git ssb

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var I = require('./valid')
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/*
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uxer (someone who observes an invite, but not directly involved):
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if we see
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  someone post an invite I
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  someone else post a confirmation C that I has been accepted A
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  // OOO that A
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  emded that A inside a C(A)
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  match valid I->A's and interpret them like follows.
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  we only care about confirmations if it's of an invite we follow,
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  and it hasn't been confirmed already.
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{
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  invited: {
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    <alice>: { <bob>: true, ...}
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  }
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  invites: { <invites>, ...}
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  accepts: { <accepts>, ...}
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}
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---
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pub
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  someone connects, using key from an open invite I
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  they request that invite I (by it's id)
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  they send a message accepting A the invite.
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  the pub then posts confirmation (I,A)
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*/
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exports.name = 'invites'
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exports.version = '1.0.0'
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exports.manifest = {
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}
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// KNOWN BUG: it's possible to accept an invite more than once,
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// but peers will ignore subsequent acceptances. it's possible
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// that this could create confusion in certain situations.
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// (but you'd get a feed that some peers thought was invited by Alice
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// other peers would think a different feed accepted that invite)
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// I guess the answer is to let alice reject the second invite?)
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// that would be easier to do if this was a levelreduce? (keys: reduce, instead of a single reduce?)
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exports.init = function (sbot, config) {
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  var index = sbot._flumeUse('invites', Reduce(1, function (acc, data) {
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    if(!acc) acc = {invited: {}, invites:{}, accepts: {}}
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    var msg = data.value
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    var invite, accept
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    if(msg.content.type === 'invite') {
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      invite = msg
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      accept = acc.accepts[data.key]
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    }
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    else if(msg.content.type === 'invite/accept') {
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      accept = msg
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      invite = acc.invites[accept.content.receipt]
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    }
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    else if(msg.content.type === 'invite/confirm') {
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      accept = msg.content.embed
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      invite = acc.invites[accept.content.receipt]
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    }
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    if(invite && accept) {
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      if(invite === true)
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        return acc
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      try {
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        I.validateAccept(accept, invite)
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        //delete matched invites, but _only_ if they are valid.
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        delete acc.accepts[accept.receipt]
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        //but remember that this invite has been processed.
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        acc.invites[accept.receipt] = true
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      } catch (err) {
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        return acc //? or store something?
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      }
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    }
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    else if(invite)
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      acc.invites[data.key] = invite
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    else if(accept)
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      acc.accepts[accept.receipt] = accept
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    return acc
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  }))
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  sbot.auth.hook(function (fn, args) {
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    var id = args[0], cb = args[1]
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    index.get(function (err, v) {
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      if(err) return cb(err)
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      for(var k in v.invites)
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        if(v.invites[k].invite === id)
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          return cb(null, {
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            allow: ['invite.getInvite', 'invites.accept'],
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            deny: null
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          })
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    })
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  })
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  //first
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  invites.getInvite = function (invite_id, cb) {
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    var self = this
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    invites.get(function (err, v) {
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      var invite = v.invites[invite_id]
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      if(err) return cb(err)
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      if(!invite)
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        cb(code(
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          new Error('unknown invite:'+invite_id),
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          'unknown-invite'
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        ))
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      else if(invite === true)
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        cb(code(
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          new Error('invite already used:'+invite_id),
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          'invite-already-used'
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        ))
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      //only allow the guest to request their own invite.
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      else if(self.id !== invite.content.invite)
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        cb(code(
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          new Error('invite did not match client id'),
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          'invite-mismatch'
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        ))
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      else
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        cb(null, v.invites[invite_id])
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    })
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  }
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  var accepted = {}
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  invites.accept = function (accept, cb) {
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    //check if the invite in question hasn't already been accepted.
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    invites.get(function (err, v) {
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      var invite_id = accept.content.receipt
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      var invite = v.invites[invite_id]
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      if(invite === true || accepted[invite_id])
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        return cb(code(
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          new Error('invite already used:'+invite_id),
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          'invite-already-used'
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        ))
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      try {
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        I.validateAccept(accept, invite)
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      } catch (err) {
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        return cb(err)
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      }
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      //there is a little race condition here
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      accepted[invite_id] = true
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      sbot.publish({type: 'invite/confirm', embed: accept}, function (err, msg) {
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        delete accepted[invite_id]
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        cb(err, msg)
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      })
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    })
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  }
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  return invites
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}
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