mirror of https://github.com/morpheus65535/bazarr
124 lines
4.5 KiB
Python
124 lines
4.5 KiB
Python
from peewee import *
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from playhouse.sqlite_ext import JSONField
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class BaseChangeLog(Model):
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timestamp = DateTimeField(constraints=[SQL('DEFAULT CURRENT_TIMESTAMP')])
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action = TextField()
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table = TextField()
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primary_key = IntegerField()
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changes = JSONField()
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class ChangeLog(object):
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# Model class that will serve as the base for the changelog. This model
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# will be subclassed and mapped to your application database.
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base_model = BaseChangeLog
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# Template for the triggers that handle updating the changelog table.
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# table: table name
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# action: insert / update / delete
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# new_old: NEW or OLD (OLD is for DELETE)
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# primary_key: table primary key column name
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# column_array: output of build_column_array()
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# change_table: changelog table name
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template = """CREATE TRIGGER IF NOT EXISTS %(table)s_changes_%(action)s
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AFTER %(action)s ON %(table)s
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BEGIN
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INSERT INTO %(change_table)s
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("action", "table", "primary_key", "changes")
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SELECT
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'%(action)s', '%(table)s', %(new_old)s."%(primary_key)s", "changes"
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FROM (
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SELECT json_group_object(
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col,
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json_array("oldval", "newval")) AS "changes"
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FROM (
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SELECT json_extract(value, '$[0]') as "col",
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json_extract(value, '$[1]') as "oldval",
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json_extract(value, '$[2]') as "newval"
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FROM json_each(json_array(%(column_array)s))
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WHERE "oldval" IS NOT "newval"
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)
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);
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END;"""
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drop_template = 'DROP TRIGGER IF EXISTS %(table)s_changes_%(action)s'
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_actions = ('INSERT', 'UPDATE', 'DELETE')
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def __init__(self, db, table_name='changelog'):
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self.db = db
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self.table_name = table_name
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def _build_column_array(self, model, use_old, use_new, skip_fields=None):
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# Builds a list of SQL expressions for each field we are tracking. This
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# is used as the data source for change tracking in our trigger.
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col_array = []
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for field in model._meta.sorted_fields:
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if field.primary_key:
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continue
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if skip_fields is not None and field.name in skip_fields:
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continue
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column = field.column_name
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new = 'NULL' if not use_new else 'NEW."%s"' % column
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old = 'NULL' if not use_old else 'OLD."%s"' % column
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if isinstance(field, JSONField):
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# Ensure that values are cast to JSON so that the serialization
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# is preserved when calculating the old / new.
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if use_old: old = 'json(%s)' % old
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if use_new: new = 'json(%s)' % new
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col_array.append("json_array('%s', %s, %s)" % (column, old, new))
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return ', '.join(col_array)
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def trigger_sql(self, model, action, skip_fields=None):
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assert action in self._actions
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use_old = action != 'INSERT'
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use_new = action != 'DELETE'
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cols = self._build_column_array(model, use_old, use_new, skip_fields)
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return self.template % {
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'table': model._meta.table_name,
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'action': action,
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'new_old': 'NEW' if action != 'DELETE' else 'OLD',
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'primary_key': model._meta.primary_key.column_name,
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'column_array': cols,
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'change_table': self.table_name}
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def drop_trigger_sql(self, model, action):
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assert action in self._actions
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return self.drop_template % {
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'table': model._meta.table_name,
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'action': action}
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@property
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def model(self):
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if not hasattr(self, '_changelog_model'):
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class ChangeLog(self.base_model):
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class Meta:
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database = self.db
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table_name = self.table_name
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self._changelog_model = ChangeLog
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return self._changelog_model
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def install(self, model, skip_fields=None, drop=True, insert=True,
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update=True, delete=True, create_table=True):
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ChangeLog = self.model
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if create_table:
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ChangeLog.create_table()
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actions = list(zip((insert, update, delete), self._actions))
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if drop:
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for _, action in actions:
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self.db.execute_sql(self.drop_trigger_sql(model, action))
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for enabled, action in actions:
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if enabled:
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sql = self.trigger_sql(model, action, skip_fields)
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self.db.execute_sql(sql)
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