#!/usr/bin/env python
# -*- coding: utf-8 -*-
#*******************************************************************************
# @Author: Anne Fouilloux (University of Oslo)
#
# @Date: July 2014
#
# @Change History:
# February 2018 - Anne Philipp (University of Vienna):
# - applied PEP8 style guide
# - added documentation
# - changed some naming
#
# @License:
# (C) Copyright 2014-2018.
#
# This software is licensed under the terms of the Apache Licence Version 2.0
# which can be obtained at http://www.apache.org/licenses/LICENSE-2.0.
#
# @Class Description:
# The GRIB API provides all necessary tools to work directly with the
# grib files. Nevertheless, the GRIB API tools are very basic and are in
# direct connection with the grib files. This class provides some higher
# functions which apply a set of GRIB API tools together in the respective
# context. So, the class initially contains a list of grib files (their
# names) and the using program then applies the methods directly on the
# class objects without having to think about how the actual GRIB API
# tools have to be arranged.
#
# @Class Content:
# - __init__
# - get_keys
# - set_keys
# - copy_dummy_msg
# - index
#
# @Class Attributes:
# - filenames
#
#*******************************************************************************
# ------------------------------------------------------------------------------
# MODULES
# ------------------------------------------------------------------------------
import os
from eccodes import (codes_grib_new_from_file, codes_is_defined, codes_get,
codes_release, codes_set, codes_write, codes_index_read,
codes_index_new_from_file, codes_index_add_file,
codes_index_write, codes_set_values)
# ------------------------------------------------------------------------------
# CLASS
# ------------------------------------------------------------------------------
[docs]class GribUtil(object):
'''
Class for GRIB utilities (new methods) based on GRIB API
'''
# --------------------------------------------------------------------------
# CLASS FUNCTIONS
# --------------------------------------------------------------------------
def __init__(self, filenames):
'''Initialise an object of GribUtil and assign a list of filenames.
Parameters
----------
filenames : :obj:`list` of :obj:`strings`
A list of filenames.
Return
------
'''
self.filenames = filenames
return
[docs] def get_keys(self, keynames, wherekeynames=[], wherekeyvalues=[]):
'''Get keyvalues for a given list of keynames a where statement
can be given (list of key and list of values)
Parameters
----------
keynames : :obj:`list` of :obj:`string`
List of keynames.
wherekeynames : :obj:`list` of :obj:`string`, optional
Default value is an empty list.
wherekeyvalues : :obj:`list` of :obj:`string`, optional
Default value is an empty list.
Return
------
return_list : :obj:`list` of :obj:`string`
List of keyvalues for given keynames.
'''
fileid = open(self.filenames, 'r')
return_list = []
while 1:
gid = codes_new_from_file(fileid)
if gid is None:
break
if len(wherekeynames) != len(wherekeyvalues):
raise Exception("Number of key values and key names must be \
the same. Give a value for each keyname!")
select = True
i = 0
for wherekey in wherekeynames:
if not codes_is_defined(gid, wherekey):
raise Exception("where key was not defined")
select = (select and (str(wherekeyvalues[i]) ==
str(codes_get(gid, wherekey))))
i += 1
if select:
llist = []
for key in keynames:
llist.extend([str(codes_get(gid, key))])
return_list.append(llist)
codes_release(gid)
fileid.close()
return return_list
[docs] def set_keys(self, fromfile, keynames, keyvalues, wherekeynames=[],
wherekeyvalues=[], strict=False, filemode='w'):
'''Opens the file to read the grib messages and then write
the selected messages (with wherekeys) to a new output file.
Also, the keyvalues of the passed list of keynames are set.
Parameters
----------
fromfile : :obj:`string`
Filename of the input file to read the grib messages from.
keynames : :obj:`list` of :obj:`string`
List of keynames to set in the selected messages.
Default is an empty list.
keyvalues : :obj:`list` of :obj:`string`
List of keyvalues to set in the selected messages.
Default is an empty list.
wherekeynames : :obj:`list` of :obj:`string`, optional
List of keynames to select correct message.
Default value is an empty list.
wherekeyvalues : :obj:`list` of :obj:`string`, optional
List of keyvalues for keynames to select correct message.
Default value is an empty list.
strict : :obj:`boolean`, optional
Decides if everything from keynames and keyvalues
is written out the grib file (False) or only those
meeting the where statement (True). Default is False.
filemode : :obj:`string`, optional
Sets the mode for the output file. Default is "w".
Return
------
'''
if len(wherekeynames) != len(wherekeyvalues):
raise Exception("Give a value for each keyname!")
fout = open(self.filenames, filemode)
fin = open(fromfile)
while 1:
gid = codes_grib_new_from_file(fin)
if gid is None:
break
select = True
i = 0
for wherekey in wherekeynames:
if not codes_is_defined(gid, wherekey):
raise Exception("wherekey was not defined")
select = (select and (str(wherekeyvalues[i]) ==
str(codes_get(gid, wherekey))))
i += 1
if select:
i = 0
for key in keynames:
if key == 'values':
codes_set_values(gid, keyvalues[i])
else:
codes_set(gid, key, keyvalues[i])
i += 1
codes_write(gid, fout)
codes_release(gid)
fin.close()
fout.close()
return
[docs] def copy_dummy_msg(self, filename_in, selectWhere=True,
keynames=[], keyvalues=[], filemode='w'):
'''Add the content of another input grib file to the objects file but
only messages corresponding to keys/values passed to the function.
The selectWhere switch decides if to copy the keys equal to (True) or
different to (False) the keynames/keyvalues list passed to the function.
Parameters
----------
filename_in : :obj:`string`
Filename of the input file to read the grib messages from.
selectWhere : :obj:`boolean`, optional
Decides if to copy the keynames and values equal to (True) or
different to (False) the keynames/keyvalues list passed to the
function. Default is True.
keynames : :obj:`list` of :obj:`string`, optional
List of keynames. Default is an empty list.
keyvalues : :obj:`list` of :obj:`string`, optional
List of keyvalues. Default is an empty list.
filemode : :obj:`string`, optional
Sets the mode for the output file. Default is "w".
Return
------
'''
if len(keynames) != len(keyvalues):
raise Exception("Give a value for each keyname!")
fin = open(filename_in)
fout = open(self.filenames, filemode)
fields = 0
while fields < 1:
gid = codes_grib_new_from_file(fin)
if gid is None:
break
select = True
i = 0
for key in keynames:
if not codes_is_defined(gid, key):
raise Exception("Key was not defined")
if selectWhere:
select = (select and (str(keyvalues[i]) ==
str(codes_get(gid, key))))
else:
select = (select and (str(keyvalues[i]) !=
str(codes_get(gid, key))))
i += 1
if select:
fields = fields + 1
codes_write(gid, fout)
codes_release(gid)
fin.close()
fout.close()
return
[docs] def index(self, index_keys=["mars"], index_file="my.idx"):
'''Create index file from a list of files if it does not exist or
read an index file.
Parameters
----------
index_keys: :obj:`list` of :obj:`string`, optional
Contains the list of key parameter names from
which the index is to be created.
Default is a list with a single entry string "mars".
index_file: :obj:`string`, optional
Filename where the indices are stored.
Default is "my.idx".
Return
------
iid: :obj:`integer`
Grib index id.
'''
print("... index will be done")
iid = None
if os.path.exists(index_file):
iid = codes_index_read(index_file)
print("Use existing index file: %s " % (index_file))
else:
for filename in self.filenames:
print("Inputfile: %s " % (filename))
if iid is None:
iid = codes_index_new_from_file(filename, index_keys)
else:
codes_index_add_file(iid, filename)
if iid is not None:
codes_index_write(iid, index_file)
print('... index done')
return iid