Fix/use option string as domain type

[Ryanmtate]

Description

Changes domains to use a Option<String> type instead of Vec<String>. This was causing an error with vc playground verification.

Other considerations

I've left the domains property as-is, but we should consider changing this value to domain. WDYT @timothee-haudebourg ?

Tested

Tested in sprucekit mobile.

[timothee-haudebourg]

There can be more than one value for the domain property, see the specification here:

If specified, the associated value MUST be either a string, or an unordered set of strings.

So Vec<String> is correct, but the serialization when there is only one value is wrong. You can fix it using the value_or_array serializer defined in the syntax module of ssi-vc crate like this:

#[serde(
    with = "value_or_array",
    skip_serializing_if = "Vec::is_empty"
)]
pub domains: Vec<String> // or &'a [String]

This way if the array contains only one item, this item will be serialized directly.

[Ryanmtate]

There can be more than one value for the domain property, see the specification here:

If specified, the associated value MUST be either a string, or an unordered set of strings.

So Vec<String> is correct, but the serialization when there is only one value is wrong. You can fix it using the value_or_array serializer defined in the syntax module of ssi-vc crate like this:

#[serde(
    with = "value_or_array",
    skip_serializing_if = "Vec::is_empty"
)]
pub domains: Vec<String> // or &'a [String]

This way if the array contains only one item, this item will be serialized directly.

Nice, this worked well!

since ssi-vc depends on data-integrity, I copied the implementation and re-used it within the data-integrity crate.

This branch is a bit of a misnomer, but the implementation is working in sprucekit mobile.

[timothee-haudebourg]

🚀

[timothee-haudebourg]

I approved it, but please wait for the end of CI to be sure 😅