rails--rails/actionpack
Sebastian Sogamoso 0547b1646d
Add Server Timing middleware (#36289)
* Add Server Timing middleware

What is server timing?
It's a specification that defines how the server can communicate the
user-agent performance metrics about the request it is responding to.

Here's the official specification:
https://www.w3.org/TR/server-timing/#dfn-server-timing-header-field

How does it work?
This introduces a new `ServerTiming` middleware only on `development` by
default, this is done using the `config.server_timing` setting.

It works by subscribing to all `ActiveSupport::Notifications` and adding
their duration to the `Server-Timing` header.

Why is this useful?
It makes looking at performance metrics in development much easier,
especially when using Chrome dev tools which includes the metrics in the
Network Inspector. Here's an example:

![](https://d3vv6lp55qjaqc.cloudfront.net/items/371h2y3B3a0U470j040u/Image%202019-05-15%20at%205.40.37%20PM.png?)

Paired on this with @guilleiguaran
2021-09-19 21:27:07 -07:00
..
bin
lib Add Server Timing middleware (#36289) 2021-09-19 21:27:07 -07:00
test Add Server Timing middleware (#36289) 2021-09-19 21:27:07 -07:00
CHANGELOG.md Preparing for 7.0.0.alpha2 release 2021-09-15 18:22:51 -04:00
MIT-LICENSE Bump license years to 2021 [ci skip] 2021-01-01 12:21:20 +09:00
README.rdoc Update ActionPack documentation to remove views mention 2021-04-22 19:00:45 -07:00
Rakefile Load framework test files in deterministic order 2019-12-16 16:55:06 +00:00
actionpack.gemspec Bump rack to remove ssl? override 2021-06-01 11:15:14 -07:00

README.rdoc

= Action Pack -- From request to response

Action Pack is a framework for handling and responding to web requests. It
provides mechanisms for *routing* (mapping request URLs to actions), defining
*controllers* that implement actions, and generating responses. In short, Action Pack
provides the controller layer in the MVC paradigm.

It consists of several modules:

* Action Dispatch, which parses information about the web request, handles
  routing as defined by the user, and does advanced processing related to HTTP
  such as MIME-type negotiation, decoding parameters in POST, PATCH, or PUT bodies,
  handling HTTP caching logic, cookies and sessions.

* Action Controller, which provides a base controller class that can be
  subclassed to implement filters and actions to handle requests. The result
  of an action is typically content generated from views.

With the Ruby on Rails framework, users only directly interface with the
Action Controller module. Necessary Action Dispatch functionality is activated
by default and Action View rendering is implicitly triggered by Action
Controller. However, these modules are designed to function on their own and
can be used outside of Rails.

You can read more about Action Pack in the {Action Controller Overview}[https://guides.rubyonrails.org/action_controller_overview.html] guide.

== Download and installation

The latest version of Action Pack can be installed with RubyGems:

  $ gem install actionpack

Source code can be downloaded as part of the Rails project on GitHub:

* https://github.com/rails/rails/tree/main/actionpack


== License

Action Pack is released under the MIT license:

* https://opensource.org/licenses/MIT


== Support

API documentation is at:

* https://api.rubyonrails.org

Bug reports for the Ruby on Rails project can be filed here:

* https://github.com/rails/rails/issues

Feature requests should be discussed on the rails-core mailing list here:

* https://discuss.rubyonrails.org/c/rubyonrails-core