如何使用保存在控制器中访问的中间件中的上下文中的“类型结构”

Question

This is my first question regarding GoLang please be gentle. I am building a test JSON API.

I have a type struct named User

type User struct {
    UserID              int
    Email               string
    FirstName           string
    LastName            string
    PasswordHash        string
}

In middleware, I verify JWT token is valid and if so, I load entire record of User and save it in the context so that it is available in handlers under.

So in middleware, I save User struct like this

    context.Set(r, "User",  *User)
    fmt.Println(*User)

    next.ServeHTTP(w, r)

Output of Println is

{12 [e-mail] Mr. Sallu $2a$14oUg3d1rm./.B/vUyhYR9/hlHfagE4tGicNc14EWK3u }

Then in the final handler I access this context and get User object.

User    := context.Get(r, "User")

fmt.Println("---User---", fmt.Sprintf(" %T ", User))
fmt.Println(User)

Output of Println is

---User---  models.User
{12 [e-mail] Mr. Sallu $2a$14oUg3d1rm./.B/vUyhYR9/hlHfagE4tGicNc14EWK3u }

The issue is that in Controller when I access User.Email I am getting an error

User.Email undefined (type interface {} is interface with no methods)

How can I fix this..? I want to use User.Email or User.UserID. Seems like context is doing something to it.

Please help

Answer 1

Everywhere in your code please use different names for variable and type.

e.g. keep type User and variable user.

In your controller, type assert your user back to User.

if u, ok := user.(User); ok {
    fmt.Println(u.Email)
}

https://tour.golang.org/methods/15