up.protocol X-Up-Version

HTTP header

This request header contains the current Unpoly version to mark this request as a fragment update.

Server-side code may check for the presence of an X-Up-Version header to distinguish fragment updates from full page loads.

The X-Up-Version header is guaranteed to be set for all requests made through Unpoly.

Example

The user updates a fragment. Unpoly automatically includes the following request header:

X-Up-Version: 1.0.0

The server chooses to render different HTML for Unpoly requests, e.g. by excluding the document <head> and only rendering the <body>. The server responds with the following HTTP:

Vary: X-Up-Version

<body>
  ...
</body>

Note

Request headers that influenced a response should be listed in a Vary response header. This tells Unpoly to partition its cache for that URL so that each request header value gets separate cache entries.