mirror of https://github.com/ecmwf/eccodes.git
Implement CodesMessage abstract class
This commit is contained in:
Daniel Lee
parent
613f5147ef
commit
a79e5cf2e5
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@ -11,33 +11,10 @@ from .. import eccodes
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class CodesFile(file):
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"""
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An abstract class to specify and/or implement behavior that files read by
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ecCodes should implement.
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An abstract class to specify and/or implement common behavior that files
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read by ecCodes should implement.
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"""
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def __enter__(self):
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return self
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def __exit__(self, type, value, traceback):
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"""Close all open messages, release GRIB file handle and close file."""
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while self.open_messages:
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self.open_messages.pop().close()
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self.file_handle.close()
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def close(self):
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"""Possibility to manually close file."""
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self.__exit__(None, None, None)
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def __len__(self):
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"""Return total number of messages in file."""
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return eccodes.codes_count_in_file(self.file_handle)
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def __iter__(self):
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return self
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def next(self):
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raise NotImplementedError
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def __init__(self, filename, mode="r"):
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"""Open file and receive codes file handle."""
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#: File handle for working with actual file on disc
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@ -48,3 +25,26 @@ class CodesFile(file):
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self.message = 0
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#: Open messages
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self.open_messages = []
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def __exit__(self, type, value, traceback):
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"""Close all open messages, release GRIB file handle and close file."""
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while self.open_messages:
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self.open_messages.pop().close()
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self.file_handle.close()
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def __len__(self):
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"""Return total number of messages in file."""
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return eccodes.codes_count_in_file(self.file_handle)
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def __enter__(self):
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return self
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def close(self):
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"""Possibility to manually close file."""
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self.__exit__(None, None, None)
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def __iter__(self):
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return self
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def next(self):
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raise NotImplementedError
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@ -0,0 +1,152 @@
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"""
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``CodesMessage`` class that implements a message readable by ecCodes that
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allows access to the message's key-value pairs in a dictionary-like manner
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and closes the message when it is no longer needed, coordinating this with
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its host file.
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Author: Daniel Lee, DWD, 2016
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"""
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from .. import eccodes
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class CodesMessage(object):
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"""
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An abstract class to specify and/or implement common behavior that
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messages read by ecCodes should implement.
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"""
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def __init__(self, codes_file=None, clone=None, sample=None,
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other_args_found=False):
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"""
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Open a message and inform the host file that it's been incremented.
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If ``codes_file`` is not supplied, the message is cloned from
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``CodesMessage`` ``clone``. If neither is supplied,
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the ``CodesMessage`` is cloned from ``sample``.
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:param codes_file: A file readable for ecCodes
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:param clone: A valid ``CodesMessage``
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:param sample: A valid sample path to create ``CodesMessage`` from
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"""
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if not other_args_found and codes_file is None and clone is None and \
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sample is None:
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raise RuntimeError("CodesMessage initialization parameters not "
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"present.")
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#: Unique ID, for ecCodes interface
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self.codes_id = None
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#: File containing message
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self.codes_file = None
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if codes_file is not None:
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self.codes_id = self.new_from_file(codes_file.file_handle)
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if self.codes_id is None:
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raise IOError("CodesFile %s is exhausted" % codes_file.name)
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self.codes_file = codes_file
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self.codes_file.message += 1
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self.codes_file.open_messages.append(self)
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elif clone is not None:
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self.codes_id = eccodes.codes_clone(clone.codes_id)
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elif sample is not None:
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self.codes_id = self.new_from_sample(sample)
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def write(self, outfile=None):
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"""Write message to file."""
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if not outfile:
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# This is a hack because the API does not accept inheritance
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outfile = self.codes_file.file_handle
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eccodes.codes_write(self.codes_id, outfile)
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@staticmethod
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def new_from_sample(samplename):
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"""For generic handling of message types."""
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raise NotImplementedError
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@staticmethod
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def new_from_file(fileobj, headers_only=False):
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"""For generic handling of message types."""
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raise NotImplementedError
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def __setitem__(self, key, value):
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"""
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Set value associated with key.
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Iterables and scalars are handled intelligently.
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"""
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# Passed value is iterable and not string
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if hasattr(value, "__iter__"):
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eccodes.codes_set_array(self.codes_id, key, value)
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else:
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eccodes.codes_set(self.codes_id, key, value)
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def keys(self, namespace=None):
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"""Get available keys in message."""
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iterator = eccodes.codes_keys_iterator_new(self.codes_id,
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namespace=namespace)
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keys = []
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while eccodes.codes_keys_iterator_next(iterator):
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key = eccodes.codes_keys_iterator_get_name(iterator)
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keys.append(key)
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eccodes.codes_keys_iterator_delete(iterator)
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return keys
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def size(self):
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"""Return size of message in bytes."""
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return eccodes.codes_get_message_size(self.codes_id)
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def dump(self):
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"""Dump message's binary content."""
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return eccodes.codes_get_message(self.codes_id)
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def get(self, key, ktype=None):
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"""Get value of a given key as its native or specified type."""
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if self.missing(key):
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raise KeyError("Key is missing from message.")
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if eccodes.codes_get_size(self.codes_id, key) > 1:
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ret = eccodes.codes_get_array(self.codes_id, key, ktype)
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else:
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ret = eccodes.codes_get(self.codes_id, key, ktype)
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return ret
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def missing(self, key):
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"""Report if key is missing."""
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return bool(eccodes.codes_is_missing(self.codes_id, key))
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def set_missing(self, key):
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"""Set a key to missing."""
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eccodes.codes_set_missing(self.codes_id, key)
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def __exit__(self, exc_type, exc_val, exc_tb):
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"""Release message handle and inform host file of release."""
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eccodes.codes_release(self.codes_id)
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def __enter__(self):
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return self
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def close(self):
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"""Possibility to manually close message."""
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self.__exit__(None, None, None)
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def __contains__(self, key):
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"""Check whether a key is present in message."""
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return key in self.keys()
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def __len__(self):
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"""Return key count."""
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return len(self.keys())
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def __getitem__(self, key):
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"""Return value associated with key as its native type."""
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return self.get(key)
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def __iter__(self):
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return iter(self.keys())
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# Not yet implemented
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# def itervalues(self):
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# return self.values()
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def items(self):
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"""Return list of tuples of all key/value pairs."""
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return [(key, self[key]) for key in self.keys()]
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@ -6,8 +6,7 @@ message when it is no longer needed, coordinating this with its host file.
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Author: Daniel Lee, DWD, 2014
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"""
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import collections
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from .codesmessage import CodesMessage
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from .. import eccodes
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@ -15,7 +14,8 @@ class IndexNotSelectedError(Exception):
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"""GRIB index was requested before selecting key/value pairs."""
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class GribMessage(object):
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class GribMessage(CodesMessage):
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"""
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A GRIB message.
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@ -59,140 +59,63 @@ class GribMessage(object):
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... # If desired, messages can be closed manually or used in with
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... msg.close()
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"""
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def __enter__(self):
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return self
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def __exit__(self, exception_type, exception_value, traceback):
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"""Release GRIB message handle and inform file of release."""
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# This assert should never trigger
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# assert self.gid is not None
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eccodes.codes_release(self.gid)
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if self.grib_index:
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self.grib_index.open_messages.remove(self)
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def close(self):
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"""Possibility to manually close message."""
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self.__exit__(None, None, None)
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def __contains__(self, key):
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"""Check whether a key is present in message."""
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return key in self.keys()
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def __len__(self):
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"""Return key count."""
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return len(self.keys())
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def __getitem__(self, key):
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"""Return value associated with key as its native type."""
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return self.get(key)
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def __setitem__(self, key, value):
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"""
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Set value associated with key.
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If the object is iterable,
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"""
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# Alternative implemented (TODO: evaluate)
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# if eccodes.codes_get_size(self.gid, key) > 1:
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# eccodes.codes_set_array(self.gid, key, value)
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# else:
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# eccodes.codes_set(self.gid, key, value)
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# Passed value is iterable and not string
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if (isinstance(value, collections.Iterable) and not
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isinstance(value, basestring)):
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eccodes.codes_set_array(self.gid, key, value)
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else:
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eccodes.codes_set(self.gid, key, value)
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def __iter__(self):
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return iter(self.keys())
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# Not yet implemented
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# def itervalues(self):
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# return self.values()
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def items(self):
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"""Return list of tuples of all key/value pairs."""
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return [(key, self[key]) for key in self.keys()]
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def keys(self, namespace=None):
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"""Get available keys in message."""
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iterator = eccodes.codes_keys_iterator_new(self.gid, namespace=namespace)
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keys = []
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while eccodes.codes_keys_iterator_next(iterator):
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key = eccodes.codes_keys_iterator_get_name(iterator)
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keys.append(key)
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eccodes.codes_keys_iterator_delete(iterator)
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return keys
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def __init__(self, grib_file=None, clone=None, sample=None, gribindex=None):
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# Arguments included explicitly to support introspection
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# TODO: Include headers_only option
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def __init__(self, codes_file=None, clone=None, sample=None,
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gribindex=None):
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"""
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Open a message and inform the GRIB file that it's been incremented.
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If ``grib_file`` is not supplied, the message is cloned from
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``GribMessage`` ``clone``. If neither is supplied, the ``GribMessage``
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is cloned from ``sample``. If ``index`` is supplied as a GribIndex, the
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message is taken from the index.
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The message is taken from ``codes_file``, cloned from ``clone`` or
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``sample``, or taken from ``index``, in that order of precedence.
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"""
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#: Unique GRIB ID, for GRIB API interface
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self.gid = None
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#: File containing message
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self.grib_file = None
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grib_args_present = True
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if gribindex is None:
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grib_args_present = False
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super(self.__class__, self).__init__(codes_file, clone, sample,
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grib_args_present)
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#: GribIndex referencing message
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self.grib_index = None
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if grib_file is not None:
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self.gid = eccodes.codes_grib_new_from_file(grib_file.file_handle)
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if self.gid is None:
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raise IOError("Grib file %s is exhausted" % grib_file.name)
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self.grib_file = grib_file
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self.grib_file.message += 1
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self.grib_file.open_messages.append(self)
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elif clone is not None:
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self.gid = eccodes.codes_clone(clone.gid)
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elif sample is not None:
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self.gid = eccodes.codes_grib_new_from_samples(sample)
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elif gribindex is not None:
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self.gid = eccodes.codes_new_from_index(gribindex.iid)
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if not self.gid:
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if gribindex is not None:
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self.codes_id = eccodes.codes_new_from_index(gribindex.iid)
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if not self.codes_id:
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raise IndexNotSelectedError("All keys must have selected "
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"values before receiving message "
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"from index.")
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self.grib_index = gribindex
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gribindex.open_messages.append(self)
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else:
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raise RuntimeError("Either grib_file, clone, sample or gribindex "
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"must be provided.")
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def size(self):
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"""Return size of message in bytes."""
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return eccodes.codes_get_message_size(self.gid)
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def __exit__(self, exc_type, exc_val, exc_tb):
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"""Release GRIB message handle and inform file of release."""
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super(self.__class__, self).__exit__(exc_type, exc_val, exc_tb)
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if self.grib_index:
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self.grib_index.open_messages.remove(self)
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def dump(self):
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"""Dump message's binary content."""
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return eccodes.codes_get_message(self.gid)
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# I'd like these to be simple function mappings but this worked better in
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# the interest of time
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@staticmethod
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def new_from_sample(samplename):
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return eccodes.codes_grib_new_from_samples(samplename)
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def get(self, key, ktype=None):
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"""Get value of a given key as its native or specified type."""
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if self.missing(key):
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raise KeyError("Key is missing from message.")
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if eccodes.codes_get_size(self.gid, key) > 1:
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ret = eccodes.codes_get_array(self.gid, key, ktype)
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else:
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ret = eccodes.codes_get(self.gid, key, ktype)
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return ret
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@staticmethod
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def new_from_file(fileobj, headers_only=False):
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return eccodes.codes_grib_new_from_file(fileobj, headers_only)
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def missing(self, key):
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"""Report if key is missing."""
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return bool(eccodes.codes_is_missing(self.gid, key))
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@property
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def gid(self):
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"""Provided for backwards compatibility."""
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return self.codes_id
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def set_missing(self, key):
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"""Set a key to missing."""
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eccodes.codes_set_missing(self.gid, key)
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@property
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def grib_file(self):
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"""Provided for backwards compatibility."""
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return self.codes_file
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def write(self, outfile=None):
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"""Write message to file."""
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if not outfile:
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# This is a hack because the API does not accept inheritance
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outfile = self.grib_file.file_handle
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eccodes.codes_write(self.gid, outfile)
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@gid.setter
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def gid(self, val):
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self.codes_id = val
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@grib_file.setter
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def grib_file(self, val):
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self.codes_file = val
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