chore: augment tokenID to token vending machine (#978)

* chore: augment tokenID to token vending machine

examples/nodejs/token-vending-machine/README.md

@@ -62,6 +62,16 @@ MomentoTokenVendingMachine.MomentoTokenVendingMachineApiEndpointE36C2123 = https
 ```
 
 This is the URL of the API Gateway endpoint for your Token Vending Machine. Now you should be able to `curl` this endpoint, and the response will be a temporary Momento API key suitable for use in a browser!
+You should see an output like:
+
+```
+{"authToken":"someShortLivedDisposableToken","expiresAt":1698119397}
+```
+
+You can also pass a tokenId as a query string to your curl command to add context to your token. This can be particularly useful when using [Momento Topics](https://www.gomomento.com/services/topics) as the tokenId can be retrieved from subscription messages, allowing your application to distinguish between different subscribers. In this case, a `name` for the user is the `tokenId` passed as a query string.
+
+`https://9jkmukxn68.execute-api.us-west-2.amazonaws.com/prod?name=Taylor`
+
 
 ## Example Apps That Use The Token Vending Machine
 

examples/nodejs/token-vending-machine/lambda/token-vending-machine/handler.ts

@@ -14,7 +14,9 @@ export const handler = async (event: APIGatewayProxyEvent): Promise<APIGatewayPr
       throw new Error("Missing required env var 'MOMENTO_API_KEY_SECRET_NAME");
     }
     console.log('headers in handler:', event.headers);
-    const vendedApiKey = await vendDisposableToken(vendorApiKeySecretName, event.headers);
+    const tokenId = event.queryStringParameters?.name;
+    console.log('tokenID inferred from queryStringParameters: ', tokenId);
+    const vendedApiKey = await vendDisposableToken(vendorApiKeySecretName, event.headers, tokenId);
     return {
       statusCode: 200,
       headers: {
@@ -41,7 +43,8 @@ interface VendedToken {
 
 async function vendDisposableToken(
   vendorApiKeySecretName: string,
-  headers: APIGatewayProxyEventHeaders
+  headers: APIGatewayProxyEventHeaders,
+  tokenId: string | undefined
 ): Promise<VendedToken> {
   const momentoAuthClient = await getMomentoAuthClient(vendorApiKeySecretName);
 
@@ -50,10 +53,15 @@ async function vendDisposableToken(
     const cognitoUserTokenPermissions = determineCognitoUserTokenScope(headers);
     generateTokenResponse = await momentoAuthClient.generateDisposableToken(
       cognitoUserTokenPermissions,
-      tokenExpiresIn
+      tokenExpiresIn,
+      {
+        tokenId: tokenId,
+      }
     );
   } else {
-    generateTokenResponse = await momentoAuthClient.generateDisposableToken(tokenPermissions, tokenExpiresIn);
+    generateTokenResponse = await momentoAuthClient.generateDisposableToken(tokenPermissions, tokenExpiresIn, {
+      tokenId: tokenId,
+    });
   }
 
   if (generateTokenResponse instanceof GenerateDisposableToken.Success) {