feat: cidV0 and cidV1 support

update multibase and multicodec
add tests
add documentation

Author: daviddias

README.md

@@ -75,7 +75,13 @@ const cid = new CID(base58Multihash)
 
 ## API
 
-### `new CID(codec[, version, hash])`
+### Constructor
+
+- `new CID(<version>, <codec>, <multihash>)`
+- `new CID(<cidStr>)`
+- `new CID(<cid.buffer>)`
+- `new CID(<multihash>)`
+- `new CID(<bs58 encoded multihash>)`
 
 ### `.codec`
 
@@ -85,7 +91,13 @@ const cid = new CID(base58Multihash)
 
 ### `.buffer`
 
-### `.toString()`
+### `.toV0()`
+
+### `.toV1()`
+
+### `.toBaseEncodedString(base)`
+
+Defaults to 'base58btc'
 
 ### `.toJSON()`
 

package.json

@@ -36,6 +36,7 @@
   },
   "dependencies": {
     "multibase": "^0.2.0",
+    "multicodec": "0.1.0",
     "multihashes": "^0.2.2"
   },
   "devDependencies": {
@@ -50,4 +51,4 @@
   "contributors": [
     "Friedel Ziegelmayer <dignifiedquire@gmail.com>"
   ]
-}
+}

src/cid.js

@@ -1,8 +1,13 @@
 'use strict'
 
+/*
+ * Consult table at: https://github.com/multiformats/multicodec
+ */
+
 module.exports = {
-  protobuf: 0,
-  raw: 1,
-  json: 2,
-  cbor: 3
+  raw: new Buffer('00', 'hex'),
+  'dag-pb': new Buffer('70', 'hex'),
+  'dag-cbor': new Buffer('71', 'hex'),
+  'eth-block': new Buffer('90', 'hex'),
+  'eth-tx': new Buffer('91', 'hex')
 }

src/codecs.js

@@ -1,5 +1,120 @@
 'use strict'
 
-const CID = require('./cid')
+const mh = require('multihashes')
+const multibase = require('multibase')
+const multicodec = require('multicodec')
+
+const codecs = require('./codecs')
+
+// CID: <mbase><version><mcodec><mhash>
+
+class CID {
+  /*
+   * if (str)
+   *   if (1st char is on multibase table) -> CID String
+   *   else -> bs58 encoded multihash
+   * else if (Buffer)
+   *   if (0 or 1) -> CID
+   *   else -> multihash
+   * else if (Number)
+   *   -> construct CID by parts
+   *
+   * ..if only JS had traits..
+   */
+  constructor (version, codec, multihash) {
+    if (typeof version === 'string') {
+      if (multibase.isEncoded(version)) { // CID String (encoded with multibase)
+        const cid = multibase.decode(version)
+        this.version = parseInt(cid.slice(0, 1).toString('hex'), 16)
+        this.codec = multicodec.getCodec(cid.slice(1))
+        this.multihash = multicodec.rmPrefix(cid.slice(1))
+      } else { // bs58 string encoded multihash
+        this.codec = 'dag-pb'
+        this.multihash = mh.fromB58String(version)
+        this.version = 0
+      }
+    } else if (Buffer.isBuffer(version)) {
+      const firstByte = version.slice(0, 1)
+      const v = parseInt(firstByte.toString('hex'), 16)
+      if (v === 0 || v === 1) { // CID
+        const cid = version
+        this.version = v
+        this.codec = multicodec.getCodec(cid.slice(1))
+        this.multihash = multicodec.rmPrefix(cid.slice(1))
+      } else { // multihash
+        this.codec = 'dag-pb'
+        this.multihash = version
+        this.version = 0
+      }
+    } else if (typeof version === 'number') {
+      if (typeof codec !== 'string') {
+        throw new Error('codec must be string')
+      }
+      if (!(version === 0 || version === 1)) {
+        throw new Error('version must be a number equal to 0 or 1')
+      }
+      mh.validate(multihash)
+      this.codec = codec
+      this.version = version
+      this.multihash = multihash
+    }
+  }
+
+  get buffer () {
+    switch (this.version) {
+      case 0:
+        return this.multihash
+      case 1:
+        return Buffer.concat([
+          Buffer('01', 'hex'),
+          Buffer(codecs[this.codec]),
+          this.multihash
+        ])
+      default:
+        throw new Error('unsupported version')
+    }
+  }
+
+  toV0 () {
+    return this.multihash
+  }
+
+  toV1 () {
+    return this.buffer
+  }
+
+  /* defaults to base58btc */
+  toBaseEncodedString (base) {
+    base = base || 'base58btc'
+
+    switch (this.version) {
+      case 0:
+        return mh.toB58String(this.multihash)
+      case 1:
+        return multibase.encode(base, this.buffer).toString()
+      default:
+        throw new Error('Unsupported version')
+    }
+  }
+
+  toJSON () {
+    return {
+      codec: this.codec,
+      version: this.version,
+      hash: this.multihash
+    }
+  }
+
+  equals (other) {
+    return this.codec === other.codec &&
+      this.version === other.version &&
+      this.multihash.equals(other.multihash)
+  }
+}
+
+CID.codecs = codecs
+CID.isCID = (other) => {
+  return other.constructor.name === 'CID'
+}
 
 module.exports = CID

src/index.js

@@ -0,0 +1,21 @@
+'use strict'
+
+// CID String: <mbase><version><mcodec><mhash>
+
+const multibase = require('multibase')
+const codecs = require('../../src').codecs
+const multihashing = require('multihashing')
+
+const mh = multihashing(Buffer('oh, hey!'), 'sha2-256')
+const cid = Buffer.concat([
+  new Buffer('01', 'hex'),
+  codecs.dagPB,
+  mh
+])
+
+const cidStr = multibase.encode('base58btc', cid).toString()
+
+console.log('CID String (multibase included)')
+console.log(cidStr)
+console.log('CID in hex (multibase not included)')
+console.log(cid.toString('hex'))