rails--rails/actionpack
Theo Julienne 16a80882f9 actionpack: Improve performance by allowing routes with custom regexes in the FSM.
The FSM used to find matching routes was previously limited to patterns
that contained parameters with the default regexp / no constraints. In
large route sets where many parameters are constrained by custom regexp,
these routes all fall back on a slow linear search over the route list.

These custom regexes were not previously able to be included in the FSM
because it transitioned between nodes using only fragments of the URI,
or path separators [/.?], but a custom regex may cross a path separator
boundary. To work around this, the TransitionTable is improved to
support remembering a point within the matching string that we started,
and continuing to attempt to match from that point up to the end of each
token. Only parameters not on a path separator boundary must still match
with a linear search after this change (e.g. `/foo-:bar/`).

This results in performance for constrainted routes that matches that of
ones using the default regexp.

Benchmark:
https://gist.github.com/theojulienne/e91fc338d180e1710e29c81a5d701fab

Before:
```
Calculating -------------------------------------
    without params      6.466k (±12.7%) i/s -     31.648k in   5.009453s
params without constraints
                        5.867k (±12.9%) i/s -     28.842k in   5.032637s
params with constraints
                      909.661  (± 7.9%) i/s -      4.536k in   5.023534s
```

After:
```
Calculating -------------------------------------
    without params      6.387k (±11.9%) i/s -     31.728k in   5.068939s
params without constraints
                        5.824k (±13.2%) i/s -     28.650k in   5.043701s
params with constraints
                        5.406k (±11.7%) i/s -     26.931k in   5.076412s
```

For github.com which has many constrainted parameters, a random sampling
of 10 URL patterns can be matched approximately 2-4x faster than before.

This commit fixes symbols as constrains as tested in
6ab985da28
2021-01-06 09:54:44 +11:00
..
bin
lib actionpack: Improve performance by allowing routes with custom regexes in the FSM. 2021-01-06 09:54:44 +11:00
test actionpack: Improve performance by allowing routes with custom regexes in the FSM. 2021-01-06 09:54:44 +11:00
CHANGELOG.md
MIT-LICENSE Bump license years to 2021 [ci skip] 2021-01-01 12:21:20 +09:00
README.rdoc
Rakefile
actionpack.gemspec

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 by rendering
*views*, which are templates of various formats. In short, Action Pack
provides the view and controller layers 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/master/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