# Τεκμηρίωση του Django - 1.10.7

# View decorators

Django provides several decorators that can be applied to views to support various HTTP features.

## Allowed HTTP methods

The decorators in `django.views.decorators.http` can be used to restrict access to views based on the request method. These decorators will return a `django.http.HttpResponseNotAllowed` if the conditions are not met.

`require_http_methods`(request_method_list)

  Decorator to require that a view only accepts particular request methods. Usage:

      from django.views.decorators.http import require_http_methods

      @require_http_methods(["GET", "POST"])
      def my_view(request):
          # I can assume now that only GET or POST requests make it this far
          # ...
          pass

  Note that request methods should be in uppercase.

`require_GET`()

  Decorator to require that a view only accepts the GET method.

`require_POST`()

  Decorator to require that a view only accepts the POST method.

`require_safe`()

  Decorator to require that a view only accepts the GET and HEAD methods. These methods are commonly considered “safe” because they should not have the significance of taking an action other than retrieving the requested resource.

  Σημείωση

  Web servers should automatically strip the content of responses to HEAD requests while leaving the headers unchanged, so you may handle HEAD requests exactly like GET requests in your views. Since some software, such as link checkers, rely on HEAD requests, you might prefer using `require_safe` instead of `require_GET`.

## Conditional view processing

The following decorators in `django.views.decorators.http` can be used to control caching behavior on particular views.

`condition`(etag_func=None, last_modified_func=None)

`etag`(etag_func)

`last_modified`(last_modified_func)

  These decorators can be used to generate `ETag` and `Last-Modified` headers; see conditional view processing.

## GZip compression

The decorators in `django.views.decorators.gzip` control content compression on a per-view basis.

`gzip_page`()

  This decorator compresses content if the browser allows gzip compression. It sets the `Vary` header accordingly, so that caches will base their storage on the `Accept-Encoding` header.

## Vary headers

The decorators in `django.views.decorators.vary` can be used to control caching based on specific request headers.

`vary_on_cookie`(func)

`vary_on_headers`(*headers)

  The `Vary` header defines which request headers a cache mechanism should take into account when building its cache key.

  See using vary headers.

## Caching

The decorators in `django.views.decorators.cache` control server and client-side caching.

`cache_control`(**kwargs)

  This decorator patches the response’s `Cache-Control` header by adding all of the keyword arguments to it. See `patch_cache_control()` for the details of the transformation.

`never_cache`(view_func)

  This decorator adds a `Cache-Control: max-age=0, no-cache, no-store, must-revalidate` header to a response to indicate that a page should never be cached.

  Before Django 1.9, `Cache-Control: max-age=0` was sent. This didn’t reliably prevent caching in all browsers.