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Leverage Momento Topics, webhooks, and tokens in your event-driven architectures

With Momento Topics, you can subscribe to messages on a topic and publish messages to a different topic. Webhooks serve as HTTP callbacks triggered in response to messages published to these topics, acting as stateless consumers. Tokens are designed to provide short-lived session tokens for users and services interacting with a system. By embedding unique identifiers (token_id) in each token, they ensure secure and traceable access to resources.

The key here is that you can use Topics to facilitate real-time communication between users by granting them short-lived tokens. These tokens can be embedded with user information (token_id), which, when messages are published, can be leveraged to access shared resources like Momento caches via webhook callbacks. For instance, you can personalize user experiences by accessing their information stored in a Momento cache by identifying the user through the token_id. Embedding information provides two significant advantages:

  • It enhances security and prevents a user from spoofing their identity.
  • It reduces data transfer costs as the user information is embedded with the token itself.

Architecture

Getting Started​

  1. Create a cache in the Momento console
  2. Create a webhook for the cache. Assign the webhook destination to a public facing endpoint. This endpoint must accept POST requests and be able to receive inbound calls from Momento. More detail about the structure of this event is described here.
  3. Create your infrastructure. For example, below is sample code that creates a lambda function URL for our webhook endpoint. It also stores your Momento auth token in AWS secrets manager.
<SdkExampleCodeBlock language={'javascript'} file={'examples/nodejs/aws/lambda-examples/webhooks/infrastructure/lib/momento-webhook-stack.ts'} />
  1. Add code to the webhook to process incoming messages. Below is sample code for the webhook lambda handler that extracts a user's token_id from the webhook payload, and access resources stored in Momento cache. It also verifies that the webhook caller is indeed Momento through the signing secret.
<SdkExampleCodeBlock language={'javascript'} file={'examples/nodejs/aws/lambda-examples/webhooks/lambda/webhook-handler/handler.ts'} />
  1. Finally, below has sample code for generating the token and publishing user messages on a topic. In a real-world, these would ideally live in separate micro-services.
<SdkExampleCodeBlock language={'javascript'} file={'examples/nodejs/aws/lambda-examples/webhooks/lambda/service-topics/handler.ts'} />

See More​

  • By integrating Momento topics, webhooks, and tokens, you can create secure and stateless asynchronous systems. This convention can be applied to a variety of use-cases such as multi-language chat app, online polling, and event-driven systems.

Multi-language chat app

Explore the source code of our live-translation chat app using webhooks.

Use webhooks with API Gateway + Lambda

Learn how to integrate Momento webhooks with Amazon API Gateway and Lambda functions