AIDK API Reference / aidk-kernel / Middleware

Type Alias: Middleware()<TArgs>

type Middleware<TArgs> = (args: TArgs, envelope: ProcedureEnvelope<TArgs>, next: (transformedArgs?: TArgs) => Promise<any>) => Promise<any>;

Defined in: packages/kernel/src/procedure.ts:63

Middleware function that can intercept and transform procedure execution.

Middleware can:

• Transform input arguments before passing to the next middleware/handler
• Modify the result after next() returns
• Short-circuit execution by not calling next()
• Handle or transform errors

Type Parameters

Type Parameter	Default type	Description
TArgs extends any[]	any[]	The argument types of the procedure

Parameters

Parameter	Type
args	TArgs
envelope	ProcedureEnvelope<TArgs>
next	(transformedArgs?: TArgs) => Promise<any>

Returns

Promise<any>

Examples

const loggingMiddleware: Middleware<[string]> = async (args, envelope, next) => {
  console.log(`${envelope.operationName} called with:`, args);
  const start = Date.now();
  try {
    const result = await next();
    console.log(`Completed in ${Date.now() - start}ms`);
    return result;
  } catch (error) {
    console.error(`Failed:`, error);
    throw error;
  }
};

const upperMiddleware: Middleware<[string]> = async (args, envelope, next) => {
  return next([args[0].toUpperCase()]);
};

See

• ProcedureEnvelope - The envelope containing execution metadata
• createPipeline - Bundle multiple middleware for reuse