From 8e89d862fb062a3874ce849a9ad8300bf0a43748 Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Fri, 13 Apr 2018 16:02:10 +0530
Subject: [PATCH] Browser viewer: Show an error message when trying to use the
 Sync function without being logged in

---
 src/calibre/srv/books.py      | 4 +++-
 src/pyj/read_book/overlay.pyj | 5 ++++-
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/src/calibre/srv/books.py b/src/calibre/srv/books.py
index 1919117fe7..565b42308b 100644
--- a/src/calibre/srv/books.py
+++ b/src/calibre/srv/books.py
@@ -148,7 +148,7 @@ def book_manifest(ctx, rd, book_id, fmt):
                     ans = jsonlib.load(f)
                 ans['metadata'] = book_as_json(db, book_id)
                 user = rd.username or None
-                ans['last_read_positions'] = db.get_last_read_positions(book_id, fmt, user)
+                ans['last_read_positions'] = db.get_last_read_positions(book_id, fmt, user) if user else []
                 return ans
             except EnvironmentError as e:
                 if e.errno != errno.ENOENT:
@@ -189,6 +189,8 @@ def get_last_read_position(ctx, rd, library_id, which):
     '''
     db = get_db(ctx, rd, library_id)
     user = rd.username or None
+    if not user:
+        raise HTTPNotFound('login required for sync')
     ans = {}
     allowed_book_ids = ctx.allowed_book_ids(rd, db)
     for item in which.split('_'):
diff --git a/src/pyj/read_book/overlay.pyj b/src/pyj/read_book/overlay.pyj
index 4b68732740..7da105ff40 100644
--- a/src/pyj/read_book/overlay.pyj
+++ b/src/pyj/read_book/overlay.pyj
@@ -137,7 +137,10 @@ class SyncBook:  # {{{
             return
         self.overlay.hide()
         if load_type is not 'load':
-            error_dialog(_('Failed to fetch sync data'), _('Failed to download last read data from server, click "Show details" for more information.'), xhr.error_html)
+            if xhr.responseText is 'login required for sync':
+                error_dialog(_('Failed to fetch sync data'), _('You must setup user accounts and login to use the sync functionality'))
+            else:
+                error_dialog(_('Failed to fetch sync data'), _('Failed to download last read data from server, click "Show details" for more information.'), xhr.error_html)
             return
         data = JSON.parse(xhr.responseText)
         book = self.overlay.view.book