In the below code my Register function is working well but the login function is showing an error with goroutines.

panic: runtime error: invalid memory address or nil pointer dereference [signal SIGSEGV: segmentation violation code=0x1 addr=0x2f0 pc=0x920427]

Please update me with a solution for this login, you can make a whole new login function just clear my concepts here.

var client *mongo.Client


func Register(c *fiber.Ctx) error {
    var data map[string]string

    if err := c.BodyParser(&data); err != nil {
        return err
    }

    passwd, _ := bcrypt.GenerateFromPassword([]byte(data["password"]), 10)

    user := models.User{
        Name:     data["name"],
        Email:    data["email"],
        Password: passwd,
    }

    _, err := dao.UserData(&user)
    if err != nil {
        return c.JSON(err)
    } else {
        response := models.Response{
            Message: "User Registered",
            Success: true,
        }
        return c.JSON(response)

    }
}


func Login(c *fiber.Ctx) error {
    var data map[string]string

    if err := c.BodyParser(&data); err != nil {
        return err
    }

    var user models.User
    var dbUser models.User

    collection := client.Database("Shashank").Collection("User")
    ctx, _ := context.WithTimeout(context.Background(), 10*time.Second)
    err := collection.FindOne(ctx, bson.M{"email": user.Email}).Decode(&dbUser)

    if err != nil {
        fmt.Println(fiber.StatusBadRequest)
    } else {
        fmt.Println(fiber.StatusOK)
    }

    if err := bcrypt.CompareHashAndPassword(user.Password, []byte(data["passwd"])); err != nil {
        c.Status(fiber.StatusBadRequest)
        return c.JSON(fiber.Map{
            "message": "incorrect password",
        })
    }
    return c.JSON(user)
}

CodePudding user response：

the first line in Login func is var data map[string]string

that does not assign any memory - merely initializes variable data to be of type map[string]string. The zero value of map type is nil.

so in the next line when you do c.BodyParser(&data) - &data is trying to dereference a nil pointer - and hence your error.

change the first line to data := map[string]string{}. Now there is a memory allocation and hence a valid memory that &data can dereference.

CodePudding user response：

AFAIK maps usually have to be properly initialised with make(). Try swapping

var data map[string]string

with

data := make(map[string]string)