Add declarative JSON requests.

pos/rest.py

@@ -3,6 +3,24 @@ from aiohttp.web import json_response
 from pos.database import User, ProductCategory, AccessToken
 
 
+def needs(*needed):
+    def decorator(func):
+        @wraps(func)
+        async def wrapper(request):
+            request_json = await request.json()
+            if not all(k in request_json.keys() for k in needed) or
+                return json_response({
+                    'err': 'malformed_request',
+                    'msg': 'Missing one or more keys: {}.'.format(
+                        ", ".join(needed))
+                    }, status=400)
+            else:
+                return func(request)
+
+        return wrapper
+    return decorator
+
+
 def auth_required(func):
     @wraps(func)
     async def wrapper(request):
@@ -35,21 +53,20 @@ def auth_required(func):
     return wrapper
 
 
+@needs('username', 'password')
 async def token_create(request):
     db = request.app['db']
     request_json = await request.json()
 
-    if not all(k in request_json.keys() for k in ['username', 'password']):
-        return json_response({'err': 'malformed_request',
-                              'msg': 'Missing username and/or password keys.'},
-                             status=400)
+    username = request_json['username']
+    password = request_json['password']
 
     with db.get_session() as session:
         user = session.query(User)                  \
-                      .filter_by(username=request_json['username']) \
+                      .filter_by(username=username) \
                       .one_or_none()
 
-    if not user or user.password != request_json['password']:
+    if not user or user.password != password:
         return json_response({'err': 'invalid_credentials'},
                              status=400)