TimestampFilter uses wrong format when timezone != GMT

[metskem]

I am using the following code(snippet) :

dateFilter := client.TimestampFilterList{}
dateFilter.Before(graceDate)

serviceInstanceListOptions := client.ServiceInstanceListOptions{
      ListOptions:          &client.ListOptions{UpdatedAts: dateFilter},
}
serviceInstances, err := cfClient.ServiceInstances.ListAll(ctx, &serviceInstanceListOptions)

This works fine as long as your local timezone is GMT, then RCF3339 formats to something like 'YYYY-MM-DDThh:mm:ssZ', which is the format the CF V3 API expects.
In my case the timezone is Europe/Amsterdam, and then RFC3339 formats to 'YYYY-MM-DDThh:mm:ss+02:00'

The ListAll call returns the error:

error executing GET request for /v3/service_instances?updated_ats%5Blt%5D=2025-05-10T11%3A54%3A11%2B02%3A00: cfclient error (CF-BadQueryParameter|10005): The query parameter is invalid: Updated ats has an invalid timestamp format. Timestamps should be formatted as 'YYYY-MM-DDThh:mm:ssZ'

My guess is this requires some tweaks in the Serializer?

Thanks!

[metskem]

BTW, the unescaped URL is

/v3/service_instances?updated_ats[lt]=2025-05-10T11:54:11+02:00

Maybe changing

timestamp.Format(time.RFC3339)

to

timestamp.UTC().Format(time.RFC3339)

would suffice.

[sneal]

You're correct, the API expects all timestamps to be in UTC, no timezone offset.

I worry that if the client serializer auto-converts the given timestamp to UTC it will not be what the consumer of the client expected. I think it's probably better to get an error so the client consumer knows to pass a UTC timestamp and knows there's a conversion happening. If anything I think I might like to see a clearer error message from the client instead of a query parameter error returned from the API. What do you think?

[metskem]

Hmm, TBH the results being returned this way would be exactly what I expected.
The timestamp passed in by the consumer is honored.
If the consumer would pass a Europe/Amsterdam timestamp of 09:00, or a UTC timestamp of 07:00, he would get the same results.