Add Jsonp helper

lib/sinatra/contrib.rb

@@ -23,6 +23,7 @@ module Common
     module Custom
       # register :Compass
       register :Decompile
+      helpers :Jsonp
     end
 
     ##

lib/sinatra/jsonp.rb

@@ -0,0 +1,72 @@
+require 'sinatra/base'
+require 'json'
+
+module Sinatra
+  ##
+  # JSONP output helper for Sinatra. Automatically detects callback params
+  # and returns proper JSONP output.
+  # If no callback params where detected it returns plain JSON.
+  # Works with jQuery jQuery.getJSON method out of the box.
+  module Jsonp
+
+    # Examples
+
+    #   Classic:
+
+    #     require "sinatra"
+    #     require "sinatra/jsonp"
+
+    #     get '/hello' do
+    #       data = ["hello","hi","hallo"]
+    #       JSONP data      # JSONP is an alias for jsonp method
+    #     end
+
+    #     # define your own callback as second string param
+    #     get '/hi' do
+    #       data = ["hello","hi","hallo"]
+    #       jsonp data, 'functionA'
+    #     end
+
+    #     # same with symbol param
+    #     get '/hallo' do
+    #       data = ["hello","hi","hallo"]
+    #       jsonp data, :functionB
+    #     end
+
+    #   Modular:
+
+    #     require "sinatra/base"
+    #     require "sinatra/jsonp"
+
+    #     class Foo < Sinatra::Base
+    #       helpers Sinatra::Jsonp
+
+    #       get '/' do
+    #         data = ["hello","hi","hallo"]
+    #         jsonp data
+    #       end
+    #     end
+    #
+    def jsonp(*args)
+      if args.size > 0
+        data = args[0].to_json
+        if args.size > 1
+          callback = args[1].to_s
+        else
+          ['callback','jscallback','jsonp','jsoncallback'].each do |x|
+            callback = params.delete(x) unless callback
+          end
+        end
+        if callback
+          content_type :js
+          response = "#{callback}(#{data})"
+        else
+          response = data
+        end
+        response
+      end
+    end
+    alias JSONP jsonp
+  end
+  helpers Jsonp
+end

spec/jsonp_spec.rb

@@ -0,0 +1,37 @@
+require "backports"
+require_relative 'spec_helper'
+
+describe Sinatra::Jsonp do
+  before do
+    mock_app do
+      helpers Sinatra::Jsonp
+
+      get '/method' do
+        data = ["hello","hi","hallo"]
+        jsonp data
+      end
+      get '/method_with_params' do
+        data = ["hello","hi","hallo"]
+        jsonp data, :functionA
+      end
+    end
+  end
+
+  it "should return JSON if no callback passed" do
+    get '/method'
+    body.should == '["hello","hi","hallo"]'
+  end
+  it "should return JSONP if callback passed via GET param" do
+    get '/method?callback=functionA'
+    body.should == 'functionA(["hello","hi","hallo"])'
+  end
+  it "should return JSONP if callback passed via method param" do
+    get '/method_with_params'
+    body.should == 'functionA(["hello","hi","hallo"])'
+  end
+  it "should return JSONP with callback passed via method params even if it passed via GET param" do
+    get '/method_with_params?callback=functionB'
+    body.should == 'functionA(["hello","hi","hallo"])'
+  end
+end
+