Flask：装饰器测试查询字符串 arguments

Question

I begin with Flask and try to create the best code possible. For some simple route, I would like to check if some required arguments are present. At this time, I create this decorator

def validate_qs_arguments(arguments):
    def decorator(fn):
        def wrapped_function(*args, **kwargs):
            for argument_name in arguments:
                if request.args.get(argument_name) is None:
                    abort(400, "'{name}' argument is missing".format(name=argument_name))
            return fn(*args, **kwargs)
        return update_wrapper(wrapped_function, fn)
    return decorator

I can use it like this:

@validate_qs_arguments(arguments=["pid", "datastream"])

It works fine. But I'm trouble than Flask doesn't provide a build-in function/decorator to do the same thing. Is it exists a better to do that? A build-in flask decorator/function?

Thanks for your help.

Answer 1

Flask doesn't provide a build-in... Flask is a micro-framework that was built around a plug-in approach. If you want more out of it, use extensions (Flask-restful is one of it as it was said in comments), or python marshmallow , or other lib, or write your own implementation.

Answer 2

Decorator func:

def check_form_key(key_list:list):
    def real_decorator(func):
        @wraps(func)
        def wrapper(*args, **kwargs):
            if request.form is None:
                return Result(False, Error("FR"))
            not_exist_key = []
            for key in key_list:
                if key in request.form:
                    continue
                else:
                    not_exist_key.append(key)

            if len(not_exist_key) > 0:
                return Result(False,"this keys not exist {0}".format(not_exist_key))
            return func(*args, **kwargs)
        return wrapper
    return real_decorator

Usage:

@check_form_key([“name”,”code”])
def check():
   pass

Answer 3

def login_required(f):
    @wraps(f)
    def decorated_function(*args, **kwargs):
        if "log" in session:
             return f(*args, **kwargs)
        else:
             return redirect(url_for("login"))
    return decorated_function