# Buggy code
def on_received_watch_confirmation():
    app.logger.debug(request.headers)
    if (
        request.headers.get("X-Goog-Channel-Token") == gdrive_watch_callback_token
        and request.headers.get("X-Goog-Resource-State") == "change"
        and request.data
    ):
        data = request.data

        def updateMetaData():
            app.logger.info("Change received from gdrive")
            app.logger.debug(data)
            try:
                j = json.loads(data)
                app.logger.info("Getting change details")
                response = gdriveutils.getChangeById(
                    gdriveutils.Gdrive.Instance().drive, j["id"]
                )
                app.logger.debug(response)
                if response:
                    dbpath = os.path.join(config.config_calibre_dir, "metadata.db")
                    if (
                        not response["deleted"]
                        and response["file"]["title"] == "metadata.db"
                        and response["file"]["md5Checksum"] != md5(dbpath)
                    ):
                        tmpDir = tempfile.gettempdir()
                        app.logger.info("Database file updated")
                        copyfile(
                            dbpath,
                            os.path.join(
                                tmpDir, "metadata.db_" + str(current_milli_time())
                            ),
                        )
                        app.logger.info(
                            "Backing up existing and downloading updated metadata.db"
                        )
                        gdriveutils.downloadFile(
                            None, "metadata.db", os.path.join(tmpDir, "tmp_metadata.db")
                        )
                        app.logger.info("Setting up new DB")
                        # prevent error on windows, as os.rename does on exisiting files
                        move(os.path.join(tmpDir, "tmp_metadata.db"), dbpath)
                        db.setup_db()
            except Exception as e:
                app.logger.info(e.message)
                app.logger.exception(e)

        updateMetaData()
    return ""


# Traceback (OperationalError)
ERROR:cps.web:Exception on /book/125 [GET]
Traceback (most recent call last):
File "/Users/jgillman/Code/calibre-web/vendor/flask/app.py", line 1817, in wsgi_app
response = self.full_dispatch_request()
File "/Users/jgillman/Code/calibre-web/vendor/flask/app.py", line 1477, in full_dispatch_request
rv = self.handle_user_exception(e)
File "/Users/jgillman/Code/calibre-web/vendor/flask/app.py", line 1381, in handle_user_exception
reraise(exc_type, exc_value, tb)
File "/Users/jgillman/Code/calibre-web/vendor/flask/app.py", line 1475, in full_dispatch_request
rv = self.dispatch_request()
File "/Users/jgillman/Code/calibre-web/vendor/flask/app.py", line 1461, in dispatch_request
return self.view_functions[rule.endpoint](**req.view_args)
File "/Users/jgillman/Code/calibre-web/vendor/flask_login.py", line 717, in decorated_view
return func(*args, **kwargs)
File "/Users/jgillman/Code/calibre-web/cps/web.py", line 381, in show_book
return render_template('detail.html', entry=entries,  cc=cc, title=entries.title, books_shelfs=book_in_shelfs)
File "/Users/jgillman/Code/calibre-web/vendor/flask/templating.py", line 128, in render_template
context, ctx.app)
File "/Users/jgillman/Code/calibre-web/vendor/flask/templating.py", line 110, in _render
rv = template.render(context)
File "/Users/jgillman/Code/calibre-web/vendor/jinja2/environment.py", line 969, in render
return self.environment.handle_exception(exc_info, True)
File "/Users/jgillman/Code/calibre-web/vendor/jinja2/environment.py", line 742, in handle_exception
reraise(exc_type, exc_value, tb)
File "/Users/jgillman/Code/calibre-web/cps/templates/detail.html", line 1, in top-level template code
{% extends "layout.html" %}
File "/Users/jgillman/Code/calibre-web/cps/templates/layout.html", line 136, in top-level template code
{% block body %}{% endblock %}
File "/Users/jgillman/Code/calibre-web/cps/templates/detail.html", line 66, in block "body"
{% if entry['custom_column_' ~ c.id]|length > 0 %}
File "/Users/jgillman/Code/calibre-web/vendor/jinja2/environment.py", line 387, in getitem
return getattr(obj, attr)
File "/Users/jgillman/Code/calibre-web/vendor/sqlalchemy/orm/attributes.py", line 316, in __get__
return self.impl.get(instance_state(instance), dict_)
File "/Users/jgillman/Code/calibre-web/vendor/sqlalchemy/orm/attributes.py", line 613, in get
value = self.callable_(state, passive)
File "/Users/jgillman/Code/calibre-web/vendor/sqlalchemy/orm/strategies.py", line 524, in _load_for_state
return self._emit_lazyload(session, state, ident_key, passive)
File "/Users/jgillman/Code/calibre-web/vendor/sqlalchemy/orm/strategies.py", line 585, in _emit_lazyload
result = q.all()
File "/Users/jgillman/Code/calibre-web/vendor/sqlalchemy/orm/query.py", line 2241, in all
return list(self)
File "/Users/jgillman/Code/calibre-web/vendor/sqlalchemy/orm/query.py", line 2353, in __iter__
return self._execute_and_instances(context)
File "/Users/jgillman/Code/calibre-web/vendor/sqlalchemy/orm/query.py", line 2368, in _execute_and_instances
result = conn.execute(querycontext.statement, self._params)
File "/Users/jgillman/Code/calibre-web/vendor/sqlalchemy/engine/base.py", line 662, in execute
params)
File "/Users/jgillman/Code/calibre-web/vendor/sqlalchemy/engine/base.py", line 761, in _execute_clauseelement
compiled_sql, distilled_params
File "/Users/jgillman/Code/calibre-web/vendor/sqlalchemy/engine/base.py", line 874, in _execute_context
context)
File "/Users/jgillman/Code/calibre-web/vendor/sqlalchemy/engine/base.py", line 1024, in _handle_dbapi_exception
exc_info
File "/Users/jgillman/Code/calibre-web/vendor/sqlalchemy/util/compat.py", line 196, in raise_from_cause
reraise(type(exception), exception, tb=exc_tb)
File "/Users/jgillman/Code/calibre-web/vendor/sqlalchemy/engine/base.py", line 867, in _execute_context
context)
File "/Users/jgillman/Code/calibre-web/vendor/sqlalchemy/engine/default.py", line 324, in do_execute
cursor.execute(statement, parameters)
OperationalError: (OperationalError) no such table: books_custom_column_1_link u'SELECT custom_column_1.id AS custom_column_1_id, custom_column_1.value AS custom_column_1_value \
nFROM custom_column_1, books_custom_column_1_link \nWHERE ? = books_custom_column_1_link.book AND custom_column_1.id = books_custom_column_1_link.value' (125,)
ERROR:tornado.access:500 GET /book/125 (::1) 89.60ms

# Fixed code
def on_received_watch_confirmation():
    app.logger.debug(request.headers)
    if (
        request.headers.get("X-Goog-Channel-Token") == gdrive_watch_callback_token
        and request.headers.get("X-Goog-Resource-State") == "change"
        and request.data
    ):
        data = request.data

        def updateMetaData():
            app.logger.info("Change received from gdrive")
            app.logger.debug(data)
            try:
                j = json.loads(data)
                app.logger.info("Getting change details")
                response = gdriveutils.getChangeById(
                    gdriveutils.Gdrive.Instance().drive, j["id"]
                )
                app.logger.debug(response)
                if response:
                    dbpath = os.path.join(config.config_calibre_dir, "metadata.db")
                    if (
                        not response["deleted"]
                        and response["file"]["title"] == "metadata.db"
                        and response["file"]["md5Checksum"] != hashlib.md5(dbpath)
                    ):
                        tmpDir = tempfile.gettempdir()
                        app.logger.info("Database file updated")
                        copyfile(
                            dbpath,
                            os.path.join(
                                tmpDir, "metadata.db_" + str(current_milli_time())
                            ),
                        )
                        app.logger.info(
                            "Backing up existing and downloading updated metadata.db"
                        )
                        gdriveutils.downloadFile(
                            None, "metadata.db", os.path.join(tmpDir, "tmp_metadata.db")
                        )
                        app.logger.info("Setting up new DB")
                        # prevent error on windows, as os.rename does on exisiting files
                        move(os.path.join(tmpDir, "tmp_metadata.db"), dbpath)
                        db.setup_db()
            except Exception as e:
                app.logger.info(e.message)
                app.logger.exception(e)

        updateMetaData()
    return ""