> Documents > Guard

Guard

A guard is a context that implemented the interface rocket.Guard, it rejects a request by returning a *response.Response.

Here is an example:

type User struct {
    Authorization *string `header:"Authorization"`
}

func (u *User) VerifyRequest() *response.Response {
    // Assuming we have a JWT verify helper function
    if verifyAuthByJWT(u.Auth) {
        return nil
    }
    return rocket.AuthError("not allowed")
}

var handler = rocket.Get("/user_data", func(_ *User) string {
    // would return data if `VerifyRequest` do not return any errors
})

Error response

rocket.AuthError: should be returned when you believe it’s an Authorization error, it would bring 403 Forbidden
```
rocket.AuthError("auth error, error: %s", err)
```
rocket.ValidateError: should be returned when you think the request was something wrong, it would return 400 Bad Request
```
rocket.ValidateError("auth error, error: %s", err)
```