FLASK REST API在POST上返回400

我正在使用flask和SQLAlchemy作为我的ORM为一个简单的Todo应用程序构建REST API。我正在使用Postman测试我的API。我在Windows 10 64位计算机上。

GET请求有效并返回使用python输入到数据库中的数据。

我想立即尝试添加任务。但是，当我发布请求时，我收到一个错误。

我在烧瓶中的路线看起来像这样。

#add task
@app.route('/todo/api/v1.0/tasks', methods=['POST'])
def create_task():
    if not request.json or not 'title' in request.json:
        raise InvalidUsage('Not a valid task!', status_code=400)
    task = {
        'title': request.json['title'],
        'description': request.json['description'],
        'done': False
    }
    Todo.add_todo(task)
    return jsonify({'task': task}), 201

它在Todo对象上调用的方法如下所示。

def add_todo(_title, _description):
    new_todo = Todo(title=_title, description=_description , completed = 0)
    db.session.add(new_todo)
    db.session.commit()

我尝试过的

我以为'邮递员Params中的可能引起了问题，因此我将其删除。但是我仍然遇到同样的错误。

Then I thought that maybe the way that Postman was sending the POST was incorrect so I checked to make sure that the Content-Type headers was correct. It is set to application/json

Finally, to confirm that the issue was that flask didn't like the request, I removed the check in the add task route to make sure the request had a title. So it looks like this.

if not request.json:

And I get the same error. So I think that the problem must be with how I'm actually sending the POST rather than some kind of formatting issue.

My entire code looks like this.

from flask import Flask
from flask_sqlalchemy import SQLAlchemy
import json
from flask import jsonify
from flask import request

app = Flask(__name__)
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///todo.db'
app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False
db = SQLAlchemy(app)

class Todo(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    title = db.Column(db.String(300), unique=False, nullable=False)
    description = db.Column(db.String(), unique=False, nullable=False)
    completed = db.Column(db.Boolean, nullable=False)

    def json(self):
        return {'id': self.id,'title': self.title, 'description': self.description, 'completed': self.completed}

    def add_todo(_title, _description):
        new_todo = Todo(title=_title, description=_description , completed = 0)
        db.session.add(new_todo)
        db.session.commit()

    def get_all_tasks():
        return [Todo.json(todo) for todo in Todo.query.all()]

    def get_task(_id):
        task = Todo.query.filter_by(id=_id).first()
        if task is not None:
            return Todo.json(task)
        else:
            raise InvalidUsage('No task found', status_code=400)

    def __repr__(self):
        return f"Todo('{self.title}')"




class InvalidUsage(Exception):
    status_code = 400

    def __init__(self, message, status_code=None, payload=None):
        Exception.__init__(self)
        self.message = message
        if status_code is not None:
            self.status_code = status_code
        self.payload = payload

    def to_dict(self):
        rv = dict(self.payload or ())
        rv['message'] = self.message
        return rv

@app.route('/')
def hello_world():
    return 'Hello to the World of Flask!'

#get all tasks
@app.route('/todo/api/v1.0/tasks', methods=['GET'])
def get_tasks():
    return_value = Todo.get_all_tasks()
    return jsonify({'tasks': return_value})

#get specific task
@app.route('/todo/api/v1.0/tasks/<int:task_id>', methods=['GET'])
def get_task(task_id):
    task = Todo.get_task(task_id)
    #if len(task) == 0:
        #raise InvalidUsage('No such task', status_code=404)
    return jsonify({'task': task})

#add task
@app.route('/todo/api/v1.0/tasks', methods=['POST'])
def create_task():
    if not request.json or not 'title' in request.json:
        raise InvalidUsage('Not a valid task!', status_code=400)
    task = {
        'title': request.json['title'],
        'description': request.json['description'],
        'done': False
    }
    Todo.add_todo(task)
    return jsonify({'task': task}), 201

#update task
@app.route('/todo/api/v1.0/tasks/<int:task_id>', methods=['PUT'])
def update_task(task_id):
    task = [task for task in tasks if task['id'] == task_id]
    if len(task) == 0:
        raise InvalidUsage('No provided updated', status_code=400)
    if not request.json:
        raise InvalidUsage('request not valid json', status_code=400)
    if 'title' in request.json and type(request.json['title']) != unicode:
        raise InvalidUsage('title not unicode', status_code=400)
    if 'description' in request.json and type(request.json['description']) != unicode:
        raise InvalidUsage('description not unicode', status_code=400)
    if 'done' in request.json and type(request.json['done']) is not bool:
        raise InvalidUsage('done not boolean', status_code=400)
    task[0]['title'] = request.json.get('title', task[0]['title'])
    task[0]['description'] = request.json.get('description', task[0]['description'])
    task[0]['done'] = request.json.get('done', task[0]['done'])
    return jsonify({'task': task[0]})

#delete task
@app.route('/todo/api/v1.0/tasks/<int:task_id>', methods=['DELETE'])
def delete_task(task_id):
    task = [task for task in tasks if task['id'] == task_id]
    if len(task) == 0:
        raise InvalidUsage('No task to delete', status_code=400)
    tasks.remove(task[0])
    return jsonify({'result': True})


@app.errorhandler(InvalidUsage)
def handle_invalid_usage(error):
    response = jsonify(error.to_dict())
    response.status_code = error.status_code
    return response

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

EDIT:

Turns out I wasn't setting the request type in POSTMAN correctly. I've updated it to 'application/json' in the header. Now I'm receiving a different error.

Bad Request Failed to decode JSON object: Expecting value: line 1 column 1 (char 0)

我已经像以前一样尝试了所有前面的步骤，但是仍然遇到此错误。

编辑2：

根据下面的响应，我尝试将这些值放入POST正文中。但是我仍然得到400条回应。