refactors Grape::Middleware::Versioner to dispatch

to versioning strategy

Author: Jerry Cheung

lib/grape.rb

@@ -21,6 +21,11 @@ module Auth
       autoload :Basic,  'grape/middleware/auth/basic'
       autoload :Digest,	'grape/middleware/auth/digest'
     end
+
+    module Versioner
+      autoload :Path,   'grape/middleware/versioner/path'
+      autoload :Header, 'grape/middleware/versioner/header'
+    end
   end
 
   module Util

lib/grape/middleware/versioner.rb

@@ -1,25 +1,25 @@
-require 'grape/middleware/base'
-
+# Versioners set env['api.version'] when a version is defined on an API and
+# on the requests. The current methods for determining version are:
+#
+#   :header - version from HTTP Accept header.
+#   :path   - version from uri. e.g. /v1/resource
+#
+# See individual classes for details.
 module Grape
   module Middleware
-    class Versioner < Base
-      def default_options
-        {
-          :pattern => /.*/i
-        }
-      end
-      
-      def before
-        pieces = env['PATH_INFO'].split('/')
-        potential_version = pieces[1]
-        if potential_version =~ options[:pattern]
-          if options[:versions] && !options[:versions].include?(potential_version)
-            throw :error, :status => 404, :message => "404 API Version Not Found"
-          end
-          
-          truncated_path = "/#{pieces[2..-1].join('/')}"
-          env['api.version'] = potential_version
-          env['PATH_INFO'] = truncated_path
+    module Versioner
+      extend self
+
+      # @param strategy [Symbol] :path or :header
+      # @return a middleware class based on strategy
+      def using(strategy)
+        case strategy
+        when :path
+          Path
+        when :header
+          Header
+        else
+          raise ArgumentError.new("Unknown :using for versioner: #{strategy}")
         end
       end
     end

lib/grape/middleware/versioner/path.rb

@@ -0,0 +1,42 @@
+require 'grape/middleware/base'
+
+module Grape
+  module Middleware
+    module Versioner
+      # This middleware sets various version related rack environment variables
+      # based on the uri path and removes the version substring from the uri
+      # path. If the version substring does not match any potential initialized
+      # versions, a 404 error is thrown.
+      # 
+      # Example: For a uri path
+      #   /v1/resource
+      # 
+      # The following rack env variables are set and path is rewritten to
+      # '/resource':
+      # 
+      #   env['api.version'] => 'v1'
+      # 
+      class Path < Base
+        def default_options
+          {
+            :pattern => /.*/i
+          }
+        end
+
+        def before
+          pieces = env['PATH_INFO'].split('/')
+          potential_version = pieces[1]
+          if potential_version =~ options[:pattern]
+            if options[:versions] && !options[:versions].include?(potential_version)
+              throw :error, :status => 404, :message => "404 API Version Not Found"
+            end
+
+            truncated_path = "/#{pieces[2..-1].join('/')}"
+            env['api.version'] = potential_version
+            env['PATH_INFO'] = truncated_path
+          end
+        end
+      end
+    end
+  end
+end

spec/grape/middleware/versioner/path_spec.rb

@@ -0,0 +1,40 @@
+require 'spec_helper'
+
+describe Grape::Middleware::Versioner::Path do
+  let(:app) { lambda{|env| [200, env, env['api.version']]} }
+  subject { Grape::Middleware::Versioner::Path.new(app, @options || {}) }
+
+  it 'should set the API version based on the first path' do
+    subject.call('PATH_INFO' => '/v1/awesome').last.should == 'v1'
+  end
+
+  it 'should cut the version out of the path' do
+    subject.call('PATH_INFO' => '/v1/awesome')[1]['PATH_INFO'].should == '/awesome'
+  end
+
+  it 'should provide a nil version if no path is given' do
+    subject.call('PATH_INFO' => '/').last.should be_nil
+  end
+
+  context 'with a pattern' do
+    before{ @options = {:pattern => /v./i} }
+    it 'should set the version if it matches' do
+      subject.call('PATH_INFO' => '/v1/awesome').last.should == 'v1'
+    end
+
+    it 'should ignore the version if it fails to match' do
+      subject.call('PATH_INFO' => '/awesome/radical').last.should be_nil
+    end
+  end
+
+  context 'with specified versions' do
+    before{ @options = {:versions => ['v1', 'v2']}}
+    it 'should throw an error if a non-allowed version is specified' do
+      catch(:error){subject.call('PATH_INFO' => '/v3/awesome')}[:status].should == 404
+    end
+
+    it 'should allow versions that have been specified' do
+      subject.call('PATH_INFO' => '/v1/asoasd').last.should == 'v1'
+    end
+  end
+end

spec/grape/middleware/versioner_spec.rb

@@ -1,40 +1,12 @@
 require 'spec_helper'
 
 describe Grape::Middleware::Versioner do
-  let(:app) { lambda{|env| [200, env, env['api.version']]} }
-  subject { Grape::Middleware::Versioner.new(app, @options || {}) }
-  
-  it 'should set the API version based on the first path' do
-    subject.call('PATH_INFO' => '/v1/awesome').last.should == 'v1'
+  let(:klass) { Grape::Middleware::Versioner }
+  it 'should recognize :path' do
+    klass.using(:path).should == Grape::Middleware::Versioner::Path
   end
-  
-  it 'should cut the version out of the path' do
-    subject.call('PATH_INFO' => '/v1/awesome')[1]['PATH_INFO'].should == '/awesome'
-  end
-  
-  it 'should provide a nil version if no path is given' do
-    subject.call('PATH_INFO' => '/').last.should be_nil
-  end
-  
-  context 'with a pattern' do
-    before{ @options = {:pattern => /v./i} }
-    it 'should set the version if it matches' do
-      subject.call('PATH_INFO' => '/v1/awesome').last.should == 'v1'
-    end
-    
-    it 'should ignore the version if it fails to match' do
-      subject.call('PATH_INFO' => '/awesome/radical').last.should be_nil
-    end
-  end
-  
-  context 'with specified versions' do
-    before{ @options = {:versions => ['v1', 'v2']}}
-    it 'should throw an error if a non-allowed version is specified' do
-      catch(:error){subject.call('PATH_INFO' => '/v3/awesome')}[:status].should == 404
-    end
-    
-    it 'should allow versions that have been specified' do
-      subject.call('PATH_INFO' => '/v1/asoasd').last.should == 'v1'
-    end
+
+  it 'should recognize :header' do
+    klass.using(:header).should == Grape::Middleware::Versioner::Header
   end
 end