CODEWITHSUNDEEP
resthttp
wberry
wberry

Reputation: 19377

HTTP response code for stale pagination

I have a web service that runs a SQL query, sorted by one of several columns, and returns a single requested page (as in skip M limit N). The UI in front of it follows a 'load more' pattern, accumulating all loaded pages of results in one view.

The problem is new and deleted records, which can happen at any time, causing the result of a 'load more' to be wrongly aligned, and depending on the sort being used, even obscuring new records that should be shown. In addition to an automatic refresh on a timer in the frontend, I'm going to add a timestamp field to the RESTful request and response format to allow the webapp to detect that the view should be completely reloaded on a 'load more' call.

My question is, what HTTP status code is a best fit for this signal? In reviewing the codes I don't see an exact fit. I thought of using 302 Found with a link to 'page 1', but I wonder if that might cause unwanted caching of the redirect. I also thought of 400 Bad Request, but there's nothing actually wrong with the request, it's just the data needs to be reloaded.

Pages are served from a POST /path call where the requested page is provided in a JSON body.

I'm not a complete purist, so anything that would make it work without caching or other side effects is acceptable, but I would like to adhere to REST principles as much as possible.

Upvotes: 0

Views: 251

Answers (1)

Vasiliy Faronov
Vasiliy Faronov

Reputation: 12310

anything that would make it work without caching or other side effects is acceptable

Responses to POST requests are not cacheable unless you explicitly mark them as such. So you can use any combination of status code, response headers and response entity to communicate the “please reload” message to the client.

You can use conditional requests. Include your client’s timestamp in the If-Unmodified-Since header. Respond with 412 Precondition Failed if client is stale. The client will have to know how to reload.

You can try 307 Temporary Redirect, but only if you encode pagination in /path, because upon receiving 307, (I’m assuming you’re doing AJAX here) XMLHttpRequest will transparently re-submit the same POST request to the new Location (at least this is what my Chromium does). Your actual page JSON will have to include metainformation on the range it covers, so that the client knows it has to replace the rows, not append them.

Upvotes: 1

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