API: Useful functions

JSONResponse, JSONSuccess and JSONError are for building answers
accept_method is a decorator to check if the method to access the view
is accepted

api/utils.py

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+# Re2o est un logiciel d'administration développé initiallement au rezometz. Il
+# se veut agnostique au réseau considéré, de manière à être installable en
+# quelques clics.
+#
+# Copyright © 2018 Maël Kervella
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License along
+# with this program; if not, write to the Free Software Foundation, Inc.,
+# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
+"""api.utils.
+
+Set of various and usefull functions for the API app
+"""
+
+from rest_framework.renderers import JSONRenderer
+from django.http import HttpResponse
+
+class JSONResponse(HttpResponse):
+    """A JSON response that can be send as an HTTP response.
+    Usefull in case of REST API.
+    """
+
+    def __init__(self, data, **kwargs):
+        """Initialisz a JSONResponse object.
+
+        Args:
+            data: the data to render as JSON (often made of lists, dicts,
+            strings, boolean and numbers). See `JSONRenderer.render(data)` for
+            further details.
+
+        Creates:
+            An HTTPResponse containing the data in JSON format.
+        """
+
+        content = JSONRenderer().render(data)
+        kwargs['content_type'] = 'application/json'
+        super(JSONResponse, self).__init__(content, **kwargs)
+
+
+class JSONError(JSONResponse):
+    """A JSON response when the request failed.
+    """
+    
+    def __init__(self, error_msg, data=None, **kwargs):
+        """Initialise a JSONError object.
+        
+        Args:
+            error_msg: A message explaining where the error is.
+            data: An optional field for further data to send along.
+    
+        Creates:
+            A JSONResponse containing a field `status` set to `error` and a field
+            `reason` containing `error_msg`. If `data` argument has been given,
+            a field `data` containing it is added to the JSON response.
+        """
+    
+        response = {
+            'status' : 'error',
+            'reason' : error_msg
+        }
+        if data is not None:
+            response['data'] = data
+        super(JSONError, self).__init__(response, **kwargs)
+
+
+class JSONSuccess(JSONResponse):
+    """A JSON response when the request suceeded.
+    """
+    
+    def __init__(self, data=None, **kwargs):
+        """Initialise a JSONSucess object.
+        
+        Args:
+            error_msg: A message explaining where the error is.
+            data: An optional field for further data to send along.
+    
+        Creates:
+            A JSONResponse containing a field `status` set to `sucess`. If `data`
+            argument has been given, a field `data` containing it is added to the
+            JSON response.
+        """
+    
+        response = {
+            'status' : 'success',
+        }
+        if data is not None:
+            response['data'] = data
+        super(JSONSuccess, self).__init__(response, **kwargs)
+
+
+def accept_method(methods):
+    """Decorator to set a list of accepted request method.
+    Check if the method used is accepted. If not, send a NotAllowed response.
+    """
+    def decorator(view):
+        def wrapper(request, *args, **kwargs):
+            if request.method in methods:
+                return view(request, *args, **kwargs)
+            else:
+                return JSONError('Invalid request method. Request methods authorize are '+str(methods))
+            return view(request, *args, **kwargs)
+        return wrapper
+    return decorator