Since most of PL/pgSQL functions accept a `uuid` domain, we get an error
if the value is not valid, forcing us to return an HTTP 500, as we
can not detect that the error was due to that.
Instead, i now validate that the slug is indeed a valid UUID before
attempting to send it to the database, returning the correct HTTP error
code and avoiding useless calls to the database.
I based the validation function of Parse() from Google’s uuid package[0]
because this function is an order or magnitude faster in benchmarks:
goos: linux
goarch: amd64
pkg: dev.tandem.ws/tandem/numerus/pkg
cpu: Intel(R) Core(TM) i5-6200U CPU @ 2.30GHz
BenchmarkValidUuid-4 36946050 29.37 ns/op
BenchmarkValidUuid_Re-4 3633169 306.70 ns/op
The regular expression used for the benchmark was:
var re = regexp.MustCompile("^[a-fA-F0-9]{8}-[a-fA-F0-9]{4}-4[a-fA-F0-9]{3}-[8|9|aA|bB][a-fA-F0-9]{3}-[a-fA-F0-9]{12}$")
And the input parameter for both functions was the following valid UUID,
because most of the time the passed UUID will be valid:
"f47ac10b-58cc-0372-8567-0e02b2c3d479"
I did not use the uuid package, even though it is in Debian’s
repository, because i only need to check whether the value is valid,
not convert it to a byte array. As far as i know, that package can not
do that.
[0]: https://github.com/google/uuid
