From 0b49c3fd2e11c63d0b778c2867499bfa7ec6ae1f Mon Sep 17 00:00:00 2001
From: Bob Aman <bobaman@google.com>
Date: Wed, 5 Jan 2011 01:09:52 +0000
Subject: [PATCH] Added User-Agent header.

git-svn-id: https://google-api-ruby-client.googlecode.com/svn/trunk@107 c1d61fac-ed7f-fcc1-18f7-ff78120a04ef
---
 lib/google/api_client.rb       | 43 ++++++++++++++++++++++++++++++++--
 spec/google/api_client_spec.rb | 39 ++++++++++++++++++++++++++++++
 2 files changed, 80 insertions(+), 2 deletions(-)

diff --git a/lib/google/api_client.rb b/lib/google/api_client.rb
index 32da5f9eb..78eeb351c 100644
--- a/lib/google/api_client.rb
+++ b/lib/google/api_client.rb
@@ -32,7 +32,9 @@ module Google
 
     def initialize(options={})
       @options = {
-        # TODO: What configuration options need to go here?
+        :user_agent => (
+          'google-api-ruby-client/' + Google::APIClient::VERSION::STRING
+        )
       }.merge(options)
       # Force immediate type-checking and short-cut resolution
       self.parser
@@ -255,6 +257,29 @@ module Google
       end).sort.last
     end
 
+    ##
+    # Returns the user agent used by the client.
+    #
+    # @return [String]
+    #   The user agent string used in the User-Agent header.
+    def user_agent
+      return @options[:user_agent]
+    end
+
+    ##
+    # Sets the user agent used by the client.
+    #
+    # @param [String, #to_str] new_user_agent
+    #   The new user agent string to use in the User-Agent header.
+    def user_agent=(new_user_agent)
+      unless new_user_agent == nil || new_user_agent.respond_to?(:to_str)
+        raise TypeError, "Expected String, got #{new_user_agent.class}."
+      end
+      new_user_agent = new_user_agent.to_str unless new_user_agent == nil
+      @options[:user_agent] = new_user_agent
+      return self.user_agent
+    end
+
     ##
     # Generates a request.
     #
@@ -371,7 +396,21 @@ module Google
     #
     # @return [Array] The response from the server.
     def transmit_request(request, adapter=self.http_adapter)
-      ::HTTPAdapter.transmit(request, adapter)
+      if self.user_agent != nil
+        # If there's no User-Agent header, set one.
+        method, uri, headers, body = request
+        unless headers.kind_of?(Enumerable)
+          # We need to use some Enumerable methods, relying on the presence of
+          # the #each method.
+          class <<headers
+            include Enumerable
+          end
+        end
+        unless headers.any? { |k, v| k.downcase == 'user-agent' }
+          headers = headers.to_a.insert(0, ['User-Agent', self.user_agent])
+        end
+      end
+      ::HTTPAdapter.transmit([method, uri, headers, body], adapter)
     end
 
     ##
diff --git a/spec/google/api_client_spec.rb b/spec/google/api_client_spec.rb
index 50036478c..e5ee0d7da 100644
--- a/spec/google/api_client_spec.rb
+++ b/spec/google/api_client_spec.rb
@@ -16,11 +16,44 @@ require 'spec_helper'
 
 require 'signet/oauth_1/client'
 require 'httpadapter/adapters/net_http'
+require 'httpadapter/adapters/mock'
 
 require 'google/api_client'
 require 'google/api_client/version'
 require 'google/api_client/parsers/json_parser'
 
+shared_examples_for 'configurable user agent' do
+  it 'should allow the user agent to be modified' do
+    @client.user_agent = 'Custom User Agent/1.2.3'
+    @client.user_agent.should == 'Custom User Agent/1.2.3'
+  end
+
+  it 'should allow the user agent to be set to nil' do
+    @client.user_agent = nil
+    @client.user_agent.should == nil
+  end
+
+  it 'should not allow the user agent to be set to bogus values' do
+    (lambda do
+      @client.user_agent = 42
+    end).should raise_error(TypeError)
+  end
+
+  it 'should transmit a User-Agent header when sending requests' do
+    @client.user_agent = 'Custom User Agent/1.2.3'
+    request = ['GET', 'http://www.google.com/', [], []]
+    adapter = HTTPAdapter::MockAdapter.request_adapter do |request, connection|
+      method, uri, headers, body = request
+      headers.should be_any { |k, v| k.downcase == 'user-agent' }
+      headers.each do |k, v|
+        v.should == @client.user_agent if k.downcase == 'user-agent'
+      end
+      [200, [], ['']]
+    end
+    @client.transmit_request(request, adapter)
+  end
+end
+
 describe Google::APIClient, 'with default configuration' do
   before do
     @client = Google::APIClient.new
@@ -37,6 +70,8 @@ describe Google::APIClient, 'with default configuration' do
   it 'should not use an authorization mechanism' do
     @client.authorization.should be_nil
   end
+
+  it_should_behave_like 'configurable user agent'
 end
 
 describe Google::APIClient, 'with default oauth configuration' do
@@ -63,6 +98,8 @@ describe Google::APIClient, 'with default oauth configuration' do
     @client.authorization.client_credential_key.should == 'anonymous'
     @client.authorization.client_credential_secret.should == 'anonymous'
   end
+
+  it_should_behave_like 'configurable user agent'
 end
 
 describe Google::APIClient, 'with custom pluggable parser' do
@@ -76,4 +113,6 @@ describe Google::APIClient, 'with custom pluggable parser' do
   it 'should use the custom parser' do
     @client.parser.should be_instance_of(FakeJsonParser)
   end
+
+  it_should_behave_like 'configurable user agent'
 end