480 lines
16 KiB
Python
480 lines
16 KiB
Python
# -*- coding: utf-8 -*-
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""" PostgreSQL client """
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import datetime
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import logging
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import sys
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import psycopg2
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log = logging.getLogger(__name__)
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#
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# Exceptions
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#
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class PgDBException(Exception):
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""" That is the base exception class for all the other exceptions provided by this module. """
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def __init__(self, error, *args, **kwargs):
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for arg, value in kwargs.items():
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setattr(self, arg, value)
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super().__init__(error.format(*args, **kwargs))
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class PgDBFailToConnect(PgDBException, RuntimeError):
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"""
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Raised on connecting error occurred
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"""
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def __init__(self, host, user, db):
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super().__init__(
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"An error occured during Postgresql database connection ({user}@{host}, database={db})",
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user=user, host=host, db=db
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)
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class PgDBDuplicatedSQLParameter(PgDBException, KeyError):
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"""
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Raised when trying to set a SQL query parameter
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and an other parameter with the same name is already set
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"""
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def __init__(self, parameter_name):
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super().__init__(
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"Duplicated SQL parameter '{parameter_name}'",
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parameter_name=parameter_name
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)
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class PgDBUnsupportedWHEREClauses(PgDBException, TypeError):
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"""
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Raised when trying to execute query with unsupported
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WHERE clauses provided
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"""
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def __init__(self, where_clauses):
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super().__init__(
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"Unsupported WHERE clauses: {where_clauses}",
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where_clauses=where_clauses
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)
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class PgDBInvalidOrderByClause(PgDBException, TypeError):
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"""
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Raised when trying to select on table with invalid
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ORDER BY clause provided
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"""
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def __init__(self, order_by):
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super().__init__(
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"Invalid ORDER BY clause: {order_by}. Must be a string or a list of two values (ordering field name and direction)",
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order_by=order_by
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)
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class PgDB:
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""" PostgreSQL client """
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date_format = '%Y-%m-%d'
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datetime_format = '%Y-%m-%d %H:%M:%S'
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def __init__(self, host, user, pwd, db, just_try=False):
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self._host = host
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self._user = user
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self._pwd = pwd
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self._db = db
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self._conn = None
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self.just_try = just_try
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def connect(self, exit_on_error=True):
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""" Connect to PostgreSQL server """
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if self._conn is None:
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try:
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log.info(
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'Connect on PostgreSQL server %s as %s on database %s',
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self._host, self._user, self._db)
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self._conn = psycopg2.connect(
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dbname=self._db,
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user=self._user,
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host=self._host,
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password=self._pwd
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)
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except Exception as err:
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log.fatal(
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'An error occured during Postgresql database connection (%s@%s, database=%s).',
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self._user, self._host, self._db, exc_info=1
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)
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if exit_on_error:
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sys.exit(1)
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else:
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raise PgDBFailToConnect(self._host, self._user, self._db) from err
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return True
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def close(self):
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""" Close connection with PostgreSQL server (if opened) """
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if self._conn:
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self._conn.close()
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self._conn = None
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def setEncoding(self, enc):
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""" Set connection encoding """
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if self._conn:
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try:
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self._conn.set_client_encoding(enc)
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return True
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except Exception:
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log.error(
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'An error occured setting Postgresql database connection encoding to "%s"',
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enc, exc_info=1
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)
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return False
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def doSQL(self, sql, params=None):
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"""
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Run SQL query and commit changes (rollback on error)
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:param sql: The SQL query
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:param params: The SQL query's parameters as dict (optional)
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:return: True on success, False otherwise
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:rtype: bool
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"""
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if self.just_try:
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log.debug("Just-try mode : do not really execute SQL query '%s'", sql)
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return True
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cursor = self._conn.cursor()
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try:
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log.debug(
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'Run SQL query "%s" %s',
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sql,
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"with params = %s" % ', '.join([
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"%s = %s" % (key, value)
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for key, value in params.items()
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]) if params else "without params"
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)
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if params is None:
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cursor.execute(sql)
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else:
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cursor.execute(sql, params)
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self._conn.commit()
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return True
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except Exception:
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log.error(
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'Error during SQL query "%s" %s',
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sql,
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"with params = %s" % ', '.join([
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"%s = %s" % (key, value)
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for key, value in params.items()
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]) if params else "without params",
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exc_info=True
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)
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self._conn.rollback()
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return False
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def doSelect(self, sql, params=None):
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"""
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Run SELECT SQL query and return list of selected rows as dict
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:param sql: The SQL query
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:param params: The SQL query's parameters as dict (optional)
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:return: List of selected rows as dict on success, False otherwise
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:rtype: list, bool
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"""
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cursor = self._conn.cursor()
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try:
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log.debug(
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'Run SQL SELECT query "%s" %s',
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sql,
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"with params = %s" % ', '.join([
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"%s = %s" % (key, value)
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for key, value in params.items()
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]) if params else "without params"
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)
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cursor.execute(sql, params)
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results = cursor.fetchall()
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return results
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except Exception:
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log.error(
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'Error during SQL query "%s" %s',
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sql,
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"with params = %s" % ', '.join([
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"%s = %s" % (key, value)
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for key, value in params.items()
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]) if params else "without params",
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exc_info=True
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)
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return False
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#
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# SQL helpers
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#
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@staticmethod
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def format_param(param):
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return '%({0})s'.format(param)
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@classmethod
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def _combine_params(cls, params, to_add=None, **kwargs):
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if to_add:
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assert isinstance(to_add, dict), "to_add must be a dict or None"
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params = cls._combine_params(params, **to_add)
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for param, value in kwargs.items():
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if param in params:
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raise PgDBDuplicatedSQLParameter(param)
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params[param] = value
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return params
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@classmethod
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def _format_where_clauses(cls, where_clauses, params=None, where_op=None):
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"""
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Format WHERE clauses
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:param where_clauses: The WHERE clauses. Could be:
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- a raw SQL WHERE clause as string
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- a tuple of two elements: a raw WHERE clause and its parameters as dict
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- a dict of WHERE clauses with field name as key and WHERE clause value as value
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- a list of any of previous valid WHERE clauses
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:param params: Dict of other already set SQL query parameters (optional)
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:param where_op: SQL operator used to combine WHERE clauses together (optional, default: AND)
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:return: A tuple of two elements: raw SQL WHERE combined clauses and parameters on success
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:rtype: string, bool
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"""
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if params is None:
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params = dict()
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if where_op is None:
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where_op = 'AND'
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if isinstance(where_clauses, str):
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return (where_clauses, params)
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if isinstance(where_clauses, tuple) and len(where_clauses) == 2 and isinstance(where_clauses[1], dict):
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cls._combine_params(params, where_clauses[1])
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return (where_clauses[0], params)
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if isinstance(where_clauses, (list, tuple)):
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sql_where_clauses = []
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for where_clause in where_clauses:
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sql2, params = cls._format_where_clauses(where_clause, params=params, where_op=where_op)
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sql_where_clauses.append(sql2)
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return (
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(" %s " % where_op).join(sql_where_clauses),
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params
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)
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if isinstance(where_clauses, dict):
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sql_where_clauses = []
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for field, value in where_clauses.items():
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param = field
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if field in params:
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idx = 1
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while param in params:
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param = '%s_%d' % (field, idx)
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idx += 1
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cls._combine_params(params, {param: value})
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sql_where_clauses.append(
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'"{field}" = {param}'.format(field=field, param=cls.format_param(param))
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)
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return (
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(" %s " % where_op).join(sql_where_clauses),
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params
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)
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raise PgDBUnsupportedWHEREClauses(where_clauses)
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@classmethod
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def _add_where_clauses(cls, sql, params, where_clauses, where_op=None):
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"""
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Add WHERE clauses to an SQL query
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:param sql: The SQL query to complete
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:param params: The dict of parameters of the SQL query to complete
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:param where_clauses: The WHERE clause (see _format_where_clauses())
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:param where_op: SQL operator used to combine WHERE clauses together (optional, default: see _format_where_clauses())
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:return:
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:rtype: A tuple of two elements: raw SQL WHERE combined clauses and parameters
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"""
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if where_clauses:
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sql_where, params = cls._format_where_clauses(where_clauses, params=params, where_op=where_op)
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sql += " WHERE " + sql_where
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return (sql, params)
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@staticmethod
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def _quote_table_name(table):
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""" Quote table name """
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return '"{0}"'.format(
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'"."'.join(
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table.split('.')
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)
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)
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def insert(self, table, values, just_try=False):
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""" Run INSERT SQL query """
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sql = 'INSERT INTO {0} ("{1}") VALUES ({2})'.format(
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self._quote_table_name(table),
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'", "'.join(values.keys()),
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", ".join([
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self.format_param(key)
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for key in values
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])
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)
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if just_try:
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log.debug("Just-try mode: execute INSERT query: %s", sql)
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return True
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log.debug(sql)
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if not self.doSQL(sql, params=values):
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log.error("Fail to execute INSERT query (SQL: %s)", sql)
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return False
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return True
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def update(self, table, values, where_clauses, where_op=None, just_try=False):
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""" Run UPDATE SQL query """
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sql = 'UPDATE {0} SET {1}'.format(
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self._quote_table_name(table),
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", ".join([
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'"{0}" = {1}'.format(key, self.format_param(key))
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for key in values
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])
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)
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params = values
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try:
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sql, params = self._add_where_clauses(sql, params, where_clauses, where_op=where_op)
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except (PgDBDuplicatedSQLParameter, PgDBUnsupportedWHEREClauses):
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log.error('Fail to add WHERE clauses', exc_info=True)
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return False
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if just_try:
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log.debug("Just-try mode: execute UPDATE query: %s", sql)
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return True
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log.debug(sql)
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if not self.doSQL(sql, params=params):
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log.error("Fail to execute UPDATE query (SQL: %s)", sql)
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return False
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return True
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def delete(self, table, where_clauses, where_op='AND', just_try=False):
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""" Run DELETE SQL query """
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sql = 'DELETE FROM {0}'.format(self._quote_table_name(table))
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params = dict()
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try:
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sql, params = self._add_where_clauses(sql, params, where_clauses, where_op=where_op)
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except (PgDBDuplicatedSQLParameter, PgDBUnsupportedWHEREClauses):
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log.error('Fail to add WHERE clauses', exc_info=True)
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return False
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if just_try:
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log.debug("Just-try mode: execute UPDATE query: %s", sql)
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return True
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log.debug(sql)
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if not self.doSQL(sql, params=params):
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log.error("Fail to execute UPDATE query (SQL: %s)", sql)
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return False
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return True
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def truncate(self, table, just_try=False):
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""" Run TRUNCATE SQL query """
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sql = 'TRUNCATE {0}'.format(self._quote_table_name(table))
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if just_try:
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log.debug("Just-try mode: execute TRUNCATE query: %s", sql)
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return True
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log.debug(sql)
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if not self.doSQL(sql):
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log.error("Fail to execute TRUNCATE query (SQL: %s)", sql)
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return False
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return True
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def select(self, table, where_clauses=None, fields=None, where_op='AND', order_by=None, just_try=False):
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""" Run SELECT SQL query """
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sql = "SELECT "
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if fields is None:
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sql += "*"
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elif isinstance(fields, str):
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sql += '"{0}"'.format(fields)
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else:
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sql += '"{0}"'.format('", "'.join(fields))
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sql += ' FROM {0}'.format(self._quote_table_name(table))
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params = dict()
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try:
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sql, params = self._add_where_clauses(sql, params, where_clauses, where_op=where_op)
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except (PgDBDuplicatedSQLParameter, PgDBUnsupportedWHEREClauses):
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log.error('Fail to add WHERE clauses', exc_info=True)
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return False
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if order_by:
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if isinstance(order_by, str):
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sql += ' ORDER BY {0}'.format(order_by)
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elif (
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isinstance(order_by, (list, tuple)) and len(order_by) == 2
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and isinstance(order_by[0], str)
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and isinstance(order_by[1], str)
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and order_by[1].upper() in ('ASC', 'UPPER')
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):
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sql += ' ORDER BY "{0}" {1}'.format(order_by[0], order_by[1].upper())
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else:
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raise PgDBInvalidOrderByClause(order_by)
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if just_try:
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log.debug("Just-try mode: execute SELECT query : %s", sql)
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return just_try
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return self.doSelect(sql, params=params)
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#
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# Depreated helpers
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#
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@classmethod
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def _quote_value(cls, value):
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""" Quote a value for SQL query """
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if value is None:
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return 'NULL'
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if isinstance(value, (int, float)):
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return str(value)
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if isinstance(value, datetime.datetime):
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value = cls._format_datetime(value)
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elif isinstance(value, datetime.date):
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value = cls._format_date(value)
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return "'%s'" % value.replace("'", "''")
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@classmethod
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def _format_datetime(cls, value):
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""" Format datetime object as string """
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assert isinstance(value, datetime.datetime)
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return value.strftime(cls.datetime_format)
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@classmethod
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def _format_date(cls, value):
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""" Format date object as string """
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assert isinstance(value, (datetime.date, datetime.datetime))
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return value.strftime(cls.date_format)
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@classmethod
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def time2datetime(cls, time):
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""" Convert timestamp to datetime string """
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return cls._format_datetime(datetime.datetime.fromtimestamp(int(time)))
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@classmethod
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def time2date(cls, time):
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""" Convert timestamp to date string """
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return cls._format_date(datetime.date.fromtimestamp(int(time)))
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