XhrRequestFix

lib/rack/contrib/xhr_request_fix.rb

@@ -0,0 +1,32 @@
+# This piece of middleware is a workaround for a problem existing in Firefox
+# If an XMLHttpRequest request (request.xhr? == true) gets redirected, FF doesn't forward the
+# non standard headers including XmlHttpRequest.
+# This code, sets an extra url parameter in this case and manually adds the header if
+# it encounters this parameter.
+#
+# @see: https://bugzilla.mozilla.org/show_bug.cgi?id=553888
+module Rack
+  class XhrRequestFix
+
+    def initialize(app, xhr_query_string = '_xhr')
+      @app = app
+      @xhr_query_string = xhr_query_string
+    end
+
+    def call(env)
+      if env["QUERY_STRING"].to_s =~ /#{@xhr_query_string}/
+        env["HTTP_X_REQUESTED_WITH"] ||= "XMLHttpRequest"
+      end
+      status, headers, body = @app.call(env)
+      if [301, 302, 303, 307].include?(status) && env["HTTP_X_REQUESTED_WITH"] == "XMLHttpRequest" && headers['Location']
+        headers["Location"] = add_xhr_to_location(headers['Location'])
+      end
+      [status, headers, body]
+    end
+
+    def add_xhr_to_location(location)
+      [location, @xhr_query_string].join(location.include?("?") ? '&' : '?')
+    end
+
+  end
+end

test/spec_rack_xhr_request_fix.rb

@@ -0,0 +1,98 @@
+require 'rubygems'
+require 'test/spec'
+require 'rack/mock'
+require 'rack/contrib/xhr_request_fix'
+require 'rack/contrib/runtime'
+
+context "Rack::XhrRequestFix" do
+  specify "sets XHR header when url param is set" do
+    env = { 'QUERY_STRING' => '_xhr' }
+    app = lambda do |env|
+      env['HTTP_X_REQUESTED_WITH'].should.equal 'XMLHttpRequest'
+      [200, {}, ""]
+    end
+    Rack::XhrRequestFix.new(app).call(env)
+  end
+
+  specify "modify location query string on redirect 301 when xhr request" do
+    env = { 'HTTP_X_REQUESTED_WITH' => 'XMLHttpRequest' }
+    app = lambda do |env|
+      [301, {"Location" => 'http://test.local'}, ""]
+    end
+    status, headers, body = Rack::XhrRequestFix.new(app).call(env)
+    headers['Location'].should =~ /_xhr/
+  end
+
+  specify "modify location query string on redirect 302 when xhr request" do
+    env = { 'HTTP_X_REQUESTED_WITH' => 'XMLHttpRequest' }
+    app = lambda do |env|
+      [302, {"Location" => 'http://test.local?lala=dude'}, ""]
+    end
+    status, headers, body = Rack::XhrRequestFix.new(app).call(env)
+    headers['Location'].should =~ /_xhr/
+    headers['Location'].should =~ /lala=dude/
+  end
+
+  specify "modify location query string on redirect 303 when xhr request" do
+    env = { 'HTTP_X_REQUESTED_WITH' => 'XMLHttpRequest' }
+    app = lambda do |env|
+      [303, {"Location" => 'http://test.local'}, ""]
+    end
+    status, headers, body = Rack::XhrRequestFix.new(app).call(env)
+    headers['Location'].should =~ /_xhr/
+  end
+
+  specify "modify location query string on redirect 307 when xhr request" do
+    env = { 'HTTP_X_REQUESTED_WITH' => 'XMLHttpRequest' }
+    app = lambda do |env|
+      [307, {"Location" => 'http://test.local'}, ""]
+    end
+    status, headers, body = Rack::XhrRequestFix.new(app).call(env)
+    headers['Location'].should =~ /_xhr/
+  end
+
+  specify "should not crash when redirecting with missing location header" do
+    env = { 'HTTP_X_REQUESTED_WITH' => 'XMLHttpRequest' }
+    app = lambda do |env|
+      [301, {}, ""]
+    end
+    lambda { Rack::XhrRequestFix.new(app).call(env) }.should.not.raise
+  end
+
+  specify "not modify location query string on redirect 307 when not xhr request" do
+    env = { }
+    app = lambda do |env|
+      [301, {"Location" => 'http://test.local'}, ""]
+    end
+    status, headers, body = Rack::XhrRequestFix.new(app).call(env)
+    headers['Location'].should.not =~ /_xhr/
+  end
+
+  specify "not modify location query string on status 200 when xhr request" do
+    env = { 'HTTP_X_REQUESTED_WITH' => 'XMLHttpRequest' }
+    app = lambda do |env|
+      [200, {"Location" => 'http://test.local'}, ""]
+    end
+    status, headers, body = Rack::XhrRequestFix.new(app).call(env)
+    headers['Location'].should.not =~ /_xhr/
+  end
+
+  specify "modify location query string with alternative token" do
+    env = { 'HTTP_X_REQUESTED_WITH' => 'XMLHttpRequest' }
+    app = lambda do |env|
+      [301, {"Location" => 'http://test.local'}, ""]
+    end
+    status, headers, body = Rack::XhrRequestFix.new(app, 'alt_token').call(env)
+    headers['Location'].should =~ /alt_token/
+  end
+
+  specify "sets XHR header with alternative token" do
+    env = { 'QUERY_STRING' => 'alt_token' }
+    app = lambda do |env|
+      env['HTTP_X_REQUESTED_WITH'].should.equal 'XMLHttpRequest'
+      [200, {}, ""]
+    end
+    Rack::XhrRequestFix.new(app, 'alt_token').call(env)
+  end
+
+end