Add sign out button

controllers/users.go

@@ -15,6 +15,7 @@ type Users struct {
 		Signin Template
 	}
 	UserService    *models.UserService
+	SessionService *models.SessionService
 }
 
 func (u Users) GetSignup(w http.ResponseWriter, r *http.Request) {
@@ -34,7 +35,22 @@ func (u Users) PostSignup(w http.ResponseWriter, r *http.Request) {
 		http.Error(w, "Internal Server Error", http.StatusInternalServerError)
 		return
 	}
-	fmt.Fprintf(w, "User created: %+v", user)
+	session, err := u.SessionService.Create(user.ID)
+	if err != nil {
+		fmt.Println(err)
+		http.Redirect(w, r, "/signin", http.StatusFound)
+		return
+	}
+
+	cookie := http.Cookie{
+		Name:     "session",
+		Value:    session.Token,
+		Path:     "/",
+		HttpOnly: true,
+	}
+	http.SetCookie(w, &cookie)
+
+	http.Redirect(w, r, "/users/me", http.StatusFound)
 }
 
 func (u Users) GetSignin(w http.ResponseWriter, r *http.Request) {
@@ -58,10 +74,16 @@ func (u Users) PostSignin(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	// Bad cookie
+	session, err := u.SessionService.Create(user.ID)
+	if err != nil {
+		fmt.Println(err)
+		http.Error(w, "Internal Server Error", http.StatusInternalServerError)
+		return
+	}
+
 	cookie := http.Cookie{
-		Name:     "bad",
-		Value:    user.Email,
+		Name:     "session",
+		Value:    session.Token,
 		Path:     "/",
 		HttpOnly: true,
 	}
@@ -70,24 +92,52 @@ func (u Users) PostSignin(w http.ResponseWriter, r *http.Request) {
 	fmt.Fprintf(w, "User authenticated: %+v", user)
 }
 
-func (u Users) CurrentUser(w http.ResponseWriter, r *http.Request) {
-	email, err := r.Cookie("bad")
+func (u Users) GetSignout(w http.ResponseWriter, r *http.Request) {
+	sessionCookie, err := r.Cookie("session")
 	if err != nil {
-		fmt.Fprint(w, "The bad cookie could not be read.")
+		http.Redirect(w, r, "/signin", http.StatusFound)
 		return
 	}
-	fmt.Fprintf(w, "Bad cookie: %s\n", email.Value)
+	err = u.SessionService.Delete(sessionCookie.Value)
+	if err != nil {
+		fmt.Println(err)
+		http.Error(w, "Internal Server Error", http.StatusInternalServerError)
+		return
+	}
+	c := http.Cookie{
+		Name:   "session",
+		MaxAge: -1,
+	}
+	http.SetCookie(w, &c)
+	http.Redirect(w, r, "/signin", http.StatusFound)
 }
 
-func WithTemplates(user_service *models.UserService, signup Template, signin Template) Users {
+func (u Users) CurrentUser(w http.ResponseWriter, r *http.Request) {
+	seshCookie, err := r.Cookie("session")
+	if err != nil {
+		fmt.Println(err)
+		http.Redirect(w, r, "/signin", http.StatusFound)
+		return
+	}
+	user, err := u.SessionService.User(seshCookie.Value)
+	if err != nil {
+		fmt.Println(err)
+		http.Redirect(w, r, "/signin", http.StatusFound)
+		return
+	}
+	fmt.Fprintf(w, "Current user: %s\n", user.Email)
+}
+
+func WithTemplates(user_service *models.UserService, session_service *models.SessionService, signup Template, signin Template) Users {
 	u := Users{}
 	u.Templates.Signup = signup
 	u.Templates.Signin = signin
 	u.UserService = user_service
+	u.SessionService = session_service
 	return u
 }
 
-func Default(user_service *models.UserService, templatePath ...string) Users {
+func Default(user_service *models.UserService, session_service *models.SessionService) Users {
 	signup_tpl := views.Must(views.FromFS(templates.FS, "signup.gohtml", "tailwind.gohtml"))
 	signin_tpl := views.Must(views.FromFS(templates.FS, "signin.gohtml", "tailwind.gohtml"))
 
@@ -100,5 +150,5 @@ func Default(user_service *models.UserService, templatePath ...string) Users {
 		panic(err)
 	}
 
-	return WithTemplates(user_service, signup_tpl, signin_tpl)
+	return WithTemplates(user_service, session_service, signup_tpl, signin_tpl)
 }

main.go

@@ -38,14 +38,15 @@ func ConnectDB() *sql.DB {
 func main() {
 	csrfKey := []byte(os.Getenv("LENSLOCKED_CSRF_KEY"))
 	if len(csrfKey) < 32 {
-		panic("Error: bad csrf protection key")
+		panic("Error: bad csrf protection key\nPlease set a key with the LENSLOCKED_CSRF_KEY env var.")
 	}
 
 	db := ConnectDB()
 	defer db.Close()
 
 	userService := models.UserService{DB: db}
-	var usersCtrlr ctrlrs.Users = ctrlrs.Default(&userService)
+	sessionService := models.SessionService{DB: db}
+	var usersCtrlr ctrlrs.Users = ctrlrs.Default(&userService, &sessionService)
 
 	r := chi.NewRouter()
 
@@ -59,6 +60,7 @@ func main() {
 	r.Post("/signup", usersCtrlr.PostSignup)
 	r.Get("/signin", usersCtrlr.GetSignin)
 	r.Post("/signin", usersCtrlr.PostSignin)
+	r.Post("/signout", usersCtrlr.GetSignout)
 
 	r.Get("/user", usersCtrlr.CurrentUser)
 

models/sessions.go

@@ -0,0 +1,116 @@
+package models
+
+import (
+	"crypto/rand"
+	"crypto/sha256"
+	"database/sql"
+	"encoding/base64"
+	"fmt"
+)
+
+func RandBytes(n int) ([]byte, error) {
+	b := make([]byte, n)
+	nRead, err := rand.Read(b)
+	if err != nil {
+		return nil, fmt.Errorf("bytes: %w", err)
+	}
+	if nRead < n {
+		return nil, fmt.Errorf("bytes: didn't read enough random bytes")
+	}
+	return b, nil
+}
+func RandString(n int) (string, error) {
+	b, err := RandBytes(n)
+	if err != nil {
+		return "", fmt.Errorf("string: %w", err)
+	}
+	return base64.URLEncoding.EncodeToString(b), nil
+}
+
+const SessionTokenBytes = 32
+
+func SessionToken() (string, error) {
+	return RandString(SessionTokenBytes)
+}
+func hash(token string) string {
+	tokenHash := sha256.Sum256([]byte(token))
+	return base64.StdEncoding.EncodeToString(tokenHash[:])
+}
+
+type Session struct {
+	ID        int
+	UserID    int
+	TokenHash string
+	// Token is only set when creating a new session. When looking up a session
+	// this will be left empty, as we only store the hash of a session token
+	// in our database and we cannot reverse it into a raw token.
+	Token string
+}
+
+type SessionService struct {
+	DB *sql.DB
+}
+
+func (ss *SessionService) Create(userID int) (*Session, error) {
+	token, err := SessionToken()
+	if err != nil {
+		return nil, fmt.Errorf("create: %w", err)
+	}
+	session := Session{
+		UserID:    userID,
+		Token:     token,
+		TokenHash: hash(token),
+	}
+
+	row := ss.DB.QueryRow(`
+    UPDATE sessions
+    SET token_hash = $2
+    WHERE user_id = $1
+    RETURNING id;
+  `, session.UserID, session.TokenHash)
+	err = row.Scan(&session.ID)
+	if err == sql.ErrNoRows {
+		row = ss.DB.QueryRow(`
+      INSERT INTO sessions (user_id, token_hash)
+      VALUES ($1, $2)
+      RETURNING id;
+    `, session.UserID, session.TokenHash)
+		err = row.Scan(&session.ID)
+	}
+
+	if err != nil {
+		return nil, fmt.Errorf("create: %w", err)
+	}
+
+	return &session, nil
+}
+
+func (ss *SessionService) Delete(token string) error {
+	tokenHash := hash(token)
+	_, err := ss.DB.Exec(`DELETE FROM sessions WHERE token_hash = $1;`, tokenHash)
+	if err != nil {
+		return fmt.Errorf("delete: %w", err)
+	}
+	return nil
+}
+
+func (ss *SessionService) User(token string) (*User, error) {
+	token_hash := hash(token)
+	var user User
+	row := ss.DB.QueryRow(`
+    SELECT (user_id) FROM sessions WHERE token_hash = $1;
+  `, token_hash)
+	err := row.Scan(&user.ID)
+	if err != nil {
+		return nil, fmt.Errorf("user: %w", err)
+	}
+	row = ss.DB.QueryRow(`
+    SELECT email, password_hash
+    FROM users WHERE id = $1;
+  `, user.ID)
+	err = row.Scan(&user.Email, &user.PasswordHash)
+	if err != nil {
+		return nil, fmt.Errorf("user: %w", err)
+	}
+	return &user, err
+}

models/sql/sessions.sql

@@ -0,0 +1,5 @@
+CREATE TABLE sessions (
+  id SERIAL PRIMARY KEY,
+  user_id INT UNIQUE, 
+  token_hash TEXT UNIQUE NOT NULL
+);

templates/tailwind.gohtml

@@ -16,6 +16,10 @@
           <a class="text-base font-semibold hover:text-blue-100 pr-8" href="/faq">FAQ</a>
         </div>
         <div class="space-x-4">
+          <form action="/signout" method="post" class="inline pr-4">
+            {{csrfField}}
+            <button type="submit">Sign out</button>
+          </form>
           <a href="/signin">Sign in</a>
           <a href="/signup" clss="px-4 py-2 bg-blue-700 hover:bg-blue-600 rounded">Sign up</a>
         </div>

views/template.go

@@ -1,8 +1,10 @@
 package views
 
 import (
+	"bytes"
 	"fmt"
 	"html/template"
+	"io"
 	"io/fs"
 	"log"
 	"net/http"
@@ -29,12 +31,14 @@ func (t Template) Execute(w http.ResponseWriter, r *http.Request, data interface
 	})
 
 	w.Header().Set("Content-Type", "text/html; charset=utf8")
-	err = tpl.Execute(w, data)
+	var buf bytes.Buffer
+	err = tpl.Execute(&buf, data)
 	if err != nil {
 		log.Printf("Error executing template: %v", err)
 		http.Error(w, "Internal Server Error", http.StatusInternalServerError)
 		return
 	}
+	io.Copy(w, &buf)
 }
 func (t Template) TestTemplate(data interface{}) error {
 	var testWriter strings.Builder
@@ -42,6 +46,11 @@ func (t Template) TestTemplate(data interface{}) error {
 	if err != nil {
 		return err
 	}
+	tpl = tpl.Funcs(template.FuncMap{
+		"csrfField": func() template.HTML {
+			return `<div class="hidden">STUB: PLACEHOLDER</div>`
+		},
+	})
 	return tpl.Execute(&testWriter, data)
 }
 
@@ -52,8 +61,8 @@ func FromFile(pattern ...string) (Template, error) {
 func FromFS(fs fs.FS, pattern ...string) (Template, error) {
 	tpl := template.New(pattern[0])
 	tpl = tpl.Funcs(template.FuncMap{
-		"csrfField": func() template.HTML {
-			return `<div class="hidden">STUB: PLACEHOLDER</div>`
+		"csrfField": func() (template.HTML, error) {
+			return `<div class="hidden">STUB: PLACEHOLDER</div>`, fmt.Errorf("csrfField Not Implimented")
 		},
 	})
 	tpl, err := tpl.ParseFS(fs, pattern...)