0b476de445
Rather than building a regexp for every route, lets use the strategy
pattern to select among objects that can match HTTP verbs. This commit
introduces strategy objects for each verb that has a predicate method on
the request object like `get?`, `post?`, etc.
When we build the route object, look up the strategy for the verbs the
user specified. If we can't find it, fall back on string matching.
Using a strategy / null object pattern (the `All` VerbMatcher is our
"null" object in this case) we can:
1) Remove conditionals
2) Drop boot time allocations
2) Drop run time allocations
3) Improve runtime performance
Here is our boot time allocation benchmark:
```ruby
require 'action_pack'
require 'action_dispatch'
route_set = ActionDispatch::Routing::RouteSet.new
routes = ActionDispatch::Routing::Mapper.new route_set
result = ObjectSpace::AllocationTracer.trace do
500.times do
routes.resources :foo
end
end
sorted = ObjectSpace::AllocationTracer.allocated_count_table.sort_by(&:last)
sorted.each do |k,v|
next if v == 0
p k => v
end
__END__
Before:
$ be ruby -rallocation_tracer route_test.rb
{:T_SYMBOL=>11}
{:T_REGEXP=>4017}
{:T_STRUCT=>6500}
{:T_MATCH=>12004}
{:T_DATA=>84092}
{:T_OBJECT=>99009}
{:T_HASH=>122015}
{:T_STRING=>216652}
{:T_IMEMO=>355137}
{:T_ARRAY=>441057}
After:
$ be ruby -rallocation_tracer route_test.rb
{:T_SYMBOL=>11}
{:T_REGEXP=>17}
{:T_STRUCT=>6500}
{:T_MATCH=>12004}
{:T_DATA=>84092}
{:T_OBJECT=>99009}
{:T_HASH=>122015}
{:T_STRING=>172647}
{:T_IMEMO=>355136}
{:T_ARRAY=>433056}
```
This benchmark adds 500 resources. Each resource has 8 routes, so it
adds 4000 routes. You can see from the results that this patch
eliminates 4000 Regexp allocations, ~44000 String allocations, and ~8000
Array allocations. With that, we can figure out that the previous code
would allocate 1 regexp, 11 strings, and 2 arrays per route *more* than
this patch in order to handle verb matching.
Next lets look at runtime allocations:
```ruby
require 'action_pack'
require 'action_dispatch'
require 'benchmark/ips'
route_set = ActionDispatch::Routing::RouteSet.new
routes = ActionDispatch::Routing::Mapper.new route_set
routes.resources :foo
route = route_set.routes.first
request = ActionDispatch::Request.new("REQUEST_METHOD" => "GET")
result = ObjectSpace::AllocationTracer.trace do
500.times do
route.matches? request
end
end
sorted = ObjectSpace::AllocationTracer.allocated_count_table.sort_by(&:last)
sorted.each do |k,v|
next if v == 0
p k => v
end
__END__
Before:
$ be ruby -rallocation_tracer route_test.rb
{:T_MATCH=>500}
{:T_STRING=>501}
{:T_IMEMO=>1501}
After:
$ be ruby -rallocation_tracer route_test.rb
{:T_IMEMO=>1001}
```
This benchmark runs 500 calls against the `matches?` method on the route
object. We check this method in the case that there are two methods
that match the same path, but they are differentiated by the verb (or
other conditionals). For example `POST /users` vs `GET /users`, same
path, different action.
Previously, we were using regexps to match against the verb. You can
see that doing the regexp match would allocate 1 match object and 1
string object each time it was called. This patch eliminates those
allocations.
Next lets look at runtime performance.
```ruby
require 'action_pack'
require 'action_dispatch'
require 'benchmark/ips'
route_set = ActionDispatch::Routing::RouteSet.new
routes = ActionDispatch::Routing::Mapper.new route_set
routes.resources :foo
route = route_set.routes.first
match = ActionDispatch::Request.new("REQUEST_METHOD" => "GET")
no_match = ActionDispatch::Request.new("REQUEST_METHOD" => "POST")
Benchmark.ips do |x|
x.report("match") do
route.matches? match
end
x.report("no match") do
route.matches? no_match
end
end
__END__
Before:
$ be ruby -rallocation_tracer runtime.rb
Calculating -------------------------------------
match 17.145k i/100ms
no match 24.244k i/100ms
-------------------------------------------------
match 259.708k (± 4.3%) i/s - 1.303M
no match 453.376k (± 5.9%) i/s - 2.279M
After:
$ be ruby -rallocation_tracer runtime.rb
Calculating -------------------------------------
match 23.958k i/100ms
no match 29.402k i/100ms
-------------------------------------------------
match 465.063k (± 3.8%) i/s - 2.324M
no match 691.956k (± 4.5%) i/s - 3.469M
```
This tests tries to see how many times it can match a request per
second. Switching to method calls and string comparison makes the
successful match case about 79% faster, and the unsuccessful case about
52% faster.
That was fun!
|
||
|---|---|---|
| actionmailer | ||
| actionpack | ||
| actionview | ||
| activejob | ||
| activemodel | ||
| activerecord | ||
| activesupport | ||
| ci | ||
| guides | ||
| railties | ||
| tasks | ||
| tools | ||
| .gitignore | ||
| .travis.yml | ||
| .yardopts | ||
| CONTRIBUTING.md | ||
| Gemfile | ||
| Gemfile.lock | ||
| load_paths.rb | ||
| rails.gemspec | ||
| RAILS_VERSION | ||
| Rakefile | ||
| README.md | ||
| RELEASING_RAILS.md | ||
| version.rb | ||
Welcome to Rails
Rails is a web-application framework that includes everything needed to create database-backed web applications according to the Model-View-Controller (MVC) pattern.
Understanding the MVC pattern is key to understanding Rails. MVC divides your application into three layers, each with a specific responsibility.
The Model layer represents your domain model (such as Account, Product,
Person, Post, etc.) and encapsulates the business logic that is specific to
your application. In Rails, database-backed model classes are derived from
ActiveRecord::Base. Active Record allows you to present the data from
database rows as objects and embellish these data objects with business logic
methods. You can read more about Active Record in its README.
Although most Rails models are backed by a database, models can also be ordinary
Ruby classes, or Ruby classes that implement a set of interfaces as provided by
the Active Model module. You can read more about Active Model in its README.
The Controller layer is responsible for handling incoming HTTP requests and
providing a suitable response. Usually this means returning HTML, but Rails controllers
can also generate XML, JSON, PDFs, mobile-specific views, and more. Controllers load and
manipulate models, and render view templates in order to generate the appropriate HTTP response.
In Rails, incoming requests are routed by Action Dispatch to an appropriate controller, and
controller classes are derived from ActionController::Base. Action Dispatch and Action Controller
are bundled together in Action Pack. You can read more about Action Pack in its
README.
The View layer is composed of "templates" that are responsible for providing appropriate representations of your application's resources. Templates can come in a variety of formats, but most view templates are HTML with embedded Ruby code (ERB files). Views are typically rendered to generate a controller response, or to generate the body of an email. In Rails, View generation is handled by Action View. You can read more about Action View in its README.
Active Record, Action Pack, and Action View can each be used independently outside Rails. In addition to them, Rails also comes with Action Mailer (README), a library to generate and send emails; Active Job (README), a framework for declaring jobs and making them run on a variety of queueing backends; and Active Support (README), a collection of utility classes and standard library extensions that are useful for Rails, and may also be used independently outside Rails.
Getting Started
-
Install Rails at the command prompt if you haven't yet:
gem install rails -
At the command prompt, create a new Rails application:
rails new myappwhere "myapp" is the application name.
-
Change directory to
myappand start the web server:cd myapp rails serverRun with
--helpor-hfor options. -
Using a browser, go to
http://localhost:3000and you'll see: "Welcome aboard: You're riding Ruby on Rails!" -
Follow the guidelines to start developing your application. You may find the following resources handy:
Contributing
We encourage you to contribute to Ruby on Rails! Please check out the Contributing to Ruby on Rails guide for guidelines about how to proceed. Join us!
Code Status
License
Ruby on Rails is released under the MIT License.