Flask 学习-34.Flask-RESTful 请求参数自定义参数校验类型 (reqparse.RequestParser() )
前言
在校验请求参数的时候，除了一些基本的required=True， type类型外，还会遇到一些校验，比如是否为空，字符串长度，以及一些自定义的参数规则。
add_argument 参数
下面是add_argument 可以使用的参数，部分源码如下：
class Argument(object):
"""
:param name: Either a name or a list of option strings, e.g. foo or
-f, --foo.
:param default: The value produced if the argument is absent from the
request.
:param dest: The name of the attribute to be added to the object
returned by :meth:`~reqparse.RequestParser.parse_args()`.
:param bool required: Whether or not the argument may be omitted (optionals
only).
:param action: The basic type of action to be taken when this argument
is encountered in the request. Valid options are "store" and "append".
:param ignore: Whether to ignore cases where the argument fails type
conversion
:param type: The type to which the request argument should be
converted. If a type raises an exception, the message in the
error will be returned in the response. Defaults to :class:`unicode`
in python2 and :class:`str` in python3.
:param location: The attributes of the :class:`flask.Request` object
to source the arguments from (ex: headers, args, etc.), can be an
iterator. The last item listed takes precedence in the result set.
:param choices: A container of the allowable values for the argument.
:param help: A brief description of the argument, returned in the
response when the argument is invalid. May optionally contain
an "{error_msg}" interpolation token, which will be replaced with
the text of the error raised by the type converter.
:param bool case_sensitive: Whether argument values in the request are
case sensitive or not (this will convert all values to lowercase)
:param bool store_missing: Whether the arguments default value should
be stored if the argument is missing from the request.
:param bool trim: If enabled, trims whitespace around the argument.
:param bool nullable: If enabled, allows null value in argument.
"""
def __init__(self, name, default=None, dest=None, required=False,
ignore=False, type=text_type, location=('json', 'values',),
choices=(), action='store', help=None, operators=('=',),
case_sensitive=True, store_missing=True, trim=False,
nullable=True):
self.name = name
self.default = default
self.dest = dest
self.required = required
self.ignore = ignore
self.location = location
self.type = type
self.choices = choices
self.action = action
self.help = help
self.case_sensitive = case_sensitive
self.operators = operators
self.store_missing = store_missing
self.trim = trim
self.nullable = nullable
nullable=False 不允许为None
required=True 设置该参数是必传项， nullable=False 是设置该参数不允许为None
class Register(Resource):
def post(self):
# 校验入参
parser = reqparse.RequestParser()
parser.add_argument('username', required=True, type=str, nullable=False, help='username is required')
parser.add_argument('password', required=True, type=str, nullable=False, help='password is required')
args = parser.parse_args()
# # 获取入参
# data = request.get_json()
print(f'请求入参：{args}')
return jsonify({
"code": 0,
"msg": "success"
})
# 注册
api.add_resource(Register, '/api/v1/register')
需注意的是这里是不能为null, 传空字符串还是可以的。
default=''设置默认值
对address 参数设置默认值，当用户没传address 参数的时候，就会取默认值
def post(self):
# 校验入参
parser = reqparse.RequestParser()
parser.add_argument('username', required=True, type=str, nullable=False, help='username is required')
parser.add_argument('password', required=True, type=str, nullable=False, help='password is required')
parser.add_argument('address', default='上海市', type=str, help='address invalid')
args = parser.parse_args()
print(f'请求入参：{args}')
请求示例
POST http://127.0.0.1:5000/api/v1/register HTTP/1.1
User-Agent: Fiddler
Host: 127.0.0.1:5000
Content-Type: application/json
Content-Length: 56
{
"username": "test",
"password" : "111111"
}
args 得到的参数
{'username': 'test', 'password': '111111', 'address': '上海市'}
choices 设置参数可选值
比如性别设置可选项：男、女
def post(self):
# 校验入参
parser = reqparse.RequestParser()
parser.add_argument('username', required=True, type=str, nullable=False, help='username is required')
parser.add_argument('password', required=True, type=str, nullable=False, help='password is required')
parser.add_argument('sex', choices=["男", "女"], type=str, help='sex invalid')
args = parser.parse_args()
print(f'请求入参：{args}')
请求示例，sex不是可选项的时候会报400
POST http://127.0.0.1:5000/api/v1/register HTTP/1.1
User-Agent: Fiddler
Host: 127.0.0.1:5000
Content-Type: application/json
Content-Length: 73
{
"username": "test",
"password" : "111111",
"sex": "x"
}
HTTP/1.1 400 BAD REQUEST
Server: Werkzeug/2.2.2 Python/3.8.5
Date: Thu, 01 Sep 2022 13:40:14 GMT
Content-Type: application/json
Content-Length: 57
Connection: close
{
"message": {
"sex": "sex invalid"
}
}
设置字符串长度
比如限制 password 是 6-16 位，由于 add_argument 没提供对应的方法，需我们自定义参数校验类型
class Register(Resource):
@staticmethod
def password_validate(value, name):
if len(value) < 6 or len(value) > 16:
raise ValueError(name + '参数长度不合法')
return value
def post(self):
# 校验入参
parser = reqparse.RequestParser()
parser.add_argument('username', required=True, type=str, nullable=False, help='username invalid')
parser.add_argument('password', required=True, type=self.password_validate,
nullable=False, help='password invalid must 6-16')
# parser.add_argument('sex', choices=["男", "女"], type=str, help='sex invalid')
args = parser.parse_args()
print(f'请求入参：{args}')
如果密码长度小于6位，会返回400
POST http://127.0.0.1:5000/api/v1/register HTTP/1.1
User-Agent: Fiddler
Host: 127.0.0.1:5000
Content-Type: application/json
Content-Length: 55
{
"username": "test",
"password" : "12345"
}
HTTP/1.1 400 BAD REQUEST
Server: Werkzeug/2.2.2 Python/3.8.5
Date: Thu, 01 Sep 2022 14:04:30 GMT
Content-Type: application/json
Content-Length: 76
Connection: close
{
"message": {
"password": "password invalid must 6-16"
}
}
