Question

我正在使用chi路由器编写一个Web应用程序，并且具有用于数据库连接字符串和大猩猩会话mysqlstore的全局变量。我想将这些传递给chi mount函数，而不是使用全局var，但是我不知道该怎么做。

这是我的代码，为简洁起见，已编辑。

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

通常，我们采用这种方式。


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()

}

Answer 2

为完整起见，这是我实施公认的解决方案的方式。希望它可以为另一个新手节省很多时间。

type appResource struct {
    tmpl  *template.Template // net/http
    store *mysqlstore.MySQLStore
    db    *sql.DB // database/sql
}

func newAppResource(store *mysqlstore.MySQLStore, db *sql.DB, tmpl *template.Template) *appResource {
    return &appResource{
        tmpl:  tmpl,
        store: store,
        db:    db,
    }
}

func main() {

  var err error

  err = godotenv.Load()
  if err != nil {
     log.Fatal("Error loading .env file")
  }

  dbUser := os.Getenv("dbUser")
  dbName := os.Getenv("dbName")
  dbPass := os.Getenv("dbPass")
  dbHost := os.Getenv("dbHost")
  dbPort := os.Getenv("dbPort")

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

  db, err := sql.Open("mysql", dBSource)
  if err != nil {
     log.Fatal(err)
  }

  sessionKey := os.Getenv("sessionKey")

  endpoint := fmt.Sprintf("%s:%s@tcp(%s:%s)/%s?parseTime=true&loc=Local", dbUser, dbPass, dbHost, dbPort, dbName)
  tableName := "sessions"
  path := "/"
  maxAge := 3600
  codecs := []byte(sessionKey)

  store, err := mysqlstore.NewMySQLStore(endpoint, tableName, path, maxAge, codecs)
  if err != nil {
    log.Println("SESSIONS STORE error")
    log.Fatal(err)
  }

  r := chi.NewRouter()

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

  r.Mount("/users", rs.userRoutes())

  httpPort := os.Getenv("httpPort")

  http.ListenAndServe(httpPort, r)
}

func (rs *appResource) adminIndex(w http.ResponseWriter, r *http.Request) {
    session, err := rs.store.Get(r, "admin-data")
    if err != nil {
        log.Fatal(err)
        http.Error(w, err.Error(), http.StatusInternalServerError)
        return
    }

    var flash map[string]interface{}

    if flashes := session.Flashes(); len(flashes) > 0 {
        v := map[string]interface{}{
            "FlashedMessages": session.Flashes(),
        }
        flash = v
    }

    if err := rs.tmpl.ExecuteTemplate(w, "admin-index", flash); err != nil {
        log.Println(err.Error())
        http.Error(w, http.StatusText(500), 500)
    }
}

如何在Golang中将vars传递给chi路由器

2 个答案: