Python中怎么使用Flask 解决跨域问题

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。

1. 引入库

pip install flask-cors

2. 配置

flask-cors 有两种用法，一种为全局使用，一种对指定的路由使用

1. 使用 CORS函数 配置全局路由

from flask import Flask, requestfrom flask_cors import CORSapp = 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

2. 使用 @cross_origin 来配置单行路由

from flask import Flask, requestfrom flask_cors import cross_originapp = 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

配置参数说明

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