Retardations in python's datetime

psycopg-timestamp-notz.py

#! /usr/bin/python2
import psycopg2
from datetime import datetime
import pytz, time

tzname = 'UTC'
TZ = pytz.timezone(tzname)
test_datetime = datetime.fromtimestamp(1341446400)


def connect(DSN = ""):
    conn = psycopg2.connect(dsn=DSN)
    cr = conn.cursor()
    cr.execute("set TIMEZONE='%s'" % tzname)
    conn.commit()
    return conn, conn.cursor()


def setup():
    conn, cr = connect()
    cr.execute('drop table if exists test_ts_tz')
    cr.execute('''CREATE TABLE test_ts_tz (
        tt timestamp without time zone
        )''')

    conn.commit()
    print 'Setup complete'


def insert():
    conn, cr = connect()

    cr.execute('''TRUNCATE test_ts_tz''')
    cr.execute('''INSERT INTO test_ts_tz VALUES ( %s )''', [test_datetime])

    conn.commit()
    print test_datetime.strftime('%s'), test_datetime.isoformat()


def select():
    conn, cr = connect()

    cr.execute('''SELECT tt FROM test_ts_tz''')
    dt, = cr.fetchone()
    print dt.strftime('%s'), dt.isoformat()
    assert dt == test_datetime



if __name__ == '__main__':
    import sys
    if len(sys.argv) < 2:
        print 'setup/insert/select'
        sys.exit(1)
    cmd = sys.argv[1]
    if cmd == 'setup':
        setup()
    elif cmd == 'insert':
        setup()
        insert()
    elif cmd == 'select':
        select()

psycopg-timestamp-tz.py

#! /usr/bin/python2
import psycopg2
from datetime import datetime
import pytz, time

tzname = 'Europe/Skopje'
TZ = pytz.timezone(tzname)
test_datetime = datetime.fromtimestamp(1341446400, TZ)


def connect(DSN = ""):
    conn = psycopg2.connect(dsn=DSN)
    cr = conn.cursor()
    cr.execute("set TIMEZONE='%s'" % tzname)
    conn.commit()
    return conn, conn.cursor()


def setup():
    conn, cr = connect()
    cr.execute('drop table if exists test_ts_tz')
    cr.execute('''CREATE TABLE test_ts_tz (
        tt timestamp with time zone
        )''')

    conn.commit()
    print 'Setup complete'


def insert():
    conn, cr = connect()

    cr.execute('''TRUNCATE test_ts_tz''')
    cr.execute('''INSERT INTO test_ts_tz VALUES ( %s )''', [test_datetime])

    conn.commit()
    print test_datetime.strftime('%s'), test_datetime.isoformat()


def select():
    conn, cr = connect()

    cr.execute('''SELECT tt FROM test_ts_tz''')
    dt, = cr.fetchone()
    print dt.strftime('%s'), dt.isoformat()
    assert dt == test_datetime



if __name__ == '__main__':
    import sys
    if len(sys.argv) < 2:
        print 'setup/insert/select'
        sys.exit(1)
    cmd = sys.argv[1]
    if cmd == 'setup':
        setup()
    elif cmd == 'insert':
        setup()
        insert()
    elif cmd == 'select':
        select()

test.sh

#!/bin/sh

echo
echo "try with the default timezone environment"
echo

echo timezone in db column
python psycopg-timestamp-tz.py insert
python psycopg-timestamp-tz.py select

echo no timezone in db column
python psycopg-timestamp-notz.py insert
python psycopg-timestamp-notz.py select


echo
echo "try with with TZ=Asia/Tokyo"
echo

export TZ=Asia/Tokyo
echo timezone in db column
python psycopg-timestamp-tz.py insert
python psycopg-timestamp-tz.py select

echo no timezone in db column
python psycopg-timestamp-notz.py insert
python psycopg-timestamp-notz.py select


echo
echo "try with with TZ=America/Mexico_City"
echo

export TZ=America/Mexico_City
echo timezone in db column
python psycopg-timestamp-tz.py insert
python psycopg-timestamp-tz.py select

echo no timezone in db column
python psycopg-timestamp-notz.py insert
python psycopg-timestamp-notz.py select

tzinfo-is-retarded.py

#! /usr/bin/python2
# retardations in python's datetime

import pytz
TZ = pytz.timezone('Europe/Skopje')

from datetime import datetime

x1 = datetime.now(tz=TZ)
x2 = datetime(x1.year, x1.month, x1.day, tzinfo=TZ)

assert x1.tzinfo == x2.tzinfo