from optparse import make_option from django.conf import settings from django.core.cache import caches from django.core.cache.backends.db import BaseDatabaseCache from django.core.management.base import BaseCommand, CommandError from django.db import connections, router, transaction, models, DEFAULT_DB_ALIAS from django.db.utils import DatabaseError from django.utils.encoding import force_text class Command(BaseCommand): help = "Creates the tables needed to use the SQL cache backend." option_list = BaseCommand.option_list + ( make_option('--database', action='store', dest='database', default=DEFAULT_DB_ALIAS, help='Nominates a database onto ' 'which the cache tables will be installed. ' 'Defaults to the "default" database.'), ) requires_model_validation = False def handle(self, *tablenames, **options): db = options.get('database') self.verbosity = int(options.get('verbosity')) if len(tablenames): # Legacy behavior, tablename specified as argument for tablename in tablenames: self.create_table(db, tablename) else: for cache_alias in settings.CACHES: cache = caches[cache_alias] if isinstance(cache, BaseDatabaseCache): self.create_table(db, cache._table) def create_table(self, database, tablename): cache = BaseDatabaseCache(tablename, {}) if not router.allow_migrate(database, cache.cache_model_class): return connection = connections[database] if tablename in connection.introspection.table_names(): if self.verbosity > 0: self.stdout.write("Cache table '%s' already exists." % tablename) return fields = ( # "key" is a reserved word in MySQL, so use "cache_key" instead. models.CharField(name='cache_key', max_length=255, unique=True, primary_key=True), models.TextField(name='value'), models.DateTimeField(name='expires', db_index=True), ) table_output = [] index_output = [] qn = connection.ops.quote_name for f in fields: field_output = [qn(f.name), f.db_type(connection=connection)] field_output.append("%sNULL" % ("NOT " if not f.null else "")) if f.primary_key: field_output.append("PRIMARY KEY") elif f.unique: field_output.append("UNIQUE") if f.db_index: unique = "UNIQUE " if f.unique else "" index_output.append("CREATE %sINDEX %s ON %s (%s);" % (unique, qn('%s_%s' % (tablename, f.name)), qn(tablename), qn(f.name))) table_output.append(" ".join(field_output)) full_statement = ["CREATE TABLE %s (" % qn(tablename)] for i, line in enumerate(table_output): full_statement.append(' %s%s' % (line, ',' if i < len(table_output) - 1 else '')) full_statement.append(');') with transaction.commit_on_success_unless_managed(): curs = connection.cursor() try: curs.execute("\n".join(full_statement)) except DatabaseError as e: raise CommandError( "Cache table '%s' could not be created.\nThe error was: %s." % (tablename, force_text(e))) for statement in index_output: curs.execute(statement) if self.verbosity > 1: self.stdout.write("Cache table '%s' created." % tablename)