Pagination in Google App EngineSearch API

Question

I want to do pagination in google app engine search api using cursors (not offset). the forward pagination is straight forward , the problem is how to implement the backward pagination.

Answer 1

I guess you're out of luck when it comes to paging backwards using cursors.

The Search API also supports the use of query cursors. Cursors are another way to indicate the point from which to begin a query, allowing you to continue a search from the end of the previous result set. Using a cursor is generally more efficient than using offsets. However, the Search API doesn't currently support a "reverse cursor" as does the Datastore API, making it more difficult to to implement backward paging. For this reason, the example application uses offsets rather than cursors to paginate its query results. You can find an example using cursors here.

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Answer 2

Sorry to revive this old question, but I have a solution for this issue given a few constraints with possible workarounds. Basically, the cursors for previous pages can be stored and reused for revisiting that page.

Constraints:

This requires that pagination is done dynamically (e.g. with Javascript) so that older cursors are not lost. Workaround if pagination is done across html pages, the cursors would need to be passed along.

Users would not be able to arbitrarily select a forward page, and would only be given next/back buttons. Though any previously visited page could easily be jumped to. Workaround could be to internally iterate and discard entries while generating cursors at pagination points until finally reaching the desired results. Then return the list of previous page cursors as well.

All of this requires a lot of extra bookkeeping and complexity, which almost makes the solution purely academic, but I suppose that would depend on how much more efficient cursors are than simply limit/offset. This could be a worthwhile endeavor if your data is such that you don't expect your users to want to jump ahead more than one page at a time (which includes most type of searches).