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Clarification Added: req-fresh.md5 #1349

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Clarification Added: req-fresh.md5 #1349

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Clarification Added
gulgulia17 Jul 6, 2022
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Update _includes/api/en/4x/req-fresh.md
gulgulia17 Jul 7, 2022
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Merge branch 'gh-pages' of github.com:expressjs/expressjs.com into pa…
bjohansebas Dec 12, 2024
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7 changes: 7 additions & 0 deletions _includes/api/en/4x/req-fresh.md
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When the response is still "fresh" in the client's cache `true` is returned, otherwise `false` is returned to indicate that the client cache is now stale and the full response should be sent.

In order to check weather the response is still "fresh" in the client's cache or not, 2 Tags will be used ETag and If-None-Match, ETag will be fetched from response (saved internally from application) and other tag will be recieved from client's request.
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When a client sends the `Cache-Control: no-cache` request header to indicate an end-to-end reload request, this module will return `false` to make handling these requests transparent.

Further details for how cache validation works can be found in the
[HTTP/1.1 Caching Specification](https://tools.ietf.org/html/rfc7234).

```js

// Get value for ETag where you saved it initially, In general you
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This comment isn't very clear. The added example is setting an etag not reading a value.
users do not need to manage or store timestamps to get etags working, so I think this will confuse people

// may use a file to store timestamps with API request name

res.set('ETag', "foo")
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The example that existed wasn't very clear to begin with. Setting an etag here doesn't mean that req.fresh will be true, so the example gets less clear with the addition.

It's easier perhaps to demonstrate that setting a new, highly random etag on every request can guarantee that req.fresh is false. That way we create an example which will always have the demonstrated output.

console.dir(req.fresh)
// => true
```