有人能帮我解决关于我在python中发布API请求的错误吗

Question

所以我有代码显示某些汽车的信息。首先，我创建了一个关于某些类型汽车的列表，如品牌、型号、年份等。我成功地创建了代码，可以使用URL向我显示所有数据或特定类型的数据。这是我的代码：

import datetime
import time
from flask import Flask, request, jsonify, make_response, abort
import mysql.connector
from mysql.connector import Error
import myfunctions

# setting up an application name
app = Flask(__name__) #set up application
app.config["DEBUG"] = True #allow to show error message in browser
cars = [
{'id': 0,
'make': 'Jeep',
'model': 'Grand Cherokee',
'year': '2000',
'color': 'black'},
{'id': 1,
'make': 'Ford',
'model': 'Mustang',
'year': '1970',
'color': 'white'},
{'id': 2,
'make': 'Dodge',
'model': 'Challenger',
'year': '2020',
'color': 'red'}
]

@app.route('/', methods=['GET'])  #routing = mapping urls to functions; home is usually mapped to '/'
def home():
return "<h1>Hi and welcome to our first API!</h1>"
# A route to return all of the cars
@app.route('/api/cars/all', methods=['GET'])
def api_all():
return jsonify(cars)
# A route to return a specific car by id e.g. http://127.0.0.1:5000/api/cars?id=1
@app.route('/api/cars', methods=['GET'])
def api_id():
if 'id' in request.args: #check for id as part of the url, use it if it's there, throw error if it isn't
id = int(request.args['id'])
else:
return "Error: No id provided."
results = [] #the resulting car(s) we want to return
for car in cars: #find the car(s) we're looking for by id
if car['id'] == id:
results.append(car)
return jsonify(results)

我的输出是：

[ { "color": "black", "id": 0, "make": "Jeep", "model": "Grand Cherokee", "year": "2000" },
{ "color": "white", "id": 1, "make": "Ford", "model": "Mustang", "year": "1970" }, 
{ "color": "red", "id": 2, "make": "Dodge", "model": "Challenger", "year": "2020" } ]

在浏览器上。

现在我想使用post方法添加关于汽车的新信息，所以这里是我的代码：

# Example to use POST as your method type, sending parameters as payload from POSTMAN (raw, JSON)
@app.route('/post-example', methods=['POST'])
def post_example():
request_data = request.get_json()
newid = request_data['id']
newmake = request_data['make']
newmodel = request_data['model']
newyear = request_data['year']
newcolor = request_data['color']
cars.append({'id': newid, 'make': newmake, 'model': newmodel, 'year': newyear, 'color': newcolor}) #adding a new car to my car collection on the server.
#IF I go check the /api/cars/all route in the browser now, I should see this car added to the returned JSON list of cars
return 'POST REQUEST WORKED'

但当我运行它时，它会弹出：

File "C:UsersUserAppDataLocalProgramsPythonPython39Libsite-packagesflaskapp.py", line 2464, in __call__
return self.wsgi_app(environ, start_response)
File "C:UsersUserAppDataLocalProgramsPythonPython39Libsite-packagesflaskapp.py", line 2450, in wsgi_app
response = self.handle_exception(e)
File "C:UsersUserAppDataLocalProgramsPythonPython39Libsite-packagesflaskapp.py", line 1867, in handle_exception
reraise(exc_type, exc_value, tb)
File "C:UsersUserAppDataLocalProgramsPythonPython39Libsite-packagesflask_compat.py", line 39, in reraise
raise value
File "C:UsersUserAppDataLocalProgramsPythonPython39Libsite-packagesflaskapp.py", line 2447, in wsgi_app
response = self.full_dispatch_request()
File "C:UsersUserAppDataLocalProgramsPythonPython39Libsite-packagesflaskapp.py", line 1952, in full_dispatch_request
rv = self.handle_user_exception(e)
File "C:UsersUserAppDataLocalProgramsPythonPython39Libsite-packagesflaskapp.py", line 1821, in handle_user_exception
reraise(exc_type, exc_value, tb)
File "C:UsersUserAppDataLocalProgramsPythonPython39Libsite-packagesflask_compat.py", line 39, in reraise
raise value
File "C:UsersUserAppDataLocalProgramsPythonPython39Libsite-packagesflaskapp.py", line 1950, in full_dispatch_request
rv = self.dispatch_request()
File "C:UsersUserAppDataLocalProgramsPythonPython39Libsite-packagesflaskapp.py", line 1936, in dispatch_request
return self.view_functions[rule.endpoint](**req.view_args)
File "D:PYTHONAPIdata_api3.py", line 81, in post_example
newid = request_data['id']
TypeError: 'NoneType' object is not subscriptable
127.0.0.1 - - [06/Apr/2021 17:25:47] "GET /api/cars/all HTTP/1.1" 200 -

有人能帮我找出错误吗？

Answer 1

返回JSON数据字典的是request.json。要获得值，请使用request.json.get('key_name')。

@app.route('/post-example', methods=['POST'])
def post_example():
newid = request.json.get('id')
newmake = request.json.get('make')
newmodel = request.json.get('model')
newyear = request.json.get('year')
newcolor = request.json.get('color')
cars.append({'id': newid, 'make': newmake, 'model': newmodel, 'year': newyear, 'color': newcolor}) #adding a new car to my car collection on the server.
#IF I go check the /api/cars/all route in the browser now, I should see this car added to the returned JSON list of cars
return 'POST REQUEST WORKED'

Answer 2

而不是使用

newid = request_data['id']

你应该使用

newid = request_data.get('id')

您应该将这些更改应用于所有字典键。

@app.route('/post-example', methods=['POST'])
def post_example():
request_data = request.get_json()
newid = request_data.get('id')
newmake = request_data.get('make')
newmodel = request_data.get('model')
newyear = request_data.get('year')
newcolor = request_data.get('color')
cars.append({
'id': newid, 
'make': newmake, 
'model': newmodel,
'year': newyear, 
'color': newcolor
})

return 'POST REQUEST WORKED'

较短版本：

@app.route('/post-example', methods=['POST'])
def post_example():
request_data = request.get_json()
cars.append(request_data)

return 'POST REQUEST WORKED'