feat: add support for text representation as CID

This change adds two functions:

- createFromCID accepts CID as String|CID|Buffer and created PeerId from
  the multihash value inside of it
- toCIDString serializes PeerId multihash into a CIDv1 in Base32,
  as agreed in libp2p/specs#209

License: MIT
Signed-off-by: Marcin Rataj <lidel@lidel.org>

package.json

@@ -40,6 +40,7 @@
     "dirty-chai": "^2.0.1"
   },
   "dependencies": {
+    "cids": "~0.7.1",
     "class-is": "^1.1.0",
     "libp2p-crypto": "~0.17.0",
     "multihashes": "~0.4.15",

src/index.js

@@ -5,6 +5,7 @@
 'use strict'
 
 const mh = require('multihashes')
+const CID = require('cids')
 const cryptoKeys = require('libp2p-crypto/src/keys')
 const assert = require('assert')
 const withIs = require('class-is')
@@ -122,6 +123,12 @@ class PeerId {
     return this._idB58String
   }
 
+  // return string representation from RFC 0001: https://github.com/libp2p/specs/pull/209
+  toCIDString () {
+    const cid = new CID(1, 'libp2p-key', this.id, 'base32')
+    return cid.toBaseEncodedString('base32')
+  }
+
   isEqual (id) {
     if (Buffer.isBuffer(id)) {
       return this.id.equals(id)
@@ -187,6 +194,18 @@ exports.createFromB58String = (str) => {
   return new PeerIdWithIs(mh.fromB58String(str))
 }
 
+exports.createFromCID = (cid) => {
+  if (typeof cid === 'string' || Buffer.isBuffer(cid)) {
+    cid = new CID(cid)
+  } else if (CID.isCID(cid)) {
+    CID.validateCID(cid) // throws on error
+  } else {
+    // provide more meaningful error than the one in CID.validateCID
+    throw new Error('Supplied cid value is neither String|CID|Buffer')
+  }
+  return new PeerIdWithIs(cid.multihash)
+}
+
 // Public Key input will be a buffer
 exports.createFromPubKey = async (key) => {
   let buf = key

test/peer-id.spec.js

@@ -8,6 +8,7 @@ chai.use(dirtyChai)
 const expect = chai.expect
 const crypto = require('libp2p-crypto')
 const mh = require('multihashes')
+const CID = require('cids')
 
 const PeerId = require('../src')
 
@@ -17,6 +18,8 @@ const testId = require('./fixtures/sample-id')
 const testIdHex = testId.id
 const testIdBytes = mh.fromHexString(testId.id)
 const testIdB58String = mh.toB58String(testIdBytes)
+const testIdCID = new CID(1, 'libp2p-key', testIdBytes)
+const testIdCIDString = testIdCID.toBaseEncodedString('base32')
 
 const goId = require('./fixtures/go-private-key')
 
@@ -63,27 +66,68 @@ describe('PeerId', () => {
     }).to.throw(/immutable/)
   })
 
-  it('recreate an Id from Hex string', () => {
+  it('recreate from Hex string', () => {
     const id = PeerId.createFromHexString(testIdHex)
-    expect(testIdBytes).to.deep.equal(id.id)
+    expect(testIdBytes).to.deep.equal(id.toBytes())
   })
 
-  it('Recreate an Id from a Buffer', () => {
+  it('recreate from a Buffer', () => {
     const id = PeerId.createFromBytes(testIdBytes)
     expect(testId.id).to.equal(id.toHexString())
+    expect(testIdBytes).to.deep.equal(id.toBytes())
   })
 
-  it('Recreate a B58 String', () => {
+  it('recreate from a B58 String', () => {
     const id = PeerId.createFromB58String(testIdB58String)
     expect(testIdB58String).to.equal(id.toB58String())
+    expect(testIdBytes).to.deep.equal(id.toBytes())
   })
 
-  it('Recreate from a Public Key', async () => {
+  it('recreate from CID object', () => {
+    const id = PeerId.createFromCID(testIdCID)
+    expect(testIdCIDString).to.equal(id.toCIDString())
+    expect(testIdBytes).to.deep.equal(id.toBytes())
+  })
+
+  it('recreate from Base58 String (CIDv0))', () => {
+    const id = PeerId.createFromCID(testIdB58String)
+    expect(testIdCIDString).to.equal(id.toCIDString())
+    expect(testIdBytes).to.deep.equal(id.toBytes())
+  })
+
+  it('recreate from CIDv1 Base32', () => {
+    const id = PeerId.createFromCID(testIdCIDString)
+    expect(testIdCIDString).to.equal(id.toCIDString())
+    expect(testId.id).to.equal(id.toHexString())
+  })
+
+  it('recreate from CID Buffer', () => {
+    const id = PeerId.createFromCID(testIdCID.buffer)
+    expect(testIdCIDString).to.equal(id.toCIDString())
+    expect(testIdBytes).to.deep.equal(id.toBytes())
+  })
+
+  it('throws on invalid CID value', async () => {
+    const invalidCID = 'QmaozNR7DZHQK1ZcU9p7QdrshMvXqWK6gpu5rmrkPdT3L'
+    expect(() => {
+      PeerId.createFromCID(invalidCID)
+    }).to.throw(/multihash unknown function code: 0x50/)
+  })
+
+  it('throws on invalid CID object', async () => {
+    const invalidCID = {}
+    expect(() => {
+      PeerId.createFromCID(invalidCID)
+    }).to.throw(/Supplied cid value is neither String|CID|Buffer/)
+  })
+
+  it('recreate from a Public Key', async () => {
     const id = await PeerId.createFromPubKey(testId.pubKey)
     expect(testIdB58String).to.equal(id.toB58String())
+    expect(testIdBytes).to.deep.equal(id.toBytes())
   })
 
-  it('Recreate from a Private Key', async () => {
+  it('recreate from a Private Key', async () => {
     const id = await PeerId.createFromPrivKey(testId.privKey)
     expect(testIdB58String).to.equal(id.toB58String())
     const encoded = Buffer.from(testId.privKey, 'base64')
@@ -92,7 +136,7 @@ describe('PeerId', () => {
     expect(id.marshalPubKey()).to.deep.equal(id2.marshalPubKey())
   })
 
-  it('Recreate from Protobuf', async () => {
+  it('recreate from Protobuf', async () => {
     const id = await PeerId.createFromProtobuf(testId.marshaled)
     expect(testIdB58String).to.equal(id.toB58String())
     const encoded = Buffer.from(testId.privKey, 'base64')