如何在Golang中将vars传递给chi路由器

Question

I'm writing a web app using chi router and have global vars for the database connection string and gorilla sessions mysqlstore. I want to pass these to the chi mount function instead of using global vars but can't figure out how to do it.

Here is my code, redacted for brevity.

var dBSource string

var store *mysqlstore.MySQLStore

func main() {

  var err error

  dBSource = fmt.Sprintf("%s:%s@tcp(%s:%s)/%s?charset=utf8", dbUser, dbPass, dbHost, dbPort, dbName)

  store, err = mysqlstore.NewMySQLStore(endpoint, tableName, path, maxAge, codecs)

  defer store.Close()

  r := chi.NewRouter()

  r.Mount("/users", usersResource{}.Routes())
}

type usersResource struct{}

func (rs usersResource) Routes() chi.Router {
    r := chi.NewRouter()

    r.Get("/", rs.List)

    return r
}

func (rs usersResource) List(w http.ResponseWriter, r *http.Request) {

    session, err := store.Get(r, "session-data")

    db, err := sql.Open("mysql", dBSource)
}

Answer 1

Usually, we do that this way.

func main() {

......
  r := chi.NewRouter()

  // keep db connection alive.
  db, err := sql.Open("mysql", dBSource)

  ur := NewUserResource(store, db)

  r.Mount("/users", ur.Routes())
}

type usersResource struct{
  store *mysqlstore.MySQLStore
// and more...
  db *YourDB
}

// new function to pass global var
func newUserResource(store *mysqlstore.MySQLStore, db *YourDB) *usersResource{
  return &usersResource {
    store: store,
    db: db,
  }
}

func (rs *usersResource) List(w http.ResponseWriter, r *http.Request) {
    // don't use global var
    session, err := ur.store.Get(r, "session-data")

    ur.db.GetWhatever()

}