Querying for a single ZIM URLs gives wrong results

[benoit74]

Querying for two ZIMs (latest one and the one before on a single title) gives expected results:

https://api.cms.openzim.org/v1/books/zims?zim_ids=8ec5b0b8-a8ce-acd9-e414-5a97d8187617&zim_ids=0ff05730-3ead-f792-b942-f0884feb70c2

{
  "urls": {
    "8ec5b0b8-a8ce-acd9-e414-5a97d8187617": [
      {
        "kind": "download",
        "url": "https://download.kiwix.org/zim/ted/ted_mul_diversity_2026-01.zim",
        "collection": "Kiwix"
      }
    ],
    "0ff05730-3ead-f792-b942-f0884feb70c2": [
      {
        "kind": "download",
        "url": "https://download.kiwix.org/zim/ted/ted_mul_diversity_2026-04.zim",
        "collection": "Kiwix"
      },
      {
        "kind": "view",
        "url": "https://browse.library.kiwix.org/viewer#ted_mul_diversity_2026-04",
        "collection": "Kiwix"
      }
    ]
  }
}

Querying for a single ZIM does not work as expected: it should give "consistent" (and accurate) results without a view link:

Currently:

https://api.cms.openzim.org/v1/books/zims?zim_ids=8ec5b0b8-a8ce-acd9-e414-5a97d8187617

{
  "urls": {
    "8ec5b0b8-a8ce-acd9-e414-5a97d8187617": [
      {
        "kind": "download",
        "url": "https://download.kiwix.org/zim/ted/ted_mul_diversity_2026-01.zim",
        "collection": "Kiwix"
      },
      {
        "kind": "view",
        "url": "https://browse.library.kiwix.org/viewer#ted_mul_diversity_2026-01",
        "collection": "Kiwix"
      }
    ]
  }
}

Expected:

{
  "urls": {
    "8ec5b0b8-a8ce-acd9-e414-5a97d8187617": [
      {
        "kind": "download",
        "url": "https://download.kiwix.org/zim/ted/ted_mul_diversity_2026-01.zim",
        "collection": "Kiwix"
      }
    ]
  }
}

[elfkuzco]

Error comes from the fact that code always try to ensure there is at least one view URL per title+flavour combination. Fix would require to know all the book ids which is the equivalent of fetching all the books in the database so you can know that the current zim_id isn't the 'latest' . Assumption was that the caller (in this case the UI) would know about all the ZIM IDs.

Not sure how to go about this but one simple way would be to constrain the query to a specific title, so, route would change too to contain the specific title we are fetching it's books. Rationale is that this route is called from a speicifc title page but I don't know how the zimfarm would know the title id. Maybe it would use a title name instead.

[benoit74]

I don't think that we need to know all the books, but only all the books of the titles associated with queried ZIM IDs.

In other words zim IDs => book IDs => title IDs => titles books IDs (all books of the titles to which the ZIM IDs are attached) => apply criteria to find latest one => filter to return only queried zim IDs

WDYT?

[elfkuzco]

Works