How to get config in middleware from route?

[seepine]

like this

app.use(async (c, next) => {
  console.log(c.req.routeConfig.expose)
  //   true
  await next()
})

app.get('/user/:name', (c) => {
  return c.text(c.req.param('name'))
},{
  expose: true
})

[stebeus]

What type of route configuration? Setting and getting values between routes per request, or something more specific?

[mujtbabbas]

Hono doesn't have a route-config API like that: there's no third metadata argument on route definitions and nothing like c.req.routeConfig on the request. Extra arguments on a route are just more handlers. The config has to travel through the context instead, and there are two patterns that cover what you're trying to do.

Pattern 1: a small middleware factory that closes over the config (closest to your snippet)

import { createMiddleware } from 'hono/factory'

type Env = { Variables: { config: { auth?: boolean } } }

const withConfig = (config: Env['Variables']['config']) =>
  createMiddleware<Env>(async (c, next) => {
    c.set('config', config)
    await next()
  })

// scope it to a path...
app.use('/user/*', withConfig({ auth: true }))

// ...or attach it per route, before the handler
app.get('/user/profile', withConfig({ auth: true }), (c) => {
  const config = c.get('config')
  // ...
})

Any middleware or handler that runs after it reads the value with c.get('config'), and declaring it under Variables keeps it typed everywhere. Your auth(c) check then just reads c.get('config')?.auth instead of c.req.routeConfig.auth.

Pattern 2: one global middleware + a config map keyed by route pattern

If the config is naturally a table (one entry per route), keep a map and look it up by the matched route pattern, which Hono exposes as c.req.routePath:

const routeConfig: Record<string, { auth?: boolean }> = {
  '/user/:id': { auth: true },
  '/post/:id': { auth: false },
}

app.use(async (c, next) => {
  c.set('config', routeConfig[c.req.routePath] ?? {})
  await next()
})

Keying by routePath rather than c.req.path matters: /user/123 and /user/456 are the same route, and the pattern is what your config table is written against.

Pattern 1 is the better default, the config sits next to the routes it applies to and there's no table to keep in sync. Pattern 2 earns its keep when config is generated or loaded from somewhere else (a database, a config file) rather than written inline.