class Merb::Router
Router stores route definitions and finds the first route that matches the incoming request URL.
Then information from route is used by dispatcher to call action on the controller.
Routes compilation.¶ ↑
The most interesting method of Router (and heart of route matching machinery) is match method generated on the fly from routes definitions. It is called routes compilation. Generated match method body contains one if/elsif statement that picks the first matching route definition and sets values to named parameters of the route.
Compilation is synchronized by mutex.
Attributes
A block that will be run around route matching. This block must yield in order for the actual matching to happen.
:api: plugin
A hash containing all the named application routes. The names are absolute (as in, all routes named in a namespace will contain the name of the namespace).
:api: private
A hash of all the application resource routes. The key of the hash is an array with each element containing the “path” for the resource for example, given the following resource routes:
resources :users do
resources :comments
end
The show comment route will have a key of [“User”, “Comment”]
:api: private
The starting point for route definition. Any route defined in a ::prepare block will defined in context of this behavior.
Examples¶ ↑
::root_behavior = Merb::Router.root_bavior.match(“/hello”)
In the previous example, all routes will have the path prefix /hello. It is important to note that this attribute must be set before any routes are defined in order for the behavior to be applied to the routes.
:api: plugin
An array containing all the application routes in order of priority.
:api: private
Public Class Methods
Add functionality to the router. This can be in the form of including a new module or directly defining new methods.
Parameters¶ ↑
- &block<Block>
-
A block of code used to extend the route builder with. This can be including a module or directly defining some new methods that should be available to building routes.
Returns¶ ↑
nil
Example¶ ↑
Merb::Router.extensions do def domain(name, domain, options={}, &block) match(:domain => domain).namespace(name, :path => nil, &block) end end
In this case, a method 'domain' will be available to the route builder which will create namespaces around domains instead of path prefixes.
This can then be used as follows.
Merb::Router.prepare do domain(:admin, "my-admin.com") do # ... routes come here ... end end
:api: public
# File lib/merb-core/dispatch/router.rb, line 310 def extensions(&block) Router::Behavior.class_eval(&block) end
Creates a route building context and evaluates the block in it. A copy of
root_behavior
(and instance of Behavior) is copied as the context.
Parameters¶ ↑
- first<Array>
-
An array containing routes that should be prepended to the routes defined in the block.
- last<Array>
-
An array containing routes that should be appended to the routes defined in the block.
Returns¶ ↑
- Merb::Router
-
Returns self to allow chaining of methods.
:api: public
# File lib/merb-core/dispatch/router.rb, line 103 def prepare(first = [], last = [], &block) @routes = [] root_behavior._with_proxy(&block) @routes = first + @routes + last compile self end
Clears the routing table. Route generation and request matching won't work anymore until a new routing table is built.
:api: private
# File lib/merb-core/dispatch/router.rb, line 115 def reset! class << self alias_method :match, :match_before_compilation end self.routes, self.named_routes, self.resource_routes = [], {}, {} end
Generates a URL from the resource(s)
Parameters¶ ↑
- resources<Symbol,Object>
-
The identifiers for the resource route to generate. These can either be symbols or objects. Symbols denote resource collection routes and objects denote the members.
- params<Hash>
-
Any extra parameters needed to generate the route.
Returns¶ ↑
- String
-
The generated URL
:api: plugin
# File lib/merb-core/dispatch/router.rb, line 255 def resource(*args) defaults = args.pop options = extract_options_from_args!(args) || {} key = [] params = [] args.each do |arg| if arg.is_a?(Symbol) || arg.is_a?(String) key << arg.to_s else key << arg.class.to_s params << arg end end unless route = Merb::Router.resource_routes[key] raise Merb::Router::GenerationError, "Resource route not found: #{args.inspect}" end params << options route.generate(params, defaults, true) end
Finds route matching URI of the request and returns a tuple of [route index, route params]. This method is called by the dispatcher and isn't as useful in applications.
Parameters¶ ↑
- request<Merb::Request>
-
request to match.
Returns¶ ↑
- Array[Integer, Hash]
-
Two-tuple: route index and route parameters. Route parameters are :controller, :action and all the named segments of the route.
:api: private
# File lib/merb-core/dispatch/router.rb, line 135 def route_for(request) index, params = if @around_match send(@around_match, request) { match(request) } else match(request) end route = routes[index] if index if !route raise ControllerExceptions::NotFound, "No routes match the request: #{request.uri}" end [route, params] end
There are three possible ways to use this method. First, if you have a named route, you can specify the route as the first parameter as a symbol and any paramters in a hash. Second, you can generate the default route by just passing the params hash, just passing the params hash. Finally, you can use the anonymous parameters. This allows you to specify the parameters to a named route in the order they appear in the router.
Parameters(Named Route)¶ ↑
- name<Symbol>
-
The name of the route.
- args<Hash>
-
Parameters for the route generation.
Parameters(Default Route)¶ ↑
- args<Hash>
-
Parameters for the route generation. This route will use the default route.
Parameters(Anonymous Parameters)¶ ↑
- name<Symbol>
-
The name of the route.
- args<Array>
-
An array of anonymous parameters to generate the route with. These parameters are assigned to the route parameters in the order that they are passed.
Returns¶ ↑
- String
-
The generated URL.
Examples¶ ↑
Named Route
::prepare do
match("/articles/:title").to(:controller => :articles, :action => :show).name("articles")
end
url(:articles, :title => “new_article”)
Default Route
::prepare do
default_routes
end
url(:controller => “articles”, :action => “new”)
Anonymous Paramters
::prepare do
match("/articles/:year/:month/:title").to(:controller => :articles, :action => :show).name("articles")
end
url(:articles, 2008, 10, “test_article”)
:api: plugin
# File lib/merb-core/dispatch/router.rb, line 221 def url(name, *args) if name.is_a?(Route) route = name else unless name.is_a?(Symbol) args.unshift(name) name = :default end unless route = Merb::Router.named_routes[name] raise Merb::Router::GenerationError, "Named route not found: #{name}" end end defaults = args.pop route.generate(args, defaults) end
Private Class Methods
Compiles the routes and creates the match
method.
:api: private
# File lib/merb-core/dispatch/router.rb, line 319 def compile if routes.any? begin eval(compiled_statement, binding, "Generated Code for Router", 1) rescue SyntaxError => e puts "\nGenerated code failed:\n #{compiled_statement}" raise e end else reset! end end
Generates the method for evaluation defining a match
method to
match a request with the defined routes.
:api: private
# File lib/merb-core/dispatch/router.rb, line 336 def compiled_statement @compiler_mutex.synchronize do condition_keys, if_statements = Set.new, "" routes.each_with_index do |route, i| route.freeze route.conditions.keys.each { |key| condition_keys << key } if_statements << route.compiled_statement(i == 0) end statement = "public\ndef match(request)\n" statement << condition_keys.inject("") do |cached, key| cached << " cached_#{key} = request.#{key}.to_s\n" end statement << if_statements statement << " else\n" statement << " [nil, {}]\n" statement << " end\n" statement << "end" end end