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
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 string action: The basic type of action to be taken when this argument
is encountered in the request. Valid options are "store" and "append".
:param bool 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/1.0 400 BAD REQUEST
Content-Type: application/json
Content-Length: 152
Server: Werkzeug/2.0.1 Python/3.8.5
Date: Sun, 04 Sep 2022 12:26:41 GMT
{
"errors": {
"sex": "sex invalid The value 'x' is not a valid choice for 'sex'."
},
"message": "Input payload validation failed"
}
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/1.0 400 BAD REQUEST
Content-Type: application/json
Content-Length: 176
Server: Werkzeug/2.0.1 Python/3.8.5
Date: Sun, 04 Sep 2022 12:32:25 GMT
{
"errors": {
"password": "password invalid must 6-16 password参数长度不合法"
},
"message": "Input payload validation failed"
}
错误信息error_msg
每个字段的错误消息可以使用help参数 to Argument（以及RequestParser.add_argument）进行自定义。
如果未提供help 参数，则该字段的错误消息将是类型错误本身的字符串表示形式。如果help提供，则错误消息将是 的值help。
help可能包含一个插值标记 ，{error_msg}它将被替换为类型错误的字符串表示形式。这允许在保留原始错误的同时自定义消息：
from flask_restx import reqparse
parser = reqparse.RequestParser()
parser.add_argument(
'foo',
choices=('one', 'two'),
help='Bad choice: {error_msg}'
)
# If a request comes in with a value of "three" for `foo`:
{
"message": {
"foo": "Bad choice: three is not a valid choice",
}
}
bundle_errors 错误处理
RequestParser 处理错误的默认方式是在发生第一个错误时中止。当您有可能需要一些时间来处理的论点时，这可能会很有用。
但是，通常最好将错误捆绑在一起并一次性发送回客户端。可以在 Flask 应用程序级别或特定的 RequestParser 实例上指定此行为。
要使用捆绑错误选项调用 RequestParser，请传入参数bundle_errors。例如
from flask_restx import reqparse
parser = reqparse.RequestParser(bundle_errors=True)
parser.add_argument('foo', type=int, required=True)
parser.add_argument('bar', type=int, required=True)
# If a request comes in not containing both 'foo' and 'bar', the error that
# will come back will look something like this.
{
"message": {
"foo": "foo error message",
"bar": "bar error message"
}
}
# The default behavior would only return the first error
parser = RequestParser()
parser.add_argument('foo', type=int, required=True)
parser.add_argument('bar', type=int, required=True)
{
"message": {
"foo": "foo error message"
}
}
BUNDLE_ERRORS 可以作为全局配置参数，例如
from flask import Flask
app = Flask(__name__)
app.config['BUNDLE_ERRORS'] = True
警告:
BUNDLE_ERRORS是覆盖bundle_errors 单个RequestParser实例中的选项的全局设置。