Added clear cache button to admin settings, updated cache busting for book cover images

cps/admin.py

@@ -38,7 +38,7 @@ from sqlalchemy import and_
 from sqlalchemy.exc import IntegrityError, OperationalError, InvalidRequestError
 from sqlalchemy.sql.expression import func, or_
 
-from . import constants, logger, helper, services
+from . import constants, logger, helper, services, fs
 from . import db, calibre_db, ub, web_server, get_locale, config, updater_thread, babel, gdriveutils
 from .helper import check_valid_domain, send_test_mail, reset_password, generate_password_hash
 from .gdriveutils import is_gdrive_ready, gdrive_support
@@ -157,6 +157,23 @@ def shutdown():
     return json.dumps(showtext), 400
 
 
+@admi.route("/clear-cache")
+@login_required
+@admin_required
+def clear_cache():
+    cache_type = request.args.get('cache_type'.strip())
+    showtext = {}
+
+    if cache_type == fs.CACHE_TYPE_THUMBNAILS:
+        log.info('clearing cover thumbnail cache')
+        showtext['text'] = _(u'Cleared cover thumbnail cache')
+        helper.clear_cover_thumbnail_cache()
+        return json.dumps(showtext)
+
+    showtext['text'] = _(u'Unknown command')
+    return json.dumps(showtext)
+
+
 @admi.route("/admin/view")
 @login_required
 @admin_required

cps/editbooks.py

@@ -595,6 +595,7 @@ def upload_cover(request, book):
                 abort(403)
             ret, message = helper.save_cover(requested_file, book.path)
             if ret is True:
+                helper.clear_cover_thumbnail_cache(book.id)
                 return True
             else:
                 flash(message, category="error")
@@ -684,6 +685,7 @@ def edit_book(book_id):
                         if result is True:
                             book.has_cover = 1
                             modif_date = True
+                            helper.clear_cover_thumbnail_cache(book.id)
                         else:
                             flash(error, category="error")
 

cps/helper.py

@@ -58,6 +58,7 @@ from .constants import STATIC_DIR as _STATIC_DIR
 from .subproc_wrapper import process_wait
 from .services.worker import WorkerThread, STAT_WAITING, STAT_FAIL, STAT_STARTED, STAT_FINISH_SUCCESS
 from .tasks.mail import TaskEmail
+from .tasks.thumbnail import TaskClearCoverThumbnailCache
 
 log = logger.create()
 
@@ -525,6 +526,7 @@ def update_dir_stucture(book_id, calibrepath, first_author=None, orignal_filepat
 
 
 def delete_book(book, calibrepath, book_format):
+    clear_cover_thumbnail_cache(book.id)
     if config.config_use_google_drive:
         return delete_book_gdrive(book, book_format)
     else:
@@ -538,9 +540,9 @@ def get_cover_on_failure(use_generic_cover):
         return None
 
 
-def get_book_cover(book_id, resolution=1):
+def get_book_cover(book_id):
     book = calibre_db.get_filtered_book(book_id, allow_show_archived=True)
-    return get_book_cover_internal(book, use_generic_cover_on_failure=True, resolution=resolution)
+    return get_book_cover_internal(book, use_generic_cover_on_failure=True)
 
 
 def get_book_cover_with_uuid(book_uuid, use_generic_cover_on_failure=True):
@@ -548,11 +550,19 @@ def get_book_cover_with_uuid(book_uuid, use_generic_cover_on_failure=True):
     return get_book_cover_internal(book, use_generic_cover_on_failure)
 
 
-def get_book_cover_internal(book, use_generic_cover_on_failure, resolution=1, disable_thumbnail=False):
+def get_cached_book_cover(cache_id):
+    parts = cache_id.split('_')
+    book_uuid = parts[0] if len(parts) else None
+    resolution = parts[2] if len(parts) > 2 else None
+    book = calibre_db.get_book_by_uuid(book_uuid) if book_uuid else None
+    return get_book_cover_internal(book, use_generic_cover_on_failure=True, resolution=resolution)
+
+
+def get_book_cover_internal(book, use_generic_cover_on_failure, resolution=None):
     if book and book.has_cover:
 
         # Send the book cover thumbnail if it exists in cache
-        if not disable_thumbnail:
+        if resolution:
             thumbnail = get_book_cover_thumbnail(book, resolution)
             if thumbnail:
                 cache = fs.FileSystem()
@@ -585,7 +595,7 @@ def get_book_cover_internal(book, use_generic_cover_on_failure, resolution=1, di
         return get_cover_on_failure(use_generic_cover_on_failure)
 
 
-def get_book_cover_thumbnail(book, resolution=1):
+def get_book_cover_thumbnail(book, resolution):
     if book and book.has_cover:
         return ub.session\
             .query(ub.Thumbnail)\
@@ -846,3 +856,6 @@ def get_download_link(book_id, book_format, client):
     else:
         abort(404)
 
+
+def clear_cover_thumbnail_cache(book_id=None):
+    WorkerThread.add(None, TaskClearCoverThumbnailCache(book_id))

cps/jinjia.py

@@ -128,8 +128,14 @@ def formatseriesindex_filter(series_index):
             return series_index
     return 0
 
+
 @jinjia.app_template_filter('uuidfilter')
 def uuidfilter(var):
     return uuid4()
 
 
+@jinjia.app_template_filter('book_cover_cache_id')
+def book_cover_cache_id(book, resolution=None):
+    timestamp = int(book.last_modified.timestamp() * 1000)
+    cache_bust = str(book.uuid) + '_' + str(timestamp)
+    return cache_bust if not resolution else cache_bust + '_' + str(resolution)

cps/schedule.py

@@ -18,12 +18,10 @@
 
 from __future__ import division, print_function, unicode_literals
 
-from . import config, db, logger, ub
 from .services.background_scheduler import BackgroundScheduler
+from .tasks.database import TaskReconnectDatabase
 from .tasks.thumbnail import TaskCleanupCoverThumbnailCache, TaskGenerateCoverThumbnails
 
-log = logger.create()
-
 
 def register_jobs():
     scheduler = BackgroundScheduler()
@@ -35,10 +33,4 @@ def register_jobs():
     scheduler.add_task(user=None, task=lambda: TaskCleanupCoverThumbnailCache(), trigger='cron', hour=4)
 
     # Reconnect metadata.db every 4 hours
-    scheduler.add(func=reconnect_db_job, trigger='interval', hours=4)
+    scheduler.add_task(user=None, task=lambda: TaskReconnectDatabase(), trigger='interval', hours=4)
-
-
-def reconnect_db_job():
-    log.info('Running background task: reconnect to calibre database')
-    calibre_db = db.CalibreDB()
-    calibre_db.reconnect_db(config, ub.app_DB_path)

cps/static/css/caliBlur.css

@@ -5167,7 +5167,7 @@ body.login > div.navbar.navbar-default.navbar-static-top > div > div.navbar-head
     pointer-events: none
 }
 
-#DeleteDomain:hover:before, #RestartDialog:hover:before, #ShutdownDialog:hover:before, #StatusDialog:hover:before, #deleteButton, #deleteModal:hover:before, body.mailset > div.container-fluid > div > div.col-sm-10 > div.discover td > a:hover {
+#DeleteDomain:hover:before, #RestartDialog:hover:before, #ShutdownDialog:hover:before, #StatusDialog:hover:before, #ClearCacheDialog:hover:before, #deleteButton, #deleteModal:hover:before, body.mailset > div.container-fluid > div > div.col-sm-10 > div.discover td > a:hover {
     cursor: pointer
 }
 
@@ -5254,7 +5254,7 @@ body.admin > div.container-fluid > div > div.col-sm-10 > div.container-fluid > d
     margin-bottom: 20px
 }
 
-body.admin:not(.modal-open) .btn-default {
+body.admin .btn-default {
     margin-bottom: 10px
 }
 
@@ -5485,7 +5485,7 @@ body.admin.modal-open .navbar {
     z-index: 0 !important
 }
 
-#RestartDialog, #ShutdownDialog, #StatusDialog, #deleteModal {
+#RestartDialog, #ShutdownDialog, #StatusDialog, #ClearCacheDialog, #deleteModal {
     top: 0;
     overflow: hidden;
     padding-top: 70px;
@@ -5495,7 +5495,7 @@ body.admin.modal-open .navbar {
     background: rgba(0, 0, 0, .5)
 }
 
-#RestartDialog:before, #ShutdownDialog:before, #StatusDialog:before, #deleteModal:before {
+#RestartDialog:before, #ShutdownDialog:before, #StatusDialog:before, #ClearCacheDialog:before, #deleteModal:before {
     content: "\E208";
     padding-right: 10px;
     display: block;
@@ -5517,18 +5517,18 @@ body.admin.modal-open .navbar {
     z-index: 99
 }
 
-#RestartDialog.in:before, #ShutdownDialog.in:before, #StatusDialog.in:before, #deleteModal.in:before {
+#RestartDialog.in:before, #ShutdownDialog.in:before, #StatusDialog.in:before, #ClearCacheDialog.in:before, #deleteModal.in:before {
     -webkit-transform: translate(0, 0);
     -ms-transform: translate(0, 0);
     transform: translate(0, 0)
 }
 
-#RestartDialog > .modal-dialog, #ShutdownDialog > .modal-dialog, #StatusDialog > .modal-dialog, #deleteModal > .modal-dialog {
+#RestartDialog > .modal-dialog, #ShutdownDialog > .modal-dialog, #StatusDialog > .modal-dialog, #ClearCacheDialog > .modal-dialog, #deleteModal > .modal-dialog {
     width: 450px;
     margin: auto
 }
 
-#RestartDialog > .modal-dialog > .modal-content, #ShutdownDialog > .modal-dialog > .modal-content, #StatusDialog > .modal-dialog > .modal-content, #deleteModal > .modal-dialog > .modal-content {
+#RestartDialog > .modal-dialog > .modal-content, #ShutdownDialog > .modal-dialog > .modal-content, #StatusDialog > .modal-dialog > .modal-content, #ClearCacheDialog > .modal-dialog > .modal-content, #deleteModal > .modal-dialog > .modal-content {
     max-height: calc(100% - 90px);
     -webkit-box-shadow: 0 5px 15px rgba(0, 0, 0, .5);
     box-shadow: 0 5px 15px rgba(0, 0, 0, .5);
@@ -5539,7 +5539,7 @@ body.admin.modal-open .navbar {
     width: 450px
 }
 
-#RestartDialog > .modal-dialog > .modal-content > .modal-header, #ShutdownDialog > .modal-dialog > .modal-content > .modal-header, #StatusDialog > .modal-dialog > .modal-content > .modal-header, #deleteModal > .modal-dialog > .modal-content > .modal-header {
+#RestartDialog > .modal-dialog > .modal-content > .modal-header, #ShutdownDialog > .modal-dialog > .modal-content > .modal-header, #StatusDialog > .modal-dialog > .modal-content > .modal-header, #ClearCacheDialog > .modal-dialog > .modal-content > .modal-header, #deleteModal > .modal-dialog > .modal-content > .modal-header {
     padding: 15px 20px;
     border-radius: 3px 3px 0 0;
     line-height: 1.71428571;
@@ -5552,7 +5552,7 @@ body.admin.modal-open .navbar {
     text-align: left
 }
 
-#RestartDialog > .modal-dialog > .modal-content > .modal-header:before, #ShutdownDialog > .modal-dialog > .modal-content > .modal-header:before, #StatusDialog > .modal-dialog > .modal-content > .modal-header:before, #deleteModal > .modal-dialog > .modal-content > .modal-header:before {
+#RestartDialog > .modal-dialog > .modal-content > .modal-header:before, #ShutdownDialog > .modal-dialog > .modal-content > .modal-header:before, #StatusDialog > .modal-dialog > .modal-content > .modal-header:before, #ClearCacheDialog > .modal-dialog > .modal-content > .modal-header:before, #deleteModal > .modal-dialog > .modal-content > .modal-header:before {
     padding-right: 10px;
     font-size: 18px;
     color: #999;
@@ -5576,6 +5576,11 @@ body.admin.modal-open .navbar {
     font-family: plex-icons-new, serif
 }
 
+#ClearCacheDialog > .modal-dialog > .modal-content > .modal-header:before {
+    content: "\EA15";
+    font-family: plex-icons-new, serif
+}
+
 #deleteModal > .modal-dialog > .modal-content > .modal-header:before {
     content: "\EA6D";
     font-family: plex-icons-new, serif
@@ -5599,6 +5604,12 @@ body.admin.modal-open .navbar {
     font-size: 20px
 }
 
+#ClearCacheDialog > .modal-dialog > .modal-content > .modal-header:after {
+    content: "Clear Cover Thumbnail Cache";
+    display: inline-block;
+    font-size: 20px
+}
+
 #deleteModal > .modal-dialog > .modal-content > .modal-header:after {
     content: "Delete Book";
     display: inline-block;
@@ -5629,7 +5640,17 @@ body.admin.modal-open .navbar {
     text-align: left
 }
 
-#RestartDialog > .modal-dialog > .modal-content > .modal-body > p, #ShutdownDialog > .modal-dialog > .modal-content > .modal-body > p, #StatusDialog > .modal-dialog > .modal-content > .modal-body > p, #deleteModal > .modal-dialog > .modal-content > .modal-body > p {
+#ClearCacheDialog > .modal-dialog > .modal-content > .modal-body {
+    padding: 20px 20px 10px;
+    font-size: 16px;
+    line-height: 1.6em;
+    font-family: Open Sans Regular, Helvetica Neue, Helvetica, Arial, sans-serif;
+    color: #eee;
+    background: #282828;
+    text-align: left
+}
+
+#RestartDialog > .modal-dialog > .modal-content > .modal-body > p, #ShutdownDialog > .modal-dialog > .modal-content > .modal-body > p, #StatusDialog > .modal-dialog > .modal-content > .modal-body > p, #ClearCacheDialog > .modal-dialog > .modal-content > .modal-body > p, #deleteModal > .modal-dialog > .modal-content > .modal-body > p {
     padding: 20px 20px 0 0;
     font-size: 16px;
     line-height: 1.6em;
@@ -5638,7 +5659,7 @@ body.admin.modal-open .navbar {
     background: #282828
 }
 
-#RestartDialog > .modal-dialog > .modal-content > .modal-body > .btn-default:not(#restart), #ShutdownDialog > .modal-dialog > .modal-content > .modal-body > .btn-default:not(#shutdown), #deleteModal > .modal-dialog > .modal-content > .modal-footer > .btn-default {
+#RestartDialog > .modal-dialog > .modal-content > .modal-body > .btn-default:not(#restart), #ShutdownDialog > .modal-dialog > .modal-content > .modal-body > .btn-default:not(#shutdown), #ClearCacheDialog > .modal-dialog > .modal-content > .modal-body > .btn-default:not(#clear_cache), #deleteModal > .modal-dialog > .modal-content > .modal-footer > .btn-default {
     float: right;
     z-index: 9;
     position: relative;
@@ -5674,6 +5695,18 @@ body.admin.modal-open .navbar {
     border-radius: 3px
 }
 
+#ClearCacheDialog > .modal-dialog > .modal-content > .modal-body > #clear_cache {
+    float: right;
+    z-index: 9;
+    position: relative;
+    margin: 25px 0 0 10px;
+    min-width: 80px;
+    padding: 10px 18px;
+    font-size: 16px;
+    line-height: 1.33;
+    border-radius: 3px
+}
+
 #deleteModal > .modal-dialog > .modal-content > .modal-footer > .btn-danger {
     float: right;
     z-index: 9;
@@ -5694,11 +5727,15 @@ body.admin.modal-open .navbar {
     margin: 55px 0 0 10px
 }
 
+#ClearCacheDialog > .modal-dialog > .modal-content > .modal-body > .btn-default:not(#clear_cache) {
+    margin: 25px 0 0 10px
+}
+
 #deleteModal > .modal-dialog > .modal-content > .modal-footer > .btn-default {
     margin: 0 0 0 10px
 }
 
-#RestartDialog > .modal-dialog > .modal-content > .modal-body > .btn-default:not(#restart):hover, #ShutdownDialog > .modal-dialog > .modal-content > .modal-body > .btn-default:not(#shutdown):hover, #deleteModal > .modal-dialog > .modal-content > .modal-footer > .btn-default:hover {
+#RestartDialog > .modal-dialog > .modal-content > .modal-body > .btn-default:not(#restart):hover, #ShutdownDialog > .modal-dialog > .modal-content > .modal-body > .btn-default:not(#shutdown):hover, #ClearCacheDialog > .modal-dialog > .modal-content > .modal-body > .btn-default:not(#clear_cache):hover, #deleteModal > .modal-dialog > .modal-content > .modal-footer > .btn-default:hover {
     background-color: hsla(0, 0%, 100%, .3)
 }
 
@@ -5732,6 +5769,21 @@ body.admin.modal-open .navbar {
     box-shadow: 0 5px 15px rgba(0, 0, 0, .5)
 }
 
+#ClearCacheDialog > .modal-dialog > .modal-content > .modal-body:after {
+    content: '';
+    position: absolute;
+    width: 100%;
+    height: 72px;
+    background-color: #323232;
+    border-radius: 0 0 3px 3px;
+    left: 0;
+    margin-top: 10px;
+    z-index: 0;
+    border-top: 1px solid #222;
+    -webkit-box-shadow: 0 5px 15px rgba(0, 0, 0, .5);
+    box-shadow: 0 5px 15px rgba(0, 0, 0, .5)
+}
+
 #deleteButton {
     position: fixed;
     top: 60px;
@@ -7322,11 +7374,11 @@ body.edituser.admin > div.container-fluid > div.row-fluid > div.col-sm-10 > div.
         background-color: transparent !important
     }
 
-    #RestartDialog > .modal-dialog, #ShutdownDialog > .modal-dialog, #StatusDialog > .modal-dialog, #deleteModal > .modal-dialog {
+    #RestartDialog > .modal-dialog, #ShutdownDialog > .modal-dialog, #StatusDialog > .modal-dialog, #ClearCacheDialog > .modal-dialog, #deleteModal > .modal-dialog {
         max-width: calc(100vw - 40px)
     }
 
-    #RestartDialog > .modal-dialog > .modal-content, #ShutdownDialog > .modal-dialog > .modal-content, #StatusDialog > .modal-dialog > .modal-content, #deleteModal > .modal-dialog > .modal-content {
+    #RestartDialog > .modal-dialog > .modal-content, #ShutdownDialog > .modal-dialog > .modal-content, #StatusDialog > .modal-dialog > .modal-content, #ClearCacheDialog > .modal-dialog > .modal-content, #deleteModal > .modal-dialog > .modal-content {
         max-width: calc(100vw - 40px);
         left: 0
     }
@@ -7476,7 +7528,7 @@ body.edituser.admin > div.container-fluid > div.row-fluid > div.col-sm-10 > div.
         padding: 30px 15px
     }
 
-    #RestartDialog.in:before, #ShutdownDialog.in:before, #StatusDialog.in:before, #deleteModal.in:before {
+    #RestartDialog.in:before, #ShutdownDialog.in:before, #StatusDialog.in:before, #ClearCacheDialog.in:before, #deleteModal.in:before {
         left: auto;
         right: 34px
     }

cps/static/js/main.js

@@ -405,6 +405,18 @@ $(function() {
             }
         });
     });
+    $("#clear_cache").click(function () {
+        $("#spinner3").show();
+        $.ajax({
+            dataType: "json",
+            url: window.location.pathname + "/../../clear-cache",
+            data: {"cache_type":"thumbnails"},
+            success: function(data) {
+                $("#spinner3").hide();
+                $("#ClearCacheDialog").modal("hide");
+            }
+        });
+    });
 
     // Init all data control handlers to default
     $("input[data-control]").trigger("change");

cps/tasks/database.py

@@ -0,0 +1,49 @@
+# -*- coding: utf-8 -*-
+
+#   This file is part of the Calibre-Web (https://github.com/janeczku/calibre-web)
+#     Copyright (C) 2020 mmonkey
+#
+#   This program is free software: you can redistribute it and/or modify
+#   it under the terms of the GNU General Public License as published by
+#   the Free Software Foundation, either version 3 of the License, or
+#   (at your option) any later version.
+#
+#   This program is distributed in the hope that it will be useful,
+#   but WITHOUT ANY WARRANTY; without even the implied warranty of
+#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#   GNU General Public License for more details.
+#
+#   You should have received a copy of the GNU General Public License
+#   along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+from __future__ import division, print_function, unicode_literals
+
+from cps import config, logger
+from cps.services.worker import CalibreTask
+
+try:
+    from urllib.request import urlopen
+except ImportError as e:
+    from urllib2 import urlopen
+
+
+class TaskReconnectDatabase(CalibreTask):
+    def __init__(self, task_message=u'Reconnecting Calibre database'):
+        super(TaskReconnectDatabase, self).__init__(task_message)
+        self.log = logger.create()
+        self.listen_address = config.get_config_ipaddress()
+        self.listen_port = config.config_port
+
+    def run(self, worker_thread):
+        address = self.listen_address if self.listen_address else 'localhost'
+        port = self.listen_port if self.listen_port else 8083
+
+        try:
+            urlopen('http://' + address + ':' + str(port) + '/reconnect')
+            self._handleSuccess()
+        except Exception as ex:
+            self._handleError(u'Unable to reconnect Calibre database: ' + str(ex))
+
+    @property
+    def name(self):
+        return "Reconnect Database"

cps/tasks/thumbnail.py

@@ -42,7 +42,6 @@ THUMBNAIL_RESOLUTION_2X = 2
 class TaskGenerateCoverThumbnails(CalibreTask):
     def __init__(self, limit=100, task_message=u'Generating cover thumbnails'):
         super(TaskGenerateCoverThumbnails, self).__init__(task_message)
-        self.self_cleanup = True
         self.limit = limit
         self.log = logger.create()
         self.app_db_session = ub.get_new_session_instance()
@@ -186,7 +185,7 @@ class TaskGenerateCoverThumbnails(CalibreTask):
 
 
 class TaskCleanupCoverThumbnailCache(CalibreTask):
-    def __init__(self, task_message=u'Validating cover thumbnail cache'):
+    def __init__(self, task_message=u'Cleaning up cover thumbnail cache'):
         super(TaskCleanupCoverThumbnailCache, self).__init__(task_message)
         self.log = logger.create()
         self.app_db_session = ub.get_new_session_instance()
@@ -265,3 +264,58 @@ class TaskCleanupCoverThumbnailCache(CalibreTask):
     @property
     def name(self):
         return "CleanupCoverThumbnailCache"
+
+
+class TaskClearCoverThumbnailCache(CalibreTask):
+    def __init__(self, book_id=None, task_message=u'Clearing cover thumbnail cache'):
+        super(TaskClearCoverThumbnailCache, self).__init__(task_message)
+        self.log = logger.create()
+        self.book_id = book_id
+        self.app_db_session = ub.get_new_session_instance()
+        self.cache = fs.FileSystem()
+
+    def run(self, worker_thread):
+        if self.app_db_session:
+            if self.book_id:
+                thumbnails = self.get_thumbnails_for_book(self.book_id)
+                for thumbnail in thumbnails:
+                    self.expire_and_delete_thumbnail(thumbnail)
+            else:
+                self.expire_and_delete_all_thumbnails()
+
+        self._handleSuccess()
+        self.app_db_session.remove()
+
+    def get_thumbnails_for_book(self, book_id):
+        return self.app_db_session\
+            .query(ub.Thumbnail)\
+            .filter(ub.Thumbnail.book_id == book_id)\
+            .all()
+
+    def expire_and_delete_thumbnail(self, thumbnail):
+        thumbnail.expiration = datetime.utcnow()
+
+        try:
+            self.app_db_session.commit()
+            self.cache.delete_cache_file(thumbnail.filename, fs.CACHE_TYPE_THUMBNAILS)
+        except Exception as ex:
+            self.log.info(u'Error expiring book thumbnail: ' + str(ex))
+            self._handleError(u'Error expiring book thumbnail: ' + str(ex))
+            self.app_db_session.rollback()
+
+    def expire_and_delete_all_thumbnails(self):
+        self.app_db_session\
+            .query(ub.Thumbnail)\
+            .update({'expiration': datetime.utcnow()})
+
+        try:
+            self.app_db_session.commit()
+            self.cache.delete_cache_dir(fs.CACHE_TYPE_THUMBNAILS)
+        except Exception as ex:
+            self.log.info(u'Error expiring book thumbnails: ' + str(ex))
+            self._handleError(u'Error expiring book thumbnails: ' + str(ex))
+            self.app_db_session.rollback()
+
+    @property
+    def name(self):
+        return "ClearCoverThumbnailCache"

cps/templates/admin.html

@@ -139,15 +139,18 @@
     </div>
   </div>
 
-    <div class="row form-group">
+  <div class="row form-group">
     <h2>{{_('Administration')}}</h2>
-      <div class="btn btn-default"><a id="debug" href="{{url_for('admin.download_debug')}}">{{_('Download Debug Package')}}</a></div>
+    <div class="btn btn-default"><a id="debug" href="{{url_for('admin.download_debug')}}">{{_('Download Debug Package')}}</a></div>
-      <div class="btn btn-default"><a id="logfile" href="{{url_for('admin.view_logfile')}}">{{_('View Logs')}}</a></div>
+    <div class="btn btn-default"><a id="logfile" href="{{url_for('admin.view_logfile')}}">{{_('View Logs')}}</a></div>
-    </div>
+  </div>
-    <div class="row form-group">
+  <div class="row form-group">
-      <div class="btn btn-default" id="restart_database" data-toggle="modal" data-target="#StatusDialog">{{_('Reconnect Calibre Database')}}</div>
+    <div class="btn btn-default" id="restart_database" data-toggle="modal" data-target="#StatusDialog">{{_('Reconnect Calibre Database')}}</div>
-      <div class="btn btn-default" id="admin_restart" data-toggle="modal" data-target="#RestartDialog">{{_('Restart')}}</div>
+    <div class="btn btn-default" id="clear_cover_thumbnail_cache" data-toggle="modal" data-target="#ClearCacheDialog">{{_('Clear Cover Thumbnail Cache')}}</div>
-      <div class="btn btn-default" id="admin_stop" data-toggle="modal" data-target="#ShutdownDialog">{{_('Shutdown')}}</div>
+  </div>
+  <div class="row form-group">
+    <div class="btn btn-default" id="admin_restart" data-toggle="modal" data-target="#RestartDialog">{{_('Restart')}}</div>
+    <div class="btn btn-default" id="admin_stop" data-toggle="modal" data-target="#ShutdownDialog">{{_('Shutdown')}}</div>
   </div>
 
   <div class="row">
@@ -226,4 +229,21 @@
     </div>
   </div>
 </div>
+<div id="ClearCacheDialog" class="modal fade" role="dialog">
+  <div class="modal-dialog modal-sm">
+    <!-- Modal content-->
+    <div class="modal-content">
+      <div class="modal-header bg-info"></div>
+      <div class="modal-body text-center">
+        <p>{{_('Are you sure you want to clear the cover thumbnail cache?')}}</p>
+        <div id="spinner3" class="spinner" style="display:none;">
+          <img id="img-spinner3" src="{{ url_for('static', filename='css/libs/images/loading-icon.gif') }}"/>
+        </div>
+        <p></p>
+        <button type="button" class="btn btn-default" id="clear_cache" >{{_('OK')}}</button>
+        <button type="button" class="btn btn-default" data-dismiss="modal">{{_('Cancel')}}</button>
+      </div>
+    </div>
+  </div>
+</div>
 {% endblock %}

cps/templates/author.html

@@ -36,7 +36,7 @@
     <div id="books" class="col-sm-3 col-lg-2 col-xs-6 book">
       <div class="cover">
         <a href="{{ url_for('web.show_book', book_id=entry.id) }}">
-            {{ book_cover_image(entry.id, entry.title) }}
+            {{ book_cover_image(entry, entry.title) }}
         </a>
       </div>
       <div class="meta">

cps/templates/book_cover.html

@@ -1,8 +1,8 @@
-{% macro book_cover_image(book_id, book_title) -%}
+{% macro book_cover_image(book, book_title) -%}
     <img
-        srcset="{{ url_for('web.get_cover', book_id=book_id, resolution=1) }} 1x,
+        srcset="{{ url_for('web.get_cached_cover', cache_id=book|book_cover_cache_id(1)) }} 1x,
-                {{ url_for('web.get_cover', book_id=book_id, resolution=2) }} 2x"
+                {{ url_for('web.get_cached_cover', cache_id=book|book_cover_cache_id(2)) }} 2x"
-        src="{{ url_for('web.get_cover', book_id=book_id) }}"
+        src="{{ url_for('web.get_cached_cover', cache_id=book|book_cover_cache_id) }}"
         alt="{{ book_title }}"
     />
 {%- endmacro %}

cps/templates/book_edit.html

@@ -4,8 +4,7 @@
 {% if book %}
   <div class="col-sm-3 col-lg-3 col-xs-12">
     <div class="cover">
-        {{ book_cover_image(book.id, book.title) }}
+        {{ book_cover_image(book, book.title) }}
-<!--        <img src="{{ url_for('web.get_cover', book_id=book.id, edit=1|uuidfilter)  }}" alt="{{ book.title }}"/>-->
     </div>
 {% if g.user.role_delete_books() %}
     <div class="text-center">

cps/templates/detail.html

@@ -4,8 +4,7 @@
   <div class="row">
     <div class="col-sm-3 col-lg-3 col-xs-5">
       <div class="cover">
-          {{ book_cover_image(entry.id, entry.title) }}
+          {{ book_cover_image(entry, entry.title) }}
-<!--          <img src="{{ url_for('web.get_cover', book_id=entry.id, edit=1|uuidfilter) }}" alt="{{ entry.title }}" />-->
       </div>
     </div>
     <div class="col-sm-9 col-lg-9 book-meta">

cps/templates/discover.html

@@ -9,7 +9,7 @@
       <div class="cover">
         {% if entry.has_cover is defined %}
           <a href="{{ url_for('web.show_book', book_id=entry.id) }}" data-toggle="modal" data-target="#bookDetailsModal" data-remote="false">
-              {{ book_cover_image(entry.id, entry.title) }}
+              {{ book_cover_image(entry, entry.title) }}
           </a>
         {% endif %}
       </div>

cps/templates/grid.html

@@ -29,7 +29,7 @@
               <div class="col-sm-3 col-lg-2 col-xs-6 book sortable" {% if entry[0].sort %}data-name="{{entry[0].series[0].name}}"{% endif %} data-id="{% if entry[0].series[0].name %}{{entry[0].series[0].name}}{% endif %}">
                   <div class="cover">
                       <a href="{{url_for('web.books_list', data=data, sort_param='new', book_id=entry[0].series[0].id )}}">
-                          {{ book_cover_image(entry[0].id, entry[0].name) }}
+                          {{ book_cover_image(entry[0], entry[0].name) }}
                           <span class="badge">{{entry.count}}</span>
                       </a>
                   </div>

cps/templates/index.html

@@ -9,7 +9,7 @@
     <div class="col-sm-3 col-lg-2 col-xs-6 book" id="books_rand">
       <div class="cover">
           <a href="{{ url_for('web.show_book', book_id=entry.id) }}" data-toggle="modal" data-target="#bookDetailsModal" data-remote="false">
-              {{ book_cover_image(entry.id, entry.title) }}
+              {{ book_cover_image(entry, entry.title) }}
           </a>
       </div>
       <div class="meta">
@@ -83,7 +83,7 @@
     <div class="col-sm-3 col-lg-2 col-xs-6 book" id="books">
       <div class="cover">
           <a href="{{ url_for('web.show_book', book_id=entry.id) }}" data-toggle="modal" data-target="#bookDetailsModal" data-remote="false">
-              {{ book_cover_image(entry.id, entry.title) }}
+              {{ book_cover_image(entry, entry.title) }}
           </a>
       </div>
       <div class="meta">

cps/templates/search.html

@@ -44,7 +44,7 @@
       <div class="cover">
         {% if entry.has_cover is defined %}
            <a href="{{ url_for('web.show_book', book_id=entry.id) }}" data-toggle="modal" data-target="#bookDetailsModal" data-remote="false">
-               {{ book_cover_image(entry.id, entry.title) }}
+               {{ book_cover_image(entry, entry.title) }}
           </a>
         {% endif %}
       </div>

cps/templates/shelf.html

@@ -31,7 +31,7 @@
     <div class="col-sm-3 col-lg-2 col-xs-6 book">
       <div class="cover">
             <a href="{{ url_for('web.show_book', book_id=entry.id) }}" data-toggle="modal" data-target="#bookDetailsModal" data-remote="false">
-                {{ book_cover_image(entry.id, entry.title) }}
+                {{ book_cover_image(entry, entry.title) }}
             </a>
       </div>
       <div class="meta">

cps/web.py

@@ -50,7 +50,7 @@ from . import babel, db, ub, config, get_locale, app
 from . import calibre_db, shelf
 from .gdriveutils import getFileFromEbooksFolder, do_gdrive_download
 from .helper import check_valid_domain, render_task_status, \
-    get_cc_columns, get_book_cover, get_download_link, send_mail, generate_random_password, \
+    get_cc_columns, get_book_cover, get_cached_book_cover, get_download_link, send_mail, generate_random_password, \
     send_registration_mail, check_send_to_kindle, check_read_formats, tags_filters, reset_password
 from .pagination import Pagination
 from .redirect import redirect_back
@@ -1177,6 +1177,12 @@ def get_cover(book_id, resolution=1):
     return get_book_cover(book_id, resolution)
 
 
+@web.route("/cached-cover/<string:cache_id>")
+@login_required_if_no_ano
+def get_cached_cover(cache_id):
+    return get_cached_book_cover(cache_id)
+
+
 @web.route("/robots.txt")
 def get_robots():
     return send_from_directory(constants.STATIC_DIR, "robots.txt")