Comment by cypriss

I believe this is solved with gocraft/web: https://github.com/gocraft/web

The middleware would be, per the example there:

  func (c *YourContext) UserRequired(rw web.ResponseWriter, r *web.Request, next web.NextMiddlewareFunc) {
      user := userFromSession(r)  // Pretend like this is defined. It reads a session cookie and returns a *User or nil.
      if user != nil {
          c.User = user
          next(rw, r)
      } else {
          rw.Header().Set("Location", "/")
          rw.WriteHeader(http.StatusMovedPermanently)
          // do NOT call next()
      }
  }

Compatibility with Handler/HandlerFunc is kept at the top level, but not at every step along the middleware chain.