Add refresh tokens for persistent login, logout button

the main JWT is stored temporarily, whereas the refresh token is stored
as a cookie and can only be used to obtain a new main token. Logout
button adds token to blocklist internally and deletes JWT and refresh
token from browser storage.

api.go

@@ -609,6 +609,11 @@ func (app *appContext) ModifyConfig(gc *gin.Context) {
 	}
 }
 
+func (app *appContext) Logout(gc *gin.Context) {
+	app.invalidIds = append(app.invalidIds, gc.GetString("userId"))
+	gc.JSON(200, map[string]bool{"success": true})
+}
+
 // func Restart() error {
 // 	defer func() {
 // 		if r := recover(); r != nil {

auth.go

@@ -4,6 +4,7 @@ import (
 	"encoding/base64"
 	"fmt"
 	"os"
+	"strconv"
 	"strings"
 	"time"
 
@@ -40,7 +41,14 @@ func (app *appContext) authenticate(gc *gin.Context) {
 	claims, ok := token.Claims.(jwt.MapClaims)
 	var userId string
 	var jfId string
-	if ok && token.Valid {
+	expiryUnix, err := strconv.ParseInt(claims["exp"].(string), 10, 64)
+	if err != nil {
+		app.debug.Printf("Auth denied: %s", err)
+		respond(401, "Unauthorized", gc)
+		return
+	}
+	expiry := time.Unix(expiryUnix, 0)
+	if ok && token.Valid && claims["type"].(string) == "bearer" && expiry.After(time.Now()) {
 		userId = claims["id"].(string)
 		jfId = claims["jfid"].(string)
 	} else {
@@ -76,20 +84,56 @@ func (app *appContext) GetToken(gc *gin.Context) {
 	auth, _ := base64.StdEncoding.DecodeString(header[1])
 	creds := strings.SplitN(string(auth), ":", 2)
 	match := false
-	var userId string
+	var userId, jfId string
 	for _, user := range app.users {
 		if user.Username == creds[0] && user.Password == creds[1] {
 			match = true
 			userId = user.UserID
 		}
 	}
-	jfId := ""
 	if !match {
 		if !app.jellyfinLogin {
 			app.info.Println("Auth failed: Invalid username and/or password")
 			respond(401, "Unauthorized", gc)
 			return
 		}
+		if creds[1] == "" {
+			token, err := jwt.Parse(creds[0], func(token *jwt.Token) (interface{}, error) {
+				if _, ok := token.Method.(*jwt.SigningMethodHMAC); !ok {
+					app.debug.Printf("Invalid JWT signing method %s", token.Header["alg"])
+					return nil, fmt.Errorf("Unexpected signing method %v", token.Header["alg"])
+				}
+				return []byte(os.Getenv("JFA_SECRET")), nil
+			})
+			if err != nil {
+				app.debug.Printf("Auth denied: %s", err)
+				respond(401, "Unauthorized", gc)
+				return
+			}
+			claims, ok := token.Claims.(jwt.MapClaims)
+			for _, id := range app.invalidIds {
+				if claims["id"].(string) == id {
+					app.debug.Printf("Auth denied: Refresh token in blocklist")
+					respond(401, "Unauthorized", gc)
+					return
+				}
+			}
+			expiryUnix, err := strconv.ParseInt(claims["exp"].(string), 10, 64)
+			if err != nil {
+				app.debug.Printf("Auth denied: %s", err)
+				respond(401, "Unauthorized", gc)
+				return
+			}
+			expiry := time.Unix(expiryUnix, 0)
+			if ok && token.Valid && claims["type"].(string) == "refresh" && expiry.After(time.Now()) {
+				userId = claims["id"].(string)
+				jfId = claims["jfid"].(string)
+			} else {
+				app.debug.Printf("Invalid token (invalid or not refresh type)")
+				respond(401, "Unauthorized", gc)
+				return
+			}
+		} else {
 			var status int
 			var err error
 			var user map[string]interface{}
@@ -119,28 +163,47 @@ func (app *appContext) GetToken(gc *gin.Context) {
 				app.users = append(app.users, newuser)
 			}
 		}
-	token, err := CreateToken(userId, jfId)
+	}
+	token, refresh, err := CreateToken(userId, jfId)
 	if err != nil {
 		respond(500, "Error generating token", gc)
 	}
-	resp := map[string]string{"token": token}
+	resp := map[string]string{"token": token, "refresh": refresh}
 	gc.JSON(200, resp)
 }
 
-func CreateToken(userId string, jfId string) (string, error) {
+func CreateToken(userId string, jfId string) (string, string, error) {
+	var token, refresh string
+	var err error
 	claims := jwt.MapClaims{
 		"valid": true,
 		"id":    userId,
-		"exp":   time.Now().Add(time.Minute * 20).Unix(),
+		"exp":   strconv.FormatInt(time.Now().Add(time.Minute*20).Unix(), 10),
 		"jfid":  jfId,
+		"type":  "bearer",
 	}
 
 	tk := jwt.NewWithClaims(jwt.SigningMethodHS256, claims)
-	token, err := tk.SignedString([]byte(os.Getenv("JFA_SECRET")))
+	token, err = tk.SignedString([]byte(os.Getenv("JFA_SECRET")))
 	if err != nil {
-		return "", err
+		return "", "", err
 	}
-	return token, nil
+
+	claims = jwt.MapClaims{
+		"valid": true,
+		"id":    userId,
+		"exp":   strconv.FormatInt(time.Now().Add(time.Hour*24).Unix(), 10),
+		"jfid":  jfId,
+		"type":  "refresh",
+	}
+
+	tk = jwt.NewWithClaims(jwt.SigningMethodHS256, claims)
+	refresh, err = tk.SignedString([]byte(os.Getenv("JFA_SECRET")))
+	if err != nil {
+		return "", "", err
+	}
+
+	return token, refresh, nil
 }
 
 func respond(code int, message string, gc *gin.Context) {

data/static/admin.js

@@ -531,20 +531,7 @@ document.getElementById('inviteForm').onsubmit = function() {
     return false;
 };
 
-document.getElementById('loginForm').onsubmit = function() {
+function tryLogin(username, password, modal, button) {
-    window.token = "";
-    let details = serializeForm('loginForm');
-    // let errorArea = document.getElementById('loginErrorArea');
-    // errorArea.textContent = '';
-    let button = document.getElementById('loginSubmit');
-    if (button.classList.contains('btn-danger')) {
-        button.classList.add('btn-primary');
-        button.classList.remove('btn-danger');
-    }
-    button.disabled = true;
-    button.innerHTML =
-        '<span class="spinner-border spinner-border-sm" role="status" aria-hidden="true" style="margin-right: 0.5rem;"></span>' +
-        'Loading...';
     let req = new XMLHttpRequest();
     req.responseType = 'json';
     req.onreadystatechange = function() {
@@ -554,6 +541,7 @@ document.getElementById('loginForm').onsubmit = function() {
                 if (errormsg == "") {
                     errormsg = "Unknown error"
                 }
+                if (modal) {
                     button.disabled = false;
                     button.textContent = errormsg;
                     if (!button.classList.contains('btn-danger')) {
@@ -567,9 +555,13 @@ document.getElementById('loginForm').onsubmit = function() {
                             button.textContent = 'Login';
                         }
                     }, 4000)
+                } else {
+                    loginModal.show();
+                }
             } else {
                 const data = this.response;
                 window.token = data['token'];
+                document.cookie = "refresh=" + data['refresh'];
                 generateInvites();
                 const interval = setInterval(function() { generateInvites(); }, 60 * 1000);
                 let day = document.getElementById('days');
@@ -582,13 +574,33 @@ document.getElementById('loginForm').onsubmit = function() {
                 addOptions(59, minutes);
                 minutes.selected = "30";
                 checkDuration();
+                if (modal) {
                     loginModal.hide();
                 }
+                document.getElementById('logoutButton').setAttribute('style', '');
+            }
         }
     };
     req.open("GET", "/getToken", true);
-    req.setRequestHeader("Authorization", "Basic " + btoa(details['username'] + ":" + details['password']));
+    req.setRequestHeader("Authorization", "Basic " + btoa(username + ":" + password));
     req.send();
+}
+
+document.getElementById('loginForm').onsubmit = function() {
+    window.token = "";
+    let details = serializeForm('loginForm');
+    // let errorArea = document.getElementById('loginErrorArea');
+    // errorArea.textContent = '';
+    let button = document.getElementById('loginSubmit');
+    if (button.classList.contains('btn-danger')) {
+        button.classList.add('btn-primary');
+        button.classList.remove('btn-danger');
+    }
+    button.disabled = true;
+    button.innerHTML =
+        '<span class="spinner-border spinner-border-sm" role="status" aria-hidden="true" style="margin-right: 0.5rem;"></span>' +
+        'Loading...';
+    tryLogin(details['username'], details['password'], true, button)
     return false;
 };
 
@@ -794,7 +806,29 @@ document.getElementById('openUsers').onclick = function () {
 };
 
 generateInvites(empty = true);
+
+let refreshToken = getCookie("refresh")
+if (refreshToken != "") {
+    tryLogin(refreshToken, "", false)
+} else {
     loginModal.show();
+}
+
+document.getElementById('logoutButton').onclick = function () {
+    let req = new XMLHttpRequest();
+    req.open("POST", "/logout", true);
+    req.responseType = 'json';
+    req.setRequestHeader("Authorization", "Basic " + btoa(window.token + ":"));
+    req.onreadystatechange = function() {
+        if (this.readyState == 4 && this.status == 200) {
+            window.token = '';
+            document.cookie = 'refresh=;';
+            location.reload();
+            return false;
+        }
+    };
+    req.send();
+}
 
 var config = {};
 var modifiedConfig = {};

data/templates/admin.html

@@ -258,6 +258,9 @@
                 <button type="button" class="btn btn-primary" id="openSettings">
                     Settings <i class="fa fa-cog"></i>
                 </button>
+                <button type="button" class="btn btn-danger" id="logoutButton" style="display: none;">
+                    Logout <i class="fa fa-sign-out"></i>
+                </button>
             </div>
             <div class="card mb-3 linkGroup">
                 <div class="card-header">Current Invites</div>

main.go

@@ -42,6 +42,7 @@ type appContext struct {
 	bsVersion        int
 	jellyfinLogin    bool
 	users            []User
+	invalidIds       []string
 	jf               Jellyfin
 	authJf           Jellyfin
 	datePattern      string
@@ -328,6 +329,7 @@ func main() {
 		router.Use(static.Serve("/invite/", static.LocalFile(filepath.Join(app.local_path, "static"), false)))
 		router.GET("/invite/:invCode", app.InviteProxy)
 		api := router.Group("/", app.webAuth())
+		api.POST("/logout", app.Logout)
 		api.POST("/generateInvite", app.GenerateInvite)
 		api.GET("/getInvites", app.GetInvites)
 		api.POST("/setNotify", app.SetNotify)