Source code for irfpy.vnpi.background

''' VEX/NPI background proxy module

It provides a getter of background proxy.

The best practice is to use :class:`DataCenterVnpiBackground` class as folows.

>>> from irfpy.vnpi import background
>>> dc = background.DataCenterVnpiBackground()
>>> import datetime
>>> tobs, (back, total) = dc.nearest(datetime.datetime(2006, 12, 5, 5, 42))
>>> print(tobs)
2006-12-05 05:42:00.898000
>>> print(back)
6.0
>>> print(total)
130.0
'''
from irfpy.util.irfpyrc import Rc
import irfpy.npicommon.background as cbg

class DataCenterVnpiBackground(cbg.DataCenterBackground):
    """ VEX NPD background data center
    """
    def __init__(self):
        """
        """
        rc = Rc()
        path = rc.get('vnpi', 'backgroundbase')

        cbg.DataCenterBackground.__init__(self, path, name="VEX NPI background")


_db = None


def _createdb(base=None):
    ''' Create database for VEX/NPI

    :keyword base: Base path of database.
    '''
    global _db
    if base is None:
        rc = Rc()
        base = rc.get('vnpi', 'backgroundbase')
        
    _db = cbg.Database(base)

def isdb():
    global _db
    if not _db is None:
        return True
    try:
        _createdb()
    except (OSError, IOError):
        _db = None

    if not _db is None:
        _db = None   # Back to the original
        return True
    else:
        return False


def get_background_level(t0, t1, refresh=False, base=None):
    ''' Get VEX/IMA background level.

    :param t0: Time start.
    :param t1: Time end.
    :keyword refresh: If ``True``, a new database is created.
    :keyword base: Give base path of the dataset. If ``None``,
        the dataset path is given from ``.irfpyrc``.
    :returns: (``time array``, ``bg array``).

    >>> import datetime
    >>> t0 = datetime.datetime(2006, 12, 4)
    >>> t1 = datetime.datetime(2006, 12, 7)
    >>> bg = get_background_level(t0, t1)
    >>> print(len(bg[1]))
    832
    '''
    if _db is None or refresh:
        _createdb(base=base)

    return _db.get_background_level(t0, t1)


import unittest
import doctest


def doctests():
    return unittest.TestSuite((
        doctest.DocTestSuite(),
        ))
if __name__ == '__main__':
    unittest.main(defaultTest='doctests')