feat(lib): check permissions before sending signals

.pubnub.yml

@@ -1,11 +1,18 @@
 ---
 name: pubnub-js-chat
-version: v0.5.2
+version: v0.6.0
 scm: github.com/pubnub/js-chat
 schema: 1
 files:
   - lib/dist/index.js
 changelog:
+  - date: 2024-03-11
+    version: v0.6.0
+    changes:
+      - type: feature
+        text: "Check PAM permissions before sending signals."
+      - type: feature
+        text: "Allow custom payloads while sending and receiving messages."
   - date: 2024-01-16
     version: v0.5.2
     changes:

lib/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@pubnub/chat",
-  "version": "0.5.2",
+  "version": "0.6.0",
   "description": "PubNub JavaScript Chat SDK",
   "author": "PubNub <[email protected]>",
   "license": "SEE LICENSE IN LICENSE",

lib/src/access-manager.ts

@@ -0,0 +1,43 @@
+import { GrantTokenPermissions } from "pubnub"
+import type { Chat } from "./entities/chat"
+
+export class AccessManager {
+  chat: Chat
+
+  constructor(chat: Chat) {
+    this.chat = chat
+  }
+
+  canI({
+    permission,
+    resourceType,
+    resourceName,
+  }: {
+    permission: keyof GrantTokenPermissions
+    resourceName: string
+    resourceType: "channels" | "uuids"
+  }) {
+    const authKey = this.chat.config.authKey
+    // we assume PAM is not enabled
+    if (!authKey) {
+      return true
+    }
+
+    const parsedToken = this.chat.sdk.parseToken(authKey)
+    const resourcePermission = parsedToken.resources?.[resourceType]?.[resourceName]?.[permission]
+    if (typeof resourcePermission === "boolean") {
+      return resourcePermission
+    }
+    const resourcePatterns = parsedToken.patterns?.[resourceType] || {}
+    const resourcePatternsKeys = Object.keys(resourcePatterns)
+    for (const pattern of resourcePatternsKeys) {
+      const regexp = new RegExp(pattern)
+      const matches = regexp.test(resourceName)
+      if (matches) {
+        return resourcePatterns[pattern][permission] || false
+      }
+    }
+
+    return false
+  }
+}

lib/src/entities/chat.ts

@@ -23,6 +23,7 @@ import { getErrorProxiedEntity, ErrorLogger } from "../error-logging"
 import { cyrb53a } from "../hash"
 import { uuidv4 } from "../uuidv4"
 import { defaultEditActionName, defaultDeleteActionName } from "../default-values"
+import { AccessManager } from "../access-manager"
 
 export type ChatConfig = {
   saveDebugLog: boolean
@@ -47,6 +48,7 @@ export type ChatConfig = {
     editMessageActionName?: string
     deleteMessageActionName?: string
   }
+  authKey?: string
 }
 
 type ChatConstructor = Partial<ChatConfig> & PubNub.PubnubConfig
@@ -69,6 +71,8 @@ export class Chat {
   readonly editMessageActionName: string
   /** @internal */
   readonly deleteMessageActionName: string
+  /** @internal */
+  readonly accessManager: AccessManager
 
   /** @internal */
   private constructor(params: ChatConstructor) {
@@ -136,7 +140,10 @@ export class Chat {
         getMessagePublishBody: customPayloads?.getMessagePublishBody,
         getMessageResponseBody: customPayloads?.getMessageResponseBody,
       },
+      authKey: pubnubConfig.authKey,
     } as ChatConfig
+
+    this.accessManager = new AccessManager(this)
   }
 
   static async init(params: ChatConstructor) {
@@ -185,7 +192,20 @@ export class Chat {
 
   /* @internal */
   signal(params: { channel: string; message: any }) {
-    return this.sdk.signal(params)
+    const canISendSignal = this.accessManager.canI({
+      permission: "write",
+      resourceName: params.channel,
+      resourceType: "channels",
+    })
+    if (canISendSignal) {
+      return this.sdk.signal(params)
+    }
+
+    throw new Error(
+      `You tried to send a signal containing message: ${JSON.stringify(
+        params.message
+      )} to channel: ${params.channel} but PubNub Access Manager prevented you from doing so.`
+    )
   }
 
   /**

lib/src/entities/membership.ts

@@ -144,11 +144,23 @@ export class Membership {
         custom: { ...this.custom, lastReadMessageTimetoken: timetoken },
       })
 
-      await this.chat.emitEvent({
-        channel: this.channel.id,
-        type: "receipt",
-        payload: { messageTimetoken: timetoken },
+      const canISendSignal = this.chat.accessManager.canI({
+        permission: "write",
+        resourceName: this.channel.id,
+        resourceType: "channels",
       })
+      if (canISendSignal) {
+        await this.chat.emitEvent({
+          channel: this.channel.id,
+          type: "receipt",
+          payload: { messageTimetoken: timetoken },
+        })
+      }
+      if (!canISendSignal && this.chat.config.saveDebugLog) {
+        console.warn(
+          `'receipt' event was not sent to channel '${this.channel.id}' because PAM did not allow it.`
+        )
+      }
 
       return response
     } catch (error) {