drf_msgpack: add code to parse/serialise msgpack

It's not actually used by clients but it's there and can be used. It
works for receiving msgpack messages, but doesn't yet work for sending
because some of the types will be converted to base64.

django_etebase/drf_msgpack/apps.py

@@ -0,0 +1,5 @@
+from django.apps import AppConfig
+
+
+class DrfMsgpackConfig(AppConfig):
+    name = 'drf_msgpack'

django_etebase/drf_msgpack/parsers.py

@@ -0,0 +1,14 @@
+import msgpack
+
+from rest_framework.parsers import BaseParser
+from rest_framework.exceptions import ParseError
+
+
+class MessagePackParser(BaseParser):
+    media_type = 'application/msgpack'
+
+    def parse(self, stream, media_type=None, parser_context=None):
+        try:
+            return msgpack.unpackb(stream.read(), raw=False)
+        except Exception as exc:
+            raise ParseError('MessagePack parse error - %s' % str(exc))

django_etebase/drf_msgpack/renderers.py

@@ -0,0 +1,15 @@
+import msgpack
+
+from rest_framework.renderers import BaseRenderer
+
+
+class MessagePackRenderer(BaseRenderer):
+    media_type = 'application/msgpack'
+    format = 'msgpack'
+    render_style = 'binary'
+    charset = None
+
+    def render(self, data, media_type=None, renderer_context=None):
+        if data is None:
+            return b''
+        return msgpack.packb(data, use_bin_type=True)

django_etebase/drf_msgpack/views.py

@@ -0,0 +1,3 @@
+from django.shortcuts import render
+
+# Create your views here.