Update the _examples/mvc/login example - add a Path property at mvc.Response and add a context.Proceed helper function

Former-commit-id: b898901fe4a324e888a6e09c93530cf7a551cf2a

_examples/mvc/login/datamodels/user.go

@@ -0,0 +1,41 @@
+package datamodels
+
+import (
+	"time"
+
+	"golang.org/x/crypto/bcrypt"
+)
+
+// User is our User example model.
+// Keep note that the tags for public-use (for our web app)
+// should be kept in other file like "web/viewmodels/user.go"
+// which could wrap by embedding the datamodels.User or
+// define completely new fields instead but for the shake
+// of the example, we will use this datamodel
+// as the only one User model in our application.
+type User struct {
+	ID             int64     `json:"id" form:"id"`
+	Firstname      string    `json:"firstname" form:"firstname"`
+	Username       string    `json:"username" form:"username"`
+	HashedPassword []byte    `json:"-" form:"-"`
+	CreatedAt      time.Time `json:"created_at" form:"created_at"`
+}
+
+// IsValid can do some very very simple "low-level" data validations.
+func (u User) IsValid() bool {
+	return u.ID > 0
+}
+
+// GeneratePassword will generate a hashed password for us based on the
+// user's input.
+func GeneratePassword(userPassword string) ([]byte, error) {
+	return bcrypt.GenerateFromPassword([]byte(userPassword), bcrypt.DefaultCost)
+}
+
+// ValidatePassword will check if passwords are matched.
+func ValidatePassword(userPassword string, hashed []byte) (bool, error) {
+	if err := bcrypt.CompareHashAndPassword(hashed, []byte(userPassword)); err != nil {
+		return false, err
+	}
+	return true, nil
+}