basic TOTP based login (note: account creation not safe)

gargoyle.go

@@ -0,0 +1,83 @@
+package main
+
+import (
+	"github.com/gin-gonic/gin"
+	"github.com/pquerna/otp/totp"
+	"gorm.io/driver/sqlite"
+	"gorm.io/gorm"
+)
+
+var (
+	db *gorm.DB
+)
+
+type User struct {
+	gorm.Model
+	Secret   string
+	Username string `gorm:"uniqueIndex"`
+	Email    string
+}
+
+func init() {
+	var err error
+	db, err = gorm.Open(sqlite.Open("test.db"), &gorm.Config{})
+	if err != nil {
+		panic("failed to connect database")
+	}
+	db.AutoMigrate(&User{})
+}
+
+func main() {
+	r := gin.Default()
+	r.GET("/ping", func(c *gin.Context) {
+		c.String(200, "format string, values ...any")
+	})
+	r.POST("/signup", signup)
+	r.POST("/login", login)
+	r.Run() // listen and serve on 0.0.0.0:8080 (for windows "localhost:8080")}
+}
+
+type Signup struct {
+	Username string `form:"username"`
+	Email    string `form:"email"`
+}
+
+func signup(c *gin.Context) {
+	var s Signup
+	c.Bind(&s)
+
+	key, err := totp.Generate(totp.GenerateOpts{AccountName: s.Username, Issuer: "me"})
+	if err != nil {
+		c.Status(502)
+		return
+	}
+
+	var user User
+	user.Email = s.Email
+	user.Username = s.Username
+	user.Secret = key.Secret()
+	db.Create(&user)
+
+	c.String(200, "%s", key.Secret())
+}
+
+type Login struct {
+	Username string `form:"username"`
+	Code     string `form:"code"`
+}
+
+func login(c *gin.Context) {
+	var login Login
+	var user User
+	c.Bind(&login)
+	if err := db.Where("username = ?", login.Username).First(&user).Error; err != nil {
+		c.String(404, "something went wrong")
+		return
+	}
+	correct := totp.Validate(login.Code, user.Secret)
+	if correct {
+		c.String(200, "success!")
+	} else {
+		c.String(404, "something went wrong")
+	}
+}