reorganization of _examples and add some new examples such as iris+groupcache+mysql+docker

Former-commit-id: ed635ee95de7160cde11eaabc0c1dcb0e460a620

_examples/mvc/login-mvc-single-responsibility/user/auth.go

@@ -0,0 +1,110 @@
+package user
+
+import (
+	"errors"
+	"strconv"
+	"strings"
+
+	"github.com/kataras/iris/v12"
+	"github.com/kataras/iris/v12/mvc"
+	"github.com/kataras/iris/v12/sessions"
+)
+
+const sessionIDKey = "UserID"
+
+// paths
+var (
+	PathLogin  = mvc.Response{Path: "/user/login"}
+	PathLogout = mvc.Response{Path: "/user/logout"}
+)
+
+// AuthController is the user authentication controller, a custom shared controller.
+type AuthController struct {
+	// context is auto-binded if struct depends on this,
+	// in this controller we don't we do everything with mvc-style,
+	// and that's neither the 30% of its features.
+	// Ctx iris.Context
+
+	Source  *DataSource
+	Session *sessions.Session
+
+	// the whole controller is request-scoped because we already depend on Session, so
+	// this will be new for each new incoming request, BeginRequest sets that based on the session.
+	UserID int64
+}
+
+// BeginRequest saves login state to the context, the user id.
+func (c *AuthController) BeginRequest(ctx iris.Context) {
+	c.UserID, _ = c.Session.GetInt64(sessionIDKey)
+}
+
+// EndRequest is here just to complete the BaseController
+// in order to be tell iris to call the `BeginRequest` before the main method.
+func (c *AuthController) EndRequest(ctx iris.Context) {}
+
+func (c *AuthController) fireError(err error) mvc.View {
+	return mvc.View{
+		Code: iris.StatusBadRequest,
+		Name: "shared/error.html",
+		Data: iris.Map{"Title": "User Error", "Message": strings.ToUpper(err.Error())},
+	}
+}
+
+func (c *AuthController) redirectTo(id int64) mvc.Response {
+	return mvc.Response{Path: "/user/" + strconv.Itoa(int(id))}
+}
+
+func (c *AuthController) createOrUpdate(firstname, username, password string) (user Model, err error) {
+	username = strings.Trim(username, " ")
+	if username == "" || password == "" || firstname == "" {
+		return user, errors.New("empty firstname, username or/and password")
+	}
+
+	userToInsert := Model{
+		Firstname: firstname,
+		Username:  username,
+		password:  password,
+	} // password is hashed by the Source.
+
+	newUser, err := c.Source.InsertOrUpdate(userToInsert)
+	if err != nil {
+		return user, err
+	}
+
+	return newUser, nil
+}
+
+func (c *AuthController) isLoggedIn() bool {
+	// we don't search by session, we have the user id
+	// already by the `BeginRequest` middleware.
+	return c.UserID > 0
+}
+
+func (c *AuthController) verify(username, password string) (user Model, err error) {
+	if username == "" || password == "" {
+		return user, errors.New("please fill both username and password fields")
+	}
+
+	u, found := c.Source.GetByUsername(username)
+	if !found {
+		// if user found with that username not found at all.
+		return user, errors.New("user with that username does not exist")
+	}
+
+	if ok, err := ValidatePassword(password, u.HashedPassword); err != nil || !ok {
+		// if user found but an error occurred or the password is not valid.
+		return user, errors.New("please try to login with valid credentials")
+	}
+
+	return u, nil
+}
+
+// if logged in then destroy the session
+// and redirect to the login page
+// otherwise redirect to the registration page.
+func (c *AuthController) logout() mvc.Response {
+	if c.isLoggedIn() {
+		c.Session.Destroy()
+	}
+	return PathLogin
+}