Python Flask大刀解決跨域問題

2020-09-30 18:01:08

欄目為大家介紹Python Flask解決跨域問題。

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 設定全域性路由
      • 2. 使用 @cross_origin 來設定單行路由
    • 設定引數說明
  • 總結
  • 參考

前言

我靠,又跨域了

使用步驟

1. 引入庫

pip install flask-cors複製程式碼

2. 設定

flask-cors 有兩種用法,一種為全域性使用,一種對指定的路由使用

1. 使用 CORS函數 設定全域性路由

from flask import Flask, requestfrom flask_cors import CORS

app = Flask(__name__)
CORS(app, supports_credentials=True)複製程式碼

其中 CORS 提供了一些引數幫助我們客製化一下操作。

常用的我們可以設定 originsmethodsallow_headerssupports_credentials

所有的設定項如下:

: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複製程式碼

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}!'複製程式碼

其中 cross_originCORS 提供一些基本相同的引數。

常用的我們可以設定 originsmethodsallow_headerssupports_credentials

所有的設定項如下:

: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複製程式碼

設定引數說明

引數型別Head預設說明
resources字典、迭代器或字串全部設定允許跨域的路由介面
origins列表、字串或正規表示式Access-Control-Allow-Origin*設定允許跨域存取的源
methods列表、字串Access-Control-Allow-Methods[GET, HEAD, POST, OPTIONS, PUT, PATCH, DELETE]設定跨域支援的請求方式
expose_headers列表、字串Access-Control-Expose-HeadersNone自定義請求響應的Head資訊
allow_headers列表、字串或正規表示式Access-Control-Request-Headers*設定允許跨域的請求頭
supports_credentials布林值Access-Control-Allow-CredentialsFalse是否允許請求傳送cookie
max_agetimedelta、整數、字串Access-Control-Max-AgeNone預檢請求的有效時長

總結

在 flask 的跨域設定中,我們可以使用 flask-cors 來進行設定,其中 CORS 函數 用來做全域性的設定, @cross_origin 來實現特定路由的設定。

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