Python Flask大刀解决跨域问题

PHP 2年前 (2020) admin
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python视频教程栏目为大家介绍Python Flask解决跨域问题。

Python Flask大刀解决跨域问题

系列文章目录

Table of Contents

  • 系列文章目录
  • 前言
  • 使用步骤
    • 1. 引入库
    • 2. 配置
      • 1. 使用 CORS函数 配置全局路由
      • 2. 使用 @cross_origin 来配置单行路由
    • 配置参数说明
  • 总结
  • 参考

前言

我靠,又跨域了

使用步骤

1. 引入库

pip install flask-cors复制代码

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 CORS
app = Flask(__name__)
CORS(app, supports_credentials=True)复制代码

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 originsmethodsallow_headerssupports_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复制代码

2. 使用 @cross_origin 来配置单行路由

from flask import Flask, requestfrom 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}!'复制代码

其中 cross_originCORS 提供一些基本相同的参数。

常用的我们可以配置 originsmethodsallow_headerssupports_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复制代码

配置参数说明

参数 类型 Head 默认 说明
resources 字典、迭代器或字符串 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

总结

在 flask 的跨域配置中,我们可以使用 flask-cors 来进行配置,其中 CORS 函数 用来做全局的配置, @cross_origin 来实现特定路由的配置。

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版权声明:admin 发表于 2020年9月30日 下午6:34。
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