使用 Flask 解决跨源资源共享问题

javascript ajax cors python flask

2022-08-30 04:22:56

对于以下帖子请求（我如何使用从 ajax 在烧瓶中发布的数据？ajaxFlask

$.ajax({
    url: "http://127.0.0.1:5000/foo", 
    type: "POST",
    contentType: "application/json",
    data: JSON.stringify({'inputVar': 1}),
    success: function( data ) { 
        alert( "success" + data );
    }   
});

我收到跨源资源共享（CORS） 错误：

No 'Access-Control-Allow-Origin' header is present on the requested resource. 
Origin 'null' is therefore not allowed access. 
The response had HTTP status code 500.

我尝试用以下两种方式解决它，但似乎没有一种奏效。

使用烧瓶-CORS

这是一个用于处理的扩展，应该使跨源AJAX成为可能。FlaskCORS

我使用此解决方案 pythonServer.py：

from flask import Flask
from flask.ext.cors import CORS, cross_origin

app = Flask(__name__)
cors = CORS(app, resources={r"/foo": {"origins": "*"}})
app.config['CORS_HEADERS'] = 'Content-Type'

@app.route('/foo', methods=['POST','OPTIONS'])
@cross_origin(origin='*',headers=['Content-Type','Authorization'])
def foo():
    return request.json['inputVar']

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

使用特定的烧瓶装饰器

这是一个官方的 Flask 代码片段，定义了一个装饰器，它应该允许它装饰的功能。CORS

我使用此解决方案 pythonServer.py：

from flask import Flask, make_response, request, current_app
from datetime import timedelta
from functools import update_wrapper

app = Flask(__name__)

def crossdomain(origin=None, methods=None, headers=None,
                max_age=21600, attach_to_all=True,
                automatic_options=True):
    if methods is not None:
        methods = ', '.join(sorted(x.upper() for x in methods))
    if headers is not None and not isinstance(headers, basestring):
        headers = ', '.join(x.upper() for x in headers)
    if not isinstance(origin, basestring):
        origin = ', '.join(origin)
    if isinstance(max_age, timedelta):
        max_age = max_age.total_seconds()

    def get_methods():
        if methods is not None:
            return methods

        options_resp = current_app.make_default_options_response()
        return options_resp.headers['allow']

    def decorator(f):
        def wrapped_function(*args, **kwargs):
            if automatic_options and request.method == 'OPTIONS':
                resp = current_app.make_default_options_response()
            else:
                resp = make_response(f(*args, **kwargs))
            if not attach_to_all and request.method != 'OPTIONS':
                return resp

            h = resp.headers

            h['Access-Control-Allow-Origin'] = origin
            h['Access-Control-Allow-Methods'] = get_methods()
            h['Access-Control-Max-Age'] = str(max_age)
            if headers is not None:
                h['Access-Control-Allow-Headers'] = headers
            return resp

        f.provide_automatic_options = False
        return update_wrapper(wrapped_function, f)
    return decorator

@app.route('/foo', methods=['GET','POST','OPTIONS'])
@crossdomain(origin="*")
def foo():
    return request.json['inputVar']

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

您能不能给出一些说明，说明为什么会这样？

答案 1

您可以通过以下简单方法获得结果：

@app.route('your route', methods=['GET'])
def yourMethod(params):
    response = flask.jsonify({'some': 'data'})
    response.headers.add('Access-Control-Allow-Origin', '*')
    return response

答案 2

好吧，我遇到了同样的问题。对于可能登陆此页面的新用户。只需遵循他们的官方文档即可。

安装烧瓶

pip install -U flask-cors

然后在应用程序初始化后，使用默认参数进行初始化：flask-cors

from flask import Flask
from flask_cors import CORS

app = Flask(__name__)
CORS(app)

@app.route("/")
def helloWorld():
   return "Hello, cross-origin-world!"