1 files changed, 54 insertions, 0 deletions
diff --git a/app/scripts/lib/ens-ipfs/resolver.js b/app/scripts/lib/ens-ipfs/resolver.js
new file mode 100644
index 000000000..fe2dc1134
--- /dev/null
+++ b/app/scripts/lib/ens-ipfs/resolver.js
@@ -0,0 +1,54 @@
+const namehash = require('eth-ens-namehash')
+const multihash = require('multihashes')
+const Eth = require('ethjs-query')
+const EthContract = require('ethjs-contract')
+const registrarAbi = require('./contracts/registrar')
+const resolverAbi = require('./contracts/resolver')
+
+module.exports = resolveEnsToIpfsContentId
+
+
+async function resolveEnsToIpfsContentId ({ provider, name }) {
+  const eth = new Eth(provider)
+  const hash = namehash.hash(name)
+  const contract = new EthContract(eth)
+  // lookup registrar
+  const chainId = Number.parseInt(await eth.net_version(), 10)
+  const registrarAddress = getRegistrarForChainId(chainId)
+  if (!registrarAddress) {
+    throw new Error(`EnsIpfsResolver - no known ens-ipfs registrar for chainId "${chainId}"`)
+  }
+  const Registrar = contract(registrarAbi).at(registrarAddress)
+  // lookup resolver
+  const resolverLookupResult = await Registrar.resolver(hash)
+  const resolverAddress = resolverLookupResult[0]
+  if (hexValueIsEmpty(resolverAddress)) {
+    throw new Error(`EnsIpfsResolver - no resolver found for name "${name}"`)
+  }
+  const Resolver = contract(resolverAbi).at(resolverAddress)
+  // lookup content id
+  const contentLookupResult = await Resolver.content(hash)
+  const contentHash = contentLookupResult[0]
+  if (hexValueIsEmpty(contentHash)) {
+    throw new Error(`EnsIpfsResolver - no content ID found for name "${name}"`)
+  }
+  const nonPrefixedHex = contentHash.slice(2)
+  const buffer = multihash.fromHexString(nonPrefixedHex)
+  const contentId = multihash.toB58String(multihash.encode(buffer, 'sha2-256'))
+  return contentId
+}
+
+function hexValueIsEmpty(value) {
+  return [undefined, null, '0x', '0x0', '0x0000000000000000000000000000000000000000000000000000000000000000'].includes(value)
+}
+
+function getRegistrarForChainId (chainId) {
+  switch (chainId) {
+    // mainnet
+    case 1:
+      return '0x314159265dd8dbb310642f98f50c066173c1259b'
+    // ropsten
+    case 3:
+      return '0x112234455c3a32fd11230c42e7bccd4a84e02010'
+  }
+}