module Roda::RodaPlugins::TypeRouting

  1. lib/roda/plugins/type_routing.rb

This plugin makes it easier to to respond to specific request data types. User agents can request specific data types by either supplying an appropriate Accept request header or by appending it as file extension to the path.


plugin :type_routing

route do |r|
  r.get 'a' do
    r.html{ "<h1>This is the HTML response</h1>" }
    r.json{ '{"json": "ok"}' }
    r.xml{ "<root>This is the XML response</root>" }
    "Unsupported data type"

This application will handle the following paths:


HTML response


JSON response


XML response


HTML, JSON, or XML response, depending on the Accept header

The response Content-Type header will be set to a suitable value when the r.html, r.json, or r.xml block is matched.

Note that if no match is found, code will continue to execute, which can result in unexpected behaviour. This should only happen if you do not handle all supported/configured types. If you want to simplify handling, you can just place the html handling after the other types, without using a separate block:

route do |r|
  r.get 'a' do
    r.json{ '{"json": "ok"}' }
    r.xml{ "<root>This is the XML response</root>" }

    "<h1>This is the HTML response</h1>"

This works correctly because Roda’s default Content-Type is text/html. Note that if you use this approach, the type_routing plugin’s :html content type will not be used for html responses, since you aren’t using an r.html block. Instead, the Content-Type header will be set to Roda’s default (which you can override via the default_headers plugin).

If the type routing is based on the Accept request header and not the file extension, then an appropriate Vary header will be set or appended to, so that HTTP caches do not serve the same result for requests with different Accept headers.

To match custom extensions, use the :types option:

plugin :type_routing, types: {
  yaml: 'application/x-yaml',
  js: 'application/javascript; charset=utf-8'

route do |r|
  r.get 'a' do
    r.yaml{ YAML.dump "YAML data" }
    r.js{ "JavaScript code" }
    # or:
    r.on_type(:js){ "JavaScript code" }
    "Unsupported data type"

Plugin options

The following plugin options are supported:


The default data type to assume if the client did not provide one. Defaults to :html.


Exclude one or more types from the default set (default set is :html, :xml, :json).


Mapping from a data type to its MIME-Type. Used both to match incoming requests and to provide Content-Type values. If the value is nil, no Content-Type will be set. The type may contain media type parameters, which will be sent to the client but ignored for request matching.


Whether to take the path extension into account. Default is true.


Whether to take the Accept header into account. Default is true.


Public Class

  1. configure


CONFIGURATION = { :mimes => { 'text/json' => :json, 'application/json' => :json, 'text/xml' => :xml, 'application/xml' => :xml, 'text/html' => :html, }.freeze, :types => { :json => 'application/json'.freeze, :xml => 'application/xml'.freeze, :html => 'text/html'.freeze, }.freeze, :use_extension => true, :use_header => true, :default_type => :html }.freeze  

Public Class methods

configure(app, opts = {})
[show source]
    # File lib/roda/plugins/type_routing.rb
110 def self.configure(app, opts = {})
111   config = (app.opts[:type_routing] || CONFIGURATION).dup
112   [:use_extension, :use_header, :default_type].each do |key|
113     config[key] = opts[key] if opts.has_key?(key)
114   end
116   types = config[:types] = config[:types].dup
117   mimes = config[:mimes] = config[:mimes].dup
119   Array(opts[:exclude]).each do |type|
120     types.delete(type)
121     mimes.reject!{|_, v| v == type}
122   end
124   if mapping = opts[:types]
125     types.merge!(mapping)
127     mapping.each do |k, v|
128       if v
129         mimes[v.split(';', 2).first] = k
130       end
131     end
132   end
134   types.freeze
135   mimes.freeze
137   type_keys = config[:types].keys
138   config[:extension_regexp] = /(.*?)\.(#{Regexp.union(})\z/
140   type_keys.each do |type|
141     app::RodaRequest.send(:define_method, type) do |&block|
142       on_type(type, &block)
143     end
144     app::RodaRequest.send(:alias_method, type, type)
145   end
147   app.opts[:type_routing] = config.freeze
148 end