This document explains all middleware components that come with Django. For\ninformation on how to use them and how to write your own middleware, see\nthe middleware usage guide.
\nEnable the site-wide cache. If these are enabled, each Django-powered page will\nbe cached for as long as the CACHE_MIDDLEWARE_SECONDS setting\ndefines. See the cache documentation.
Adds a few conveniences for perfectionists:
\nForbids access to user agents in the DISALLOWED_USER_AGENTS\nsetting, which should be a list of compiled regular expression objects.
Performs URL rewriting based on the APPEND_SLASH and\nPREPEND_WWW settings.
If APPEND_SLASH is True and the initial URL doesn’t end\nwith a slash, and it is not found in the URLconf, then a new URL is\nformed by appending a slash at the end. If this new URL is found in the\nURLconf, then Django redirects the request to this new URL. Otherwise,\nthe initial URL is processed as usual.
For example, foo.com/bar will be redirected to foo.com/bar/ if\nyou don’t have a valid URL pattern for foo.com/bar but do have a\nvalid pattern for foo.com/bar/.
If PREPEND_WWW is True, URLs that lack a leading «www.»\nwill be redirected to the same URL with a leading «www.»
Both of these options are meant to normalize URLs. The philosophy is that\neach URL should exist in one, and only one, place. Technically a URL\nfoo.com/bar is distinct from foo.com/bar/ – a search-engine\nindexer would treat them as separate URLs – so it’s best practice to\nnormalize URLs.
Handles ETags based on the USE_ETAGS setting. If\nUSE_ETAGS is set to True, Django will calculate an ETag\nfor each request by MD5-hashing the page content, and it’ll take care of\nsending Not Modified responses, if appropriate.
Sets the Content-Length header for non-streaming responses.
Defaults to HttpResponsePermanentRedirect. Subclass\nCommonMiddleware and override the attribute to customize the redirects\nissued by the middleware.
Sends broken link notification emails to MANAGERS (see\nError reporting).
Compresses content for browsers that understand GZip compression (all modern\nbrowsers).
\nThis middleware should be placed before any other middleware that need to\nread or write the response body so that compression happens afterward.
\nIt will NOT compress content if any of the following are true:
\nThe content body is less than 200 bytes long.
The response has already set the Content-Encoding header.
The request (the browser) hasn’t sent an Accept-Encoding header\ncontaining gzip.
If the response has an ETag header, the ETag is made weak to comply with\nRFC 7232 Section 2.1.
You can apply GZip compression to individual views using the\ngzip_page() decorator.
Handles conditional GET operations. If the response doesn’t have an ETag\nheader, the middleware adds one if needed. If the response has a ETag or\nLast-Modified header, and the request has If-None-Match or\nIf-Modified-Since, the response is replaced by an\nHttpResponseNotModified.
Enables language selection based on data from the request. It customizes\ncontent for each user. See the internationalization documentation.
\nDefaults to HttpResponseRedirect. Subclass\nLocaleMiddleware and override the attribute to customize the redirects\nissued by the middleware.
Enables cookie- and session-based message support. See the\nmessages documentation.
\nThe django.middleware.security.SecurityMiddleware provides several security\nenhancements to the request/response cycle. Each one can be independently\nenabled or disabled with a setting.
For sites that should only be accessed over HTTPS, you can instruct modern\nbrowsers to refuse to connect to your domain name via an insecure connection\n(for a given period of time) by setting the «Strict-Transport-Security»\nheader. This reduces your exposure to some SSL-stripping man-in-the-middle\n(MITM) attacks.
\nSecurityMiddleware will set this header for you on all HTTPS responses if\nyou set the SECURE_HSTS_SECONDS setting to a non-zero integer value.
When enabling HSTS, it’s a good idea to first use a small value for testing,\nfor example, SECURE_HSTS_SECONDS = 3600 for one\nhour. Each time a Web browser sees the HSTS header from your site, it will\nrefuse to communicate non-securely (using HTTP) with your domain for the given\nperiod of time. Once you confirm that all assets are served securely on your\nsite (i.e. HSTS didn’t break anything), it’s a good idea to increase this value\nso that infrequent visitors will be protected (31536000 seconds, i.e. 1 year,\nis common).
Additionally, if you set the SECURE_HSTS_INCLUDE_SUBDOMAINS setting\nto True, SecurityMiddleware will add the includeSubDomains directive\nto the Strict-Transport-Security header. This is recommended (assuming all\nsubdomains are served exclusively using HTTPS), otherwise your site may still\nbe vulnerable via an insecure connection to a subdomain.
If you wish to submit your site to the browser preload list, set the\nSECURE_HSTS_PRELOAD setting to True. That appends the\npreload directive to the Strict-Transport-Security header.
X-Content-Type-Options: nosniffLink to this heading#Some browsers will try to guess the content types of the assets that they\nfetch, overriding the Content-Type header. While this can help display\nsites with improperly configured servers, it can also pose a security\nrisk.
If your site serves user-uploaded files, a malicious user could upload a\nspecially-crafted file that would be interpreted as HTML or JavaScript by\nthe browser when you expected it to be something harmless.
\nTo prevent the browser from guessing the content type and force it to\nalways use the type provided in the Content-Type header, you can pass\nthe X-Content-Type-Options: nosniff header. SecurityMiddleware will\ndo this for all responses if the SECURE_CONTENT_TYPE_NOSNIFF setting\nis True.
Note that in most deployment situations where Django isn’t involved in serving\nuser-uploaded files, this setting won’t help you. For example, if your\nMEDIA_URL is served directly by your front-end Web server (nginx,\nApache, etc.) then you’d want to set this header there. On the other hand, if\nyou are using Django to do something like require authorization in order to\ndownload files and you cannot set the header using your Web server, this\nsetting will be useful.
X-XSS-Protection: 1; mode=blockLink to this heading#Some browsers have the ability to block content that appears to be an XSS\nattack. They work by looking for JavaScript content in the GET or POST\nparameters of a page. If the JavaScript is replayed in the server’s response,\nthe page is blocked from rendering and an error page is shown instead.
\nThe X-XSS-Protection header is used to control the operation of the\nXSS filter.
\nTo enable the XSS filter in the browser, and force it to always block\nsuspected XSS attacks, you can pass the X-XSS-Protection: 1; mode=block\nheader. SecurityMiddleware will do this for all responses if the\nSECURE_BROWSER_XSS_FILTER setting is True.
If your site offers both HTTP and HTTPS connections, most users will end up\nwith an unsecured connection by default. For best security, you should redirect\nall HTTP connections to HTTPS.
\nIf you set the SECURE_SSL_REDIRECT setting to True,\nSecurityMiddleware will permanently (HTTP 301) redirect all HTTP\nconnections to HTTPS.
If the SECURE_SSL_HOST setting has a value, all redirects will be\nsent to that host instead of the originally-requested host.
If there are a few pages on your site that should be available over HTTP, and\nnot redirected to HTTPS, you can list regular expressions to match those URLs\nin the SECURE_REDIRECT_EXEMPT setting.
Enables session support. See the session documentation.
\nAdds the site attribute representing the current site to every incoming\nHttpRequest object. See the sites documentation.
Adds the user attribute, representing the currently-logged-in user, to\nevery incoming HttpRequest object. See Authentication in Web requests.
Middleware for utilizing Web server provided authentication. See\nAutenticación con el uso de REMOTE_USER for usage details.
\nMiddleware for utilizing Web server provided authentication when enabled only\non the login page. See Usando REMOTE_USER en paginas de ingreso solamente for usage\ndetails.
\nAdds protection against Cross Site Request Forgeries by adding hidden form\nfields to POST forms and checking requests for the correct value. See the\nCross Site Request Forgery protection documentation.
\nX-Frame-Options middlewareLink to this heading#Simple clickjacking protection via the X-Frame-Options header.
\nHere are some hints about the ordering of various Django middleware classes:
\nIt should go near the top of the list if you’re going to turn on the SSL\nredirect as that avoids running through a bunch of other unnecessary\nmiddleware.
\nBefore those that modify the Vary header (SessionMiddleware,\nGZipMiddleware, LocaleMiddleware).
Before any middleware that may change or use the response body.
\nAfter UpdateCacheMiddleware: Modifies Vary header.
Before CommonMiddleware: uses its ETag header when\nUSE_ETAGS = True.
After UpdateCacheMiddleware: Modifies Vary header.
One of the topmost, after SessionMiddleware (uses session data) and\nUpdateCacheMiddleware (modifies Vary header).
Before any middleware that may change the response (it calculates ETags).
After GZipMiddleware so it won’t calculate an ETag header on gzipped\ncontents.
Close to the top: it redirects when APPEND_SLASH or\nPREPEND_WWW are set to True.
Before any view middleware that assumes that CSRF attacks have been dealt\nwith.
\nIt must come after SessionMiddleware if you’re using\nCSRF_USE_SESSIONS.
After SessionMiddleware: uses session storage.
After SessionMiddleware: can use session-based storage.
After any middleware that modifies the Vary header: that header is used\nto pick a value for the cache hash-key.
Should be near the bottom as it’s a last-resort type of middleware.
\nShould be near the bottom as it’s a last-resort type of middleware.
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