feat(webui): bootstrap session handling and login process

pkg/webui/login.go

@@ -0,0 +1,115 @@
+package webui
+
+import (
+	"context"
+	"fmt"
+	"html/template"
+	"net/http"
+	"regexp"
+
+	"git.adyxax.org/adyxax/tfstated/pkg/database"
+	"git.adyxax.org/adyxax/tfstated/pkg/model"
+)
+
+var loginTemplate = template.Must(template.ParseFS(htmlFS, "html/base.html", "html/login.html"))
+
+type loginPage struct {
+	Forbidden bool
+	Username  string
+}
+
+func handleLoginGET() http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Cache-Control", "no-store, no-cache")
+
+		session := r.Context().Value(model.SessionContextKey{})
+		if session != nil {
+			http.Redirect(w, r, "/", http.StatusFound)
+			return
+		}
+
+		render(w, loginTemplate, http.StatusOK, loginPage{})
+	})
+}
+
+func handleLoginPOST(db *database.DB) http.Handler {
+	var validUsername = regexp.MustCompile(`^[a-zA-Z]\w*$`)
+	renderForbidden := func(w http.ResponseWriter, username string) {
+		render(w, loginTemplate, http.StatusForbidden, loginPage{
+			Forbidden: true,
+			Username:  username,
+		})
+	}
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if err := r.ParseForm(); err != nil {
+			errorResponse(w, http.StatusBadRequest, err)
+			return
+		}
+		username := r.FormValue("username")
+		password := r.FormValue("password")
+
+		if username == "" || password == "" { // the webui cannot issue this
+			errorResponse(w, http.StatusBadRequest, fmt.Errorf("Forbidden"))
+			return
+		}
+		if ok := validUsername.MatchString(username); !ok {
+			renderForbidden(w, username)
+			return
+		}
+		account, err := db.LoadAccountByUsername(username)
+		if err != nil {
+			errorResponse(w, http.StatusInternalServerError, err)
+			return
+		}
+		if account == nil || !account.CheckPassword(password) {
+			renderForbidden(w, username)
+			return
+		}
+		if err := db.TouchAccount(account); err != nil {
+			errorResponse(w, http.StatusInternalServerError, err)
+			return
+		}
+		sessionId, err := db.CreateSession(account)
+		if err != nil {
+			errorResponse(w, http.StatusInternalServerError, err)
+			return
+		}
+		http.SetCookie(w, &http.Cookie{
+			Name:     cookieName,
+			Value:    sessionId,
+			Quoted:   false,
+			Path:     "/",
+			MaxAge:   8 * 3600, // 1 hour sessions
+			HttpOnly: true,
+			SameSite: http.SameSiteStrictMode,
+			Secure:   true,
+		})
+		http.Redirect(w, r, "/", http.StatusFound)
+	})
+}
+
+func loginMiddleware(db *database.DB) func(http.Handler) http.Handler {
+	return func(next http.Handler) http.Handler {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			w.Header().Set("Cache-Control", "no-store, no-cache")
+			session := r.Context().Value(model.SessionContextKey{})
+			if session == nil {
+				http.Redirect(w, r, "/login", http.StatusFound)
+				return
+			}
+			account, err := db.LoadAccountById(session.(*model.Session).AccountId)
+			if err != nil {
+				errorResponse(w, http.StatusInternalServerError, err)
+				return
+			}
+			if account == nil {
+				// this could happen if the account was deleted in the short
+				// time between retrieving the session and here
+				http.Redirect(w, r, "/login", http.StatusFound)
+				return
+			}
+			ctx := context.WithValue(r.Context(), model.AccountContextKey{}, account)
+			next.ServeHTTP(w, r.WithContext(ctx))
+		})
+	}
+}