Middleware

A middleware.ts file applies to all handlers in its folder and subdirectories.

Runs before schema validation and the handler.
Can short-circuit by throwing HTTPException (e.g. 401) — the client gets { error, message, code }.
Shares context with the handler via c.set(key, value) and c.get(key).
Exports a single function or an array of functions (executed left → right).

Single middleware:


// app/orders/middleware.ts
import type { MiddlewareHandler } from "hono";
import { HTTPException } from "hono/http-exception";
 
const auth: MiddlewareHandler = async (c, next) => {
  const token = c.req.header("authorization");
  if (!token) {
    throw new HTTPException(401, { message: "Unauthorized" });
  }
  c.set("user", { id: "123" });
  await next();
};
 
export default auth;

Middleware pipeline:


// app/orders/middleware.ts
import type { MiddlewareHandler } from "hono";
import { HTTPException } from "hono/http-exception";
 
const logger: MiddlewareHandler = async (c, next) => {
  console.log(`[${c.req.method}] ${c.req.path}`);
  await next();
};
 
const auth: MiddlewareHandler = async (c, next) => {
  if (!c.req.header("authorization")) {
    throw new HTTPException(401, { message: "Unauthorized" });
  }
  c.set("user", { id: "123" });
  await next();
};
 
export default [logger, auth];

Reading context in a handler:


export default async function handler(c) {
  const user = c.get("user");
  return { user };
}

Execution order:


Request → Parent Middleware → Child Middleware → Schema Validation → Handler → Response