git ssb

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/* ssb-about
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 * factored out of ssb-notifier
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 *
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 * TODO:
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 * - publish as own module
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 * - handle live updates and reconnecting
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 * - deprecate when ssb-names is used in scuttlebot
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 */
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var pull = require('pull-stream')
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var cat = require('pull-cat')
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var asyncMemo = require('asyncmemo')
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var u = require('./util')
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var ref = require('ssb-ref')
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function getLink(obj) {
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  return typeof obj === 'string' ? obj : obj ? obj.link : null
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}
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module.exports = function (sbot, id) {
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  var getAbout = asyncMemo(getAboutFull, sbot, id)
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  getAbout.getName = function (id, cb) {
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    getAbout(id, function (err, about) {
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      cb(err, about && about.name)
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    })
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  }
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  getAbout.getImage = function (id, cb) {
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    getAbout(id, function (err, about) {
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      cb(err, about && about.image)
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    })
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  }
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  return getAbout
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}
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// Get About info (name and icon) for a feed.
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function getAboutFull(sbot, source, dest, cb) {
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  var info = {}
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  var target = dest.target || dest
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  var owner = dest.owner || dest
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  pull(
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    cat([
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      // First get About info that we gave them.
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      sbot.links({
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        source: source,
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        dest: target,
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        rel: 'about',
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        values: true,
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        reverse: true
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      }),
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      // If that isn't enough, then get About info that they gave themselves.
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      sbot.links({
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        source: owner,
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        dest: target,
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        rel: 'about',
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        values: true,
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        reverse: true
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      }),
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      // If that isn't enough, then get About info from other feeds
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      sbot.links({
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        dest: target,
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        rel: 'about',
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        values: true,
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        reverse: true
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      }),
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      // Finally, get About info from the thing itself (if possible)
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      u.readOnce(function (cb) {
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        if (ref.isMsg(target)) {
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          sbot.get(target, function (err, value) {
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            cb(null, {key: target, value: value})
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          })
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        } else {
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          cb()
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        }
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      })
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    ]),
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    pull.filter(function (msg) {
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      return msg && msg.value && msg.value.content
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    }),
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    pull.drain(function (msg) {
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      if (info.name && info.image) return false
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      var c = msg.value.content
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      if (!info.name && c.name)
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        info.name = c.name
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      if (!info.image && c.image)
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        info.image = getLink(c.image)
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    }, function (err) {
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        if (err && err !== true) return cb(err)
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        if (!info.name) info.name = u.truncate(target, 20)
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        cb(null, info)
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    })
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  )
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  // Keep updated as changes are made
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  pull(
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    sbot.links({
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      dest: target,
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      rel: 'about',
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      live: true,
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      old: false,
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      values: true,
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    }),
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    pull.drain(function (msg) {
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      if (!msg.value) return
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      var c = msg.value.content
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      if (!c) return
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      if (msg.value.author == source || msg.value.author == owner) {
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        // TODO: give about from source (self) priority over about from owner
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        if (c.name)
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          info.name = c.name
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        if (c.image)
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          info.image = getLink(c.image)
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      } else {
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        if (c.name && !info.name)
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          info.name = c.name
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        if (c.image && !info.image)
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          info.image = getLink(c.image)
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      }
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    }, function (err) {
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      if (err) console.error('about', err)
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    })
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  )
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}
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