From 869fb9691f877116d5b15a92de006d0daf4d70e5 Mon Sep 17 00:00:00 2001
From: René 'Necoro' Neumann <necoro@necoro.eu>
Date: Thu, 17 Oct 2024 00:27:08 +0200
Subject: Restructure and change to chi as muxing framework

---
 pages/login.go | 123 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 123 insertions(+)
 create mode 100644 pages/login.go

(limited to 'pages/login.go')

diff --git a/pages/login.go b/pages/login.go
new file mode 100644
index 0000000..fb7859a
--- /dev/null
+++ b/pages/login.go
@@ -0,0 +1,123 @@
+package pages
+
+import (
+	"context"
+	"database/sql"
+	"errors"
+	"gosten/csrf"
+	"gosten/form"
+	"gosten/session"
+	"log"
+	"net/http"
+	"net/url"
+
+	"golang.org/x/crypto/bcrypt"
+)
+
+type userContextKey struct{}
+
+const (
+	sessionDuration  = 86400 * 7 // 7 days
+	loginQueryMarker = "next"
+)
+
+func RequireAuth(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		s := session.From(r)
+
+		if !s.IsNew() && s.Authenticated {
+			u, err := Q.GetUserById(r.Context(), s.UserID)
+			if err == nil {
+				// authenticated --> done
+				ctx := context.WithValue(r.Context(), userContextKey{}, u.ID)
+				next.ServeHTTP(w, r.WithContext(ctx))
+				return
+			}
+
+			s.Invalidate()
+			s.Save(w, r)
+		}
+
+		// redirect to login with next-param
+		v := url.Values{}
+		v.Set(loginQueryMarker, r.URL.Path)
+		redirPath := "/login?" + v.Encode()
+		http.Redirect(w, r, redirPath, http.StatusFound)
+	})
+}
+
+type User struct {
+	Name       string  `form:"options=required,autofocus"`
+	Password   string  `form:"type=password;options=required"`
+	RememberMe bool    `form:"type=checkbox;value=y;options=checked"`
+	Errors     []error `form:"-"`
+	csrf.Csrf
+}
+
+func showLoginPage(w http.ResponseWriter, u User) {
+	showTemplate(w, "login", u)
+}
+
+func Login() http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		if session.From(r).Authenticated {
+			http.Redirect(w, r, "/", http.StatusFound)
+		}
+		u := User{}
+		u.SetCsrfField(r)
+		showLoginPage(w, u)
+	}
+}
+
+func userId(r *http.Request) int32 {
+	return r.Context().Value(userContextKey{}).(int32)
+}
+
+func checkLogin(ctx context.Context, user User) (bool, int32) {
+	dbUser, err := Q.GetUserByName(ctx, user.Name)
+	if err == nil {
+		hash := []byte(dbUser.Pwd)
+		pwd := []byte(user.Password)
+
+		if bcrypt.CompareHashAndPassword(hash, pwd) != nil {
+			return false, 0
+		}
+	} else if errors.Is(err, sql.ErrNoRows) {
+		return false, 0
+	} else {
+		log.Panicf("Could not load user '%s': %v", user.Name, err)
+	}
+
+	return true, dbUser.ID
+}
+
+func HandleLogin(w http.ResponseWriter, r *http.Request) {
+	u := User{}
+	form.Parse(r, &u)
+
+	ok, userId := checkLogin(r.Context(), u)
+
+	if !ok {
+		u.Errors = []error{form.FieldError{Field: "Password", Issue: "Invalid"}}
+		showLoginPage(w, u)
+		return
+	}
+
+	s := session.From(r)
+	if u.RememberMe {
+		s.MaxAge(sessionDuration) // 1 week
+	} else {
+		s.MaxAge(0)
+	}
+
+	s.UserID = userId
+	s.Authenticated = true
+	s.Save(w, r)
+
+	// redirect
+	next := r.URL.Query().Get(loginQueryMarker)
+	if next == "" {
+		next = "/"
+	}
+	http.Redirect(w, r, next, http.StatusFound)
+}
-- 
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