login handling

1 files changed, 48 insertions, 5 deletions

diff --git a/main.go b/main.go
index f97c639..863e1ff 100644
--- a/main.go
+++ b/main.go
@@ -2,7 +2,9 @@ package main
 
 import (
 	"database/sql"
+	"errors"
 	"flag"
+	"fmt"
 	"log"
 	"net"
 	"net/http"
@@ -11,6 +13,7 @@ import (
 
 	"github.com/gorilla/handlers"
 	"github.com/gorilla/schema"
+	"golang.org/x/crypto/bcrypt"
 
 	"gosten/model"
 	"gosten/templ"
@@ -56,8 +59,22 @@ func main() {
 }
 
 type User struct {
-	Name     string `form:"options=required"`
-	Password string `form:"type=password;options=required"`
+	Name     string  `form:"options=required"`
+	Password string  `form:"type=password;options=required"`
+	Errors   []error `form:"-"`
+}
+
+type fieldError struct {
+	Field string
+	Issue string
+}
+
+func (fe fieldError) Error() string {
+	return fmt.Sprintf("%s: %v", fe.Field, fe.Issue)
+}
+
+func (fe fieldError) FieldError() (field, err string) {
+	return fe.Field, fe.Issue
 }
 
 func showTemplate(tpl string, data any) http.HandlerFunc {
@@ -68,14 +85,40 @@ func showTemplate(tpl string, data any) http.HandlerFunc {
 	}
 }
 
-func handleLogin(w http.ResponseWriter, r *http.Request) {
-	u := User{}
+func parseForm[T any](r *http.Request, data *T) {
 	if err := r.ParseForm(); err != nil {
 		log.Panic("Parsing form: ", err)
 	}
-	if err := s.Decode(&u, r.PostForm); err != nil {
+	if err := s.Decode(data, r.PostForm); err != nil {
 		log.Panic("Decoding form: ", err)
 	}
+}
+
+func handleLogin(w http.ResponseWriter, r *http.Request) {
+	u := User{}
+	parseForm(r, &u)
+
+	invalid := false
+
+	dbUser, err := Q.GetUserByName(r.Context(), u.Name)
+	if err == nil {
+		hash := []byte(dbUser.Pwd)
+		pwd := []byte(u.Password)
+
+		if bcrypt.CompareHashAndPassword(hash, pwd) != nil {
+			invalid = true
+		}
+	} else if errors.Is(err, sql.ErrNoRows) {
+		invalid = true
+	} else {
+		log.Panicf("Could not load user '%s': %v", u.Name, err)
+	}
+
+	if invalid {
+		u.Errors = []error{fieldError{"Password", "Invalid"}}
+		showTemplate("login", u).ServeHTTP(w, r)
+		return
+	}
 
 	showTemplate("login2", u).ServeHTTP(w, r)
 }