Class: Alf::Rack::Response

Inherits:
Rack::Response
  • Object
show all
Defined in:
lib/alf/rack/response.rb

Overview

Specialization of ::Rack::Response that automatically handles the encoding of tuples and relations according to HTTP_ACCEPT and available renderers.

Example:

“‘ require ’sinatra’

use Alf::Rack::Connect{|cfg| … }

get ‘/users’ do

# get the connection (see Alf::Rack::Connect)
conn = ...

# The body relation/relvar will automatically be encoded to
# whatever format the user want among the available ones.
# The Content-Type response header is set accordingly.
Alf::Rack::Response.new(env){|r|
  r.body = conn.query{ users }
}.finish

end “‘

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(env = {}) ⇒ Response

Prepares a Response instance for a given Rack environment. Raises an AcceptError if no renderer can be found for the HTTP_ACCEPT header.



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# File 'lib/alf/rack/response.rb', line 31

def initialize(env = {})
  @renderer = Response.renderer!(env)
  super([], 200, 'Content-Type' => @renderer.mime_type)
end

Class Method Details

.accept(env) ⇒ Object

Returns the HTTP_ACCEPT header of env. Defaults to ‘application/json’



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# File 'lib/alf/rack/response.rb', line 61

def accept(env)
  env['HTTP_ACCEPT'] || 'application/json'
end

.renderer(env) ⇒ Object

Returns the best renderer to use given HTTP_ACCEPT header and available Alf renderers.



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# File 'lib/alf/rack/response.rb', line 47

def renderer(env)
  media_type = ::Rack::Accept::MediaType.new(accept(env))
  if best = media_type.best_of(supported_media_types)
    Renderer.each.find{|(name,_,r)| r.mime_type == best }.last
  end
end

.renderer!(env) ⇒ Object

Returns the renderer to use for env. Raises an AcceptError if no renderer can be found.



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# File 'lib/alf/rack/response.rb', line 56

def renderer!(env)
  renderer(env) || raise(AcceptError, "Unsupported content type `#{accept(env)}`")
end

.supported_media_types ⇒ Object

Returns media types supported by the Renderer class.



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# File 'lib/alf/rack/response.rb', line 66

def supported_media_types
  Renderer.each.map{|(_,_,r)| r.mime_type}.compact.sort
end

Instance Method Details

#body=(payload) ⇒ Object

Sets the body of the response to payload. The latter can be any object that Alf is able to render through the IO renderers (relations, relvars, tuples, etc.).



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# File 'lib/alf/rack/response.rb', line 39

def body=(payload)
  super(@renderer.new(payload))
end