Class: Rack::Acceptable::Formats

Inherits:
Object
  • Object
show all
Defined in:
lib/rack/acceptable/middleware/formats.rb

Overview

  • Fishes out all acceptable formats (in the appropriate order). The idea is to let the user decide about the preferred one, since the Accept request-header is not only thing the response depends on.

  • Stops processing and responds with 406 ‘Not Acceptable’ only if there’s no acceptable formats and wildcard has a zero quality or not explicitly mentioned; i.e, decreases (slightly) the the number of application calls in compliance with notes in RFC 2616, sec. 10.4.7.

Example

@provides = {
  :json => %w(text/x-json application/json),
  :xml  => %w(application/xml text/xml),
  :text => %w(text/plain text/*)
  }

use Rack::Acceptable::Formats @provides

Constant Summary collapse

CANDIDATES = 
'rack-acceptable.formats.candidates'

Instance Method Summary collapse

Constructor Details

#initialize(app, provides) ⇒ Formats

– RFC 2616, section 10.4.7: Note: HTTP/1.1 servers are allowed to return responses which are not acceptable according to the accept headers sent in the request. In some cases, this may even be preferable to sending a 406 response. User agents are encouraged to inspect the headers of an incoming response to determine if it is acceptable. ++



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# File 'lib/rack/acceptable/middleware/formats.rb', line 39

def initialize(app, provides)
  @app, @types = app, {}
  provides.each { |f,types| types.each { |t| @types[t] = f } }
  @types.update(Const::MEDIA_RANGE_WILDCARD => :all)
end

Instance Method Details

#call(env) ⇒ Object 



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# File 'lib/rack/acceptable/middleware/formats.rb', line 45

def call(env)
  if accepts = env[Const::ENV_HTTP_ACCEPT]
    accepts = Utils.extract_qvalues(accepts)
    i = 0
    accepts = accepts.sort_by { |_,q| [-q,i+=1] }
    accepts.reject! { |t,q| q == 0 || !@types.key?(t) }
    if accepts.empty?
      return Const::NOT_ACCEPTABLE_RESPONSE
    else
      accepts.map! { |t,_| @types[t] }.uniq!
      env[CANDIDATES] = accepts
    end
  else
    env[CANDIDATES] = [:all]
  end
  @app.call(env)
#rescue
#  @app.call(env)
end