Allow custom query string normalization

Useful for changing the Rails-style querystrings, i.e.
key[]=1&key[]=2 could become key=1&key=2

Closes gh-8

lib/httparty.rb

@@ -201,6 +201,37 @@ module HTTParty
       default_options[:pem] = pem_contents
     end
 
+    # Override the way query strings are normalized.
+    # Helpful for overriding the default rails normalization of Array queries.
+    #
+    # For a query:
+    #   get '/', :query => {:selected_ids => [1,2,3]}
+    #
+    # The default query string normalizer returns:
+    #   /?selected_ids[]=1&selected_ids[]=2&selected_ids[]=3
+    #
+    # Let's change it to this:
+    #  /?selected_ids=1&selected_ids=2&selected_ids=3
+    #
+    # Pass a Proc to the query normalizer which accepts the yielded query.
+    #
+    # @example Modifying Array query strings
+    #   class ServiceWrapper
+    #     include HTTParty
+    #
+    #     query_string_normalizer proc { |query|
+    #       query.map do |key, value|
+    #         value.map {|v| "#{key}=#{v}"}
+    #       end.join('&')
+    #     }
+    #   end
+    #
+    # @param [Proc] normalizer the new normalizer
+    # @yield [Hash] query hash option
+    def query_string_normalizer(normalizer)
+      default_options[:query_string_normalizer] = normalizer
+    end
+
     # Allows setting an OpenSSL certificate authority file
     #
     #   class Foo

lib/httparty/request.rb

@@ -103,7 +103,7 @@ module HTTParty
     end
 
     def body
-      options[:body].is_a?(Hash) ? options[:body].to_params : options[:body]
+      options[:body].is_a?(Hash) ? normalize_query(options[:body]) : options[:body]
     end
 
     def credentials
@@ -118,6 +118,18 @@ module HTTParty
       credentials[:password]
     end
 
+    def normalize_query(query)
+      if query_string_normalizer
+        query_string_normalizer.call(query)
+      else
+        query.to_params
+      end
+    end
+
+    def query_string_normalizer
+      options[:query_string_normalization]
+    end
+
     def setup_raw_request
       @raw_request = http_method.new(uri.request_uri)
       @raw_request.body = body if body
@@ -146,12 +158,13 @@ module HTTParty
       query_string_parts << uri.query unless uri.query.nil?
 
       if options[:query].is_a?(Hash)
-        query_string_parts << options[:default_params].merge(options[:query]).to_params
+        query_string_parts << normalize_query(options[:default_params].merge(options[:query]))
       else
-        query_string_parts << options[:default_params].to_params unless options[:default_params].empty?
+        query_string_parts << normalize_query(options[:default_params]) unless options[:default_params].empty?
         query_string_parts << options[:query] unless options[:query].nil?
       end
 
+
       query_string_parts.size > 0 ? query_string_parts.join('&') : nil
     end
 

spec/httparty/request_spec.rb

@@ -5,6 +5,18 @@ describe HTTParty::Request do
     @request = HTTParty::Request.new(Net::HTTP::Get, 'http://api.foo.com/v1', :format => :xml)
   end
 
+  let(:array_normalization_proc) do
+    proc do |query|
+      query.map do |key, value|
+        if value.is_a?(Array)
+          value.map {|v| "#{key}=#{v}"}
+        else
+          {key => value}.to_params
+        end
+      end.flatten.sort.join('&')
+    end
+  end
+
   describe "initialization" do
     it "sets parser to HTTParty::Parser" do
       request = HTTParty::Request.new(Net::HTTP::Get, 'http://google.com')
@@ -74,6 +86,36 @@ describe HTTParty::Request do
         @request.options[:default_params] = {}
         @request.uri.query.should be_nil
       end
+
+      it "respects the query string normalization proc" do
+        @request.options[:query_string_normalization] = array_normalization_proc
+        @request.options[:query] = {:page => 1, :foo => %w(bar baz)}
+        URI.unescape(@request.uri.query).should == "foo=bar&foo=baz&page=1"
+      end
+
+      context "when representing an array" do
+        it "doesn't modify strings" do
+          @request.options[:query] = "foo=bar&foo=baz"
+          URI.unescape(@request.uri.query).should == "foo=bar&foo=baz"
+        end
+
+        it "converts a ruby array into a Rails supported query string" do
+          @request.options[:query] = {:foo => %w(bar baz)}
+          URI.unescape(@request.uri.query).should == "foo[]=bar&foo[]=baz"
+        end
+      end
+    end
+  end
+
+  describe "#setup_raw_request" do
+    context "when query_string_normalization is set" do
+      it "sets the body to the return value of the proc" do
+        @request.options[:query_string_normalization] = array_normalization_proc
+        @request.options[:body] = {:page => 1, :foo => %w(bar baz)}
+        @request.send(:setup_raw_request)
+        body = @request.instance_variable_get(:@raw_request).body
+        URI.unescape(body).should == "foo=bar&foo=baz&page=1"
+      end
     end
   end