app/django/db/backends/util.py
author Sverre Rabbelier <srabbelier@gmail.com>
Sun, 25 Jan 2009 16:28:07 +0000
changeset 987 6fd5c561b446
parent 323 ff1a9aa48cfd
permissions -rw-r--r--
Cache sidebar with a simple caching API We cache the sidebar once for every user, the downside is that once the user meets new access criteria, their sidebar does not get updated. This can be fixed by calling soc.cache.sidebar.flush() when appropriate. Patch by: Sverre Rabbelier

import datetime
from time import time

from django.utils.hashcompat import md5_constructor

try:
    import decimal
except ImportError:
    from django.utils import _decimal as decimal    # for Python 2.3

class CursorDebugWrapper(object):
    def __init__(self, cursor, db):
        self.cursor = cursor
        self.db = db # Instance of a BaseDatabaseWrapper subclass

    def execute(self, sql, params=()):
        start = time()
        try:
            return self.cursor.execute(sql, params)
        finally:
            stop = time()
            sql = self.db.ops.last_executed_query(self.cursor, sql, params)
            self.db.queries.append({
                'sql': sql,
                'time': "%.3f" % (stop - start),
            })

    def executemany(self, sql, param_list):
        start = time()
        try:
            return self.cursor.executemany(sql, param_list)
        finally:
            stop = time()
            self.db.queries.append({
                'sql': '%s times: %s' % (len(param_list), sql),
                'time': "%.3f" % (stop - start),
            })

    def __getattr__(self, attr):
        if attr in self.__dict__:
            return self.__dict__[attr]
        else:
            return getattr(self.cursor, attr)

    def __iter__(self):
        return iter(self.cursor)

###############################################
# Converters from database (string) to Python #
###############################################

def typecast_date(s):
    return s and datetime.date(*map(int, s.split('-'))) or None # returns None if s is null

def typecast_time(s): # does NOT store time zone information
    if not s: return None
    hour, minutes, seconds = s.split(':')
    if '.' in seconds: # check whether seconds have a fractional part
        seconds, microseconds = seconds.split('.')
    else:
        microseconds = '0'
    return datetime.time(int(hour), int(minutes), int(seconds), int(float('.'+microseconds) * 1000000))

def typecast_timestamp(s): # does NOT store time zone information
    # "2005-07-29 15:48:00.590358-05"
    # "2005-07-29 09:56:00-05"
    if not s: return None
    if not ' ' in s: return typecast_date(s)
    d, t = s.split()
    # Extract timezone information, if it exists. Currently we just throw
    # it away, but in the future we may make use of it.
    if '-' in t:
        t, tz = t.split('-', 1)
        tz = '-' + tz
    elif '+' in t:
        t, tz = t.split('+', 1)
        tz = '+' + tz
    else:
        tz = ''
    dates = d.split('-')
    times = t.split(':')
    seconds = times[2]
    if '.' in seconds: # check whether seconds have a fractional part
        seconds, microseconds = seconds.split('.')
    else:
        microseconds = '0'
    return datetime.datetime(int(dates[0]), int(dates[1]), int(dates[2]),
        int(times[0]), int(times[1]), int(seconds), int(float('.'+microseconds) * 1000000))

def typecast_boolean(s):
    if s is None: return None
    if not s: return False
    return str(s)[0].lower() == 't'

def typecast_decimal(s):
    if s is None or s == '':
        return None
    return decimal.Decimal(s)

###############################################
# Converters from Python to database (string) #
###############################################

def rev_typecast_boolean(obj, d):
    return obj and '1' or '0'

def rev_typecast_decimal(d):
    if d is None:
        return None
    return str(d)

def truncate_name(name, length=None):
    """Shortens a string to a repeatable mangled version with the given length.
    """
    if length is None or len(name) <= length:
        return name

    hash = md5_constructor(name).hexdigest()[:4]

    return '%s%s' % (name[:length-4], hash)

def format_number(value, max_digits, decimal_places):
    """
    Formats a number into a string with the requisite number of digits and
    decimal places.
    """
    return u"%.*f" % (decimal_places, value)