Fix yaml rendering

2 files changed, 58 insertions, 3 deletions

diff --git a/rest_framework/renderers.py b/rest_framework/renderers.py
index 91cf16bb..e5e4134b 100644
--- a/rest_framework/renderers.py
+++ b/rest_framework/renderers.py
@@ -18,7 +18,7 @@ from rest_framework.utils import encoders
 from rest_framework.utils.breadcrumbs import get_breadcrumbs
 from rest_framework.utils.mediatypes import get_media_type_params
 from rest_framework import VERSION
-from rest_framework import serializers
+from rest_framework import serializers, parsers
 
 
 class BaseRenderer(object):
@@ -125,6 +125,7 @@ class YAMLRenderer(BaseRenderer):
 
     media_type = 'application/yaml'
     format = 'yaml'
+    encoder = encoders.SafeDumper
 
     def render(self, data, accepted_media_type=None, renderer_context=None):
         """
@@ -133,7 +134,7 @@ class YAMLRenderer(BaseRenderer):
         if data is None:
             return ''
 
-        return yaml.safe_dump(data)
+        return yaml.dump(data, stream=None, Dumper=self.encoder)
 
 
 class HTMLRenderer(BaseRenderer):
@@ -240,7 +241,8 @@ class BrowsableAPIRenderer(BaseRenderer):
         if method == 'DELETE' or method == 'OPTIONS':
             return True  # Don't actually need to return a form
 
-        if not getattr(view, 'get_serializer', None):
+        if (not getattr(view, 'get_serializer', None) or
+            not parsers.FormParser in getattr(view, 'parser_classes')):
             media_types = [parser.media_type for parser in view.parser_classes]
             return self.get_generic_content_form(media_types)
 
diff --git a/rest_framework/utils/encoders.py b/rest_framework/utils/encoders.py
index 6655acbc..2d1fb353 100644
--- a/rest_framework/utils/encoders.py
+++ b/rest_framework/utils/encoders.py
@@ -3,8 +3,11 @@ Helper classes for parsers.
 """
 import datetime
 import decimal
+import types
 from django.utils import simplejson as json
+from django.utils.datastructures import SortedDict
 from rest_framework.compat import timezone
+from rest_framework.serializers import DictWithMetadata, SortedDictWithMetadata
 
 
 class JSONEncoder(json.JSONEncoder):
@@ -36,3 +39,53 @@ class JSONEncoder(json.JSONEncoder):
         elif hasattr(o, '__iter__'):
             return [i for i in o]
         return super(JSONEncoder, self).default(o)
+
+
+try:
+    import yaml
+except ImportError:
+    SafeDumper = None
+else:
+    # Adapted from http://pyyaml.org/attachment/ticket/161/use_ordered_dict.py
+    class SafeDumper(yaml.SafeDumper):
+        """
+        Handles decimals as strings.
+        Handles SortedDicts as usual dicts, but preserves field order, rather
+        than the usual behaviour of sorting the keys.
+        """
+        def represent_decimal(self, data):
+            return self.represent_scalar('tag:yaml.org,2002:str', str(data))
+
+        def represent_mapping(self, tag, mapping, flow_style=None):
+            value = []
+            node = yaml.MappingNode(tag, value, flow_style=flow_style)
+            if self.alias_key is not None:
+                self.represented_objects[self.alias_key] = node
+            best_style = True
+            if hasattr(mapping, 'items'):
+                mapping = list(mapping.items())
+                if not isinstance(mapping, SortedDict):
+                    mapping.sort()
+            for item_key, item_value in mapping:
+                node_key = self.represent_data(item_key)
+                node_value = self.represent_data(item_value)
+                if not (isinstance(node_key, yaml.ScalarNode) and not node_key.style):
+                    best_style = False
+                if not (isinstance(node_value, yaml.ScalarNode) and not node_value.style):
+                    best_style = False
+                value.append((node_key, node_value))
+            if flow_style is None:
+                if self.default_flow_style is not None:
+                    node.flow_style = self.default_flow_style
+                else:
+                    node.flow_style = best_style
+            return node
+
+    SafeDumper.add_representer(SortedDict,
+            yaml.representer.SafeRepresenter.represent_dict)
+    SafeDumper.add_representer(DictWithMetadata,
+            yaml.representer.SafeRepresenter.represent_dict)
+    SafeDumper.add_representer(SortedDictWithMetadata,
+            yaml.representer.SafeRepresenter.represent_dict)
+    SafeDumper.add_representer(types.GeneratorType,
+            yaml.representer.SafeRepresenter.represent_list)