6 files changed, 248 insertions, 6 deletions
diff --git a/docs/api-guide/versioning.md b/docs/api-guide/versioning.md
new file mode 100644
index 00000000..df814894
--- /dev/null
+++ b/docs/api-guide/versioning.md
@@ -0,0 +1,9 @@
+source: versioning.py
+
+# Versioning
+
+> Versioning an interface is just a "polite" way to kill deployed clients.
+> 
+> &mdash; [Roy Fielding][cite].
+
+[cite]: http://www.slideshare.net/evolve_conference/201308-fielding-evolve/31
+\ No newline at end of file
diff --git a/rest_framework/reverse.py b/rest_framework/reverse.py
index a74e8aa2..8fcca55b 100644
--- a/rest_framework/reverse.py
+++ b/rest_framework/reverse.py
@@ -9,6 +9,18 @@ from django.utils.functional import lazy
 
 def reverse(viewname, args=None, kwargs=None, request=None, format=None, **extra):
     """
+    If versioning is being used then we pass any `reverse` calls through
+    to the versioning scheme instance, so that the resulting URL
+    can be modified if needed.
+    """
+    scheme = getattr(request, 'versioning_scheme', None)
+    if scheme is not None:
+        return scheme.reverse(viewname, args, kwargs, request, format, **extra)
+    return _reverse(viewname, args, kwargs, request, format, **extra)
+
+
+def _reverse(viewname, args=None, kwargs=None, request=None, format=None, **extra):
+    """
     Same as `django.core.urlresolvers.reverse`, but optionally takes a request
     and returns a fully qualified URL, using the request to get the base URL.
     """
diff --git a/rest_framework/settings.py b/rest_framework/settings.py
index 6c26256a..da3be38d 100644
--- a/rest_framework/settings.py
+++ b/rest_framework/settings.py
@@ -46,6 +46,7 @@ DEFAULTS = {
     'DEFAULT_THROTTLE_CLASSES': (),
     'DEFAULT_CONTENT_NEGOTIATION_CLASS': 'rest_framework.negotiation.DefaultContentNegotiation',
     'DEFAULT_METADATA_CLASS': 'rest_framework.metadata.SimpleMetadata',
+    'DEFAULT_VERSIONING_CLASS': None,
 
     # Generic view behavior
     'DEFAULT_PAGINATION_SERIALIZER_CLASS': 'rest_framework.pagination.PaginationSerializer',
@@ -123,6 +124,7 @@ IMPORT_STRINGS = (
     'DEFAULT_THROTTLE_CLASSES',
     'DEFAULT_CONTENT_NEGOTIATION_CLASS',
     'DEFAULT_METADATA_CLASS',
+    'DEFAULT_VERSIONING_CLASS',
     'DEFAULT_PAGINATION_SERIALIZER_CLASS',
     'DEFAULT_FILTER_BACKENDS',
     'EXCEPTION_HANDLER',
@@ -139,7 +141,9 @@ def perform_import(val, setting_name):
     If the given setting is a string import notation,
     then perform the necessary import or imports.
     """
-    if isinstance(val, six.string_types):
+    if val is None:
+        return None
+    elif isinstance(val, six.string_types):
         return import_from_string(val, setting_name)
     elif isinstance(val, (list, tuple)):
         return [import_from_string(item, setting_name) for item in val]
diff --git a/rest_framework/versioning.py b/rest_framework/versioning.py
new file mode 100644
index 00000000..2ca8efff
--- /dev/null
+++ b/rest_framework/versioning.py
@@ -0,0 +1,96 @@
+# coding: utf-8
+from __future__ import unicode_literals
+from rest_framework.reverse import _reverse
+from rest_framework.utils.mediatypes import _MediaType
+import re
+
+
+class BaseVersioning(object):
+    def determine_version(self, request, *args, **kwargs):
+        msg = '{cls}.determine_version() must be implemented.'
+        raise NotImplemented(msg.format(
+            cls=self.__class__.__name__
+        ))
+
+    def reverse(self, viewname, args=None, kwargs=None, request=None, format=None, **extra):
+        return _reverse(viewname, args, kwargs, request, format, **extra)
+
+
+class QueryParameterVersioning(BaseVersioning):
+    """
+    GET /something/?version=0.1 HTTP/1.1
+    Host: example.com
+    Accept: application/json
+    """
+    default_version = None
+    version_param = 'version'
+
+    def determine_version(self, request, *args, **kwargs):
+        return request.query_params.get(self.version_param)
+
+    def reverse(self, viewname, args=None, kwargs=None, request=None, format=None, **extra):
+        url = super(QueryParameterVersioning, self).reverse(
+            viewname, args, kwargs, request, format, **kwargs
+        )
+        if request.version is not None:
+            return replace_query_param(url, self.version_param, request.version)
+        return url
+
+
+class HostNameVersioning(BaseVersioning):
+    """
+    GET /something/ HTTP/1.1
+    Host: v1.example.com
+    Accept: application/json
+    """
+    default_version = None
+    hostname_regex = re.compile(r'^([a-zA-Z0-9]+)\.[a-zA-Z0-9]+\.[a-zA-Z0-9]+$')
+
+    def determine_version(self, request, *args, **kwargs):
+        hostname, seperator, port = request.get_host().partition(':')
+        match = self.hostname_regex.match(hostname)
+        if not match:
+            return self.default_version
+        return match.group(1)
+
+    # We don't need to implement `reverse`, as the hostname will already be
+    # preserved as part of the standard `reverse` implementation.
+
+
+class AcceptHeaderVersioning(BaseVersioning):
+    """
+    GET /something/ HTTP/1.1
+    Host: example.com
+    Accept: application/json; version=1.0
+    """
+    default_version = None
+    version_param = 'version'
+
+    def determine_version(self, request, *args, **kwargs):
+        media_type = _MediaType(request.accepted_media_type)
+        return media_type.params.get(self.version_param, self.default_version)
+
+    # We don't need to implement `reverse`, as the versioning is based
+    # on the `Accept` header, not on the request URL.
+
+
+class URLPathVersioning(BaseVersioning):
+    """
+    GET /1.0/something/ HTTP/1.1
+    Host: example.com
+    Accept: application/json
+    """
+    default_version = None
+    version_param = 'version'
+
+    def determine_version(self, request, *args, **kwargs):
+        return kwargs.get(self.version_param, self.default_version)
+
+    def reverse(self, viewname, args=None, kwargs=None, request=None, format=None, **extra):
+        if request.version is not None:
+            kwargs = {} if (kwargs is None) else kwargs
+            kwargs[self.version_param] = request.version
+
+        return super(URLPathVersioning, self).reverse(
+            viewname, args, kwargs, request, format, **kwargs
+        )
diff --git a/rest_framework/views.py b/rest_framework/views.py
index b39724c2..12bb78bd 100644
--- a/rest_framework/views.py
+++ b/rest_framework/views.py
@@ -95,6 +95,7 @@ class APIView(View):
     permission_classes = api_settings.DEFAULT_PERMISSION_CLASSES
     content_negotiation_class = api_settings.DEFAULT_CONTENT_NEGOTIATION_CLASS
     metadata_class = api_settings.DEFAULT_METADATA_CLASS
+    versioning_class = api_settings.DEFAULT_VERSIONING_CLASS
 
     # Allow dependency injection of other settings to make testing easier.
     settings = api_settings
@@ -314,6 +315,16 @@ class APIView(View):
             if not throttle.allow_request(request, self):
                 self.throttled(request, throttle.wait())
 
+    def determine_version(self, request, *args, **kwargs):
+        """
+        If versioning is being used, then determine any API version for the
+        incoming request. Returns a two-tuple of (version, versioning_scheme)
+        """
+        if self.versioning_class is None:
+            return (None, None)
+        scheme = self.versioning_class()
+        return (scheme.determine_version(request, *args, **kwargs), scheme)
+
     # Dispatch methods
 
     def initialize_request(self, request, *args, **kwargs):
@@ -322,11 +333,13 @@ class APIView(View):
         """
         parser_context = self.get_parser_context(request)
 
-        return Request(request,
-                       parsers=self.get_parsers(),
-                       authenticators=self.get_authenticators(),
-                       negotiator=self.get_content_negotiator(),
-                       parser_context=parser_context)
+        return Request(
+            request,
+            parsers=self.get_parsers(),
+            authenticators=self.get_authenticators(),
+            negotiator=self.get_content_negotiator(),
+            parser_context=parser_context
+        )
 
     def initial(self, request, *args, **kwargs):
         """
@@ -343,6 +356,10 @@ class APIView(View):
         neg = self.perform_content_negotiation(request)
         request.accepted_renderer, request.accepted_media_type = neg
 
+        # Determine the API version, if versioning is in use.
+        version, scheme = self.determine_version(request, *args, **kwargs)
+        request.version, request.versioning_scheme = version, scheme
+
     def finalize_response(self, request, response, *args, **kwargs):
         """
         Returns the final response object.
diff --git a/tests/test_versioning.py b/tests/test_versioning.py
new file mode 100644
index 00000000..d90b29a1
--- /dev/null
+++ b/tests/test_versioning.py
@@ -0,0 +1,104 @@
+from django.conf.urls import url
+from rest_framework import versioning
+from rest_framework.decorators import APIView
+from rest_framework.response import Response
+from rest_framework.reverse import reverse
+from rest_framework.test import APIRequestFactory, APITestCase
+
+
+class RequestVersionView(APIView):
+    def get(self, request, *args, **kwargs):
+        return Response({'version': request.version})
+
+class ReverseView(APIView):
+    def get(self, request, *args, **kwargs):
+        return Response({'url': reverse('another', request=request)})
+
+
+factory = APIRequestFactory()
+
+mock_view = lambda request: None
+
+urlpatterns = [
+    url(r'^another/$', mock_view, name='another')
+]
+
+
+class TestRequestVersion:
+    def test_unversioned(self):
+        view = RequestVersionView.as_view()
+
+        request = factory.get('/endpoint/')
+        response = view(request)
+        assert response.data == {'version': None}
+
+    def test_query_param_versioning(self):
+        scheme = versioning.QueryParameterVersioning
+        view = RequestVersionView.as_view(versioning_class=scheme)
+
+        request = factory.get('/endpoint/?version=1.2.3')
+        response = view(request)
+        assert response.data == {'version': '1.2.3'}
+
+        request = factory.get('/endpoint/')
+        response = view(request)
+        assert response.data == {'version': None}
+
+    def test_host_name_versioning(self):
+        scheme = versioning.HostNameVersioning
+        view = RequestVersionView.as_view(versioning_class=scheme)
+
+        request = factory.get('/endpoint/', HTTP_HOST='v1.example.org')
+        response = view(request)
+        assert response.data == {'version': 'v1'}
+
+        request = factory.get('/endpoint/')
+        response = view(request)
+        assert response.data == {'version': None}
+
+    def test_accept_header_versioning(self):
+        scheme = versioning.AcceptHeaderVersioning
+        view = RequestVersionView.as_view(versioning_class=scheme)
+
+        request = factory.get('/endpoint/', HTTP_ACCEPT='application/json; version=1.2.3')
+        response = view(request)
+        assert response.data == {'version': '1.2.3'}
+
+        request = factory.get('/endpoint/', HTTP_ACCEPT='application/json')
+        response = view(request)
+        assert response.data == {'version': None}
+
+    def test_url_path_versioning(self):
+        scheme = versioning.URLPathVersioning
+        view = RequestVersionView.as_view(versioning_class=scheme)
+
+        request = factory.get('/1.2.3/endpoint/')
+        response = view(request, version='1.2.3')
+        assert response.data == {'version': '1.2.3'}
+
+        request = factory.get('/endpoint/')
+        response = view(request)
+        assert response.data == {'version': None}
+
+
+class TestURLReversing(APITestCase):
+    urls = 'tests.test_versioning'
+
+    def test_reverse_unversioned(self):
+        view = ReverseView.as_view()
+
+        request = factory.get('/endpoint/')
+        response = view(request)
+        assert response.data == {'url': 'http://testserver/another/'}
+
+    def test_reverse_host_name_versioning(self):
+        scheme = versioning.HostNameVersioning
+        view = ReverseView.as_view(versioning_class=scheme)
+
+        request = factory.get('/endpoint/', HTTP_HOST='v1.example.org')
+        response = view(request)
+        assert response.data == {'url': 'http://v1.example.org/another/'}
+
+        request = factory.get('/endpoint/')
+        response = view(request)
+        assert response.data == {'url': 'http://testserver/another/'}