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Parameter Decorators

Parameter decorators provide a convenient way to inject user session information directly into your controller methods. InversifyJS HTTP Better Auth provides framework-specific decorators that extract and parse authentication data from incoming requests.

Available Decorators​

@Controller('/api')
class UserController {
  @ApplyMiddleware(betterAuthMiddlewareServiceIdentifier)
  @Get('/profile')
  public async getProfile(
    @ExpressUserSession() session: UserSession<BetterAuthOptions>,
  ): Promise<UserSession<BetterAuthOptions>> {
    return session;
  }
}
Required middleware

You must apply betterAuthMiddlewareServiceIdentifier middleware to any controller relying on session decorators or apply betterAuthMiddlewareServiceIdentifier as global middleware.

Return Types​

All decorators return either:

  • UserSession<TOptions> - When a valid session is found
  • null - When no valid session is found

Handling Authenticated Users​

@Controller('/api')
class UserController {
  @ApplyMiddleware(betterAuthMiddlewareServiceIdentifier)
  @Get('/user-info')
  public async getUserInfo(
    @HonoUserSession() session: UserSession<BetterAuthOptions>,
  ): Promise<{ id: string; email: string; name: string }> {
    return {
      email: session.user.email,
      id: session.user.id,
      name: session.user.name,
    };
  }
}

Handling Optional Authentication​

@Controller('/api')
class OptionalAuthController {
  @ApplyMiddleware(betterAuthMiddlewareServiceIdentifier)
  @Get('/optional-auth')
  public async optionalAuth(
    @HonoUserSession() session: UserSession<BetterAuthOptions> | null,
  ): Promise<{ authenticated: boolean; userId?: string }> {
    if (session === null) {
      return { authenticated: false };
    }

    return {
      authenticated: true,
      userId: session.user.id,
    };
  }
}

Error Handling​

If the Better Auth middleware is not applied, the decorators will throw an error during request processing. Always ensure the middleware is properly configured:

@Controller('/api')
export class BadController {
  @Get('/profile')
  public async getProfile(
    @HonoUserSession() session: UserSession<BetterAuthOptions>, // Error!
  ): Promise<UserSession<BetterAuthOptions>> {
    return session;
  }
}

// ✅ This works - middleware properly applied
@ApplyMiddleware(betterAuthMiddlewareServiceIdentifier)
@Controller('/api')
export class GoodController {
  @Get('/profile')
  public async getProfile(
    @HonoUserSession() session: UserSession<BetterAuthOptions>,
  ): Promise<UserSession<BetterAuthOptions>> {
    return session;
  }
}