invite-code client flow

The boardAbout 1 minSpecs

The invite-code client and relay exchange specification describe the delivery and usage of invites-code to clients.

Invites-code are specified hereopen in new window
and can be redeemed on a server. Once a server get back an invitation it will follow the client and as described in message flow specification, server will allow authentication of the client and further network communication processing.
Relay serve a dedicated page for querying invite at GET /invite.
The /invite/ page present a riddle intended to be solvable by a human only.
The /invite/ page must be human-readable webpage.
The /invite/ page must pose a session cookie, client must present back the session cookie on the next step.
Relay expect client to send POST http query /invite/invite-captcha-reponse with the variable captcha in POST body containing the human solved puzzle answer.
Clients should immediately connect to server using the connectWithInvite method.
Server must accept connectWithInvite and respond by internally publishing a follow client message.
Client must then immediately disconnect.
Server must accept SSB connection from client it follow and allow them the following methods: follow, createHistoryStream

In NodeJS this translates to this:

    app.get('/invite/'), (req: Request, res: Response) => {
        // remember riddle response in server session              
    });

    app.post('/invite/invite-captcha-reponse', (req: any, res: Response) => {
        var riddleResponse = req.body.captcha;
        // compare posted response with response expected in server session 
    });

Using a sequence diagram this translates to this:

Upon success, /invite/invite-captcha-reponse must put the invite, as-is in its HTML title tag and may in the visible part of the webpage.
Upon failure, server must not generate and deliver invite.
Client may request and use invite at anytime to be followed and authenticated by the relay.
/invite/ and /invite/invite-captcha-reponse must be valid W3C HTML.
The /invite/ and /invite/invite-captcha-reponse page must be served over HTTPS and port 443 for public domains
The /invite/ and /invite/invite-captcha-reponse page must be served and over HTTP and port 80 for onions domains.
The /invite/ and /invite/invite-captcha-reponse page must optimize for mobile with small screen devices