Python Flask-Restful POST 不接受 JSON 参数

Python Flask-Restful POST not taking JSON arguments

提问by sudhishkr

I am very new to Flask (& Flask-Restful).

我对 Flask（和 Flask-Restful）很陌生。

My problem : jsonarguments for a POSTis getting set to NONE(not working).

我的问题： a 的json参数POST设置为NONE（不工作）。

I am able to take arguments from the form-data, using POSTMANplugin for chrome. But, when i switch to raw(& feed a json), it fails to read the json & assigns a NONEto all my arguments.

我可以form-data使用POSTMANchrome 插件从, 中获取参数。但是，当我切换到raw(& feed a json) 时，它无法读取 json 并将 a 分配NONE给我的所有参数。

I have read some related stackoverflow posts related to this : link1, link2, link3... none of these helped me.

我已经阅读了一些与此相关的 stackoverflow 帖子：link1、link2、link3……这些都没有帮助我。

I am using python-2.6, Flask-Restful-0.3.3, Flask-0.10.1, Chrome, POSTMANon Oracle Linux 6.5.

我使用python-2.6，Flask-Restful-0.3.3，Flask-0.10.1，Chrome，POSTMAN在Oracle的Linux 6.5。

Python codeapp.py:

蟒蛇代码app.py：

from flask import Flask, jsonify
from flask_restful import reqparse, abort, Api, Resource

app = Flask(__name__)
api = Api(app)

parser = reqparse.RequestParser()
parser.add_argument('username', type=str)
parser.add_argument('password', type=str)

class HelloWorld(Resource):
    def post(self):
        args = parser.parse_args()
        un = str(args['username'])
        pw = str(args['password'])
        return jsonify(u=un, p=pw)

api.add_resource(HelloWorld, '/testing')

if __name__ == '__main__':
    app.run(host='0.0.0.0', port=5444 ,debug=True)

Testing thisusing POSTMAN:

使用POSTMAN以下方法测试：

• Using form-data: works perfectly !
• Using raw-> json: causes this issue

• 使用form-data：完美运行！
• 使用raw-> json：导致此问题

Things tried #1:

尝试过的事情#1：

Add jsonparameter to my add_argument()method in app.py

将json参数添加到我的add_argument()方法中app.py

parser = reqparse.RequestParser()
parser.add_argument('username', type=str, location='json') # added json
parser.add_argument('password', type=str, location='json') # added json

Input: { "username": "hello", "password": "world" }

Input：{“用户名”：“你好”，“密码”：“世界”}

Output: { "p": "None", "u": "None" }

Output：{“p”：“无”，“u”：“无”}

Things tried #2:

尝试过的事情#2：

Change type to unicodein add_argument()method in app.py

将类型更改为unicodeinadd_argument()方法app.py

parser = reqparse.RequestParser()
parser.add_argument('username', type=unicode, location='json') # change type to unicode
parser.add_argument('password', type=unicode, location='json') # change type to unicode

Input: { "username": "hello", "password": "world" }

Input：{“用户名”：“你好”，“密码”：“世界”}

Output: { "p": "None", "u": "None" }

Output：{“p”：“无”，“u”：“无”}

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PS :I will keep updating my question, with every failed attempt. Please let me know if you need any more info to make this question more clear.

PS：每次尝试失败时，我都会不断更新我的问题。如果您需要更多信息以使这个问题更清楚，请告诉我。

采纳答案by junnytony

According to the documentation for Request.jsonand the new Request.get_json, you should have the mimetype on your POST request set to application/json. This is the only way flask will automatically parse your JSON data into the Request.jsonproperty which (I believe) is what Flask-Restful depends on to retrieve JSON data.

根据Request.json和新的Request.get_json的文档，您应该将 POST 请求中的 mimetype 设置为application/json。这是flask 将您的JSON 数据自动解析为Request.json属性的唯一方法（我相信）这是Flask-Restful 检索JSON 数据所依赖的属性。

NOTE: The newer get_jsonfunction has an option to force the parsing of POST data as JSON irrespective of the mimetype

注意：较新的get_json函数有一个选项可以强制将 POST 数据解析为 JSON，而不管 mimetype

回答by sudhishkr

junnytony's answer gave me a hint, and I went ahead with this approach. get_jsonseems to have done the trick.

junnytony 的回答给了我一个提示，我继续采用这种方法。get_json似乎已经成功了。

from flask import Flask, jsonify, request
from flask_restful import reqparse, abort, Api, Resource

app = Flask(__name__)
api = Api(app)

#parser = reqparse.RequestParser()
#parser.add_argument('username', type=unicode, location='json')
#parser.add_argument('password', type=unicode, location='json')

class HelloWorld(Resource):
    def post(self):
        json_data = request.get_json(force=True)
        un = json_data['username']
        pw = json_data['password']
        #args = parser.parse_args()
        #un = str(args['username'])
        #pw = str(args['password'])
        return jsonify(u=un, p=pw)

api.add_resource(HelloWorld, '/testing')

if __name__ == '__main__':
    app.run(host='0.0.0.0', port=5444 ,debug=True)

回答by Cleb

I ran into a similar issue and here is a solution that works for me. let's say your application looks like this:

我遇到了类似的问题，这里有一个对我有用的解决方案。假设您的应用程序如下所示：

from flask import Flask, jsonify
from flask_restful import Api, Resource, reqparse

app = Flask(__name__)
api = Api(app)

# Define parser and request args
parser = reqparse.RequestParser()
parser.add_argument('last_name', type=str)
parser.add_argument('first_name', type=str)
# not the type=dict
parser.add_argument('personal_data', type=dict)


class Item(Resource):

    def post(self):

        args = parser.parse_args()

        ln = args['last_name']
        fn = args['first_name']
        # we can also easily parse nested structures
        age = args['personal_data']['age']
        nn = args['personal_data']['nicknames']

        return jsonify(fn=fn, ln=ln, age=age, nn=nn)


api.add_resource(Item, '/item')

if __name__ == '__main__':
    app.run(debug=True)

Now, you can easily create some JSON data:

现在，您可以轻松创建一些 JSON 数据：

import json

d = {'last_name': 'smith', 'first_name': 'john', 'personal_data': {'age': 18, 'height': 180, 'nicknames': ['johnny', 'grandmaster']}}

print(json.dumps(d, indent=4))

{
    "last_name": "smith",
    "first_name": "john",
    "personal_data": {
        "age": 18,
        "height": 180,
        "nicknames": [
            "johnny",
            "grandmaster"
        ]
    }
}

json.dumps(d)
'{"last_name": "smith", "first_name": "john", "personal_data": {"age": 18, "height": 180, "nicknames": ["johnny", "grandmaster"]}}'

and call the application:

并调用应用程序：

curl http://localhost:5000/item -d '{"last_name": "smith", "first_name": "john", "personal_data": {"age": 18, "height": 180, "nicknames": ["johnny", "grandmaster"]}}'

This will crash with the error (I shortened the traceback):

这将因错误而崩溃（我缩短了回溯）：

age = args['personal_data']['age']
TypeError: 'NoneType' object is not subscriptable

age = args['personal_data']['age']
TypeError: 'NoneType' 对象不可下标

the reason is that the header is not specified. If we add the

原因是未指定标题。如果我们添加

-H "Content-Type: application/json"

and then call

然后打电话

curl http://localhost:5000/item -H "Content-Type: application/json" -d '{"last_name": "smith", "first_name": "john", "personal_data": {"age": 18, "height": 180, "nicknames": ["johnny", "grandmaster"]}}'

The output looks as expected:

输出看起来如预期：

{
  "age": 18, 
  "fn": "john", 
  "ln": "smith", 
  "nn": [
    "johnny", 
    "grandmaster"
  ]
}

The function can be also further simplified to:

该函数还可以进一步简化为：

class Item(Resource):

    def post(self):

        json_data = request.get_json()
        # create your response below

as shown above.

如上图所示。

回答by moutaz samir

After forcing the request to parse json, it worked with me. Here is the code:

强制请求解析 json 后，它与我一起工作。这是代码：

from flask import Flask, jsonify, request
from flask_restful import reqparse, abort, Api, Resource

app = Flask(__name__)
api = Api(app)

parser = reqparse.RequestParser()
parser.add_argument('username', type=str)
parser.add_argument('password', type=str)

class HelloWorld(Resource):
    def post(self):
        request.get_json(force=True)
        args = parser.parse_args()
        un = str(args['username'])
        pw = str(args['password'])
        return jsonify(u=un, p=pw)

api.add_resource(HelloWorld, '/testing')

if __name__ == '__main__':
    app.run(host='0.0.0.0', port=5444 ,debug=True)