Browsers usually add no-cache to requests when users are force reloading a page. The no-store response directive indicates that any caches of any kind (private or shared) should not store this response. If you don’t add a Cache-Control header because the response is not intended to be cached, that could cause an unexpected result. Cache storage is allowed to cache it heuristically — so if you have any requirements on caching, you should always indicate them explicitly, in the Cache-Control header.

HTTP allows caches to reuse stale responses when they are disconnected from the origin server. Must-revalidate is a way to prevent this from happening – either the stored response is revalidated with the origin server or a 504 (Gateway Timeout) response is generated. The must-revalidate response directive indicates that the response can be stored in caches and can be reused while fresh. If the response becomes stale, it must be validated with the origin server before reuse. If you forget to add private to a response with personalized content, then that response can be stored in a shared cache and end up being reused for multiple users, which can cause personal information to leak.

If the sense of « don’t cache » that you want is actually « don’t store », then no-store is the directive to use. This section lists directives that affect caching — both response directives and request directives. This is to keep it a safe and useful space for MoneySaving discussions. Threads that are – or become – political in nature may be removed in line with the Forum’s rules. For content that’s generated dynamically, or that’s static but updated often, you want a user to always receive the most up-to-date version.

Here, an error is considered any response with a status code of 500, 502, 503, or 504. When a user reloads the browser, the browser will send conditional requests for validating to the origin server. In general, when pages are under Basic Auth or Digest Auth, the browser sends requests with the Authorization header. This means that the response is access-controlled for restricted users (who have accounts), and it’s fundamentally not shared-cacheable, even if it has max-age.

Cache-Control header

There are no cache directives for clearing already-stored responses from caches on intermediate servers. The no-store request directive allows a client to request that caches refrain from storing the request and corresponding response — even if the origin server’s response could be stored. The stale-if-error response directive indicates that the cache can reuse a stale response when an upstream server generates an error, or when the kiting credit cards error is generated locally.

Caching static assets with « cache busting »

The average monthly rent for a house in Redmond is about $3,870. By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy. Alright, this is due to the pain that godaddy gives me by implementing their own caching in a MANAGED WORDPRESS hosting. I looked it up and as it turns out, their flush caching facility is not available to me in the wordpress dashboard as it is a subdirectory /wp/ installation.

immutable

The stale-while-revalidate response directive indicates that the cache could reuse a stale response while it revalidates it to a cache. The proxy-revalidate response directive is the equivalent of must-revalidate, but specifically for shared caches only. The no-cache response directive indicates that the response can be stored in caches, but the response must be validated with the origin server before each reuse, even when the cache is disconnected from the origin server. This usually means the response can be reused for subsequent requests, depending on request directives.

Cache that exists between the origin server and clients (e.g., Proxy, CDN). It stores a single response and reuses it with multiple users — so developers should avoid storing personalized contents to be cached in the shared cache. The public response directive indicates that the response can be stored in a shared cache. Responses for requests with Authorization header fields must not be stored in a shared cache; however, the public directive will cause such responses to be stored in a shared cache.

Imagine that clients/caches store a fresh response for a path, with no request flight to the server. Clients can use this header when the origin server is down or too slow and can accept cached responses from caches even if they are a bit old. The no-cache request directive asks caches to validate the response with the origin server before reuse. If a request doesn’t have an Authorization header, or you are already using s-maxage or must-revalidate in the response, then you don’t need to use public. If you want caches to always check for content updates while reusing stored content, no-cache is the directive to use.

When you use a cache-busting pattern for resources and apply them to a long max-age, you can also add immutable to avoid revalidation. The must-understand response directive indicates that a cache should store the response only if it understands the requirements for caching based on status code. No-cache allows caches to store a response but requires them to revalidate it before reuse.

You should always use a real HTTP header for headers such as Cache-Control and Pragma. The list is just examples of different techniques, it’s not for directinsertion. If copied, the second would overwrite the first and thefourth would overwrite the third because of the http-equivdeclarations AND fail with the W3C validator. At most, one could haveone of each http-equiv declarations; pragma, cache-control andexpires. These are completely outdated when using modern up to date browsers.After IE9 anyway. Chrome and Firefox specifically does not work with these as you would expect, if at all.

• Caching headers are unreliable in meta elements; for one,any web proxies between the site and the user will completely ignorethem.
• This section lists directives that affect caching — both response directives and request directives.
• In the browser, I get a cached version of the stylesheet which does not reflect the recent one.
• If a cache doesn’t support must-understand, it will be ignored.

Middleware to turn off caching

It does this by requiring caches to revalidate each request with the origin server. Ask the origin server whether or not the stored response is still fresh. Usually, the revalidation is done through a conditional request.

Resources

If no request happened during that period, the cache became stale and the next request will revalidate normally. Revalidation will make the cache be fresh again, so it appears to clients that it was always fresh during that period — effectively hiding the latency penalty of revalidation from them. The immutable response directive indicates that the response will not be updated while it’s fresh. If a cache supports must-understand, it stores the response with an understanding of cache requirements based on its status code.

The Cache-Control header is used to specify directives for caching mechanisms in both HTTP requests and responses. Adding no-cache to the response causes revalidation to the server, so you can serve a fresh response every time — or if the client already has a new one, just respond 304 Not Modified. If you don’t want a response stored in caches, use the no-store directive. For example, a request with the header above indicates that the browser will accept a stale response from the cache that has expired within the last hour.

Which neighborhoods have the most houses for rent in Redmond, WA?

Must-understand should be coupled with no-store for fallback behavior. This feature is well established and works across many devices and browser versions.

• The no-cache response directive indicates that the response can be stored in caches, but the response must be validated with the origin server before each reuse, even when the cache is disconnected from the origin server.
• This is to keep it a safe and useful space for MoneySaving discussions.
• If copied, the second would overwrite the first and thefourth would overwrite the third because of the http-equivdeclarations AND fail with the W3C validator.
• It does this by requiring caches to revalidate each request with the origin server.
• It stores a single response and reuses it with multiple users — so developers should avoid storing personalized contents to be cached in the shared cache.

You should always use a real HTTP header for headers such asCache-Control and Pragma. Many browsers use this directive for reloading, as explained below. No-transform indicates that any intermediary (regardless of whether it implements a cache) shouldn’t transform the response contents. To comfortably afford a house in Redmond based on average rent prices, a household would need an annual income of $155,000.

When you update the library or edit the picture, new content should have a new URL, and caches aren’t reused. You can add a long max-age value and immutable because the content will never change. No-cache allows clients to request the most up-to-date response even if the cache has a fresh response. Note that the major browsers do not support requests with max-stale.

Use a no-cache to make sure that the HTML response itself is not cached. No-cache could cause revalidation, and the client will correctly receive a new version of the HTML response and static assets. The React library version will change when you update the library, and hero.png will also change when you edit the picture. When you build static assets with versioning/hashing mechanisms, adding a version/hash to the filename or query string is a good way to manage caching. Clients can use this header when the user requires the response to not only be fresh, but also requires that it won’t be updated for a period of time.