datetime_parser.py

def parse_datetime(d):
    """
    Datetime parser

    Creates datetimes from input into format yyyy-mm-dd hh:mm:ss
    
    Needs proper validation!

    Should accept following:
    yyyy
    yyyy-mm
    yyyy-mm-dd
    yyyy hh:mm
    yyyy hh:mm:ss
    yyyy-mm hh:mm
    yyyy-mm hh:mm:ss
    yyyy-mm-dd hh:mm
    yyyy-mm-dd hh:mm:ss

    """
    year = None
    month = None
    day = None
    hours = None
    minutes = None
    seconds = None

    # Check for size limit
    if not d or len(d) > 19:        
        return '%s-%s-%s %s:%s:%s' %(year,month,day,hours,minutes,seconds)

    # Check for invalid characters
    reg = re.match("^[\s0-9:-]+$", d)
    if not reg:        
        return '%s-%s-%s %s:%s:%s' %(year,month,day,hours,minutes,seconds)

    date_set = False
    time_set = False

    d = d.split(' ')
    for item in d:
        # Check if we have time or date
        if len(item) > 3 and item[2] == ':':
            item = item.split(':')
            try:
                hours = item[0]
            except Exception, e:
                hours = "00"
            try:
                minutes = item[1]
            except Exception, e:
                minutes = "00"
            try:
                seconds = item[2]
            except Exception, e:
                seconds = "00"

            time_set = True
        else:
            item = item.split('-')
            try:
                year = item[0]
            except Exception, e:
                year = "1970"
            try:
                month = item[1]
            except Exception, e:
                month = "01"
            try:
                day = item[2]
            except Exception, e:
                day = "01"
         
            date_set = True

    if not date_set:
        year = "1970"
        month = "01"
        day = "01"
    if not time_set:
        hours = "00"
        minutes = "00"
        seconds = "00"

    return '%s-%s-%s %s:%s:%s' %(year,month,day,hours,minutes,seconds)  

def query_tests(query,match):
    result = parse_datetime(query)
    if 'None' in result and match is False:
        print "Test for %s: FAIL" %(query)
    elif result == match:
        print "Test for %s: OK" %(query)
    else:
        print "Test for %s: FAIL" %(query)

# PASS
query_tests("2012","2012-01-01 00:00:00")
query_tests("2012-10","2012-10-01 00:00:00")
query_tests("2012-10-15","2012-10-15 00:00:00")
query_tests("2012-10-15 10:00","2012-10-15 10:00:00")
query_tests("2012-10-15 10:33","2012-10-15 10:33:00")
query_tests("2012-10-15 10:00:00","2012-10-15 10:00:00")
query_tests("2012-10-15 10:33:33","2012-10-15 10:33:33")
query_tests("2012 10:00","2012-01-01 10:00:00")
query_tests("2012 10:00:00","2012-01-01 10:00:00")
query_tests("2012 10:33","2012-01-01 10:33:00")
query_tests("2012 10:33:33","2012-01-01 10:33:33")
query_tests("2012-10 10:00","2012-10-01 10:00:00")
query_tests("2012-10 10:00:00","2012-10-01 10:00:00")
query_tests("2012-10 10:33","2012-10-01 10:33:00")
query_tests("2012-10 10:33:33","2012-10-01 10:33:33")
query_tests("10:00","1970-01-01 10:00:00")
query_tests("10:00:00","1970-01-01 10:00:00")

# FAIL

query_tests("2012/\ frfr ",False)
query_tests("2012 10",False)
query_tests("2012-10-15 10",False) 
query_tests("2012-10 10",False)
query_tests("2012 10 10",False)
query_tests("2012-10 10-10",False)
query_tests("2012:10 10:33:33",False)
query_tests("2012 10-10 10:33:33",False)
query_tests("2012-10 10:33-10",False)