Feature request: implement parser decorator

[am29d]

Use case

Similar to middy middleware we want to use build-in schemas and envelopes to parse and extract events using decorators.

Solution/User Experience

Based on the RFC the decorator should take model and envelope as an param object:

const order = z.object({
  id: z.number(),
  description: z.string(),
});

type Order = z.infer<typeof order>;

class Lambda implements LambdaInterface {
  // Decorate your handler class method
  @logger.injectLambdaContext()
  @parser({eventBridgeEnvelope, order})
  public async handler(
    _event: OrderModel,
    _context: Context
  ): Promise<void> {
    logger.info(`Received order model ${_event}`);
  }
}

we should also be able to pass only the model, which can be a custom event or an extension of the built-in schema i.e.

const order = z.object({
  id: z.number(),
  description: z.string(),
});

const customEBschema = EventBridgeSchema.extend({
  detail: order,
});

Alternative solutions

No response

Acknowledgment

• This feature request meets Powertools for AWS Lambda (TypeScript) Tenets
• Should this be considered in other Powertools for AWS Lambda languages? i.e. Python, Java, and .NET

Future readers

Please react with 👍 and your use case to help us understand customer demand.

[github-actions]

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