RFC3986

[spralja]

RFC5545 specifies that the URI value data type must follow the generic URI syntax defined in RFC3986.
In vUri it is stated that:

Uniform resource identifier is basically just an unquoted string.

Is this strictly the case?
If not what would be an example of an invalid URI string?

[niccokunzmann]

From my perspective, there seem to be no restrictions on UID.

However, https://www.rfc-editor.org/rfc/rfc7986.html#section-5.3 states:

This specification updates
[RFC5545] by stating that "UID" values MUST NOT include any data that
might identify a user, host, domain, or any other security- or
privacy-sensitive information. It is RECOMMENDED that calendar user
agents now generate "UID" values that are hex-encoded random
Universally Unique Identifier (UUID) values as defined in
Sections 4.4 and 4.5 of [RFC4122].

See also

• RFC 7986 - additional parameters and values #655
• icalendar.UIDGenerator