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Working with HTTP Cache Response Header
Tutorial on how to work with HTTP Cache Response header in Fano Framework

HTTP Cache Header

Adding HTTP Cache Header

To add http cache header (RFC 7324), Fano Framework provides built-in middleware TCacheControlMiddleware.

To add HTTP cache header, create middleware or register its factory class TCacheControlMiddlewareFactory within container.

container.add(
    'cacheControl',
    TCacheControlMiddlewareFactory.create().useETag()
);

and then, attach middleware to route that will need to be added with HTTP cache header.

router.get(
    '/',
    container['homeController'] as IRequestHandler
).add(container['cacheControl'] as IMiddleware);

How it works

When this middleware attached to route, additional steps is taken:

  • If method is not cacheable (not GET nor HEAD) then nothing is done else,
  • Cache-Control header is added to response header,
  • If ETag is used then MD5 hash of response body is computed and ETag header is added to response with hash value of response body.
  • If request contains If-None-Match header, its value is compared with ETag value, if they are matched or If-None-Match equals "*", then response is considered not modified.
  • If ETag comparison return false and response contains header Last-Modified and request contains header If-Modified-Since, both headers values are compared. If Last-Modified is older then response is considered not modified.
  • If response is not modified, instance TNotModifiedResponse is returned instead. Read Not modified response section for more information this class.

Read source code if you want to know more.

Setting Cache-Control header value

Set type

cacheType() method set type of cache, accepts value of ctPrivate or ctPublic value. If it is not set ctPrivate is assumed.

container.add(
    'cacheControl',
    TCacheControlMiddlewareFactory.create().cacheType(ctPublic)
);

Prevent cache to be stored

noStore() method enable no-store value.

container.add(
    'cacheControl',
    TCacheControlMiddlewareFactory.create().noStore()
);

Set max-age value

maxAge() method set max-age value.

container.add(
    'cacheControl',
    //set max-age=3600 (1 hour)
    TCacheControlMiddlewareFactory.create().maxAge(60*60)
);

if max-age is set with 0 value, it implies no-cache.

Enable ETag header

useETag() method enable ETag header. When enable, ETag response header is added to response with value equals to MD5 hash of response body.

container.add(
    'cacheControl',
    TCacheControlMiddlewareFactory.create().useETag()
);

Set must-revalidate

mustRevalidate method enable must-revalidate value.

container.add(
    'cacheControl',
    TCacheControlMiddlewareFactory.create().mustRevalidate()
);

All methods above can be chained,

container.add(
    'cacheControl',
    TCacheControlMiddlewareFactory.create()
        .cacheType(ctPublic)
        .mustRevalidate()
        .useETag()
);

Prevent browser from caching response

To prevent browser from caching response, you can use something like following example

container.add(
    'no-cache',
    TCacheControlMiddlewareFactory.create()
        .noStore()
        .mustRevalidate()
);

or you can use TNoCacheMiddleware which specifically provided for this purpose

container.add('no-cache', TNoCacheMiddlewareFactory.create());

Explore more