是否有 shorter/better 方法来验证请求参数？

Question

我一直重复这样的块来验证请求参数。有没有 shorter/better 方法来实现这个？

count = request.args.get('count', DEFAULT_COUNT)
if count:
    try:
        count = int(count)
    except ValueError:
        count = DEFAULT_COUNT

Answer 1

是的。 args attribute of a Flask/Werkzeug Request object is an ImmutableMultiDict, which is a subclass of MultiDict. The MultiDict.get() 方法接受一个 type 参数，它完全符合您的要求：

count = request.args.get('count', DEFAULT_COUNT, type=int)

这是文档的相关部分：

get(key, default=None, type=None)

Return the default value if the requested data doesn’t exist. If type is provided and is a callable it should convert the value, return it or raise a ValueError if that is not possible. In this case the function will return the default as if the value was not found:
>>> d = TypeConversionDict(foo='42', bar='blub')
>>> d.get('foo', type=int)
42
>>> d.get('bar', -1, type=int)
-1

是否有 shorter/better 方法来验证请求参数？

Is there a shorter/better way to validate request params?

python

validation

python-2.7

flask

werkzeug