Merge pull request #72 from xmtp/jazzz/preflight-address-check

Add ability to check addresses prior to sending a message

src/Client.ts

@@ -53,12 +53,14 @@ export default class Client {
   waku: Waku
   address: string
   keys: PrivateKeyBundle
-  private contacts: Map<string, PublicKeyBundle> // addresses and key bundles that we already have connection with
+  private contacts: Set<string> // address which we have connected to
+  private knownPublicKeyBundles: Map<string, PublicKeyBundle> // addresses and key bundles that we have witnessed
   private _conversations: Conversations
 
   constructor(waku: Waku, keys: PrivateKeyBundle) {
     this.waku = waku
-    this.contacts = new Map<string, PublicKeyBundle>()
+    this.contacts = new Set<string>()
+    this.knownPublicKeyBundles = new Map<string, PublicKeyBundle>()
     this.keys = keys
     this.address = keys.identityKey.publicKey.walletSignatureAddress()
     this._conversations = new Conversations(this)
@@ -102,7 +104,7 @@ export default class Client {
   }
 
   // retrieve a key bundle from given user's contact topic
-  async getUserContact(
+  async getUserContactFromNetwork(
     peerAddress: string
   ): Promise<PublicKeyBundle | undefined> {
     const recipientKeys = (
@@ -118,25 +120,58 @@ export default class Client {
     return recipientKeys.length > 0 ? recipientKeys[0] : undefined
   }
 
+  /**
+   * Returns the cached PublicKeyBundle if one is known for the given address or fetches
+   * one from the network
+   */
+
+  async getUserContact(
+    peerAddress: string
+  ): Promise<PublicKeyBundle | undefined> {
+    const existingBundle = this.knownPublicKeyBundles.get(peerAddress)
+
+    if (existingBundle) {
+      return existingBundle
+    }
+
+    const newBundle = await this.getUserContactFromNetwork(peerAddress)
+
+    if (newBundle) {
+      this.knownPublicKeyBundles.set(peerAddress, newBundle)
+    }
+
+    return newBundle
+  }
+
+  /**
+   * Check if @peerAddress can be messaged, specifically it checks that a PublicKeyBundle can be
+   * found for the given address
+   */
+  public async canMessage(peerAddress: string): Promise<boolean> {
+    const keyBundle = await this.getUserContact(peerAddress)
+    return keyBundle !== undefined
+  }
+
   /**
    * Send a message to the wallet identified by @peerAddress
    */
   async sendMessage(peerAddress: string, msgString: string): Promise<void> {
     let topics: string[]
-    let recipient = this.contacts.get(peerAddress)
+    const recipient = await this.getUserContact(peerAddress)
+
     if (!recipient) {
-      recipient = await this.getUserContact(peerAddress)
-      if (!recipient) {
-        throw new Error(`recipient ${peerAddress} is not registered`)
-      }
-      this.contacts.set(peerAddress, recipient)
+      throw new Error(`recipient ${peerAddress} is not registered`)
+    }
+
+    if (!this.contacts.has(peerAddress)) {
       topics = [
         buildUserIntroTopic(peerAddress),
         buildDirectMessageTopic(this.address, peerAddress),
       ]
       if (peerAddress !== this.address) {
         topics.push(buildUserIntroTopic(this.address))
       }
+      this.contacts.add(peerAddress)
     } else {
       topics = [buildDirectMessageTopic(this.address, peerAddress)]
     }

test/Client.test.ts

@@ -47,9 +47,9 @@ describe('Client', () => {
 
       it('user contacts published', async () => {
         await sleep(10)
-        const alicePublic = await alice.getUserContact(alice.address)
+        const alicePublic = await alice.getUserContactFromNetwork(alice.address)
         assert.deepEqual(alice.keys.getPublicKeyBundle(), alicePublic)
-        const bobPublic = await bob.getUserContact(bob.address)
+        const bobPublic = await bob.getUserContactFromNetwork(bob.address)
         assert.deepEqual(bob.keys.getPublicKeyBundle(), bobPublic)
       })
 
@@ -176,6 +176,14 @@ describe('Client', () => {
           alice.sendMessage('unregistered address', 'hello as well')
         ).rejects.toThrow('recipient unregistered address is not registered')
       })
+
+      it('Check address can be sent to', async () => {
+        const can_mesg_a = await alice.canMessage('NOT AN ADDRESS')
+        assert.equal(can_mesg_a, false)
+
+        const can_mesg_b = await alice.canMessage(bob.address)
+        assert.equal(can_mesg_b, true)
+      })
     })
   })
 })