Out-of-date TAF returned for nearest airport

[flaparoo]

Hi

My interpretation of requesting a TAF for the nearest airport would be that the nearest valid report is returned. However, the API currently returns a TAF from the nearest airport, regardless whether or not it is still valid.

For example, the request https://avwx.rest/api/taf/-31.52,115.94?onfail=nearest resulted in (filtered for end_time, meta and raw):

{
  "end_time": {
    "dt": "2023-12-04T09:00:00Z",
    "repr": "0409"
  },
  "meta": {
    "stations_updated": "2023-10-28",
    "timestamp": "2023-12-04T11:28:55.201236Z"
  },
  "raw": "YGIG 032209Z 0400/0409 20008KT 9999 SCT025 FM040200 22016KT 9999 FEW035 RMK T 22 26 27 23 Q 1016 1016 1016 1016"
}

Note the report end-time of "0409" but the request was made almost 2.5h later (ie. after "0411").
Also note that I've tried the onfail=nearest option, but it didn't make a difference.

An airport with a 24/7 TAF (YPEA) would be available only slightly further away from the requested location.

[devdupont]

I agree with your assessment. Right now, the only validity check is made against the cached version, not one that comes in as a new report, which is what I guess happened here.

Under normal circumstances, the API is designed to return expired reports if that is still the latest one provided by the regional service. However, I do agree that an invalid report, even if it's the most recent, should trigger the nearest fallback when explicitly specified. I don't agree with changing it under other circumstances.

This work can be included alongside #33 since they both involve the nearest onfail handling.