resolver.js

'use strict'

const mh = require('multihashes')
const promisify = require('promisify-es6')
const reduce = require('async/reduce')
const CID = require('cids')
const Unixfs = require('ipfs-unixfs')
const debug = require('debug')
const log = debug('jsipfs:http:response:resolver')
log.error = debug('jsipfs:http:response:resolver:error')

const dirView = require('./dir-view')
const pathUtil = require('./utils/path')

function getIndexFiles (links) {
  const INDEX_HTML_FILES = [
    'index.html',
    'index.htm',
    'index.shtml'
  ]

  return links.filter((link) => INDEX_HTML_FILES.indexOf(link.name) !== -1)
}

const directory = promisify((ipfs, path, multihash, callback) => {
  mh.validate(mh.fromB58String(multihash))

  ipfs.object.get(multihash, { enc: 'base58' }, (err, dagNode) => {
    if (err) {
      return callback(err)
    }

    // Test if it is a Website
    const indexFiles = getIndexFiles(dagNode.links)

    if (indexFiles.length) {
      return callback(null, indexFiles)
    }

    return callback(null, dirView.render(path, dagNode.links))
  })
})

const multihash = promisify((ipfs, path, callback) => {
  const parts = pathUtil.splitPath(path)
  let firstMultihash = parts.shift()
  let currentCid

  reduce(
    parts,
    firstMultihash,
    (memo, item, next) => {
      try {
        currentCid = new CID(mh.fromB58String(memo))
      } catch (err) {
        return next(err)
      }

      log('memo: ', memo)
      log('item: ', item)

      ipfs.dag.get(currentCid, (err, result) => {
        if (err) {
          return next(err)
        }

        const dagNode = result.value
        // find multihash of requested named-file in current dagNode's links
        let multihashOfNextFile
        const nextFileName = item

        for (let link of dagNode.links) {
          if (link.name === nextFileName) {
            // found multihash of requested named-file
            multihashOfNextFile = mh.toB58String(link.multihash)
            log('found multihash: ', multihashOfNextFile)
            break
          }
        }

        if (!multihashOfNextFile) {
          return next(new Error(`no link named "${nextFileName}" under ${memo}`))
        }

        next(null, multihashOfNextFile)
      })
    }, (err, result) => {
      if (err) {
        return callback(err)
      }

      let cid
      try {
        cid = new CID(mh.fromB58String(result))
      } catch (err) {
        return callback(err)
      }

      ipfs.dag.get(cid, (err, dagResult) => {
        if (err) {
          return callback(err)
        }

        let dagDataObj = Unixfs.unmarshal(dagResult.value.data)
        if (dagDataObj.type === 'directory') {
          let isDirErr = new Error('This dag node is a directory')
          // add memo (last multihash) as a fileName so it can be used by directory
          isDirErr.fileName = result
          return callback(isDirErr)
        }

        callback(null, { multihash: result })
      })
    })
})

module.exports = {
  directory: directory,
  multihash: multihash
}