Extend "personium-localunit:" url scheme and support it.

[SawamiWataru]

URL Scheme "personium-localunit"

URL scheme, "personium-localunit" was originally introduced to allow users to use relative URL from unit root so that the following two URL are to be interpreted as identical.

personium-localunit:{/path/}
{UnitRootURL}{/path/}

This worked well for path-based Cell URL and users can write the URL of a certain Cell without explicitly writing out UNIT FQDN which may change upon domain name change events.

Further consideration needed for per-Cell FQDN setting

From 1.7.x, Personium now urges users to use per-Cell FQDN style. Using the above URL scheme, however, the new per-Cell FQDN style Cell URL can not be written in a "relative" manner. So we need to introduce new mechanism to provide ways to write Cell URL without explicitly writing out Unit Root URL.

Extension of the scheme.

By extending the current "personium-localunit" URL scheme to allow a new syntax using two colons, the above goal can be achieved.

Single colon

This syntax remains the same as the existing spec.

relative URL	interepretation	note
personium-localunit:/__ctl	https://unit.example/_ctl
personium-localunit:/cellname/	https://unit.example/cellname/
personium-localunit:cellname/	https://unit.example/cellname/
personium-localunit:cellname	https://unit.example/cellname

Two colons

Newly introduced syntax, writing cell name after the first colon, followed by another colon and the cell-local path allows users to write any URL on another cell on the same unit in a relative manner.

relative URL	interepretation	note
personium-localunit:cellname:	https://cellname.unit.example
personium-localunit:cellname:/	https://cellname.unit.example/
personium-localunit:cellname:/box/some/path	https://cellname.unit.example/box/some/path

Implementations required

Util function to interpret the newly introduced syntax of this URL scheme

Issuing TransCell Token

URL specified in the "p_target" parameter should interpret new syntax at TokenEndpoint

TransCell Token evaluation