Python Flask大刀解決跨域問題

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系列文章目錄

Table of Contents

• 系列文章目錄
• 前言
• 使用步驟
  • 1. 引入庫
  • 2. 設定
    • 1. 使用CORS函數 設定全域路由
    • 2. 使用@cross_origin 來設定單行路由
  • #設定參數說明
##總結
• 參考

---

前言

我靠，又跨域了

使用步驟

1. 引入庫

pip install flask-cors复制代码

2. 設定

flask-cors 有兩種用法，一種為全域使用，一種對指定的路由使用

1. 使用

CORS函數 設定全域路由

from flask import Flask, requestfrom flask_cors import CORS

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

其中

CORS 提供了一些參數來幫助我們自訂操作。

常用的我們可以設定

origins、methods、allow_headers、supports_credentials

#所有的設定項目如下：

: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 來設定單行路由

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_origin 和CORS 提供一些基本上相同的參數。

常用的我們可以設定

origins、methods、allow_headers、supports_credentials

#所有的配置項目如下：

: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

配置參數說明

參數#resources#originsmethodsexpose_headersallow_headers#supports_credentials#max_age##總結

##類型	Head	預設	說明
#字典、迭代器或字串	無	全部	配置允許跨域的路由介面
列表、字串或正規表示式	Access-Control-Allow-Origin	*	配置允許跨網域存取的來源
列表、字串	Access-Control-Allow-Methods	[GET, HEAD, POST, OPTIONS, PUT, PATCH, DELETE]	#配置跨域支持的請求方式
清單、字串	Access-Control-Expose-Headers	None	#自訂請求回應的Head訊息
#清單、字串或正規表示式	Access-Control-Request-Headers	*	配置允許跨域的請求頭
布林值	Access-Control- Allow-Credentials	False	是否允許請求發送cookie
timedelta、整數、字串	Access-Control-Max-Age	None	#預檢請求的有效時長

在flask 的跨域配置中，我們可以使用

flask-cors

來進行配置，其中

CORS 函數 用來做全域的配置, @cross_origin 來實現特定路由的配置。

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