一尘不染

Gorilla Web Toolikit:len(session.Flashes())为0

go

我有一个正在尝试放在一起的注册表单,用简单的逻辑在服务器端用简单的ifs检查了表单验证,例如

if username == "" || < 5 {
    session.AddFlash("Username is too short")
    session.Save(r, w)
}

然后,在我进行的验证结束时,效果很好(出于调试目的)

fmt.Println(len(session.Flashes())) which returns 3

然后我检查是否有像这样的表格错误

if len(session.Flashes()) != 0 {
    // Perform Redirect and show flashes
} else {
    // Set proper session variables and log user in
}

那么,3 > 0为什么else触发语句而不是if语句的第一部分呢?我只是不确定为什么会这样发生。谢谢,如果您需要更多信息,请告诉我,实际的代码片段:

if username == "" || len(username) < 4 {
    session.AddFlash("Username is too short")
    session.Save(r, w)
}
if email == "" || len(email) < 5 {
    session.AddFlash("Email is too short")
    session.Save(r, w)
}
if firstname == "" || len(firstname) < 3 {
    session.AddFlash("Firstname is too short")
    session.Save(r, w)
}
if lastname == "" || len(lastname) < 3 {
    session.AddFlash("Lastname is too short")
    session.Save(r, w)
}

fmt.Println(len(session.Flashes()) > 0) // true

if len(session.Flashes()) != 0 {
    fmt.Println("Why am I here also")
    type Page struct {
        Title    string
        Username interface{}
        Errors   []interface{}
    }

    session, _ := common.GetSession(r)
    data := &Page{"Register", session.Values["username"], session.Flashes()}
    session.Save(r, w)

    tmpl, err := template.ParseFiles("views/register/register.html")
    if err != nil {
        http.Error(w, "Failed to load page.", 500)
    }
    tmpl.ExecuteTemplate(w, "register", data)
} else {
    fmt.Println("Why am I here")
    _, err := db.Query("// Perform DB Query")
    if err != nil {
        http.Error(w, "Sorry we had trouble saving your account to the database, try again in a bit.", 500)
    }

    session.Values["username"] = r.FormValue("username")
    session.Values["authenticated"] = true

    session.Save(r, w)

    http.Redirect(w, r, "/", 303)
}

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2020-07-02

共1个答案

一尘不染

它的文档记录不是很好,但是显然从会话中Flashes 删除了 闪烁并返回了它们:

func (s *Session) Flashes(vars ...string) []interface{} {
    var flashes []interface{}
    key := flashesKey
    if len(vars) > 0 {
        key = vars[0]
    }
    if v, ok := s.Values[key]; ok {
        // Drop the flashes and return it.
        delete(s.Values, key)
        flashes = v.([]interface{})
    }
    return flashes
}

源代码在这里

这里的解决方案是使用一个单独的变量来保存验证状态:

valid := true
if username == "" || len(username) < 4 {
    valid = false
    session.AddFlash("Username is too short")
    session.Save(r, w)
}
// ...
if !valid {
    // ...
} else {
    // ...
}

编辑: 获取闪光灯而不删除它们的另一种方法是Values直接从其中获取它们:

flashes := session.Values["_flash"].([]interface{})
2020-07-02