Add API endpoint to check if a user exists in database

Signed-off-by: Sachin S. Kamath <sskamath96@gmail.com>

hodor/controllers/user.py

@@ -10,7 +10,7 @@ from sqlalchemy.exc import IntegrityError
 def get_all_users():
     # TODO: Authentication for calling this API endpoint. Admin only.
     """
-    This function iterates the database to find all users and returns it as JSON.
+    This function iterates the database to find all users and returns as JSON
     :return: Response Code
     """
     response = dict()
@@ -20,8 +20,8 @@ def get_all_users():
     for user in User.get_all():
         current_user = dict()
         '''
-        This can be done by directly dumping the dictionary but there's always a risk of data leak.
-        So, we pick what we need to give out out of the API.
+        This can be done by directly dumping the dictionary but there's always
+        a risk of data leak.So, we pick what we need to give out out of the API
         '''
         current_user['username'] = user.username
         current_user['first_name'] = user.first_name
@@ -33,7 +33,8 @@ def get_all_users():
     return response
 
 
-@app.route('/users/new', methods=['GET', 'POST'])
+# Register a user
+@app.route('/users/new', methods=['POST'])
 def add_new_user():
     """
     This function adds a new user
@@ -48,21 +49,61 @@ def add_new_user():
             newuser['last_name'] = str(request.data.get('last_name').strip())
             newuser['email'] = str(request.data.get('email').strip())
             newuser['password'] = str(request.data.get('password').strip())
-            newuser['verification_code'] = str(request.data.get('verification_code').strip())
+            newuser['verification_code'] = str(request.data.get(
+                'verification_code').strip())
         except Exception as e:
             print(e)
             abort(500)
         user = User(**newuser)
         user.save()
-    return make_response(jsonify(status=201, msg="User {} successfully added to database".format(user.username)), 201)
+    return make_response(jsonify(status=201, msg="User {} successfully added" +
+                                 "to database".format(user.username)), 201)
+
+
+#################################################
+# Check for an existing user in the database    #
+#################################################
+@app.route('/users/check', methods=['POST'])
+def check_for_existing_user():
+    errors = []
+    # If the username field is passed, checl the username field.
+    if request.data.get('username'):
+        check_username = str(request.data.get('username').strip())
+        user_checkuser = User.query.filter_by(username=check_username).first()
+        if user_checkuser:
+            errors.append({
+                'field': 'username',
+                'error': '{} is taken'.format(check_username)
+            })
+        del(user_checkuser)
+
+    # If the email field is set, check for duplicate email
+    if request.data.get('email'):
+        check_email = str(request.data.get('email').strip())
+        user_checkmail = User.query.filter_by(email=check_email).first()
+        if user_checkmail:
+            errors.append({
+                'field': 'email',
+                'error': '{} exists in the database'.format(check_email)
+            })
+
+    if errors:
+        return make_response(jsonify(status=400, err=errors), 400)
+    else:
+        return jsonify(
+            status=200,
+            msg="ok"
+        )
 
 
 @app.errorhandler(IntegrityError)
 def handle_sqlalchemy_assertion_error(err):
     try:
         '''
-        err.orig.args is from the DBAPIError class of SQLAlchemy. It usually contains the original error message.
-        The below is an attempt to clean up the message and only return the relevant part to API
+        err.orig.args is from the DBAPIError class of SQLAlchemy. It usually
+        contains the original error message.
+        The below is an attempt to clean up the message and only return the
+        relevant part to API
         '''
         errmsg = err.orig.args[0].split('\n')[1][9:]
     except IndexError: