利用Flas解决跨源资源共享问题

Question

对于以下ajaxpost请求Flask（how can I use data posted from ajax in flask?）：

$.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 );
    }   
});

我得到一个^{}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.

我试着用以下两种方法来解决这个问题，但似乎都不管用。

1. 使用烧瓶CORS

这是一个处理CORS的Flask扩展，应该可以实现跨源AJAX。

• http://flask-cors.readthedocs.org/en/latest/
• How to enable CORS in flask and heroku
• Flask-cors wrapper not working when jwt auth wrapper is applied.
• Javascript - No 'Access-Control-Allow-Origin' header is present on the requested resource

MypythonServer.py使用此解决方案：

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()

1. 使用特定的烧瓶装饰器

这是一个定义decorator的正式的Flask代码片段，它应该允许对它所修饰的函数进行CORS。

• http://flask.pocoo.org/snippets/56/
• Python Flask cross site HTTP POST - doesn't work for specific allowed origins
• http://chopapp.com/#351l7gc3

MypythonServer.py使用此解决方案：

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()

你能告诉我为什么吗？

Answer 1

您可以通过一个简单的：

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

Answer 2

嗯，我也面临同样的问题。对于可能登录此页的新用户。 只需遵循他们的官方文件。

安装烧瓶cors

pip install -U flask-cors

然后在应用程序初始化之后，使用默认参数初始化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!"

Answer 3

在对你的代码进行了一些修改之后，它像一个冠军一样工作

# initialization
app = Flask(__name__)
app.config['SECRET_KEY'] = 'the quick brown fox jumps over the lazy   dog'
app.config['CORS_HEADERS'] = 'Content-Type'

cors = CORS(app, resources={r"/foo": {"origins": "http://localhost:port"}})

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

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

我把*换成了本地主机。因为我在很多博客和帖子中都读到过，所以您应该允许访问特定的域