Django后端接口配置及跨域请求
Django后端接口配置及跨域请求
- view返回是Json格式
#python中返回是字典格式
dict_ob = models.objects.all().values() #返回的是字典类型
#将结果转化为list
list_dict_ob = list(dict_ob) #将外层字典转化为列表（数组）
#引入JsonResponse模块
from django.http import JsonResponse
#返回前端所需类型
try:
return JsonResponse({
'code':1,
'data':list_dict_ob
})
except Exception as e:
return JsonResponse({
'code':0,
'msg':'获取学生信息出现异常，具体错误：'+str(e)
})
2.跨域请求
协议、主机、端口任意一个同都是跨域请求
有两种方案
一、前端解决jsonp
二、后端解决
注：Django框架中通过django-cors-headers解决
-
安装
pip install django-cors-headers -
注册到Settings的INSTALLD_APPS中
INSTALLED_APPS = [
'corsheaders'
]
3.添加到中间件MIDDLEWARE中
MIDDLEWARE = [
'corsheaders.middleware.CorsMiddleware',
'django.middleware.csrf.CsrfViewMiddleware',
#一定要在csrf前面
]
4.cors配置-
- 1.添加白名单
CORS_ORIGIN_WHITELIST =('192.168.0.1:8080',) #允许访问的域名，注是前端访问的列表。
- 对另一种形式的名单（注：可以添加本地模式）
CORS_ALLOWED_ORIGINS = [
"https://example.com",
"https://sub.example.com",
"http://localhost:3080",#允许访问的域名，注是前端访问的列表。
"http://127.0.0.1:9000",
]
-
2.设置cors cookie
CORS_ALLOW_CREDENTIALS = True
英文版
===================
django-cors-headers
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A Django App that adds Cross-Origin Resource Sharing (CORS) headers to
responses. This allows in-browser requests to your Django application from
other origins.
About CORS
Adding CORS headers allows your resources to be accessed on other domains. It’s
important you understand the implications before adding the headers, since you
could be unintentionally opening up your site’s private data to others.
Some good resources to read on the subject are:
- Julia Evans’
introductory comic <https://drawings.jvns.ca/cors/>__ and
educational quiz <https://questions.wizardzines.com/cors.html>__. - Jake Archibald’s
How to win at CORS <https://jakearchibald.com/2021/cors/>__ - The
MDN Article <https://developer.mozilla.org/en-US/docs/Web/HTTP/CORS>_ - The
HTML5 Rocks Tutorial <https://www.html5rocks.com/en/tutorials/cors/>_ - The
Wikipedia Page <https://en.wikipedia.org/wiki/Cross-origin_resource_sharing>_
Requirements
Python 3.7 to 3.10 supported.
Django 2.2 to 4.0 supported.
Want to work smarter and faster?
Check out my book Boost Your Django DX <https://adamchainz.gumroad.com/l/byddx>__ which covers many ways to improve your development experience.
Setup
Install from pip:
… code-block:: sh
python -m pip install django-cors-headers
and then add it to your installed apps:
… code-block:: python
INSTALLED_APPS = [
...,
"corsheaders",
...,
]
Make sure you add the trailing comma or you might get a ModuleNotFoundError
(see this blog post <https://adamj.eu/tech/2020/06/29/why-does-python-raise-modulenotfounderror-when-modifying-installed-apps/>__).
You will also need to add a middleware class to listen in on responses:
… code-block:: python
MIDDLEWARE = [
...,
"corsheaders.middleware.CorsMiddleware",
"django.middleware.common.CommonMiddleware",
...,
]
CorsMiddleware should be placed as high as possible, especially before any
middleware that can generate responses such as Django’s CommonMiddleware or
Whitenoise’s WhiteNoiseMiddleware. If it is not before, it will not be able
to add the CORS headers to these responses.
Also if you are using CORS_REPLACE_HTTPS_REFERER it should be placed before
Django’s CsrfViewMiddleware (see more below).
About
django-cors-headers was created in January 2013 by Otto Yiu. It went
unmaintained from August 2015 and was forked in January 2016 to the package
django-cors-middleware <https://github.com/zestedesavoir/django-cors-middleware>_
by Laville Augustin at Zeste de Savoir.
In September 2016, Adam Johnson, Ed Morley, and others gained maintenance
responsibility for django-cors-headers
(Issue 110 <https://github.com/adamchainz/django-cors-headers/issues/110>__)
from Otto Yiu.
Basically all of the changes in the forked django-cors-middleware were
merged back, or re-implemented in a different way, so it should be possible to
switch back. If there’s a feature that hasn’t been merged, please open an issue
about it.
django-cors-headers has had 40+ contributors <https://github.com/adamchainz/django-cors-headers/graphs/contributors>__
in its time; thanks to every one of them.
Configuration
Configure the middleware’s behaviour in your Django settings. You must set at
least one of three following settings:
CORS_ALLOWED_ORIGINSCORS_ALLOWED_ORIGIN_REGEXESCORS_ALLOW_ALL_ORIGINS
CORS_ALLOWED_ORIGINS: Sequence[str]
A list of origins that are authorized to make cross-site HTTP requests.
The origins in this setting will be allowed, and the requesting origin will be echoed back to the client in the |Access-Control-Allow-Origin header|__.
Defaults to ``[]``.
.. |Access-Control-Allow-Origin header| replace:: ``Access-Control-Allow-Origin`` header
__ https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Access-Control-Allow-Origin
An Origin is defined by `the CORS RFC Section 3.2 <https://tools.ietf.org/html/rfc6454#section-3.2>`_ as a URI scheme + hostname + port, or one of the special values ``'null'`` or ``'file://'``.
Default ports (HTTPS = 443, HTTP = 80) are optional.
The special value ``null`` is sent by the browser in `"privacy-sensitive contexts" <https://tools.ietf.org/html/rfc6454#section-6>`__, such as when the client is running from a ``file://`` domain.
The special value `file://` is sent accidentally by some versions of Chrome on Android as per `this bug <https://bugs.chromium.org/p/chromium/issues/detail?id=991107>`__.
Example:
.. code-block:: python
CORS_ALLOWED_ORIGINS = [
"https://example.com",
"https://sub.example.com",
"http://localhost:8080",
"http://127.0.0.1:9000",
]
Previously this setting was called ``CORS_ORIGIN_WHITELIST``, which still works as an alias, with the new name taking precedence.
``CORS_ALLOWED_ORIGIN_REGEXES: Sequence[str | Pattern[str]]``
A list of strings representing regexes that match Origins that are authorized to make cross-site HTTP requests.
Defaults to [].
Useful when CORS_ALLOWED_ORIGINS is impractical, such as when you have a large number of subdomains.
Example:
… code-block:: python
CORS_ALLOWED_ORIGIN_REGEXES = [
r"^https://\w+\.example\.com$",
]
Previously this setting was called CORS_ORIGIN_REGEX_WHITELIST, which still works as an alias, with the new name taking precedence.
CORS_ALLOW_ALL_ORIGINS: bool
If ``True``, all origins will be allowed.
Other settings restricting allowed origins will be ignored.
Defaults to ``False``.
Setting this to ``True`` can be *dangerous*, as it allows any website to make cross-origin requests to yours.
Generally you'll want to restrict the list of allowed origins with ``CORS_ALLOWED_ORIGINS`` or ``CORS_ALLOWED_ORIGIN_REGEXES``.
Previously this setting was called ``CORS_ORIGIN_ALLOW_ALL``, which still works as an alias, with the new name taking precedence.
--------------
The following are optional settings, for which the defaults probably suffice.
``CORS_URLS_REGEX: str | Pattern[str]``
A regex which restricts the URL’s for which the CORS headers will be sent.
Defaults to r'^.*$', i.e. match all URL’s.
Useful when you only need CORS on a part of your site, e.g. an API at /api/.
Example:
… code-block:: python
CORS_URLS_REGEX = r"^/api/.*$"
CORS_ALLOW_METHODS: Sequence[str]
A list of HTTP verbs that are allowed for the actual request.
Defaults to:
.. code-block:: python
CORS_ALLOW_METHODS = [
"DELETE",
"GET",
"OPTIONS",
"PATCH",
"POST",
"PUT",
]
The default can be imported as ``corsheaders.defaults.default_methods`` so you can just extend it with your custom methods.
This allows you to keep up to date with any future changes.
For example:
.. code-block:: python
from corsheaders.defaults import default_methods
CORS_ALLOW_METHODS = list(default_methods) + [
"POKE",
]
``CORS_ALLOW_HEADERS: Sequence[str]``
The list of non-standard HTTP headers that you permit in requests from the browser.
Sets the |Access-Control-Allow-Headers header|__ in responses to preflight requests <https://developer.mozilla.org/en-US/docs/Glossary/Preflight_request>__.
Defaults to:
… |Access-Control-Allow-Headers header| replace:: Access-Control-Allow-Headers header
__ https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Access-Control-Allow-Headers
… code-block:: python
CORS_ALLOW_HEADERS = [
"accept",
"accept-encoding",
"authorization",
"content-type",
"dnt",
"origin",
"user-agent",
"x-csrftoken",
"x-requested-with",
]
The default can be imported as corsheaders.defaults.default_headers so you can extend it with your custom headers.
This allows you to keep up to date with any future changes.
For example:
… code-block:: python
from corsheaders.defaults import default_headers
CORS_ALLOW_HEADERS = list(default_headers) + [
"my-custom-header",
]
CORS_EXPOSE_HEADERS: Sequence[str]
The list of extra HTTP headers to expose to the browser, in addition to the default `safelisted headers <https://developer.mozilla.org/en-US/docs/Glossary/CORS-safelisted_response_header>`__.
If non-empty, these are declared in the |Access-Control-Expose-Headers header|__.
Defaults to ``[]``.
.. |Access-Control-Expose-Headers header| replace:: ``Access-Control-Expose-Headers`` header
__ https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Access-Control-Expose-Headers
``CORS_PREFLIGHT_MAX_AGE: int``
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The number of seconds the browser can cache the preflight response.
This sets the |Access-Control-Max-Age header|__ in preflight responses.
If this is 0 (or any falsey value), no max age header will be sent.
Defaults to ``86400`` (one day).
.. |Access-Control-Max-Age header| replace:: ``Access-Control-Max-Age`` header
__ https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Access-Control-Max-Age
**Note:**
Browsers send `preflight requests <https://developer.mozilla.org/en-US/docs/Glossary/Preflight_request>`__ before certain “non-simple” requests, to check they will be allowed.
Read more about it in the `CORS MDN article <https://developer.mozilla.org/en-US/docs/Web/HTTP/CORS#preflighted_requests>`_.
``CORS_ALLOW_CREDENTIALS: bool``
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
If ``True``, cookies will be allowed to be included in cross-site HTTP requests.
This sets the |Access-Control-Allow-Credentials header|__ in preflight and normal responses.
Defaults to ``False``.
Note: in Django 2.1 the `SESSION_COOKIE_SAMESITE`_ setting was added, set to ``'Lax'`` by default, which will prevent Django's session cookie being sent cross-domain.
Change the setting to ``None`` if you need to bypass this security restriction.
.. _SESSION_COOKIE_SAMESITE: https://docs.djangoproject.com/en/stable/ref/settings/#std:setting-SESSION_COOKIE_SAMESITE
CSRF Integration
----------------
Most sites will need to take advantage of the `Cross-Site Request Forgery
protection <https://docs.djangoproject.com/en/stable/ref/csrf/>`_ that Django
offers. CORS and CSRF are separate, and Django has no way of using your CORS
configuration to exempt sites from the ``Referer`` checking that it does on
secure requests. The way to do that is with its `CSRF_TRUSTED_ORIGINS setting
<https://docs.djangoproject.com/en/stable/ref/settings/#csrf-trusted-origins>`_.
For example:
.. code-block:: python
CORS_ALLOWED_ORIGINS = [
"http://read.only.com",
"http://change.allowed.com",
]
CSRF_TRUSTED_ORIGINS = [
"http://change.allowed.com",
]
``CORS_REPLACE_HTTPS_REFERER: bool``
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
``CSRF_TRUSTED_ORIGINS`` was introduced in Django 1.9, so users of earlier
versions will need an alternate solution. If ``CORS_REPLACE_HTTPS_REFERER`` is
``True``, ``CorsMiddleware`` will change the ``Referer`` header to something
that will pass Django's CSRF checks whenever the CORS checks pass. Defaults to
``False``.
Note that unlike ``CSRF_TRUSTED_ORIGINS``, this setting does not allow you to
distinguish between domains that are trusted to *read* resources by CORS and
domains that are trusted to *change* resources by avoiding CSRF protection.
With this feature enabled you should also add
``corsheaders.middleware.CorsPostCsrfMiddleware`` after
``django.middleware.csrf.CsrfViewMiddleware`` in your ``MIDDLEWARE_CLASSES`` to
undo the ``Referer`` replacement:
.. code-block:: python
MIDDLEWARE_CLASSES = [
...,
"corsheaders.middleware.CorsMiddleware",
...,
"django.middleware.csrf.CsrfViewMiddleware",
"corsheaders.middleware.CorsPostCsrfMiddleware",
...,
]
Signals
-------
If you have a use case that requires more than just the above configuration,
you can attach code to check if a given request should be allowed. For example,
this can be used to read the list of origins you allow from a model. Attach any
number of handlers to the ``check_request_enabled``
`Django signal <https://docs.djangoproject.com/en/stable/ref/signals/>`_, which
provides the ``request`` argument (use ``**kwargs`` in your handler to protect
against any future arguments being added). If any handler attached to the
signal returns a truthy value, the request will be allowed.
For example you might define a handler like this:
.. code-block:: python
# myapp/handlers.py
from corsheaders.signals import check_request_enabled
from myapp.models import MySite
def cors_allow_mysites(sender, request, **kwargs):
return MySite.objects.filter(host=request.headers["Origin"]).exists()
check_request_enabled.connect(cors_allow_mysites)
Then connect it at app ready time using a `Django AppConfig
<https://docs.djangoproject.com/en/stable/ref/applications/>`_:
.. code-block:: python
# myapp/__init__.py
default_app_config = "myapp.apps.MyAppConfig"
.. code-block:: python
# myapp/apps.py
from django.apps import AppConfig
class MyAppConfig(AppConfig):
name = "myapp"
def ready(self):
# Makes sure all signal handlers are connected
from myapp import handlers # noqa
A common use case for the signal is to allow *all* origins to access a subset
of URL's, whilst allowing a normal set of origins to access *all* URL's. This
isn't possible using just the normal configuration, but it can be achieved with
a signal handler.
First set ``CORS_ALLOWED_ORIGINS`` to the list of trusted origins that are
allowed to access every URL, and then add a handler to
``check_request_enabled`` to allow CORS regardless of the origin for the
unrestricted URL's. For example:
.. code-block:: python
# myapp/handlers.py
from corsheaders.signals import check_request_enabled
def cors_allow_api_to_everyone(sender, request, **kwargs):
return request.path.startswith("/api/")
check_request_enabled.connect(cors_allow_api_to_everyone)