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R3600/modules/bibfield/lib/bibfield_utils.py
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bibfield_utils.py
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# -*- coding: utf-8 -*-
##
## This file is part of Invenio.
## Copyright (C) 2004, 2005, 2006, 2007, 2008, 2010, 2011, 2013 CERN.
##
## Invenio is free software; you can redistribute it and/or
## modify it under the terms of the GNU General Public License as
## published by the Free Software Foundation; either version 2 of the
## License, or (at your option) any later version.
##
## Invenio is distributed in the hope that it will be useful, but
## WITHOUT ANY WARRANTY; without even the implied warranty of
## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
## General Public License for more details.
##
## You should have received a copy of the GNU General Public License
## along with Invenio; if not, write to the Free Software Foundation, Inc.,
## 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
"""
BibField Utils
Helper classes and functions to work with BibField
"""
import re
__revision__ = "$Id$"
import os
import datetime
from invenio.config import CFG_PYLIBDIR
from invenio.pluginutils import PluginContainer
CFG_BIBFIELD_FUNCTIONS = PluginContainer(os.path.join(CFG_PYLIBDIR, 'invenio', 'bibfield_functions', '*.py'))
class BibFieldException(Exception):
"""
General exception to use within BibField
"""
pass
class BibFieldCheckerException(Exception):
"""
Exception raised when some error happens during checking
"""
pass
class BibFieldDict(object):
"""
This class implements a I{dict} mostly and uses special key naming for
accessing as describe in __getitem__
>>> #Creating a dictionary
>>> d = BibFieldDict()
>>> #Filling up the dictionary
>>> d['foo'] = {'a': 'world', 'b':'hello'}
>>> d['a'] = [ {'b':1}, {'b':2}, {'b':3} ]
>>> d['_c'] = "random.randint(1,100)"
>>> #Accessing data inside the dictionary
>>> d['a']
>>> d['a[0]']
>>> d['a.b']
>>> d['a[1:]']
>>> d['_c'] #this value will be calculated on the fly
"""
def __init__(self):
self.rec_json = {}
self._aliases = {}
self._do_not_cache = []
self._init_fase = True
def __getitem__(self, key):
"""
As in C{dict.__getitem__} but using BibField name convention.
@param key: String containing the name of the field and subfield.
For e.g. lest work with:
{'a': [ {'b':1}, {'b':2}, {'b':3} ], '_c': [42, random.randint(1,100)"] }
- 'a' -> All the 'a' field info
[{'b': 1}, {'b': 2}, {'b': 3}]
- 'a[0]' -> All the info of the first element inside 'a'
{'b': 1}
- 'a[0].b' -> Field 'b' for the first element in 'a'
1
- 'a[1:]' -> All the 'a' field info but the first
[{'b': 2}, {'b': 3}]
- 'a.b' -> All the 'b' inside 'b'
[1, 2, 3]
- '_c- -> will give us the random number that is cached
42
- ... any other combination ...
- ... as deep as the dictionary is ...
NOTE: accessing one value in a normal way, meaning d['a'], is almost as
fast as accessing a regular dictionary. But using the special name
convention is a bit slower than using the regular access.
d['a[0].b'] -> 10000 loops, best of 3: 18.4 us per loop
d['a'][0]['b'] -> 1000000 loops, best of 3: 591 ns per loop
@return: The value of the field, this might be, a dictionary, a list,
a string, or any combination of the three depending on the value of
field
"""
try:
if '.' not in key and '[' not in key:
dict_part = self.rec_json[key]
else:
dict_part = self.rec_json
for group in prepare_field_keys(key):
dict_part = self._get_intermediate_value(dict_part, group)
except KeyError, err:
return self[key.replace(err.message, self._aliases[err.message].replace('[n]', '[1:]'), 1)]
if re.search('^_[a-zA-Z0-9]', key):
if key in self._do_not_cache:
self.update_field_cache(key)
dict_part = dict_part[0]
return dict_part
def __setitem__(self, key, value):
"""
As in C{dict.__setitem__} but using BibField name convention.
@note: at creation time dict['a[-1]'] = 'something' will mean
dict['a'].append('something') and if the field already exists and is
not a list, then this method will create a list with the existing value
and append the new one,
dict['a'] = 'first value' -> {'a':'first value'}
dict['a'] = 'second value' -> {'a':['first value', 'second value']}
There is one class variable self._init_fase for that matter.
@param key: String containing the name of the field and subfield.
@param value: The new value
"""
if self._init_fase:
if '.' not in key and '[' not in key:
if not key in self.rec_json:
self.rec_json[key] = value
return
tmp = self.rec_json[key]
if tmp is None:
self.rec_json[key] = value
else:
if not isinstance(tmp, list):
self.rec_json[key] = [tmp]
self.rec_json[key].append(value)
else:
try:
dict_part = eval("self.rec_json%s" % (''.join(prepare_field_keys(key)),)) # kwalitee: disable=eval
except:
build_data_structure(self.rec_json, key)
dict_part = eval("self.rec_json%s" % (''.join(prepare_field_keys(key)),))
if dict_part:
exec("self.rec_json%s.append(value)" % (''.join(prepare_field_keys(key, write=True)[:-1]),))
else:
exec("self.rec_json%s = value" % (''.join(prepare_field_keys(key)),))
else:
if '.' not in key and '[' not in key:
self.rec_json[key] = value
else:
try:
exec("self.rec_json%s = value" % (''.join(prepare_field_keys(key)),))
except:
build_data_structure(self.rec_json, key)
exec("self.rec_json%s = value" % (''.join(prepare_field_keys(key)),))
def __delitem__(self, key):
"""
As in C{dict.__delitem__}.
@note: It only works with first keys
"""
del self.rec_json[key]
def __contains__(self, key):
"""
As in C{dict.__contains__} but using BibField name convention.
@param key: Name of the key
@return: True if the dictionary contains the special key
"""
if '.' not in key and '[' not in key:
return key in self.rec_json
try:
self[key]
except:
return False
return True
def __eq__(self, other):
"""@see C{dict.__eq__}"""
try:
return dict.__eq__(self.rec_json, other.rec_json)
except:
return False
def __repr__(self):
"""@see C{dict.__repr__}"""
return repr(self.rec_json)
def __iter__(self):
"""@see C{dict.__iter__}"""
return iter(self.rec_json)
def __len__(self):
"""@see C{dict.__len__}"""
return len(self.rec_json)
def keys(self):
"""@see C{dict.keys}"""
return self.rec_json.keys()
def iteritems(self):
"""@see C{dict.iteritems}"""
return self.rec_json.iteritems()
def iterkeys(self):
"""@see C{dict.iterkeys}"""
return self.rec_json.iterkeys()
def itervalues(self):
"""@see C{dict.itervalues}"""
return self.rec_json.itervalues()
def has_key(self, key):
"""
As in C{dict.has_key} but using BibField name convention.
@see __contains__(self, key)
"""
return self.__contains__(key)
def get(self, field=None, default=None, reset_cache=False, formatstring=None, formatfunction=None):
"""
As in C{dict.get} it Retrieves the value of field from the json structure
but using BibField name convention and also applies some formating if
present.
@see __getitem__(self, key)
@param field: Name of the field/s to retrieve. If it is None then it
will return the entire dictionary.
@param default: in case of error this value will be returned
@param formatstring: Optional parameter to format the output value.
This could be a format string, like this example:
>>> d['foo'] = {'a': 'world', 'b':'hello'}
>>> get('foo', formatstring="{0[b]} {0[a]}!")
>>> 'hello world!'
@param formatfunction: Optional parameter to format the output value.
This parameter must be function and must handle all the possible
parameter types (strin, dict or list)
@return: The value of the field, this might be, a dictionary, a list,
a string, or any combination of the three depending on the value of
field. If any formating parameter is present, then the return value
will be the formated value.
"""
if field.startswith('_') and reset_cache:
self.update_field_cache(field)
value = self.rec_json
if field:
try:
value = self.__getitem__(field)
except:
return default
if not value:
return default
if formatstring:
value = self._apply_formatstring(value, formatstring)
if formatfunction:
value = formatfunction(value)
return value
def update_field_cache(self, field):
"""
Updates the value of the cache for the given calculated field
"""
calculated_field = self.rec_json.get(field)
if calculated_field and field.startswith('_'):
calculated_field[0] = self._try_to_eval(calculated_field[1])
def update_all_fields_cache(self):
"""
Update the cache of all the calculated fields
@see: update_field_cache()
"""
for field in [key for key in self.keys() if key.startswith('_')]:
self.update_field_cache(field)
def _try_to_eval(self, string, bibfield_functions_only=False, **context):
"""
This method takes care of evaluating the python expression, and, if an
exception happens, it tries to import the needed module from bibfield_functions
or from the python path using plugin utils
@param string: String to evaluate
@param context: Context needed, in some cases, to evaluate the string
@return: The value of the expression inside string
"""
if not string:
return None
res = None
imports = []
while (True):
try:
res = eval(string, globals().update(context), locals()) # kwalitee: disable=eval
except NameError, err:
import_name = err.message.split("'")[1]
if not import_name in imports:
if import_name in CFG_BIBFIELD_FUNCTIONS:
globals()[import_name] = CFG_BIBFIELD_FUNCTIONS[import_name]
elif not bibfield_functions_only:
globals()[import_name] = __import__(import_name)
imports.append(import_name)
continue
assert False, 'Error not expected when trying to import bibfield function module'
return res
def _apply_formatstring(self, value, formatstring):
"""
Helper function that simply formats the result of get() using a
format string
If the value is of type datetime it tries to apply the format using
strftime(formatstring).
@see: get(self, field=None, formatstring=None, formatfunction=None)
@param value: String, dict or list to apply the format string
@param formatstring: formatstring
@return: Formated value of "value"
"""
if not value:
return ''
if isinstance(value, datetime.datetime):
if formatstring == value.strftime(formatstring):
value = value.isoformat()
else:
return value.strftime(formatstring)
if isinstance(value, list):
tmp = ''
for element in value:
tmp += self._apply_formatstring(element, formatstring)
return tmp
elif isinstance(value, dict) or isinstance(value, basestring):
return formatstring.format(value)
else:
assert False, 'String, Dictionay or List expected'
def _get_intermediate_value(self, dict_part, field):
"""
Helper function that fetch the value of some field from dict_part
@see: get(self, field=None, formatstring=None, formatfunction=None)
@param dict_part: Dictionary or list containing all the information from
this method will fetch field.
@param field: Name or index of the field to fetch from dict_part
@return: The value of the field, this might be, a dictionary, a list,
a string, or any combination of the three depending on the value of
field
"""
if isinstance(dict_part, dict):
return eval('dict_part%s' % field) # kwalitee: disable=eval
elif isinstance(dict_part, list):
tmp = []
for element in dict_part:
tmp.append(self._get_intermediate_value(element, field))
return tmp
else:
assert False, 'Dictionay or List expected get %s' % (type(dict_part),)
class BlobWrapper(object):
"""
Wrapper class to work easily with the blob and the information related to it
inside the *Reader
"""
def __init__(self, blob, **kw):
self.__info = kw
self.blob = blob
def __getattr__(self, name):
"""Trick to access the information inside self.__info using dot syntax"""
try:
return self.__info[name]
except KeyError:
raise AttributeError("%r object has no attribute %r" % (type(self).__name__, name))
class CoolDict(dict):
"""
C{dict} but it keeps track of which elements has been consumed/accessed
and which not
"""
def __init__(self, *args, **kwargs):
dict.__init__(self, *args, **kwargs)
self._consumed = {}
if self:
for key, value in dict.iteritems(self):
self[key] = value
def __getitem__(self, key):
"""
As in C{dict} but in this case the key could be a compiled regular expression.
Also update the consumed list in case the item is not a list or other
dictionary.
@return: Like in C{dict.__getitem__} or, if a regular expression is used,
a list containing all the items inside the dictionary which key matches
the regular expression ([] if none)
"""
if isinstance(key, re._pattern_type):
keys = filter(key.match, self.keys())
values = []
for key in keys:
value = dict.get(self, key)
values.append(dict.get(self, key))
if not isinstance(value, dict) and not isinstance(value, list):
self._consumed[key] = True
return values
else:
try:
value = dict.get(self, key)
if not isinstance(value, dict) and not isinstance(value, list):
self._consumed[key] = True
return value
except:
return None
def __setitem__(self, key, value):
"""
As in C{dict} but in this case it takes care of updating the consumed
value for each element inside value depending on its type.
"""
if isinstance(value, dict):
dict.__setitem__(self, key, CoolDict(value))
self._consumed[key] = self[key]._consumed
elif isinstance(value, list):
dict.__setitem__(self, key, CoolList(value))
self._consumed[key] = self[key]._consumed
else:
dict.__setitem__(self, key, value)
self._consumed[key] = False
def extend(self, key, value):
"""
If the key is present inside the dictionary it creates a list (it not
present) and extends it with the new value. Almost as in C{list.extend}
"""
if key in self:
current_value = dict.get(self, key)
if not isinstance(current_value, list):
current_value = CoolList([current_value])
current_value.append(value)
value = current_value
self[key] = value
def iteritems(self):
""" As in C{dict} but it updates the consumed value if needed"""
for key, value in dict.iteritems(self):
if not isinstance(value, dict) and not isinstance(value, list):
self._consumed[key] = True
yield key, value
raise StopIteration
@property
def consumed(self):
for key, value in self._consumed.iteritems():
if not isinstance(value, dict) and not isinstance(value, list):
if not value:
return False
elif not dict.get(self, key).consumed:
return False
return True
class CoolList(list):
"""
C{list} but it keeps track of which elements has been consumed/accessed and
which not
"""
def __init__(self, *args, **kwargs):
list.__init__(self, *args, **kwargs)
self._consumed = []
if self:
for i, value in enumerate(list.__iter__(self)):
self._consumed.append(None)
self[i] = value
def __getitem__(self, index):
"""As in C{list}, also update the consumed list in case the item is not
a dictionary or other list.
@return: Like in C{list.__getitem__}
"""
value = list.__getitem__(self, index)
if not isinstance(value, dict) and not isinstance(value, list):
self._consumed[index] = True
return value
def __setitem__(self, index, value):
"""
As in C{list} but in this case it takes care of updating the consumed
value for each element inside value depending on its type
"""
if isinstance(value, dict):
list.__setitem__(self, index, CoolDict(value))
self._consumed[index] = self[index]._consumed
elif isinstance(value, list):
list.__setitem__(self, index, CoolList(value))
self._consumed[index] = self[index]._consumed
else:
list.__setitem__(self, index, value)
self._consumed[index] = False
def __iter__(self, *args, **kwargs):
""" As in C{dict} but it updates the consumed value if needed"""
for index, value in enumerate(list.__iter__(self)):
if not isinstance(value, dict) and not isinstance(value, list):
self._consumed[index] = True
yield value
raise StopIteration
def append(self, element):
"""@see __setitem__() """
self += [None]
self._consumed += [None]
self[len(self) - 1] = element
@property
def consumed(self):
for index, value in enumerate(self._consumed):
if not isinstance(value, dict) and not isinstance(value, list):
if not value:
return False
elif not list.__getitem__(self, index).consumed:
return False
return True
def prepare_field_keys(field, write=False):
"""
Helper function to split the name of the fields and the indexes in a
proper way to be used by eval function
@see: bibfield.get()
@param field: String containing all the names and indexes
@param write: If the fields are use to write inside the record then the
granularity is lower for convenience
@return: List of string that can be evaluated by eval function
"""
parts = field.split('.')
keys = []
for part in parts:
if '[' in part:
if write:
keys.append('["%s"]' % (part[:part.find('[')]))
keys.append(part[part.find('['):].replace('n', '-1'))
else:
keys.append('["%s"]%s' % (part[:part.find('[')], part[part.find('['):].replace('n', '-1')))
else:
keys.append('["%s"]' % part)
return keys
def build_data_structure(record, field):
"""
Helper functions that builds the record structure
@param record: Existing data structure
@param field: New field to add to the structure
"""
eval_string = ''
for key in prepare_field_keys(field, write=True):
if key == '[-1]':
try:
eval("record%s.append(None)" % (eval_string,)) # kwalitee: disable=eval
except AttributeError:
exec("record%s=[None]" % (eval_string,))
elif key == '[0]':
try:
eval("record%s" % (eval_string + key,)) # kwalitee: disable=eval
rec_part = eval("record%s" % (eval_string,)) # kwalitee: disable=eval
if not isinstance(rec_part, list):
pass
rec_part.insert(0, None)
except TypeError:
exec("record%s=list([None])" % (eval_string,))
else:
try:
eval("record%s" % (eval_string + key,)) # kwalitee: disable=eval
except KeyError:
exec("record%s=None" % (eval_string + key,))
except TypeError:
exec("record%s={}" % (eval_string,))
exec("record%s=None" % (eval_string + key,))
eval_string += key
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