git ssb

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var ref = require('ssb-ref')
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var caps = {invite: require('./cap')}
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var ssbKeys = require('ssb-keys')
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var createIsBase64 = require('is-canonical-base64')
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function isObject (o) {
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  return o && 'object' === typeof o
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}
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// signatures have a type (eg `.ed25519`) at the end,
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// but not gonna check it right here.
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var signature_rx = createIsBase64('', '\\.sig\\.\\w+')
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var box_rx = createIsBase64()
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function isSignature(b) {
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  return signature_rx.test(b)
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}
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function isMaybeBase64(b) {
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  return b === undefined || box_rx.test(b)
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}
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exports.isInvite = function (msg, caps) {
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  if(!isObject(caps)) throw new Error('caps must be provided')
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  //return true
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  return isObject(msg) && isObject(msg.content) && (
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    'user-invite' === msg.content.type &&
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    ref.isFeed(msg.content.host) &&
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    ref.isFeed(msg.content.invite) &&
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    isMaybeBase64(msg.content.reveal) &&
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    isMaybeBase64(msg.content.public) &&
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    // signature must be valid !!!
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    ssbKeys.verifyObj(msg.content.invite, caps.userInvite, msg.content)
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  )
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}
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exports.isAccept = function (msg) {
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  return isObject(msg) && isObject(msg.content) && (
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    'user-invite/accept' === msg.content.type &&
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    msg.content.id == msg.author &&
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    ref.isMsg(msg.content.receipt) &&
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    isMaybeBase64(msg.content.key) &&
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    // can't verify this without having the invite message.
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    // (that's intentional, forces implementers not to cut corners,
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    // but to check that the receipt is correct)
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    isSignature(msg.content.signature)
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  )
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}
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exports.isConfirm = function (msg) {
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  return isObject(msg) && isObject(msg.content) && (
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    'user-invite/confirm' === msg.content.type &&
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    exports.isAccept(msg.content.embed) &&
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    //second pointer back to receipt, so that links can find it
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    //(since it unfortunately does not handle links nested deeper
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    //inside objects. when we look up the message,
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    //confirm that content.embed.content.receipt is the same)
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    msg.content.embed.content.receipt === msg.content.receipt
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  )
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}
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