Files
pretix_original/src/pretix/helpers/database.py
Raphael Michel 353dce789d Fix #515 -- Add check-in lists (#693)
* Data model and migration

* Some backwards compatibility

* CRUD for checkin lists

* Show and perform checkins

* Correct numbers in table and dashboard widget

* event creation and cloning

* Allow to link specific exports and pass options per query

* Play with the CSV export

* PDF export

* Collapse exports by default

* Improve PDF exporter

* Addon stuff

* Subevent stuff, pretixdroid tests

* pretixdroid tests

* Add CRUD API

* Test compatibility

* Fix test

* DB-independent sorting behavior

* Add CRUD and coyp tests

* Re-enable pretixdroid plugin

* pretixdroid config

* Tests & fixes
2017-12-04 18:12:23 +01:00

60 lines
1.9 KiB
Python

import contextlib
from django.db import transaction
from django.db.models.expressions import OrderBy
class DummyRollbackException(Exception):
pass
@contextlib.contextmanager
def rolledback_transaction():
"""
This context manager runs your code in a database transaction that will be rolled back in the end.
This can come in handy to simulate the effects of a database operation that you do not actually
want to perform.
Note that rollbacks are a very slow operation on most database backends. Also, long-running
transactions can slow down other operations currently running and you should not use this
in a place that is called frequently.
"""
try:
with transaction.atomic():
yield
raise DummyRollbackException()
except DummyRollbackException:
pass
else:
raise Exception('Invalid state, should have rolled back.')
@contextlib.contextmanager
def casual_reads():
"""
Kept for backwards compatibility.
"""
yield
class FixedOrderBy(OrderBy):
# Workaround for https://code.djangoproject.com/ticket/28848
template = '%(expression)s %(ordering)s'
def as_sql(self, compiler, connection, template=None, **extra_context):
if not template:
if self.nulls_last:
template = '%s NULLS LAST' % self.template
elif self.nulls_first:
template = '%s NULLS FIRST' % self.template
connection.ops.check_expression_support(self)
expression_sql, params = compiler.compile(self.expression)
placeholders = {
'expression': expression_sql,
'ordering': 'DESC' if self.descending else 'ASC',
}
placeholders.update(extra_context)
template = template or self.template
params = params * template.count('%(expression)s')
return (template % placeholders).rstrip(), params