git ssb

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var FlumeQueryLinks = require('./lib/flumeview-links-raw')
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var ref = require('ssb-ref')
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var deepEqual = require('deep-equal')
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var extend = require('xtend')
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var matchChannel = /^#[^\s#]+$/
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var ssbKeys = require('ssb-keys')
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var toUrlFriendly = require('base64-url').escape
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var indexes = [
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  { key: 'DTS', value: [['dest'], ['timestamp']] },
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  { key: 'DTA', value: [['dest'], ['value', 'timestamp']] }, // asserted timestamp
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  { key: 'TDT', value: [['value', 'content', 'type'], ['dest'], ['value', 'timestamp']] }
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]
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var indexVersion = 3
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exports.name = 'backlinks'
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exports.version = require('./package.json').version
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exports.manifest = {
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  read: 'source'
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}
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exports.init = function (ssb, config) {
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  return ssb._flumeUse(
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    `backlinks-${toUrlFriendly(ssb.id.slice(1, 10))}`,
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    FlumeQueryLinks(indexes, extractLinks, indexVersion, unbox)
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  )
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  function unbox (msg) {
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    if (typeof msg.value.content === 'string') {
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      var value = unboxValue(msg.value)
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      if (value) {
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        return {
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          key: msg.key, value: value, timestamp: msg.timestamp
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        }
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      }
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    }
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    return msg
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  }
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  function unboxValue (value) {
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    var plaintext = null
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    try {
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      plaintext = ssbKeys.unbox(value.content, ssb.keys.private)
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    } catch (ex) {}
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    if (!plaintext) return null
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    return {
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      previous: value.previous,
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      author: value.author,
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      sequence: value.sequence,
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      timestamp: value.timestamp,
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      hash: value.hash,
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      content: plaintext,
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      private: true
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    }
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  }
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}
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function extractLinks (msg, emit) {
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  var links = new Set()
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  walk(msg.value.content, function (path, value) {
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    // HACK: handle legacy channel mentions
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    if (deepEqual(path, ['channel']) && typeof value === 'string' && value.length < 30) {
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      value = `#${value.replace(/\s/g, '')}`
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    }
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    // TODO: should add channel matching to ref.type
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    if (ref.type(value) || isChannel(value)) {
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      links.add(value)
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    }
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  })
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  links.forEach(link => {
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    emit(extend(msg, {
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      dest: link
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    }))
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  })
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}
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function isChannel (value) {
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  return typeof value === 'string' && value.length < 30 && matchChannel.test(value)
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}
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function walk (obj, fn, prefix) {
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  if (obj && typeof obj === 'object') {
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    for (var k in obj) {
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      walk(obj[k], fn, (prefix || []).concat(k))
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    }
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  } else {
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    fn(prefix, obj)
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  }
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}
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