Handle permission errors for static files (Fix for #2358)

Version bump

cps/cache_buster.py

@@ -47,13 +47,16 @@ def init_cache_busting(app):
         for filename in filenames:
             # compute version component
             rooted_filename = os.path.join(dirpath, filename)
+            try:
                 with open(rooted_filename, 'rb') as f:
                     file_hash = hashlib.md5(f.read()).hexdigest()[:7] # nosec
-
                 # save version to tables
                 file_path = rooted_filename.replace(static_folder, "")
                 file_path = file_path.replace("\\", "/")  # Convert Windows path to web path
                 hash_table[file_path] = file_hash
+            except PermissionError:
+                log.error("No permission to access {} file.".format(rooted_filename))
+
     log.debug('Finished computing cache-busting values')
 
     def bust_filename(filename):

cps/constants.py

@@ -154,7 +154,7 @@ def selected_roles(dictionary):
 BookMeta = namedtuple('BookMeta', 'file_path, extension, title, author, cover, description, tags, series, '
                                   'series_id, languages, publisher')
 
-STABLE_VERSION = {'version': '0.6.18'}
+STABLE_VERSION = {'version': '0.6.19 Beta'}
 
 NIGHTLY_VERSION = dict()
 NIGHTLY_VERSION[0] = '$Format:%H$'

cps/error_handler.py

@@ -42,8 +42,9 @@ def error_http(error):
 
 def internal_error(error):
     return render_template('http_error.html',
-                           error_code="Internal Server Error",
+                           error_code="500 Internal Server Error",
-                           error_name=str(error),
+                           error_name='The server encountered an internal error and was unable to complete your '
+                                      'request. There is an error in the application.',
                            issue=True,
                            unconfigured=False,
                            error_stack=traceback.format_exc().split("\n"),

cps/helper.py

@@ -698,9 +698,12 @@ def delete_book(book, calibrepath, book_format):
 
 def get_cover_on_failure(use_generic_cover):
     if use_generic_cover:
+        try:
             return send_from_directory(_STATIC_DIR, "generic_cover.jpg")
-    else:
+        except PermissionError:
-        return None
+            log.error("No permission to access generic_cover.jpg file.")
+            abort(403)
+    abort(404)
 
 
 def get_book_cover(book_id):

cps/render_template.py

@@ -18,11 +18,11 @@
 
 from flask import render_template, request
 from flask_babel import gettext as _
-from flask import g
+from flask import g, abort
 from werkzeug.local import LocalProxy
 from flask_login import current_user
 
-from . import config, constants, ub, logger, db, calibre_db
+from . import config, constants, logger
 from .ub import User
 
 
@@ -119,6 +119,10 @@ def get_sidebar_config(kwargs=None):
 # Returns the template for rendering and includes the instance name
 def render_title_template(*args, **kwargs):
     sidebar, simple = get_sidebar_config(kwargs)
+    try:
         return render_template(instance=config.config_calibre_web_title, sidebar=sidebar, simple=simple,
-                           accept=constants.EXTENSIONS_UPLOAD, # read_book_ids=get_readbooks_ids(),
+                               accept=constants.EXTENSIONS_UPLOAD,
                                *args, **kwargs)
+    except PermissionError:
+        log.error("No permission to access {} file.".format(args[0]))
+        abort(403)

cps/web.py

@@ -1368,7 +1368,11 @@ def get_cover(book_id):
 
 @web.route("/robots.txt")
 def get_robots():
+    try:
         return send_from_directory(constants.STATIC_DIR, "robots.txt")
+    except PermissionError:
+        log.error("No permission to access robots.txt file.")
+        abort(403)
 
 
 @web.route("/show/<int:book_id>/<book_format>", defaults={'anyname': 'None'})