Custom Param Decorators

Create custom param decorators with createRouterParamDecorator(). The factory receives your decoration-time input and the NestRpcExecutionContext at runtime.

import { createRouterParamDecorator, Router, Route } from '@nestjs-rpc/server';

// Retrieves the user from the session: req.session.user
const SessionUser = createRouterParamDecorator((_, ctx) => ctx.switchToHttp().getRequest().session.user);

@Router()
export class UserRouter {
  @Route()
  me(_: unknown, @SessionUser() user: { id: string }) {
    return user;
  }
}

Built-ins:

• Req / Res / Next from Nest HTTP adapter
• Input convenience for raw input (equivalent to first param)

Rule: The input parameter is always index 0 and cannot be decorated—reserve custom decorators for subsequent parameters.