Structuring examples - Pushed to iris-contrib/examples as well.

Former-commit-id: 24ee6ce233d83f0b394afc6c69b5a88243406045

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

@@ -0,0 +1,124 @@
+package user
+
+import (
+	"errors"
+	"strconv"
+	"strings"
+
+	"github.com/kataras/iris"
+)
+
+// paths
+const (
+	PathLogin  = "/user/login"
+	PathLogout = "/user/logout"
+)
+
+// the session key for the user id comes from the Session.
+const (
+	sessionIDKey = "UserID"
+)
+
+// AuthController is the user authentication controller, a custom shared controller.
+type AuthController struct {
+	iris.SessionController
+
+	Source *DataSource
+	User   Model `iris:"model"`
+}
+
+// BeginRequest saves login state to the context, the user id.
+func (c *AuthController) BeginRequest(ctx iris.Context) {
+	c.SessionController.BeginRequest(ctx)
+
+	if userID := c.Session.Get(sessionIDKey); userID != nil {
+		ctx.Values().Set(sessionIDKey, userID)
+	}
+}
+
+func (c *AuthController) fireError(err error) {
+	if err != nil {
+		c.Ctx.Application().Logger().Debug(err.Error())
+
+		c.Status = 400
+		c.Data["Title"] = "User Error"
+		c.Data["Message"] = strings.ToUpper(err.Error())
+		c.Tmpl = "shared/error.html"
+	}
+}
+
+func (c *AuthController) redirectTo(id int64) {
+	if id > 0 {
+		c.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 `SaveState` middleware.
+	return c.Values.Get(sessionIDKey) != nil
+}
+
+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() {
+	if c.isLoggedIn() {
+		// c.Manager is the Sessions manager created
+		// by the embedded SessionController, automatically.
+		c.Manager.DestroyByID(c.Session.ID())
+		return
+	}
+
+	c.Path = PathLogin
+}
+
+// AllowUser will check if this client is a logged user,
+// if not then it will redirect that guest to the login page
+// otherwise it will allow the execution of the next handler.
+func AllowUser(ctx iris.Context) {
+	if ctx.Values().Get(sessionIDKey) != nil {
+		ctx.Next()
+		return
+	}
+	ctx.Redirect(PathLogin)
+}

_examples/structuring/login-mvc-single-responsibility-package/user/controller.go

@@ -0,0 +1,133 @@
+package user
+
+const (
+	pathMyProfile = "/user/me"
+	pathRegister  = "/user/register"
+)
+
+// Controller is responsible to handle the following requests:
+// GET  			/user/register
+// POST 			/user/register
+// GET 				/user/login
+// POST 			/user/login
+// GET 				/user/me
+// GET				/user/{id:long} | long is a new param type, it's the int64.
+// All HTTP Methods /user/logout
+type Controller struct {
+	AuthController
+}
+
+// GetRegister handles GET:/user/register.
+func (c *Controller) GetRegister() {
+	if c.isLoggedIn() {
+		c.logout()
+		return
+	}
+
+	c.Data["Title"] = "User Registration"
+	c.Tmpl = pathRegister + ".html"
+}
+
+// PostRegister handles POST:/user/register.
+func (c *Controller) PostRegister() {
+	// we can either use the `c.Ctx.ReadForm` or read values one by one.
+	var (
+		firstname = c.Ctx.FormValue("firstname")
+		username  = c.Ctx.FormValue("username")
+		password  = c.Ctx.FormValue("password")
+	)
+
+	user, err := c.createOrUpdate(firstname, username, password)
+	if err != nil {
+		c.fireError(err)
+		return
+	}
+
+	// setting a session value was never easier.
+	c.Session.Set(sessionIDKey, user.ID)
+	// succeed, nothing more to do here, just redirect to the /user/me.
+
+	// When redirecting from POST to GET request you -should- use this HTTP status code,
+	// however there're some (complicated) alternatives if you
+	// search online or even the HTTP RFC.
+	c.Status = 303 // "See Other" RFC 7231
+
+	// Redirect to GET: /user/me
+	// by changing the Path (and the status code because we're in POST request at this case).
+	c.Path = pathMyProfile
+}
+
+// GetLogin handles GET:/user/login.
+func (c *Controller) GetLogin() {
+	if c.isLoggedIn() {
+		c.logout()
+		return
+	}
+	c.Data["Title"] = "User Login"
+	c.Tmpl = PathLogin + ".html"
+}
+
+// PostLogin handles POST:/user/login.
+func (c *Controller) PostLogin() {
+	var (
+		username = c.Ctx.FormValue("username")
+		password = c.Ctx.FormValue("password")
+	)
+
+	user, err := c.verify(username, password)
+	if err != nil {
+		c.fireError(err)
+		return
+	}
+
+	c.Session.Set(sessionIDKey, user.ID)
+	c.Path = pathMyProfile
+}
+
+// AnyLogout handles any method on path /user/logout.
+func (c *Controller) AnyLogout() {
+	c.logout()
+}
+
+// GetMe handles GET:/user/me.
+func (c *Controller) GetMe() {
+	id, err := c.Session.GetInt64(sessionIDKey)
+	if err != nil || id <= 0 {
+		// when not already logged in.
+		c.Path = PathLogin
+		return
+	}
+
+	u, found := c.Source.GetByID(id)
+	if !found {
+		// if the  session exists but for some reason the user doesn't exist in the "database"
+		// then logout him and redirect to the register page.
+		c.logout()
+		return
+	}
+
+	// set the model and render the view template.
+	c.User = u
+	c.Data["Title"] = "Profile of " + u.Username
+	c.Tmpl = pathMyProfile + ".html"
+}
+
+func (c *Controller) renderNotFound(id int64) {
+	c.Status = 404
+	c.Data["Title"] = "User Not Found"
+	c.Data["ID"] = id
+	c.Tmpl = "user/notfound.html"
+}
+
+// GetBy handles GET:/user/{id:long},
+// i.e http://localhost:8080/user/1
+func (c *Controller) GetBy(userID int64) {
+	// we have /user/{id}
+	// fetch and render user json.
+	if user, found := c.Source.GetByID(userID); !found {
+		// not user found with that ID.
+		c.renderNotFound(userID)
+	} else {
+		c.Ctx.JSON(user)
+	}
+}

_examples/structuring/login-mvc-single-responsibility-package/user/datasource.go

@@ -0,0 +1,114 @@
+package user
+
+import (
+	"errors"
+	"sync"
+	"time"
+)
+
+// IDGenerator would be our user ID generator
+// but here we keep the order of users by their IDs
+// so we will use numbers that can be easly written
+// to the browser to get results back from the REST API.
+// var IDGenerator = func() string {
+// 	return uuid.NewV4().String()
+// }
+
+// DataSource is our data store example.
+type DataSource struct {
+	Users map[int64]Model
+	mu    sync.RWMutex
+}
+
+// NewDataSource returns a new user data source.
+func NewDataSource() *DataSource {
+	return &DataSource{
+		Users: make(map[int64]Model),
+	}
+}
+
+// GetBy receives a query function
+// which is fired for every single user model inside
+// our imaginary database.
+// When that function returns true then it stops the iteration.
+//
+// It returns the query's return last known boolean value
+// and the last known user model
+// to help callers to reduce the loc.
+//
+// But be carefully, the caller should always check for the "found"
+// because it may be false but the user model has actually real data inside it.
+//
+// It's actually a simple but very clever prototype function
+// I'm think of and using everywhere since then,
+// hope you find it very useful too.
+func (d *DataSource) GetBy(query func(Model) bool) (user Model, found bool) {
+	d.mu.RLock()
+	for _, user = range d.Users {
+		found = query(user)
+		if found {
+			break
+		}
+	}
+	d.mu.RUnlock()
+	return
+}
+
+// GetByID returns a user model based on its ID.
+func (d *DataSource) GetByID(id int64) (Model, bool) {
+	return d.GetBy(func(u Model) bool {
+		return u.ID == id
+	})
+}
+
+// GetByUsername returns a user model based on the Username.
+func (d *DataSource) GetByUsername(username string) (Model, bool) {
+	return d.GetBy(func(u Model) bool {
+		return u.Username == username
+	})
+}
+
+func (d *DataSource) getLastID() (lastID int64) {
+	d.mu.RLock()
+	for id := range d.Users {
+		if id > lastID {
+			lastID = id
+		}
+	}
+	d.mu.RUnlock()
+
+	return lastID
+}
+
+// InsertOrUpdate adds or updates a user to the (memory) storage.
+func (d *DataSource) InsertOrUpdate(user Model) (Model, error) {
+	// no matter what we will update the password hash
+	// for both update and insert actions.
+	hashedPassword, err := GeneratePassword(user.password)
+	if err != nil {
+		return user, err
+	}
+	user.HashedPassword = hashedPassword
+
+	// update
+	if id := user.ID; id > 0 {
+		_, found := d.GetByID(id)
+		if !found {
+			return user, errors.New("ID should be zero or a valid one that maps to an existing User")
+		}
+		d.mu.Lock()
+		d.Users[id] = user
+		d.mu.Unlock()
+		return user, nil
+	}
+
+	// insert
+	id := d.getLastID() + 1
+	user.ID = id
+	d.mu.Lock()
+	user.CreatedAt = time.Now()
+	d.Users[id] = user
+	d.mu.Unlock()
+
+	return user, nil
+}

_examples/structuring/login-mvc-single-responsibility-package/user/model.go

@@ -0,0 +1,36 @@
+package user
+
+import (
+	"time"
+
+	"golang.org/x/crypto/bcrypt"
+)
+
+// Model is our User example model.
+type Model struct {
+	ID        int64  `json:"id"`
+	Firstname string `json:"firstname"`
+	Username  string `json:"username"`
+	// password is the client-given password
+	// which will not be stored anywhere in the server.
+	// It's here only for actions like registration and update password,
+	// because we caccept a Model instance
+	// inside the `DataSource#InsertOrUpdate` function.
+	password       string
+	HashedPassword []byte    `json:"-"`
+	CreatedAt      time.Time `json:"created_at"`
+}
+
+// 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
+}