add basic validation support

api/core.py

@@ -2,6 +2,7 @@ from flask import Flask, jsonify, Response, request
 from flask_sqlalchemy import SQLAlchemy
 from api.extensions.esales import Esales
 from api.helpers import check_api_key
+from api.validators import ValidationError
 
 db = SQLAlchemy()
 esales = Esales()
@@ -15,8 +16,16 @@ def create_app(config_name='config'):
 
     # register errors handlers
     @app.errorhandler(404)
-    def on_404(e):
-        return jsonify(dict(error='Not found')), 404
+    def on_404(error):
+        response = jsonify({'status': 404, 'message': 'The requested resource was not found'})
+        response.status_code = 404
+        return response
+
+    @app.errorhandler(ValidationError)
+    def on_validation_error(error):
+        response = jsonify({'status': 400, 'message': error.message})
+        response.status_code = 400
+        return response
 
     # register blueprints
     from api.views import server, designers, categories

api/validators.py

@@ -0,0 +1,14 @@
+# coding=UTF-8
+
+class ValidationError(Exception):
+
+    def __init__(self, message):
+        Exception.__init__(self)
+        self.message = message
+
+
+def validate_keys_exists(obj, *keys):
+    for key in keys:
+        if not key in obj:
+            raise ValidationError('No {} is specified'.format(key))
+    return True

api/views/designers.py

@@ -1,6 +1,8 @@
 from flask import Blueprint, request, jsonify
 from api import db, tasks
 from api.models import Designer
+from api.validators import validate_keys_exists
+
 
 mod = Blueprint('designers', __name__, url_prefix='/designers')
 
@@ -14,6 +16,7 @@ def list():
 @mod.route("/", methods=["POST"])
 def create():
     data = request.json
+    validate_keys_exists(data, 'username', 'name')
     designer = Designer(**data)
     db.session.add(designer)
     db.session.commit()