The final say for what is and is not a valid
Because, from a technical point-of-view, a
Also, there currently is no canonical syntax for a
But, having said that, we can infer a minimum syntax for what should be considered a valid
Part of the process of resolving a
Here is an example of transforming a
at sign ↓ @joeblow@example.com ← Fediverse ID acct:joeblow@example.com ← acct URI ↑ no at sign
A client would then make a request to:
https://example.com/.well-known/host-meta
To discover what the (template) URL for
https://example.com/.well-known/webfinger?resource={uri}
Then make a request to:
https://example.com/.well-known/webfinger?resource=acct:joeblow@example.com
Inferring from IETF RFC-7565 (The 'acct' URI Scheme) and referenced IEFC RFCs, the syntax of a
fediverseID = "@" actor "@" host
Where “actor” is defined as:
actor = unreserved / sub-delims 0*( unreserved / pct-encoded / sub-delims ) unreserved = ALPHA / DIGIT / "-" / "." / "_" / "~" sub-delims = "!" / "$" / "&" / "'" / "(" / ")" / "*" / "+" / "," / ";" / "=" pct-encoded = "%" HEXDIG HEXDIG ALPHA = %x41-5A / %x61-7A ; A-Z / a-z DIGIT = %x30-39 ; 0-9 HEXDIG = DIGIT / "A" / "B" / "C" / "D" / "E" / "F"
(Again note that an implementation could support more characters for “actor” than what is given by this definition.)
And “host” is defined as
host = IP-literal / IPv4address / reg-name IP-literal = "[" ( IPv6address / IPvFuture ) "]" IPv6address = 6( h16 ":" ) ls32 / "::" 5( h16 ":" ) ls32 / [ h16 ] "::" 4( h16 ":" ) ls32 / [ *1( h16 ":" ) h16 ] "::" 3( h16 ":" ) ls32 / [ *2( h16 ":" ) h16 ] "::" 2( h16 ":" ) ls32 / [ *3( h16 ":" ) h16 ] "::" h16 ":" ls32 / [ *4( h16 ":" ) h16 ] "::" ls32 / [ *5( h16 ":" ) h16 ] "::" h16 / [ *6( h16 ":" ) h16 ] "::" h16 = 1*4HEXDIG ls32 = ( h16 ":" h16 ) / IPv4address IPvFuture = "v" 1*HEXDIG "." 1*( unreserved / sub-delims / ":" ) IPv4address = dec-octet "." dec-octet "." dec-octet "." dec-octet dec-octet = DIGIT ; 0-9 / %x31-39 DIGIT ; 10-99 / "1" 2DIGIT ; 100-199 / "2" %x30-34 DIGIT ; 200-249 / "25" %x30-35 ; 250-255 reg-name = *( unreserved / pct-encoded / sub-delims )