Markup.html), and also take into account these [additional -directives](http://docs.seattlerb.org/rdoc/RDoc/Parser/Ruby.html). +directives](https://ruby.github.io/rdoc/RDoc/Parser/Ruby.html). Wording ------- diff --git a/guides/source/asset_pipeline.md b/guides/source/asset_pipeline.md index 805b0f0d62..e6d5aed135 100644 --- a/guides/source/asset_pipeline.md +++ b/guides/source/asset_pipeline.md @@ -35,7 +35,7 @@ rails new appname --skip-sprockets ``` Rails automatically adds the `sass-rails`, `coffee-rails` and `uglifier` -gems to your Gemfile, which are used by Sprockets for asset compression: +gems to your `Gemfile`, which are used by Sprockets for asset compression: ```ruby gem 'sass-rails' @@ -44,8 +44,8 @@ gem 'coffee-rails' ``` Using the `--skip-sprockets` option will prevent Rails from adding -them to your Gemfile, so if you later want to enable -the asset pipeline you will have to add those gems to your Gemfile. Also, +them to your `Gemfile`, so if you later want to enable +the asset pipeline you will have to add those gems to your `Gemfile`. Also, creating an application with the `--skip-sprockets` option will generate a slightly different `config/application.rb` file, with a require statement for the sprockets railtie that is commented-out. You will have to remove @@ -850,7 +850,7 @@ This mode uses more memory, performs more poorly than the default and is not recommended. If you are deploying a production application to a system without any -pre-existing JavaScript runtimes, you may want to add one to your Gemfile: +pre-existing JavaScript runtimes, you may want to add one to your `Gemfile`: ```ruby group :production do diff --git a/guides/source/caching_with_rails.md b/guides/source/caching_with_rails.md index 96650b5be9..780e69c146 100644 --- a/guides/source/caching_with_rails.md +++ b/guides/source/caching_with_rails.md @@ -32,7 +32,7 @@ Basic Caching This is an introduction to three types of caching techniques: page, action and fragment caching. By default Rails provides fragment caching. In order to use page and action caching you will need to add `actionpack-page_caching` and -`actionpack-action_caching` to your Gemfile. +`actionpack-action_caching` to your `Gemfile`. By default, caching is only enabled in your production environment. To play around with caching locally you'll want to enable caching in your local @@ -366,9 +366,9 @@ There are some common options used by all cache implementations. These can be pa * `:namespace` - This option can be used to create a namespace within the cache store. It is especially useful if your application shares a cache with other applications. -* `:compress` - This option can be used to indicate that compression should be used in the cache. This can be useful for transferring large cache entries over a slow network. +* `:compress` - Enabled by default. Compresses cache entries so more data can be stored in the same memory footprint, leading to fewer cache evictions and higher hit rates. -* `:compress_threshold` - This option is used in conjunction with the `:compress` option to indicate a threshold under which cache entries should not be compressed. This defaults to 16 kilobytes. +* `:compress_threshold` - Defaults to 1kB. Cache entries larger than this threshold, specified in bytes, are compressed. * `:expires_in` - This option sets an expiration time in seconds for the cache entry when it will be automatically removed from the cache. @@ -444,6 +444,53 @@ The `write` and `fetch` methods on this cache accept two additional options that config.cache_store = :mem_cache_store, "cache-1.example.com", "cache-2.example.com" ``` +### ActiveSupport::Cache::RedisCacheStore + +The Redis cache store takes advantage of Redis support for least-recently-used +and least-frequently-used key eviction when it reaches max memory, allowing it +to behave much like a Memcached cache server. + +Deployment note: Redis doesn't expire keys by default, so take care to use a +dedicated Redis cache server. Don't fill up your persistent-Redis server with +volatile cache data! Read the +[Redis cache server setup guide](https://redis.io/topics/lru-cache) in detail. + +For an all-cache Redis server, set `maxmemory-policy` to an `allkeys` policy. +Redis 4+ support least-frequently-used (`allkeys-lfu`) eviction, an excellent +default choice. Redis 3 and earlier should use `allkeys-lru` for +least-recently-used eviction. + +Set cache read and write timeouts relatively low. Regenerating a cached value +is often faster than waiting more than a second to retrieve it. Both read and +write timeouts default to 1 second, but may be set lower if your network is +consistently low latency. + +Cache reads and writes never raise exceptions. They just return `nil` instead, +behaving as if there was nothing in the cache. To gauge whether your cache is +hitting exceptions, you may provide an `error_handler` to report to an +exception gathering service. It must accept three keyword arguments: `method`, +the cache store method that was originally called; `returning`, the value that +was returned to the user, typically `nil`; and `exception`, the exception that +was rescued. + +Putting it all together, a production Redis cache store may look something +like this: + +```ruby +cache_servers = %w[ "redis://cache-01:6379/0", "redis://cache-02:6379/0", … ], +config.cache_store = :redis_cache_store, url: cache_servers, + + connect_timeout: 30, # Defaults to 20 seconds + read_timeout: 0.2, # Defaults to 1 second + write_timeout: 0.2, # Defaults to 1 second + + error_handler: -> (method:, returning:, exception:) { + # Report errors to Sentry as warnings + Raven.capture_exception exception, level: 'warning", + tags: { method: method, returning: returning } + } +``` + ### ActiveSupport::Cache::NullStore This cache store implementation is meant to be used only in development or test environments and it never stores anything. This can be very useful in development when you have code that interacts directly with `Rails.cache` but caching may interfere with being able to see the results of code changes. With this cache store, all `fetch` and `read` operations will result in a miss. diff --git a/guides/source/command_line.md b/guides/source/command_line.md index 88c559921c..648645af7c 100644 --- a/guides/source/command_line.md +++ b/guides/source/command_line.md @@ -290,7 +290,7 @@ INFO: You can also use the alias "c" to invoke the console: `rails c`. You can specify the environment in which the `console` command should operate. ```bash -$ bin/rails console staging +$ bin/rails console -e staging ``` If you wish to test out some code without changing any data, you can do that by invoking `rails console --sandbox`. diff --git a/guides/source/configuring.md b/guides/source/configuring.md index 7a32607eb7..fee644d4d4 100644 --- a/guides/source/configuring.md +++ b/guides/source/configuring.md @@ -578,6 +578,8 @@ Defaults to `'signed cookie'`. * `config.action_view.form_with_generates_remote_forms` determines whether `form_with` generates remote forms or not. This defaults to `true`. +* `config.action_view.form_with_generates_ids` determines whether `form_with` generates ids on inputs. This defaults to `true`. + ### Configuring Action Mailer There are a number of settings available on `config.action_mailer`: @@ -973,7 +975,7 @@ By default Rails ships with three environments: "development", "test", and "prod Imagine you have a server which mirrors the production environment but is only used for testing. Such a server is commonly called a "staging server". To define an environment called "staging" for this server, just create a file called `config/environments/staging.rb`. Please use the contents of any existing file in `config/environments` as a starting point and make the necessary changes from there. -That environment is no different than the default ones, start a server with `rails server -e staging`, a console with `rails console staging`, `Rails.env.staging?` works, etc. +That environment is no different than the default ones, start a server with `rails server -e staging`, a console with `rails console -e staging`, `Rails.env.staging?` works, etc. ### Deploy to a subdirectory (relative url root) @@ -1003,11 +1005,11 @@ Deploying your application using a reverse proxy has definite advantages over tr Many modern web servers can be used as a proxy server to balance third-party elements such as caching servers or application servers. -One such application server you can use is [Unicorn](http://unicorn.bogomips.org/) to run behind a reverse proxy. +One such application server you can use is [Unicorn](https://bogomips.org/unicorn/) to run behind a reverse proxy. In this case, you would need to configure the proxy server (NGINX, Apache, etc) to accept connections from your application server (Unicorn). By default Unicorn will listen for TCP connections on port 8080, but you can change the port or configure it to use sockets instead. -You can find more information in the [Unicorn readme](http://unicorn.bogomips.org/README.html) and understand the [philosophy](http://unicorn.bogomips.org/PHILOSOPHY.html) behind it. +You can find more information in the [Unicorn readme](https://bogomips.org/unicorn/README.html) and understand the [philosophy](https://bogomips.org/unicorn/PHILOSOPHY.html) behind it. Once you've configured the application server, you must proxy requests to it by configuring your web server appropriately. For example your NGINX config may include: @@ -1035,7 +1037,7 @@ server { } ``` -Be sure to read the [NGINX documentation](http://nginx.org/en/docs/) for the most up-to-date information. +Be sure to read the [NGINX documentation](https://nginx.org/en/docs/) for the most up-to-date information. Rails Environment Settings @@ -1057,7 +1059,7 @@ After loading the framework and any gems in your application, Rails turns to loa NOTE: You can use subfolders to organize your initializers if you like, because Rails will look into the whole file hierarchy from the initializers folder on down. -TIP: If you have any ordering dependency in your initializers, you can control the load order through naming. Initializer files are loaded in alphabetical order by their path. For example, `01_critical.rb` will be loaded before `02_normal.rb`. +TIP: While Rails supports numbering of initializer file names for load ordering purposes, a better technique is to place any code that need to load in a specific order within the same file. This reduces file name churn, makes dependencies more explicit, and can help surface new concepts within your application. Initialization events --------------------- diff --git a/guides/source/documents.yaml b/guides/source/documents.yaml index 59205ee465..2a4abab116 100644 --- a/guides/source/documents.yaml +++ b/guides/source/documents.yaml @@ -159,6 +159,11 @@ url: engines.html description: This guide explains how to write a mountable engine. work_in_progress: true + - + name: Threading and Code Execution in Rails + url: threading_and_code_execution.html + description: This guide describes the considerations needed and tools available when working directly with concurrency in a Rails application. + work_in_progress: true - name: Contributing to Ruby on Rails documents: @@ -189,6 +194,10 @@ url: upgrading_ruby_on_rails.html description: This guide helps in upgrading applications to latest Ruby on Rails versions. - + name: Ruby on Rails 5.2 Release Notes + url: 5_2_release_notes.html + description: Release notes for Rails 5.2. + - name: Ruby on Rails 5.1 Release Notes url: 5_1_release_notes.html description: Release notes for Rails 5.1. diff --git a/guides/source/engines.md b/guides/source/engines.md index b226eac347..33694cf76a 100644 --- a/guides/source/engines.md +++ b/guides/source/engines.md @@ -921,7 +921,7 @@ engine: mattr_accessor :author_class ``` -This method works like its brothers, `attr_accessor` and `cattr_accessor`, but +This method works like its siblings, `attr_accessor` and `cattr_accessor`, but provides a setter and getter method on the module with the specified name. To use it, it must be referenced using `Blorgh.author_class`. @@ -982,7 +982,7 @@ Blorgh.author_class = "User" WARNING: It's very important here to use the `String` version of the class, rather than the class itself. If you were to use the class, Rails would attempt to load that class and then reference the related table. This could lead to -problems if the table wasn't already existing. Therefore, a `String` should be +problems if the table didn't already exist. Therefore, a `String` should be used and then converted to a class using `constantize` in the engine later on. Go ahead and try to create a new article. You will see that it works exactly in the @@ -1514,7 +1514,7 @@ To hook into the initialization process of one of the following classes use the ## Configuration hooks -These are the available configuration hooks. They do not hook into any particular framework, instead they run in context of the entire application. +These are the available configuration hooks. They do not hook into any particular framework, but instead they run in context of the entire application. | Hook | Use Case | | ---------------------- | ------------------------------------------------------------------------------------- | diff --git a/guides/source/form_helpers.md b/guides/source/form_helpers.md index 4ce67df93a..f8ec389b01 100644 --- a/guides/source/form_helpers.md +++ b/guides/source/form_helpers.md @@ -920,7 +920,7 @@ When an association accepts nested attributes `fields_for` renders its block onc ```ruby def new @person = Person.new - 2.times { @person.addresses.build} + 2.times { @person.addresses.build } end ``` diff --git a/guides/source/i18n.md b/guides/source/i18n.md index e6aa6181cc..2b545e6b82 100644 --- a/guides/source/i18n.md +++ b/guides/source/i18n.md @@ -977,7 +977,7 @@ en: ``` NOTE: In order to use this helper, you need to install [DynamicForm](https://github.com/joelmoss/dynamic_form) -gem by adding this line to your Gemfile: `gem 'dynamic_form'`. +gem by adding this line to your `Gemfile`: `gem 'dynamic_form'`. ### Translations for Action Mailer E-Mail Subjects diff --git a/guides/source/initialization.md b/guides/source/initialization.md index 1541ea38cd..c4f1df487b 100644 --- a/guides/source/initialization.md +++ b/guides/source/initialization.md @@ -93,7 +93,7 @@ require 'bundler/setup' # Set up gems listed in the Gemfile. In a standard Rails application, there's a `Gemfile` which declares all dependencies of the application. `config/boot.rb` sets -`ENV['BUNDLE_GEMFILE']` to the location of this file. If the Gemfile +`ENV['BUNDLE_GEMFILE']` to the location of this file. If the `Gemfile` exists, then `bundler/setup` is required. The require is used by Bundler to configure the load path for your Gemfile's dependencies. diff --git a/guides/source/layout.html.erb b/guides/source/layout.html.erb index 334595e4d2..3981199e95 100644 --- a/guides/source/layout.html.erb +++ b/guides/source/layout.html.erb @@ -99,9 +99,9 @@ To get started, you can read our <%= link_to 'documentation contributions', 'http://edgeguides.rubyonrails.org/contributing_to_ruby_on_rails.html#contributing-to-the-rails-documentation' %> section. </p> <p> - You may also find incomplete content, or stuff that is not up to date. + You may also find incomplete content or stuff that is not up to date. Please do add any missing documentation for master. Make sure to check - <%= link_to 'Edge Guides','http://edgeguides.rubyonrails.org' %> first to verify + <%= link_to 'Edge Guides', 'http://edgeguides.rubyonrails.org' %> first to verify if the issues are already fixed or not on the master branch. Check the <%= link_to 'Ruby on Rails Guides Guidelines', 'ruby_on_rails_guides_guidelines.html' %> for style and conventions. @@ -111,7 +111,7 @@ <%= link_to 'open an issue', 'https://github.com/rails/rails/issues' %>. </p> <p>And last but not least, any kind of discussion regarding Ruby on Rails - documentation is very welcome in the <%= link_to 'rubyonrails-docs mailing list', 'https://groups.google.com/forum/#!forum/rubyonrails-docs' %>. + documentation is very welcome on the <%= link_to 'rubyonrails-docs mailing list', 'https://groups.google.com/forum/#!forum/rubyonrails-docs' %>. </p> </div> </div> diff --git a/guides/source/layouts_and_rendering.md b/guides/source/layouts_and_rendering.md index b9b327252f..4d79b2db89 100644 --- a/guides/source/layouts_and_rendering.md +++ b/guides/source/layouts_and_rendering.md @@ -285,7 +285,7 @@ the response. Using `:plain` or `:html` might be more appropriate most of the time. NOTE: Unless overridden, your response returned from this render option will be -`text/html`, as that is the default content type of Action Dispatch response. +`text/plain`, as that is the default content type of Action Dispatch response. #### Options for `render` @@ -1266,7 +1266,7 @@ You can also pass in arbitrary local variables to any partial you are rendering In this case, the partial will have access to a local variable `title` with the value "Products Page". -TIP: Rails also makes a counter variable available within a partial called by the collection, named after the member of the collection followed by `_counter`. For example, if you're rendering `@products`, within the partial you can refer to `product_counter` to tell you how many times the partial has been rendered. This does not work in conjunction with the `as: :value` option. +TIP: Rails also makes a counter variable available within a partial called by the collection, named after the title of the partial followed by `_counter`. For example, when rendering a collection `@products` the partial `_product.html.erb` can access the variable `product_counter` which indexes the number of times it has been rendered within the enclosing view. You can also specify a second partial to be rendered between instances of the main partial by using the `:spacer_template` option: diff --git a/guides/source/rails_on_rack.md b/guides/source/rails_on_rack.md index aa1476ecc0..5718b9ddfc 100644 --- a/guides/source/rails_on_rack.md +++ b/guides/source/rails_on_rack.md @@ -122,6 +122,7 @@ use ActiveRecord::Migration::CheckPending use ActionDispatch::Cookies use ActionDispatch::Session::CookieStore use ActionDispatch::Flash +use ActionDispatch::ContentSecurityPolicy::Middleware use Rack::Head use Rack::ConditionalGet use Rack::ETag @@ -249,7 +250,7 @@ Much of Action Controller's functionality is implemented as Middlewares. The fol **`Rails::Rack::Logger`** -* Notifies the logs that the request has began. After request is complete, flushes all the logs. +* Notifies the logs that the request has begun. After the request is complete, flushes all the logs. **`ActionDispatch::ShowExceptions`** @@ -289,7 +290,7 @@ Much of Action Controller's functionality is implemented as Middlewares. The fol **`Rack::ConditionalGet`** -* Adds support for "Conditional `GET`" so that server responds with nothing if page wasn't changed. +* Adds support for "Conditional `GET`" so that server responds with nothing if the page wasn't changed. **`Rack::ETag`** diff --git a/guides/source/security.md b/guides/source/security.md index cfa777d433..eeb005b661 100644 --- a/guides/source/security.md +++ b/guides/source/security.md @@ -52,7 +52,7 @@ User.find(session[:user_id]) NOTE: _The session ID is a 32-character random hex string._ -The session ID is generated using `SecureRandom.hex` which generates a random hex string using platform specific methods (such as OpenSSL, /dev/urandom or Win32) for generating cryptographically secure random numbers. Currently it is not feasible to brute-force Rails' session IDs. +The session ID is generated using `SecureRandom.hex` which generates a random hex string using platform specific methods (such as OpenSSL, /dev/urandom or Win32 CryptoAPI) for generating cryptographically secure random numbers. Currently it is not feasible to brute-force Rails' session IDs. ### Session Hijacking @@ -192,9 +192,9 @@ rotations going at any one time. For more details on key rotation with encrypted and signed messages as well as the various options the `rotate` method accepts, please refer to the -[MessageEncryptor API](api.rubyonrails.org/classes/ActiveSupport/MessageEncryptor.html) +[MessageEncryptor API](http://api.rubyonrails.org/classes/ActiveSupport/MessageEncryptor.html) and -[MessageVerifier API](api.rubyonrails.org/classes/ActiveSupport/MessageVerifier.html) +[MessageVerifier API](http://api.rubyonrails.org/classes/ActiveSupport/MessageVerifier.html) documentation. ### Replay Attacks for CookieStore Sessions diff --git a/guides/source/testing.md b/guides/source/testing.md index c5b2a694e7..f28c4c224a 100644 --- a/guides/source/testing.md +++ b/guides/source/testing.md @@ -319,6 +319,8 @@ specify to make your test failure messages clearer. | `assert_not_includes( collection, obj, [msg] )` | Ensures that `obj` is not in `collection`.| | `assert_in_delta( expected, actual, [delta], [msg] )` | Ensures that the numbers `expected` and `actual` are within `delta` of each other.| | `assert_not_in_delta( expected, actual, [delta], [msg] )` | Ensures that the numbers `expected` and `actual` are not within `delta` of each other.| +| `assert_in_epsilon ( expected, actual, [epsilon], [msg] )` | Ensures that the numbers `expected` and `actual` have a relative error less than `epsilon`.| +| `assert_not_in_epsilon ( expected, actual, [epsilon], [msg] )` | Ensures that the numbers `expected` and `actual` don't have a relative error less than `epsilon`.| | `assert_throws( symbol, [msg] ) { block }` | Ensures that the given block throws the symbol.| | `assert_raises( exception1, exception2, ... ) { block }` | Ensures that the given block raises one of the given exceptions.| | `assert_instance_of( class, obj, [msg] )` | Ensures that `obj` is an instance of `class`.| @@ -645,7 +647,7 @@ system tests should live. If you want to change the default settings you can change what the system tests are "driven by". Say you want to change the driver from Selenium to -Poltergeist. First add the `poltergeist` gem to your Gemfile. Then in your +Poltergeist. First add the `poltergeist` gem to your `Gemfile`. Then in your `application_system_test_case.rb` file do the following: ```ruby @@ -671,6 +673,17 @@ class ApplicationSystemTestCase < ActionDispatch::SystemTestCase end ``` +If you want to use a headless browser, you could use Headless Chrome or Headless Firefox by adding +`headless_chrome` or `headless_firefox` in the `:using` argument. + +```ruby +require "test_helper" + +class ApplicationSystemTestCase < ActionDispatch::SystemTestCase + driven_by :selenium, using: :headless_chrome +end +``` + If your Capybara configuration requires more setup than provided by Rails, this additional configuration could be added into the `application_system_test_case.rb` file. diff --git a/guides/source/threading_and_code_execution.md b/guides/source/threading_and_code_execution.md new file mode 100644 index 0000000000..3d3d31b97e --- /dev/null +++ b/guides/source/threading_and_code_execution.md @@ -0,0 +1,324 @@ +**DO NOT READ THIS FILE ON GITHUB, GUIDES ARE PUBLISHED ON http://guides.rubyonrails.org.** + +Threading and Code Execution in Rails +===================================== + +After reading this guide, you will know: + +* What code Rails will automatically execute concurrently +* How to integrate manual concurrency with Rails internals +* How to wrap all application code +* How to affect application reloading + +-------------------------------------------------------------------------------- + +Automatic Concurrency +--------------------- + +Rails automatically allows various operations to be performed at the same time. + +When using a threaded web server, such as the default Puma, multiple HTTP +requests will be served simultaneously, with each request provided its own +controller instance. + +Threaded Active Job adapters, including the built-in Async, will likewise +execute several jobs at the same time. Action Cable channels are managed this +way too. + +These mechanisms all involve multiple threads, each managing work for a unique +instance of some object (controller, job, channel), while sharing the global +process space (such as classes and their configurations, and global variables). +As long as your code doesn't modify any of those shared things, it can mostly +ignore that other threads exist. + +The rest of this guide describes the mechanisms Rails uses to make it "mostly +ignorable", and how extensions and applications with special needs can use them. + +Executor +-------- + +The Rails Executor separates application code from framework code: any time the +framework invokes code you've written in your application, it will be wrapped by +the Executor. + +The Executor consists of two callbacks: `to_run` and `to_complete`. The Run +callback is called before the application code, and the Complete callback is +called after. + +### Default callbacks + +In a default Rails application, the Executor callbacks are used to: + +* track which threads are in safe positions for autoloading and reloading +* enable and disable the Active Record query cache +* return acquired Active Record connections to the pool +* constrain internal cache lifetimes + +Prior to Rails 5.0, some of these were handled by separate Rack middleware +classes (such as `ActiveRecord::ConnectionAdapters::ConnectionManagement`), or +directly wrapping code with methods like +`ActiveRecord::Base.connection_pool.with_connection`. The Executor replaces +these with a single more abstract interface. + +### Wrapping application code + +If you're writing a library or component that will invoke application code, you +should wrap it with a call to the executor: + +```ruby +Rails.application.executor.wrap do + # call application code here +end +``` + +TIP: If you repeatedly invoke application code from a long-running process, you +may want to wrap using the Reloader instead. + +Each thread should be wrapped before it runs application code, so if your +application manually delegates work to other threads, such as via `Thread.new` +or Concurrent Ruby features that use thread pools, you should immediately wrap +the block: + +```ruby +Thread.new do + Rails.application.executor.wrap do + # your code here + end +end +``` + +NOTE: Concurrent Ruby uses a `ThreadPoolExecutor`, which it sometimes configures +with an `executor` option. Despite the name, it is unrelated. + +The Executor is safely re-entrant; if it is already active on the current +thread, `wrap` is a no-op. + +If it's impractical to wrap the application code in a block (for +example, the Rack API makes this problematic), you can also use the `run!` / +`complete!` pair: + +```ruby +Thread.new do + execution_context = Rails.application.executor.run! + # your code here +ensure + execution_context.complete! if execution_context +end +``` + +### Concurrency + +The Executor will put the current thread into `running` mode in the Load +Interlock. This operation will block temporarily if another thread is currently +either autoloading a constant or unloading/reloading the application. + +Reloader +-------- + +Like the Executor, the Reloader also wraps application code. If the Executor is +not already active on the current thread, the Reloader will invoke it for you, +so you only need to call one. This also guarantees that everything the Reloader +does, including all its callback invocations, occurs wrapped inside the +Executor. + +```ruby +Rails.application.reloader.wrap do + # call application code here +end +``` + +The Reloader is only suitable where a long-running framework-level process +repeatedly calls into application code, such as for a web server or job queue. +Rails automatically wraps web requests and Active Job workers, so you'll rarely +need to invoke the Reloader for yourself. Always consider whether the Executor +is a better fit for your use case. + +### Callbacks + +Before entering the wrapped block, the Reloader will check whether the running +application needs to be reloaded -- for example, because a model's source file has +been modified. If it determines a reload is required, it will wait until it's +safe, and then do so, before continuing. When the application is configured to +always reload regardless of whether any changes are detected, the reload is +instead performed at the end of the block. + +The Reloader also provides `to_run` and `to_complete` callbacks; they are +invoked at the same points as those of the Executor, but only when the current +execution has initiated an application reload. When no reload is deemed +necessary, the Reloader will invoke the wrapped block with no other callbacks. + +### Class Unload + +The most significant part of the reloading process is the Class Unload, where +all autoloaded classes are removed, ready to be loaded again. This will occur +immediately before either the Run or Complete callback, depending on the +`reload_classes_only_on_change` setting. + +Often, additional reloading actions need to be performed either just before or +just after the Class Unload, so the Reloader also provides `before_class_unload` +and `after_class_unload` callbacks. + +### Concurrency + +Only long-running "top level" processes should invoke the Reloader, because if +it determines a reload is needed, it will block until all other threads have +completed any Executor invocations. + +If this were to occur in a "child" thread, with a waiting parent inside the +Executor, it would cause an unavoidable deadlock: the reload must occur before +the child thread is executed, but it cannot be safely performed while the parent +thread is mid-execution. Child threads should use the Executor instead. + +Framework Behavior +------------------ + +The Rails framework components use these tools to manage their own concurrency +needs too. + +`ActionDispatch::Executor` and `ActionDispatch::Reloader` are Rack middlewares +that wraps the request with a supplied Executor or Reloader, respectively. They +are automatically included in the default application stack. The Reloader will +ensure any arriving HTTP request is served with a freshly-loaded copy of the +application if any code changes have occurred. + +Active Job also wraps its job executions with the Reloader, loading the latest +code to execute each job as it comes off the queue. + +Action Cable uses the Executor instead: because a Cable connection is linked to +a specific instance of a class, it's not possible to reload for every arriving +websocket message. Only the message handler is wrapped, though; a long-running +Cable connection does not prevent a reload that's triggered by a new incoming +request or job. Instead, Action Cable uses the Reloader's `before_class_unload` +callback to disconnect all its connections. When the client automatically +reconnects, it will be speaking to the new version of the code. + +The above are the entry points to the framework, so they are responsible for +ensuring their respective threads are protected, and deciding whether a reload +is necessary. Other components only need to use the Executor when they spawn +additional threads. + +### Configuration + +The Reloader only checks for file changes when `cache_classes` is false and +`reload_classes_only_on_change` is true (which is the default in the +`development` environment). + +When `cache_classes` is true (in `production`, by default), the Reloader is only +a pass-through to the Executor. + +The Executor always has important work to do, like database connection +management. When `cache_classes` and `eager_load` are both true (`production`), +no autoloading or class reloading will occur, so it does not need the Load +Interlock. If either of those are false (`development`), then the Executor will +use the Load Interlock to ensure constants are only loaded when it is safe. + +Load Interlock +-------------- + +The Load Interlock allows autoloading and reloading to be enabled in a +multi-threaded runtime environment. + +When one thread is performing an autoload by evaluating the class definition +from the appropriate file, it is important no other thread encounters a +reference to the partially-defined constant. + +Similarly, it is only safe to perform an unload/reload when no application code +is in mid-execution: after the reload, the `User` constant, for example, may +point to a different class. Without this rule, a poorly-timed reload would mean +`User.new.class == User`, or even `User == User`, could be false. + +Both of these constraints are addressed by the Load Interlock. It keeps track of +which threads are currently running application code, loading a class, or +unloading autoloaded constants. + +Only one thread may load or unload at a time, and to do either, it must wait +until no other threads are running application code. If a thread is waiting to +perform a load, it doesn't prevent other threads from loading (in fact, they'll +cooperate, and each perform their queued load in turn, before all resuming +running together). + +### `permit_concurrent_loads` + +The Executor automatically acquires a `running` lock for the duration of its +block, and autoload knows when to upgrade to a `load` lock, and switch back to +`running` again afterwards. + +Other blocking operations performed inside the Executor block (which includes +all application code), however, can needlessly retain the `running` lock. If +another thread encounters a constant it must autoload, this can cause a +deadlock. + +For example, assuming `User` is not yet loaded, the following will deadlock: + +```ruby +Rails.application.executor.wrap do + th = Thread.new do + Rails.application.executor.wrap do + User # inner thread waits here; it cannot load + # User while another thread is running + end + end + + th.join # outer thread waits here, holding 'running' lock +end +``` + +To prevent this deadlock, the outer thread can `permit_concurrent_loads`. By +calling this method, the thread guarantees it will not dereference any +possibly-autoloaded constant inside the supplied block. The safest way to meet +that promise is to put it as close as possible to the blocking call: + +```ruby +Rails.application.executor.wrap do + th = Thread.new do + Rails.application.executor.wrap do + User # inner thread can acquire the load lock, + # load User, and continue + end + end + + ActiveSupport::Dependencies.interlock.permit_concurrent_loads do + th.join # outer thread waits here, but has no lock + end +end +``` + +Another example, using Concurrent Ruby: + +```ruby +Rails.application.executor.wrap do + futures = 3.times.collect do |i| + Concurrent::Future.execute do + Rails.application.executor.wrap do + # do work here + end + end + end + + values = ActiveSupport::Dependencies.interlock.permit_concurrent_loads do + futures.collect(&:value) + end +end +``` + + +### ActionDispatch::DebugLocks + +If your application is deadlocking and you think the Load Interlock may be +involved, you can temporarily add the ActionDispatch::DebugLocks middleware to +`config/application.rb`: + +```ruby +config.middleware.insert_before Rack::Sendfile, + ActionDispatch::DebugLocks +``` + +If you then restart the application and re-trigger the deadlock condition, +`/rails/locks` will show a summary of all threads currently known to the +interlock, which lock level they are holding or awaiting, and their current +backtrace. + +Generally a deadlock will be caused by the interlock conflicting with some other +external lock or blocking I/O call. Once you find it, you can wrap it with +`permit_concurrent_loads`. + diff --git a/guides/source/upgrading_ruby_on_rails.md b/guides/source/upgrading_ruby_on_rails.md index 9bc87e4bf0..eae73c3e1b 100644 --- a/guides/source/upgrading_ruby_on_rails.md +++ b/guides/source/upgrading_ruby_on_rails.md @@ -45,7 +45,7 @@ TIP: Ruby 1.8.7 p248 and p249 have marshaling bugs that crash Rails. Ruby Enterp ### The Update Task Rails provides the `app:update` task (`rake rails:update` on 4.2 and earlier). After updating the Rails version -in the Gemfile, run this task. +in the `Gemfile`, run this task. This will help you with the creation of new files and changes of old files in an interactive session. @@ -179,7 +179,7 @@ See [#19034](https://github.com/rails/rails/pull/19034) for more details. `assigns` and `assert_template` have been extracted to the `rails-controller-testing` gem. To continue using these methods in your controller tests, add `gem 'rails-controller-testing'` to -your Gemfile. +your `Gemfile`. If you are using Rspec for testing, please see the extra configuration required in the gem's documentation. @@ -212,7 +212,7 @@ true. `ActiveModel::Serializers::Xml` has been extracted from Rails to the `activemodel-serializers-xml` gem. To continue using XML serialization in your application, add `gem 'activemodel-serializers-xml'` -to your Gemfile. +to your `Gemfile`. ### Removed Support for Legacy `mysql` Database Adapter @@ -278,7 +278,7 @@ You can now just call the dependency once with a wildcard. ### `ActionView::Helpers::RecordTagHelper` moved to external gem (record_tag_helper) -`content_tag_for` and `div_for` have been removed in favor of just using `content_tag`. To continue using the older methods, add the `record_tag_helper` gem to your Gemfile: +`content_tag_for` and `div_for` have been removed in favor of just using `content_tag`. To continue using the older methods, add the `record_tag_helper` gem to your `Gemfile`: ```ruby gem 'record_tag_helper', '~> 1.0' @@ -415,7 +415,7 @@ First, add `gem 'web-console', '~> 2.0'` to the `:development` group in your `Ge ### Responders -`respond_with` and the class-level `respond_to` methods have been extracted to the `responders` gem. To use them, simply add `gem 'responders', '~> 2.0'` to your Gemfile. Calls to `respond_with` and `respond_to` (again, at the class level) will no longer work without having included the `responders` gem in your dependencies: +`respond_with` and the class-level `respond_to` methods have been extracted to the `responders` gem. To use them, simply add `gem 'responders', '~> 2.0'` to your `Gemfile`. Calls to `respond_with` and `respond_to` (again, at the class level) will no longer work without having included the `responders` gem in your dependencies: ```ruby # app/controllers/users_controller.rb @@ -559,7 +559,7 @@ Read the [gem's readme](https://github.com/rails/rails-html-sanitizer) for more The documentation for `PermitScrubber` and `TargetScrubber` explains how you can gain complete control over when and how elements should be stripped. -If your application needs to use the old sanitizer implementation, include `rails-deprecated_sanitizer` in your Gemfile: +If your application needs to use the old sanitizer implementation, include `rails-deprecated_sanitizer` in your `Gemfile`: ```ruby gem 'rails-deprecated_sanitizer' @@ -617,7 +617,7 @@ migration DSL counterpart. The migration procedure is as follows: -1. remove `gem "foreigner"` from the Gemfile. +1. remove `gem "foreigner"` from the `Gemfile`. 2. run `bundle install`. 3. run `bin/rake db:schema:dump`. 4. make sure that `db/schema.rb` contains every foreign key definition with @@ -769,7 +769,7 @@ and has been removed from Rails. If your application currently depends on MultiJSON directly, you have a few options: -1. Add 'multi_json' to your Gemfile. Note that this might cease to work in the future +1. Add 'multi_json' to your `Gemfile`. Note that this might cease to work in the future 2. Migrate away from MultiJSON by using `obj.to_json`, and `JSON.parse(str)` instead. @@ -810,7 +810,7 @@ part of the rewrite, the following features have been removed from the encoder: If your application depends on one of these features, you can get them back by adding the [`activesupport-json_encoder`](https://github.com/rails/activesupport-json_encoder) -gem to your Gemfile. +gem to your `Gemfile`. #### JSON representation of Time objects @@ -1135,7 +1135,7 @@ full support for the last few changes in the specification. ### Gemfile -Rails 4.0 removed the `assets` group from Gemfile. You'd need to remove that +Rails 4.0 removed the `assets` group from `Gemfile`. You'd need to remove that line from your `Gemfile` when upgrading. You should also update your application file (in `config/application.rb`): @@ -1147,7 +1147,7 @@ Bundler.require(*Rails.groups) ### vendor/plugins -Rails 4.0 no longer supports loading plugins from `vendor/plugins`. You must replace any plugins by extracting them to gems and adding them to your Gemfile. If you choose not to make them gems, you can move them into, say, `lib/my_plugin/*` and add an appropriate initializer in `config/initializers/my_plugin.rb`. +Rails 4.0 no longer supports loading plugins from `vendor/plugins`. You must replace any plugins by extracting them to gems and adding them to your `Gemfile`. If you choose not to make them gems, you can move them into, say, `lib/my_plugin/*` and add an appropriate initializer in `config/initializers/my_plugin.rb`. ### Active Record @@ -1214,7 +1214,7 @@ end ### Active Resource -Rails 4.0 extracted Active Resource to its own gem. If you still need the feature you can add the [Active Resource gem](https://github.com/rails/activeresource) in your Gemfile. +Rails 4.0 extracted Active Resource to its own gem. If you still need the feature you can add the [Active Resource gem](https://github.com/rails/activeresource) in your `Gemfile`. ### Active Model @@ -1414,7 +1414,7 @@ config.active_record.mass_assignment_sanitizer = :strict ### vendor/plugins -Rails 3.2 deprecates `vendor/plugins` and Rails 4.0 will remove them completely. While it's not strictly necessary as part of a Rails 3.2 upgrade, you can start replacing any plugins by extracting them to gems and adding them to your Gemfile. If you choose not to make them gems, you can move them into, say, `lib/my_plugin/*` and add an appropriate initializer in `config/initializers/my_plugin.rb`. +Rails 3.2 deprecates `vendor/plugins` and Rails 4.0 will remove them completely. While it's not strictly necessary as part of a Rails 3.2 upgrade, you can start replacing any plugins by extracting them to gems and adding them to your `Gemfile`. If you choose not to make them gems, you can move them into, say, `lib/my_plugin/*` and add an appropriate initializer in `config/initializers/my_plugin.rb`. ### Active Record diff --git a/guides/source/working_with_javascript_in_rails.md b/guides/source/working_with_javascript_in_rails.md index b2716c7faa..c3dff1772c 100644 --- a/guides/source/working_with_javascript_in_rails.md +++ b/guides/source/working_with_javascript_in_rails.md @@ -188,15 +188,20 @@ bind to the `ajax:success` event. On failure, use `ajax:error`. Check it out: ```coffeescript $(document).ready -> - $("#new_article").on("ajax:success", (e, data, status, xhr) -> + $("#new_article").on("ajax:success", (event) -> + [data, status, xhr] = event.detail $("#new_article").append xhr.responseText - ).on "ajax:error", (e, xhr, status, error) -> + ).on "ajax:error", (event) -> $("#new_article").append "<p>ERROR</p>" ``` Obviously, you'll want to be a bit more sophisticated than that, but it's a start. +NOTE: As of Rails 5.1 and the new `rails-ujs`, the parameters `data, status, xhr` +have been bundled into `event.detail`. For information about the previously used +`jquery-ujs` in Rails 5 and earlier, read the [`jquery-ujs` wiki](https://github.com/rails/jquery-ujs/wiki/ajax). + #### link_to [`link_to`](http://api.rubyonrails.org/classes/ActionView/Helpers/UrlHelper.html#method-i-link_to) @@ -225,7 +230,7 @@ and write some CoffeeScript like this: ```coffeescript $ -> - $("a[data-remote]").on "ajax:success", (e, data, status, xhr) -> + $("a[data-remote]").on "ajax:success", (event) -> alert "The article was deleted." ``` @@ -343,39 +348,6 @@ This generates a form with: <input data-disable-with="Saving..." type="submit"> ``` -Dealing with Ajax events ------------------------- - -Here are the different events that are fired when you deal with elements -that have a `data-remote` attribute: - -NOTE: All handlers bound to these events are always passed the event object as the -first argument. The table below describes the extra parameters passed after the -event argument. For example, if the extra parameters are listed as `xhr, settings`, -then to access them, you would define your handler with `function(event, xhr, settings)`. - -| Event name | Extra parameters | Fired | -|---------------------|------------------|-------------------------------------------------------------| -| `ajax:before` | | Before the whole ajax business, aborts if stopped. | -| `ajax:beforeSend` | xhr, options | Before the request is sent, aborts if stopped. | -| `ajax:send` | xhr | When the request is sent. | -| `ajax:success` | xhr, status, err | After completion, if the response was a success. | -| `ajax:error` | xhr, status, err | After completion, if the response was an error. | -| `ajax:complete` | xhr, status | After the request has been completed, no matter the outcome.| -| `ajax:aborted:file` | elements | If there are non-blank file inputs, aborts if stopped. | - -### Stoppable events - -If you stop `ajax:before` or `ajax:beforeSend` by returning false from the -handler method, the Ajax request will never take place. The `ajax:before` event -is also useful for manipulating form data before serialization. The -`ajax:beforeSend` event is also useful for adding custom request headers. - -If you stop the `ajax:aborted:file` event, the default behavior of allowing the -browser to submit the form via normal means (i.e. non-Ajax submission) will be -canceled and the form will not be submitted at all. This is useful for -implementing your own Ajax file upload workaround. - ### Rails-ujs event handlers Rails 5.1 introduced rails-ujs and dropped jQuery as a dependency. @@ -405,6 +377,22 @@ document.body.addEventListener('ajax:success', function(event) { }) ``` +NOTE: As of Rails 5.1 and the new `rails-ujs`, the parameters `data, status, xhr` +have been bundled into `event.detail`. For information about the previously used +`jquery-ujs` in Rails 5 and earlier, read the [`jquery-ujs` wiki](https://github.com/rails/jquery-ujs/wiki/ajax). + +### Stoppable events + +If you stop `ajax:before` or `ajax:beforeSend` by returning false from the +handler method, the Ajax request will never take place. The `ajax:before` event +can manipulate form data before serialization and the +`ajax:beforeSend` event is useful for adding custom request headers. + +If you stop the `ajax:aborted:file` event, the default behavior of allowing the +browser to submit the form via normal means (i.e. non-Ajax submission) will be +canceled and the form will not be submitted at all. This is useful for +implementing your own Ajax file upload workaround. + Server-Side Concerns -------------------- @@ -504,7 +492,7 @@ replace the entire `<body>` of the page with the `<body>` of the response. It will then use PushState to change the URL to the correct one, preserving refresh semantics and giving you pretty URLs. -The only thing you have to do to enable Turbolinks is have it in your Gemfile, +The only thing you have to do to enable Turbolinks is have it in your `Gemfile`, and put `//= require turbolinks` in your JavaScript manifest, which is usually `app/assets/javascripts/application.js`. |