feat: metadata book (#638)

* feat: metadata book * chore: address review * chore: address review
libp2p · May 28, 2020 · 166d705 · 166d705
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diff --git a/doc/API.md b/doc/API.md
@@ -29,6 +29,11 @@
   * [`peerStore.keyBook.delete`](#peerstorekeybookdelete)
   * [`peerStore.keyBook.get`](#peerstorekeybookget)
   * [`peerStore.keyBook.set`](#peerstorekeybookset)
+  * [`peerStore.metadataBook.delete`](#peerstoremetadatabookdelete)
+  * [`peerStore.metadataBook.deleteValue`](#peerstoremetadatabookdeletevalue)
+  * [`peerStore.metadataBook.get`](#peerstoremetadatabookget)
+  * [`peerStore.metadataBook.getValue`](#peerstoremetadatabookgetvalue)
+  * [`peerStore.metadataBook.set`](#peerstoremetadatabookset)
   * [`peerStore.protoBook.add`](#peerstoreprotobookadd)
   * [`peerStore.protoBook.delete`](#peerstoreprotobookdelete)
   * [`peerStore.protoBook.get`](#peerstoreprotobookget)
@@ -939,6 +944,146 @@ const publicKey = peerId.pubKey
 peerStore.keyBook.set(peerId, publicKey)
 ```
 
+### peerStore.metadataBook.delete
+
+Delete the provided peer from the book.
+
+`peerStore.metadataBook.delete(peerId)`
+
+#### Parameters
+
+| Name | Type | Description |
+|------|------|-------------|
+| peerId | [`PeerId`][peer-id] | peerId to remove |
+
+#### Returns
+
+| Type | Description |
+|------|-------------|
+| `boolean` | true if found and removed |
+
+#### Example
+
+```js
+peerStore.metadataBook.delete(peerId)
+// false
+peerStore.metadataBook.set(peerId, 'nickname', Buffer.from('homePeer'))
+peerStore.metadataBook.delete(peerId)
+// true
+```
+
+### peerStore.metadataBook.deleteValue
+
+Deletes the provided peer metadata key-value pair from the book.
+
+`peerStore.metadataBook.deleteValue(peerId, key)`
+
+#### Parameters
+
+| Name | Type | Description |
+|------|------|-------------|
+| peerId | [`PeerId`][peer-id] | peerId to remove |
+| key | `string` | key of the metadata value to remove |
+
+#### Returns
+
+| Type | Description |
+|------|-------------|
+| `boolean` | true if found and removed |
+
+#### Example
+
+```js
+peerStore.metadataBook.deleteValue(peerId, 'location')
+// false
+peerStore.metadataBook.set(peerId, 'location', Buffer.from('Berlin'))
+peerStore.metadataBook.deleteValue(peerId, 'location')
+// true
+```
+
+### peerStore.metadataBook.get
+
+Get the known metadata of a provided peer.
+
+`peerStore.metadataBook.get(peerId)`
+
+#### Parameters
+
+| Name | Type | Description |
+|------|------|-------------|
+| peerId | [`PeerId`][peer-id] | peerId to get |
+
+#### Returns
+
+| Type | Description |
+|------|-------------|
+| `Map<string, Buffer>` | Peer Metadata |
+
+#### Example
+
+```js
+peerStore.metadataBook.get(peerId)
+// undefined
+peerStore.metadataBook.set(peerId, 'location', Buffer.from('Berlin'))
+peerStore.metadataBook.get(peerId)
+// Metadata Map
+```
+
+### peerStore.metadataBook.getValue
+
+Get specific metadata of a provided peer.
+
+`peerStore.metadataBook.getValue(peerId)`
+
+#### Parameters
+
+| Name | Type | Description |
+|------|------|-------------|
+| peerId | [`PeerId`][peer-id] | peerId to get |
+| key | `string` | key of the metadata value to get |
+
+#### Returns
+
+| Type | Description |
+|------|-------------|
+| `Map<string, Buffer>` | Peer Metadata |
+
+#### Example
+
+```js
+peerStore.metadataBook.getValue(peerId, 'location')
+// undefined
+peerStore.metadataBook.set(peerId, 'location', Buffer.from('Berlin'))
+peerStore.metadataBook.getValue(peerId, 'location')
+// Metadata Map
+```
+
+### peerStore.metadataBook.set
+
+Set known metadata of a given `peerId`.
+
+`peerStore.metadataBook.set(peerId, key, value)`
+
+#### Parameters
+
+| Name | Type | Description |
+|------|------|-------------|
+| peerId | [`PeerId`][peer-id] | peerId to set |
+| key | `string` | key of the metadata value to store |
+| value | `Buffer` | metadata value to store |
+
+#### Returns
+
+| Type | Description |
+|------|-------------|
+| `MetadataBook` | Returns the Metadata Book component |
+
+#### Example
+
+```js
+peerStore.metadataBook.set(peerId, 'location', Buffer.from('Berlin'))
+```
+
 ### peerStore.protoBook.delete
 
 Delete the provided peer from the book.

diff --git a/src/peer-store/README.md b/src/peer-store/README.md
@@ -75,7 +75,11 @@ A `peerId.toB58String()` identifier mapping to a `Set` of protocol identifier st
 
 #### Metadata Book
 
-**Not Yet Implemented**
+The `metadataBook` keeps track of the known metadata of a peer. Its metadata is stored in a key value fashion, where a key identifier (`string`) represents a metadata value (`Buffer`).
+
+`Map<string, Map<string, Buffer>>`
+
+A `peerId.toB58String()` identifier mapping to the peer metadata Map.
 
 ### API
 
@@ -85,13 +89,16 @@ Access to its underlying books:
 
 - `peerStore.addressBook.*`
 - `peerStore.keyBook.*`
+- `peerStore.metadataBook.*`
 - `peerStore.protoBook.*`
 
 ### Events
 
 - `peer` - emitted when a new peer is added.
 - `change:multiaadrs` - emitted when a known peer has a different set of multiaddrs.
 - `change:protocols` - emitted when a known peer supports a different set of protocols.
+- `change:pubkey` - emitted when a peer's public key is known.
+- `change:metadata` - emitted when known metadata of a peer changes.
 
 ## Data Persistence
 
@@ -123,8 +130,6 @@ All public keys are stored under the following pattern:
 
 **MetadataBook**
 
-_NOT_YET_IMPLEMENTED_
-
 Metadata is stored under the following key pattern:
 
 `/peers/metadata/<b32 peer id no padding>/<key>`

diff --git a/src/peer-store/address-book.js b/src/peer-store/address-book.js
@@ -97,7 +97,6 @@ class AddressBook extends Book {
   /**
    * Add known addresses of a provided peer.
    * If the peer is not known, it is set with the given addresses.
-   * @override
    * @param {PeerId} peerId
    * @param {Array<Multiaddr>} multiaddrs
    * @returns {AddressBook}

diff --git a/src/peer-store/index.js b/src/peer-store/index.js
@@ -10,6 +10,7 @@ const PeerId = require('peer-id')
 
 const AddressBook = require('./address-book')
 const KeyBook = require('./key-book')
+const MetadataBook = require('./metadata-book')
 const ProtoBook = require('./proto-book')
 
 const {
@@ -21,6 +22,8 @@ const {
  * @fires PeerStore#peer Emitted when a new peer is added.
  * @fires PeerStore#change:protocols Emitted when a known peer supports a different set of protocols.
  * @fires PeerStore#change:multiaddrs Emitted when a known peer has a different set of multiaddrs.
+ * @fires PeerStore#change:pubkey Emitted emitted when a peer's public key is known.
+ * @fires PeerStore#change:metadata Emitted when the known metadata of a peer change.
  */
 class PeerStore extends EventEmitter {
   /**
@@ -47,6 +50,11 @@ class PeerStore extends EventEmitter {
      */
     this.keyBook = new KeyBook(this)
 
+    /**
+     * MetadataBook containing a map of peerIdStr to their metadata Map.
+     */
+    this.metadataBook = new MetadataBook(this)
+
     /**
      * ProtoBook containing a map of peerIdStr to supported protocols.
      */
@@ -68,31 +76,17 @@ class PeerStore extends EventEmitter {
    * @returns {Map<string, Peer>}
    */
   get peers () {
-    const peersData = new Map()
+    const storedPeers = new Set([
+      ...this.addressBook.data.keys(),
+      ...this.keyBook.data.keys(),
+      ...this.protoBook.data.keys(),
+      ...this.metadataBook.data.keys()
+    ])
 
-    // AddressBook
-    for (const [idStr, addresses] of this.addressBook.data.entries()) {
-      const id = this.keyBook.data.get(idStr) || PeerId.createFromCID(idStr)
-      peersData.set(idStr, {
-        id,
-        addresses,
-        protocols: this.protoBook.get(id) || []
-      })
-    }
-
-    // ProtoBook
-    for (const [idStr, protocols] of this.protoBook.data.entries()) {
-      const pData = peersData.get(idStr)
-      const id = this.keyBook.data.get(idStr) || PeerId.createFromCID(idStr)
-
-      if (!pData) {
-        peersData.set(idStr, {
-          id,
-          addresses: [],
-          protocols: Array.from(protocols)
-        })
-      }
-    }
+    const peersData = new Map()
+    storedPeers.forEach((idStr) => {
+      peersData.set(idStr, this.get(PeerId.createFromCID(idStr)))
+    })
 
     return peersData
   }
@@ -106,8 +100,9 @@ class PeerStore extends EventEmitter {
     const addressesDeleted = this.addressBook.delete(peerId)
     const keyDeleted = this.keyBook.delete(peerId)
     const protocolsDeleted = this.protoBook.delete(peerId)
+    const metadataDeleted = this.metadataBook.delete(peerId)
 
-    return addressesDeleted || keyDeleted || protocolsDeleted
+    return addressesDeleted || keyDeleted || protocolsDeleted || metadataDeleted
   }
 
   /**
@@ -122,16 +117,18 @@ class PeerStore extends EventEmitter {
 
     const id = this.keyBook.data.get(peerId.toB58String())
     const addresses = this.addressBook.get(peerId)
+    const metadata = this.metadataBook.get(peerId)
     const protocols = this.protoBook.get(peerId)
 
-    if (!addresses && !protocols) {
+    if (!id && !addresses && !metadata && !protocols) {
       return undefined
     }
 
     return {
       id: id || peerId,
       addresses: addresses || [],
-      protocols: protocols || []
+      protocols: protocols || [],
+      metadata: metadata
     }
   }
 }