Unable to parse `updated_at` timestamp from Auth0

[phated]

I'm working on integrating this library with Auth0 and ran into an issue where the format of their updated_at field fails to parse. Their format is "2020-06-16T03:23:10.426Z".

I changed this type to String in the claims.rs and it parses successfully.

[ramosbugs]

looks like @auth0 isn't following the OIDC spec:

Time the End-User's information was last updated. Its value is a JSON number representing the number of seconds from 1970-01-01T0:0:0Z as measured in UTC until the date/time.

somehow they're a certified OIDC implementation but haven't bothered to follow the spec here, making their product incompatible with strongly-typed clients that do adhere to the spec.

that said, I would accept a PR that makes the serde parser also accept ISO 8601 date/time strings behind a non-default feature flag. the updated_at method should continue to return Option<DateTime<Utc>> though.

[phated]

I tried looking into this and the macros leave me complete stumped on trying to PR what you are asking for ☹️

[ramosbugs]

it's probably easiest to add the logic here:

openidconnect-rs/src/macros.rs

Lines 428 to 453 in 82aa3c6

	Option(DateTime(Seconds($field:ident)))) => {
	if $field.is_some() {
	return Err(serde::de::Error::duplicate_field(stringify!($field)));
	} else if let Some(language_tag) = $language_tag_opt {
	return Err(
	serde::de::Error::custom(
	format!(
	concat!("unexpected language tag `{}` for key `", stringify!($field), "`"),
	language_tag.as_ref()
	)
	)
	);
	}
	let seconds = $map.next_value::<Option<Seconds>>()?;
	$field = seconds
	.map(|sec| seconds_to_utc(&sec).map_err(|_| serde::de::Error::custom(
	format!(
	concat!(
	"failed to parse `{}` as UTC datetime (in seconds) for key `",
	stringify!($field),
	"`"
	),
	*sec,
	)
	))).transpose()?;
	};

[ramosbugs]

basically instead of $map.next_value::<Option<Seconds>> we probably need to replace Option<Seconds> with serde_json::Value or some other enum that accepts both strings and JSON numbers, and then accepts/parses the string representation only if the feature flag is enabled