Backend for Frontend Using API Gateway
Publication date: April 27, 2022 (Diagram history)
This architecture shows how frontend client applications apply the Backend for Frontend (BFF) pattern to load UI-ready data projections and refresh the UI with event-driven notifications. You use Amazon API Gateway WebSockets to push real-time updates when microservices raise events about mutations in domain aggregates.
Backend for Frontend Using API Gateway
The following steps describe the architecture:
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Purpose-built BFF event consumers catch events from your application and update denormalized data projections in Amazon DynamoDB for frontend consumption.
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On UI load, frontend clients authenticate with Amazon Cognito, then query data by invoking the BFF API built with API Gateway. The API fetches data from DynamoDB directly or through a BFF query handler built with AWS Lambda.
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Frontend clients subscribe for subsequent data changes by connecting to a BFF WebSocket endpoint provided by API Gateway, which triggers an update of the connected clients table.
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BFF event consumers continue to process all relevant events from your application and update the denormalized frontend data view in real time.
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Amazon DynamoDB Streams captures all events from data changes in the BFF database. A Lambda trigger asynchronously invokes a BFF stream-handler function when it detects new stream records.
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The BFF stream handler pushes notifications to clients connected to API Gateway WebSockets.
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Frontend clients receive the change notification from API Gateway and refresh the UI content.
Further reading
For additional information, refer to the following resources:
Diagram history
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| Change | Description | Date |
|---|---|---|
Initial publication | Reference architecture diagram first published. | April 27, 2022 |
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