feat: export blockstore key encode/decode utils (#206)

* feat: export blockstore key encode/decode utils

These have already been duplicated twice in js-ipfs. This exposes utility functions to encode a CID as a blockstore Key and decode a blockstore Key to a CID.

refs https://github.com/ipfs/js-ipfs/pull/2022/files#r303389863

License: MIT
Signed-off-by: Alan Shaw <[email protected]>

* chore: appease linter

License: MIT
Signed-off-by: Alan Shaw <[email protected]>

Author: Alan Shaw

README.md

@@ -141,7 +141,7 @@ Arguments:
     * `root` (defaults to [`datastore-fs`](https://github.com/ipfs/js-datastore-fs#readme) in Node.js and [`datastore-level`](https://github.com/ipfs/js-datastore-level#readme) in the browser). Defines the back-end type used for gets and puts of values at the root (`repo.set()`, `repo.get()`)
     * `blocks` (defaults to [`datastore-fs`](https://github.com/ipfs/js-datastore-fs#readme) in Node.js and [`datastore-level`](https://github.com/ipfs/js-datastore-level#readme) in the browser). Defines the back-end type used for gets and puts of values at `repo.blocks`.
     * `keys` (defaults to [`datastore-fs`](https://github.com/ipfs/js-datastore-fs#readme) in Node.js and [`datastore-level`](https://github.com/ipfs/js-datastore-level#readme) in the browser). Defines the back-end type used for gets and puts of encrypted keys at `repo.keys`
-    * `datastore` (defaults to [`datastore-level`](https://github.com/ipfs/js-datastore-level#readme)). Defines the back-end type used as the key-valye store used for gets and puts of values at `repo.datastore`.
+    * `datastore` (defaults to [`datastore-level`](https://github.com/ipfs/js-datastore-level#readme)). Defines the back-end type used as the key-value store used for gets and puts of values at `repo.datastore`.
 
 ```js
 const repo = new Repo('path/to/repo')

src/blockstore-utils.js

@@ -0,0 +1,29 @@
+'use strict'
+
+const base32 = require('base32.js')
+const { Key } = require('interface-datastore')
+const CID = require('cids')
+
+/**
+ * Transform a cid to the appropriate datastore key.
+ *
+ * @param {CID} cid
+ * @returns {Key}
+ */
+exports.cidToKey = cid => {
+  const enc = new base32.Encoder()
+  return new Key('/' + enc.write(cid.buffer).finalize(), false)
+}
+
+/**
+ * Transform a datastore Key instance to a CID
+ *
+ * @param {Key} key
+ * @returns {CID}
+ */
+exports.keyToCid = key => {
+  // Block key is of the form /<base32 encoded string>
+  const decoder = new base32.Decoder()
+  const buff = decoder.write(key.toString().slice(1)).finalize()
+  return new CID(Buffer.from(buff))
+}

src/blockstore.js

@@ -2,32 +2,10 @@
 
 const core = require('datastore-core')
 const ShardingStore = core.ShardingDatastore
-const Key = require('interface-datastore').Key
-const base32 = require('base32.js')
 const Block = require('ipfs-block')
 const CID = require('cids')
 const errcode = require('err-code')
-
-/**
- * Transform a raw buffer to a base32 encoded key.
- *
- * @param {Buffer} rawKey
- * @returns {Key}
- */
-const keyFromBuffer = (rawKey) => {
-  const enc = new base32.Encoder()
-  return new Key('/' + enc.write(rawKey).finalize(), false)
-}
-
-/**
- * Transform a cid to the appropriate datastore key.
- *
- * @param {CID} cid
- * @returns {Key}
- */
-const cidToDsKey = (cid) => {
-  return keyFromBuffer(cid.buffer)
-}
+const { cidToKey } = require('./blockstore-utils')
 
 module.exports = async (filestore, options) => {
   const store = await maybeWithSharding(filestore, options)
@@ -65,7 +43,7 @@ function createBaseStore (store) {
       if (!CID.isCID(cid)) {
         throw errcode(new Error('Not a valid cid'), 'ERR_INVALID_CID')
       }
-      const key = cidToDsKey(cid)
+      const key = cidToKey(cid)
       let blockData
       try {
         blockData = await store.get(key)
@@ -78,7 +56,7 @@ function createBaseStore (store) {
             throw err
           }
 
-          const otherKey = cidToDsKey(otherCid)
+          const otherKey = cidToKey(otherCid)
           const blockData = await store.get(otherKey)
           await store.put(key, blockData)
           return new Block(blockData, cid)
@@ -98,7 +76,7 @@ function createBaseStore (store) {
         throw new Error('invalid block')
       }
 
-      const k = cidToDsKey(block.cid)
+      const k = cidToKey(block.cid)
       const exists = await store.has(k)
       if (exists) return
       return store.put(k, block.data)
@@ -112,7 +90,7 @@ function createBaseStore (store) {
      */
     async putMany (blocks) {
       const keys = blocks.map((b) => ({
-        key: cidToDsKey(b.cid),
+        key: cidToKey(b.cid),
         block: b
       }))
 
@@ -141,11 +119,11 @@ function createBaseStore (store) {
         throw errcode(new Error('Not a valid cid'), 'ERR_INVALID_CID')
       }
 
-      const exists = await store.has(cidToDsKey(cid))
+      const exists = await store.has(cidToKey(cid))
       if (exists) return exists
       const otherCid = cidToOtherVersion(cid)
       if (!otherCid) return false
-      return store.has(cidToDsKey(otherCid))
+      return store.has(cidToKey(otherCid))
     },
     /**
      * Delete a block from the store
@@ -157,7 +135,7 @@ function createBaseStore (store) {
       if (!CID.isCID(cid)) {
         throw errcode(new Error('Not a valid cid'), 'ERR_INVALID_CID')
       }
-      return store.delete(cidToDsKey(cid))
+      return store.delete(cidToKey(cid))
     },
     /**
      * Close the store

src/index.js

@@ -298,6 +298,7 @@ async function getSize (queryFn) {
 }
 
 module.exports = IpfsRepo
+module.exports.utils = { blockstore: require('./blockstore-utils') }
 module.exports.repoVersion = repoVersion
 module.exports.errors = ERRORS
 

test/blockstore-utils-test.js

@@ -0,0 +1,22 @@
+/* eslint-env mocha */
+'use strict'
+
+const chai = require('chai')
+chai.use(require('dirty-chai'))
+const { expect } = chai
+const { Key } = require('interface-datastore')
+const CID = require('cids')
+const Repo = require('../src')
+
+module.exports = () => {
+  describe('blockstore utils', () => {
+    it('converts a CID to a datastore Key and back', () => {
+      const originalCid = new CID('Qme6KJdKcp85TYbLxuLV7oQzMiLremD7HMoXLZEmgo6Rnh')
+      const key = Repo.utils.blockstore.cidToKey(originalCid)
+      expect(key instanceof Key).to.be.true()
+      const cid = Repo.utils.blockstore.keyToCid(key)
+      expect(cid instanceof CID).to.be.true()
+      expect(originalCid.toString()).to.equal(cid.toString())
+    })
+  })
+}

test/browser.js

@@ -19,6 +19,7 @@ describe('IPFS Repo Tests on the Browser', () => {
 
   require('./repo-test')(repo)
   require('./blockstore-test')(repo)
+  require('./blockstore-utils-test')()
   require('./datastore-test')(repo)
   require('./keystore-test')(repo)
   require('./config-test')(repo)

test/node.js

@@ -103,4 +103,6 @@ describe('IPFS Repo Tests onNode.js', () => {
       require('./interop-test')(repo)
     }
   }))
+
+  require('./blockstore-utils-test')()
 })