Python中怎么使用Flask 解决跨域问题，很多新手对此不是很清楚，为了帮助大家解决这个难题，下面小编将为大家详细讲解，有这方面需求的人可以来学习下，希望你能有所收获。
pip install flask-cors
flask-cors 有两种用法，一种为全局使用，一种对指定的路由使用
CORS函数 配置全局路由from flask import Flask, request from flask_cors import CORS app = Flask(__name__) CORS(app, supports_credentials=True)
其中 CORS 提供了一些参数帮助我们定制一下操作。
常用的我们可以配置 origins、methods、allow_headers、supports_credentials
所有的配置项如下：
:param resources: The series of regular expression and (optionally) associated CORS options to be applied to the given resource path. If the argument is a dictionary, it's keys must be regular expressions, and the values must be a dictionary of kwargs, identical to the kwargs of this function. If the argument is a list, it is expected to be a list of regular expressions, for which the app-wide configured options are applied. If the argument is a string, it is expected to be a regular expression for which the app-wide configured options are applied. Default : Match all and apply app-level configuration :type resources: dict, iterable or string :param origins: The origin, or list of origins to allow requests from. The origin(s) may be regular expressions, case-sensitive strings, or else an asterisk Default : '*' :type origins: list, string or regex :param methods: The method or list of methods which the allowed origins are allowed to access for non-simple requests. Default : [GET, HEAD, POST, OPTIONS, PUT, PATCH, DELETE] :type methods: list or string :param expose_headers: The header or list which are safe to expose to the API of a CORS API specification. Default : None :type expose_headers: list or string :param allow_headers: The header or list of header field names which can be used when this resource is accessed by allowed origins. The header(s) may be regular expressions, case-sensitive strings, or else an asterisk. Default : '*', allow all headers :type allow_headers: list, string or regex :param supports_credentials: Allows users to make authenticated requests. If true, injects the `Access-Control-Allow-Credentials` header in responses. This allows cookies and credentials to be submitted across domains. :note: This option cannot be used in conjuction with a '*' origin Default : False :type supports_credentials: bool :param max_age: The maximum time for which this CORS request maybe cached. This value is set as the `Access-Control-Max-Age` header. Default : None :type max_age: timedelta, integer, string or None :param send_wildcard: If True, and the origins parameter is `*`, a wildcard `Access-Control-Allow-Origin` header is sent, rather than the request's `Origin` header. Default : False :type send_wildcard: bool :param vary_header: If True, the header Vary: Origin will be returned as per the W3 implementation guidelines. Setting this header when the `Access-Control-Allow-Origin` is dynamically generated (e.g. when there is more than one allowed origin, and an Origin than '*' is returned) informs CDNs and other caches that the CORS headers are dynamic, and cannot be cached. If False, the Vary header will never be injected or altered. Default : True :type vary_header: bool
@cross_origin 来配置单行路由from flask import Flask, request
from flask_cors import cross_origin
app = Flask(__name__)
@app.route('/')
@cross_origin(supports_credentials=True)
def hello():
name = request.args.get("name", "World")
return f'Hello, {name}!'其中 cross_origin 和 CORS 提供一些基本相同的参数。
常用的我们可以配置 origins、methods、allow_headers、supports_credentials
所有的配置项如下：
:param origins: The origin, or list of origins to allow requests from. The origin(s) may be regular expressions, case-sensitive strings, or else an asterisk Default : '*' :type origins: list, string or regex :param methods: The method or list of methods which the allowed origins are allowed to access for non-simple requests. Default : [GET, HEAD, POST, OPTIONS, PUT, PATCH, DELETE] :type methods: list or string :param expose_headers: The header or list which are safe to expose to the API of a CORS API specification. Default : None :type expose_headers: list or string :param allow_headers: The header or list of header field names which can be used when this resource is accessed by allowed origins. The header(s) may be regular expressions, case-sensitive strings, or else an asterisk. Default : '*', allow all headers :type allow_headers: list, string or regex :param supports_credentials: Allows users to make authenticated requests. If true, injects the `Access-Control-Allow-Credentials` header in responses. This allows cookies and credentials to be submitted across domains. :note: This option cannot be used in conjuction with a '*' origin Default : False :type supports_credentials: bool :param max_age: The maximum time for which this CORS request maybe cached. This value is set as the `Access-Control-Max-Age` header. Default : None :type max_age: timedelta, integer, string or None :param send_wildcard: If True, and the origins parameter is `*`, a wildcard `Access-Control-Allow-Origin` header is sent, rather than the request's `Origin` header. Default : False :type send_wildcard: bool :param vary_header: If True, the header Vary: Origin will be returned as per the W3 implementation guidelines. Setting this header when the `Access-Control-Allow-Origin` is dynamically generated (e.g. when there is more than one allowed origin, and an Origin than '*' is returned) informs CDNs and other caches that the CORS headers are dynamic, and cannot be cached. If False, the Vary header will never be injected or altered. Default : True :type vary_header: bool :param automatic_options: Only applies to the `cross_origin` decorator. If True, Flask-CORS will override Flask's default OPTIONS handling to return CORS headers for OPTIONS requests. Default : True :type automatic_options: bool
| 参数 | 类型 | Head | 默认 | 说明 |
|---|---|---|---|---|
| resources | 字典、迭代器或字符串 | 无 | 全部 | 配置允许跨域的路由接口 |
| origins | 列表、字符串或正则表达式 | Access-Control-Allow-Origin | * | 配置允许跨域访问的源 |
| methods | 列表、字符串 | Access-Control-Allow-Methods | [GET, HEAD, POST, OPTIONS, PUT, PATCH, DELETE] | 配置跨域支持的请求方式 |
| expose_headers | 列表、字符串 | Access-Control-Expose-Headers | None | 自定义请求响应的Head信息 |
| allow_headers | 列表、字符串或正则表达式 | Access-Control-Request-Headers | * | 配置允许跨域的请求头 |
| supports_credentials | 布尔值 | Access-Control-Allow-Credentials | False | 是否允许请求发送cookie |
| max_age | timedelta、整数、字符串 | Access-Control-Max-Age | None | 预检请求的有效时长 |
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