rack-rewrite-dynamic

Rack rewrite is a great tool if you have static based rewrites. What do you do when dynamic slug based rewrites are needed to make your SEO seeking client happy?

Consider the following requirements:

/slug_name/another_slug_name should be rendered by /controller/id /filter_slug-another_filter_slug-resources_name should be renderd by /resources_name?color_ids[]=42&color_ids[]=43&category_ids[]=42

You could try to setup custom routing using rack-rewrite arbitrary rewriting feature. Rack-rewrite-dynamic wraps these use cases and provides an easy way to create your own if you need to do so.

Add this line to your application's Gemfile:

gem 'rack-rewrite-dynamic'

And then execute:

$ bundle

Or install it yourself as:

$ gem install rack-rewrite-dynamic

Rack-rewrite-dynamic currently assumes its being used as a middleware. It also assumes you have a Slug model using the friendly_id gem. The slug model should have a polymorphic association to the models that are used for SEO urls.

class Slug < ActiveRecord::Base
  extend FriendlyId
  friendly_id :content, use: [:slugged, :history]
  belongs_to :sluggable, :polymorphic => true
end

Rack-rewrite-dynamic provides two types of slug based url matchers:

To set up the rewrites, hook into rack-rewrite middleware in config/application.rb

config.middleware.insert_after "ActiveRecord::QueryCache", 'Rack::Rewrite' do |base|
  rewriter = 'Rack::Rewrite::Dynamic::Rewrites'.constantize.new do
    rewrite url_parts: [{'Category' => 'slug', 'IceCream' => 'slug'}]
  end
  rewriter.apply_rewrites(base)
end

The example rewrites /category_slug/ice_cream_slug to /ice_creams/42 so the rails app can have

resources :ice_creams

defined as usual.

To set up a url rewriter use

config.middleware.insert_after "ActiveRecord::QueryCache", 'Rack::Rewrite' do |base|
  rewriter = 'Rack::Rewrite::Dynamic::Rewrites'.constantize.new do
    rewrite_filter separator: '-', target: 'cars', suffix: 'cars'
  end
  rewriter.apply_rewrites(base)
end

The example rewrites /color_slug-another_color_slug-category_slug-cars to /cars?color_ids[]=42&color_ids[]=43&category_ids[]=42 so the rails app can have

resources :cars

defined as usual and use the filter attributes on the index page.

If the two built in rewrites do not fit your need, you can create your own. You can use one of our own rewriters as a template. The only requirement is to have a perform instance method that receives a match object of the url and a rack_env object containing the request information from the rack environment. To bring in some functionality that should be useful include our base module.

class MyRewriter
  include Rack::Rewrite::Dynamic::Base

  def perform(match, rack_env)
    # some awesome rewriting
  end
end

You can then pass them in as an argument to the rewrite method.

config.middleware.insert_after "ActiveRecord::QueryCache", 'Rack::Rewrite' do |base|
  rewriter = 'Rack::Rewrite::Dynamic::Rewrites'.constantize.new do
    rewrite {option: 'value'}, MyRewriter
  end
  rewriter.apply_rewrites(base)
end

If you wish to use a different slug class you may pass it in as an argument when defining the rewrite.

config.middleware.insert_after "ActiveRecord::QueryCache", 'Rack::Rewrite' do |base|
  rewriter = 'Rack::Rewrite::Dynamic::Rewrites'.constantize.new do
    rewrite url_parts: [{'Category' => 'slug', 'IceCream' => 'slug'}], slug_name: 'AnotherSlug'
  end
  rewriter.apply_rewrites(base)
end

By default the rewrites assume you have a rails application to generate the routing. If you with to have a custom route generator, you can supply it when defining the rewrite. It needs to respond to a route_for(slug) message and return a string representing the url.

class TestGenerator
  def self.route_for slug
    'some/path'
  end
end

config.middleware.insert_after "ActiveRecord::QueryCache", 'Rack::Rewrite' do |base|
  rewriter = 'Rack::Rewrite::Dynamic::Rewrites'.constantize.new do
    rewrite url_parts: [{'Category' => 'slug', 'IceCream' => 'slug'}], route_generator_name: 'TestGenerator'
  end
  rewriter.apply_rewrites(base)
end

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create new Pull Request