Add support for 'Optional' Data Type

Author: Ge0rg3

README.md

@@ -11,20 +11,21 @@
 ## Simple Usage
 ```py
 from flask import Flask
-from typing import List
+from typing import List, Optional
 from flask_parameter_validation import ValidateParameters, Route, Json
 
 app = Flask(__name__)
 
+
 @app.route("/update/<int:id>", methods=["POST"])
 @ValidateParameters()
 def hello(
         id: int = Route(),
         username: str = Json(min_length=5, blacklist="<>"),
         age: int = Json(min_int=18, max_int=99),
         nicknames: List[str] = Json(),
-        password_expiry: int = Json(5)
-    ):
+        password_expiry: Optional[int] = Json(5)
+     ):
     return "Hello World!"
 
 if __name__ == "__main__":

flask_parameter_validation/parameter_validation.py

@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 import typing
 from inspect import signature
@@ -39,6 +39,7 @@ def nested_func(**kwargs):
                 param_type = arg.default  # ie. Route(), Json()
                 param_name = arg.name  # ie. id, username
                 param_annotation = arg.annotation or typing.Any  # ie. str, int
+                is_list_or_union = hasattr(param_annotation, "__args__")
                 # Ensure param type is valid
                 if param_type.__class__ not in request_inputs.keys():
                     return self.error_function("Invalid parameter type.")
@@ -55,9 +56,15 @@ def nested_func(**kwargs):
                 # If no default and no input, error
                 elif user_input is None:
                     ptype = param_type.name
-                    return self.error_function(
+                    error_response = self.error_function(
                         f"Required {ptype} parameter '{param_name}' not given."
                     )
+                    # If "None" is allowed in Union, then continue
+                    if is_list_or_union:
+                        if type(None) not in param_annotation.__args__:
+                            return error_response
+                    else:
+                        return error_response
 
                 # If typing's Any, ClassVar or Optional, don't validate type
                 if isinstance(param_annotation, typing._SpecialForm):
@@ -68,7 +75,7 @@ def nested_func(**kwargs):
                 else:
                     allowed_types = []
                     # If List or Union, get all "inner" types
-                    if hasattr(param_annotation, "__args__"):
+                    if is_list_or_union:
                         allowed_types = param_annotation.__args__
                     else:
                         allowed_types = (param_annotation,)
@@ -82,6 +89,9 @@ def nested_func(**kwargs):
                         valid = all(
                             isinstance(i, allowed_types) for i in user_input
                         )
+                    elif type(user_input) != list and annotation_is_list:
+                        allowed_types = [list]
+                        valid = False
                     else:
                         # If not list, just validate singular data type
                         valid = isinstance(user_input, allowed_types)
@@ -96,9 +106,17 @@ def nested_func(**kwargs):
                             f"Parameter '{param_name}' {e}"
                         )
                 else:
+                    if type(None) in allowed_types:
+                        allowed_types = list(allowed_types)
+                        allowed_types.remove(type(None))
+                        startphrase = "Optional parameter"
+                    else:
+                        startphrase = "Parameter"
                     types = "/".join(t.__name__ for t in allowed_types)
+                    if annotation_is_list:
+                        types = "List[" + types + "]"
                     return decorator_self.error_function(
-                        f"Parameter '{param_name}' should be type {types}."
+                        f"{startphrase} '{param_name}' should be type {types}."
                     )
 
             return f(**parsed_inputs)

setup.py

@@ -11,7 +11,7 @@
 
 setup(
     name='Flask-Parameter-Validation',
-    version='1.0.16',
+    version='1.0.17',
     url='https://github.com/Ge0rg3/Flask-Parameter-Validation',
     license='MIT',
     author='George Omnet',