Restrict stream_id Character Set for URL Parameter Compatibility

[thomasdarimont]

The current specification draft for the Shared Signals Framework defines stream_id as follows:

stream_id

Transmitter-Supplied, REQUIRED. A string that uniquely identifies the stream. A Transmitter MUST generate a unique ID for each of its non-deleted streams at the time of stream creation.

Since stream_id is intended to be used as a URL parameter, it is important to ensure that the character set is restricted to those that are safe for use in URLs. Without such a restriction, there is potential for issues with URL encoding/decoding or interoperability across systems.

Proposed Change

Add the following normative language to the specification:

The stream_id value MUST be limited to characters that are safe for use in URL parameters as defined in RFC3986.
Specifically, stream_id MUST conform to the "unreserved" character set defined in Section 2.3 of RFC 3986, which includes alphanumeric
characters (A-Z, a-z, 0-9), hyphen (-), period (.), underscore (_), and tilde (~).
A Transmitter MUST validate that all stream_id values conform to this character set.

This addition ensures that stream_id is URL-safe and can be used reliably as a URL parameter without requiring additional encoding or risk of invalid characters.

[tulshi]

We could include this in v1, marked it as such, but we can discuss in today's call.

[FragLegs]

If we want to maintain backwards compatibility, we need to say that this character set is RECOMMENDED