Class: Rack::JSONP

Inherits:
Object
  • Object
show all
Includes:
Utils
Defined in:
lib/rack/contrib/jsonp.rb

Overview

A Rack middleware for providing JSON-P support.

Full credit to Flinn Mueller (actsasflinn.com/) for this contribution.

Constant Summary collapse

VALID_CALLBACK = 
/\A[a-zA-Z_$](?:\.?[\w$])*\z/

Instance Method Summary collapse

Constructor Details

#initialize(app) ⇒ JSONP

Returns a new instance of JSONP.



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# File 'lib/rack/contrib/jsonp.rb', line 29

def initialize(app)
  @app = app
end

Instance Method Details

#call(env) ⇒ Object

Proxies the request to the application, stripping out the JSON-P callback method and padding the response with the appropriate callback format if the returned body is application/json

Changes nothing if no callback param is specified.



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# File 'lib/rack/contrib/jsonp.rb', line 39

def call(env)
  request = Rack::Request.new(env)

  status, headers, response = @app.call(env)

  if STATUS_WITH_NO_ENTITY_BODY.include?(status)
    return status, headers, response
  end

  headers = HEADERS_KLASS.new.merge(headers)

  if is_json?(headers) && has_callback?(request)
    callback = request.params['callback']
    return bad_request unless valid_callback?(callback)

    response = pad(callback, response)

    # No longer json, its javascript!
    headers['Content-Type'] = headers['Content-Type'].gsub('json', 'javascript')

    # Set new Content-Length, if it was set before we mutated the response body
    if headers['Content-Length']
      length = response.map(&:bytesize).reduce(0, :+)
      headers['Content-Length'] = length.to_s
    end
  end

  [status, headers, response]
end