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Your IP : 216.73.216.11
"""
PYTHON SOFTWARE FOUNDATION LICENSE VERSION 2
--------------------------------------------
1. This LICENSE AGREEMENT is between the Python Software Foundation
("PSF"), and the Individual or Organization ("Licensee") accessing and
otherwise using this software ("Python") in source or binary form and
its associated documentation.
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grants Licensee a nonexclusive, royalty-free, world-wide license to reproduce,
analyze, test, perform and/or display publicly, prepare derivative works,
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4. PSF is making Python available to Licensee on an "AS IS"
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"""
############################################################################
# Changes:
# Added new parameter in dialect 'replace_nulls_with' to compare it against
# the value to be quoted or not.
# Handle the null value if value is None or equal to
# 'replace_nulls_with' then it represents the null value, so no need to
# quote it.
############################################################################
__all__ = ["QUOTE_MINIMAL", "QUOTE_ALL", "QUOTE_NONNUMERIC", "QUOTE_NONE",
"Error", "Dialect", "__doc__", "Excel", "ExcelTab",
"field_size_limit", "Reader", "Writer", "register_dialect",
"get_dialect", "list_dialects", "unregister_dialect",
"__version__", "DictReader", "DictWriter"]
import re
import numbers
from io import StringIO
from csv import (
QUOTE_MINIMAL, QUOTE_ALL, QUOTE_NONNUMERIC, QUOTE_NONE,
__version__, __doc__, Error, field_size_limit,
)
class QuoteStrategy():
quoting = None
def __init__(self, dialect):
if self.quoting is not None:
assert dialect.quoting == self.quoting
self.dialect = dialect
self.setup()
escape_pattern_quoted = r'({quotechar})'.format(
quotechar=re.escape(self.dialect.quotechar or '"'))
escape_pattern_unquoted = r'([{specialchars}])'.format(
specialchars=re.escape(self.specialchars))
self.escape_re_quoted = re.compile(escape_pattern_quoted)
self.escape_re_unquoted = re.compile(escape_pattern_unquoted)
def setup(self):
"""Optional method for strategy-wide optimizations."""
def quoted(self, field=None, raw_field=None, only=None):
"""Determine whether this field should be quoted."""
raise NotImplementedError(
'quoted must be implemented by a subclass')
@property
def specialchars(self):
"""The special characters that need to be escaped."""
raise NotImplementedError(
'specialchars must be implemented by a subclass')
def escape_re(self, quoted=None):
if quoted:
return self.escape_re_quoted
return self.escape_re_unquoted
def escapechar(self, quoted=None):
if quoted and self.dialect.doublequote:
return self.dialect.quotechar
return self.dialect.escapechar
def prepare(self, raw_field, only=None):
field = str(raw_field if raw_field is not None else '')
quoted = self.quoted(field=field, raw_field=raw_field, only=only)
escape_re = self.escape_re(quoted=quoted)
escapechar = self.escapechar(quoted=quoted)
if escape_re.search(field):
escapechar = '\\\\' if escapechar == '\\' else escapechar
if escapechar:
escape_replace = \
r'{escapechar}\1'.format(escapechar=escapechar)
field = escape_re.sub(escape_replace, field)
if quoted:
field = '{quotechar}{field}{quotechar}'.format(
quotechar=self.dialect.quotechar, field=field)
return field
class QuoteMinimalStrategy(QuoteStrategy):
quoting = QUOTE_MINIMAL
def setup(self):
self.quoted_re = re.compile(r'[{specialchars}]'.format(
specialchars=re.escape(self.specialchars)))
@property
def specialchars(self):
return (
self.dialect.lineterminator +
self.dialect.quotechar +
self.dialect.delimiter +
(self.dialect.escapechar or '')
)
def quoted(self, field, only, **kwargs):
if field == self.dialect.quotechar and not self.dialect.doublequote:
# If the only character in the field is the quotechar, and
# doublequote is false, then just escape without outer quotes.
return False
return field == '' and only or bool(self.quoted_re.search(field))
class QuoteAllStrategy(QuoteStrategy):
quoting = QUOTE_ALL
@property
def specialchars(self):
return self.dialect.quotechar
def quoted(self, raw_field, **kwargs):
# Handle the null value if raw_field is None or equal to
# replace_nulls_with then it represents the null value, so no need to
# quote it.
if raw_field is None or raw_field == self.dialect.replace_nulls_with:
return False
return True
class QuoteNonnumericStrategy(QuoteStrategy):
quoting = QUOTE_NONNUMERIC
@property
def specialchars(self):
return (
self.dialect.lineterminator +
self.dialect.quotechar +
self.dialect.delimiter +
(self.dialect.escapechar or '')
)
def quoted(self, raw_field, **kwargs):
# Handle the null value if raw_field is None or equal to
# replace_nulls_with then it represents the null value, so no need to
# quote it.
if raw_field is None or raw_field == self.dialect.replace_nulls_with:
return False
return not isinstance(raw_field, numbers.Number)
class QuoteNoneStrategy(QuoteStrategy):
quoting = QUOTE_NONE
@property
def specialchars(self):
return (
self.dialect.lineterminator +
(self.dialect.quotechar or '') +
self.dialect.delimiter +
(self.dialect.escapechar or '')
)
def quoted(self, field, only, **kwargs):
if field == '' and only:
raise Error('single empty field record must be quoted')
return False
class Writer():
def __init__(self, fileobj, dialect='excel', **fmtparams):
if fileobj is None:
raise TypeError('fileobj must be file-like, not None')
self.fileobj = fileobj
if isinstance(dialect, str):
dialect = get_dialect(dialect)
try:
self.dialect = Dialect.combine(dialect, fmtparams)
except Error as e:
raise TypeError(*e.args)
strategies = {
QUOTE_MINIMAL: QuoteMinimalStrategy,
QUOTE_ALL: QuoteAllStrategy,
QUOTE_NONNUMERIC: QuoteNonnumericStrategy,
QUOTE_NONE: QuoteNoneStrategy,
}
self.strategy = strategies[self.dialect.quoting](self.dialect)
def writerow(self, row):
if row is None:
raise Error('row must be an iterable')
row = list(row)
only = len(row) == 1
row = [self.strategy.prepare(field, only=only) for field in row]
line = self.dialect.delimiter.join(row) + self.dialect.lineterminator
return self.fileobj.write(line)
def writerows(self, rows):
for row in rows:
self.writerow(row)
START_RECORD = 0
START_FIELD = 1
ESCAPED_CHAR = 2
IN_FIELD = 3
IN_QUOTED_FIELD = 4
ESCAPE_IN_QUOTED_FIELD = 5
QUOTE_IN_QUOTED_FIELD = 6
EAT_CRNL = 7
AFTER_ESCAPED_CRNL = 8
class Reader():
def __init__(self, fileobj, dialect='excel', **fmtparams):
self.input_iter = iter(fileobj)
if isinstance(dialect, str):
dialect = get_dialect(dialect)
try:
self.dialect = Dialect.combine(dialect, fmtparams)
except Error as e:
raise TypeError(*e.args)
self.fields = None
self.field = None
self.line_num = 0
def parse_reset(self):
self.fields = []
self.field = []
self.state = START_RECORD
self.numeric_field = False
def parse_save_field(self):
field = ''.join(self.field)
self.field = []
if self.numeric_field:
field = float(field)
self.numeric_field = False
self.fields.append(field)
def parse_add_char(self, c):
if len(self.field) >= field_size_limit():
raise Error('field size limit exceeded')
self.field.append(c)
def parse_process_char(self, c):
switch = {
START_RECORD: self._parse_start_record,
START_FIELD: self._parse_start_field,
ESCAPED_CHAR: self._parse_escaped_char,
AFTER_ESCAPED_CRNL: self._parse_after_escaped_crnl,
IN_FIELD: self._parse_in_field,
IN_QUOTED_FIELD: self._parse_in_quoted_field,
ESCAPE_IN_QUOTED_FIELD: self._parse_escape_in_quoted_field,
QUOTE_IN_QUOTED_FIELD: self._parse_quote_in_quoted_field,
EAT_CRNL: self._parse_eat_crnl,
}
return switch[self.state](c)
def _parse_start_record(self, c):
if c == '\0':
return
elif c == '\n' or c == '\r':
self.state = EAT_CRNL
return
self.state = START_FIELD
return self._parse_start_field(c)
def _parse_start_field(self, c):
if c == '\n' or c == '\r' or c == '\0':
self.parse_save_field()
self.state = START_RECORD if c == '\0' else EAT_CRNL
elif (c == self.dialect.quotechar and
self.dialect.quoting != QUOTE_NONE):
self.state = IN_QUOTED_FIELD
elif c == self.dialect.escapechar:
self.state = ESCAPED_CHAR
elif c == ' ' and self.dialect.skipinitialspace:
pass # Ignore space at start of field
elif c == self.dialect.delimiter:
# Save empty field
self.parse_save_field()
else:
# Begin new unquoted field
if self.dialect.quoting == QUOTE_NONNUMERIC:
self.numeric_field = True
self.parse_add_char(c)
self.state = IN_FIELD
def _parse_escaped_char(self, c):
if c == '\n' or c == '\r':
self.parse_add_char(c)
self.state = AFTER_ESCAPED_CRNL
return
if c == '\0':
c = '\n'
self.parse_add_char(c)
self.state = IN_FIELD
def _parse_after_escaped_crnl(self, c):
if c == '\0':
return
return self._parse_in_field(c)
def _parse_in_field(self, c):
# In unquoted field
if c == '\n' or c == '\r' or c == '\0':
# End of line - return [fields]
self.parse_save_field()
self.state = START_RECORD if c == '\0' else EAT_CRNL
elif c == self.dialect.escapechar:
self.state = ESCAPED_CHAR
elif c == self.dialect.delimiter:
self.parse_save_field()
self.state = START_FIELD
else:
# Normal character - save in field
self.parse_add_char(c)
def _parse_in_quoted_field(self, c):
if c != '\0' and c == self.dialect.escapechar:
self.state = ESCAPE_IN_QUOTED_FIELD
elif c != '\0' and (c == self.dialect.quotechar and
self.dialect.quoting != QUOTE_NONE):
if self.dialect.doublequote:
self.state = QUOTE_IN_QUOTED_FIELD
else:
self.state = IN_FIELD
elif c != '\0':
self.parse_add_char(c)
def _parse_escape_in_quoted_field(self, c):
if c == '\0':
c = '\n'
self.parse_add_char(c)
self.state = IN_QUOTED_FIELD
def _parse_quote_in_quoted_field(self, c):
if (self.dialect.quoting != QUOTE_NONE and
c == self.dialect.quotechar):
# save "" as "
self.parse_add_char(c)
self.state = IN_QUOTED_FIELD
elif c == self.dialect.delimiter:
self.parse_save_field()
self.state = START_FIELD
elif c == '\n' or c == '\r' or c == '\0':
# End of line = return [fields]
self.parse_save_field()
self.state = START_RECORD if c == '\0' else EAT_CRNL
elif not self.dialect.strict:
self.parse_add_char(c)
self.state = IN_FIELD
else:
# illegal
raise Error("{delimiter}' expected after '{quotechar}".format(
delimiter=self.dialect.delimiter,
quotechar=self.dialect.quotechar,
))
def _parse_eat_crnl(self, c):
if c != '\n' and c != '\r' and c == '\0':
self.state = START_RECORD
elif c != '\n' and c != '\r':
raise Error('new-line character seen in unquoted field - do you '
'need to open the file in universal-newline mode?')
def __iter__(self):
return self
def __next__(self):
self.parse_reset()
while True:
try:
lineobj = next(self.input_iter)
except StopIteration:
if len(self.field) != 0 or self.state == IN_QUOTED_FIELD:
if self.dialect.strict:
raise Error('unexpected end of data')
self.parse_save_field()
if self.fields:
break
raise
if not isinstance(lineobj, str):
typ = type(lineobj)
typ_name = 'bytes' if typ == bytes else typ.__name__
err_str = ('iterator should return strings, not {0}'
' (did you open the file in text mode?)')
raise Error(err_str.format(typ_name))
self.line_num += 1
for c in lineobj:
if c == '\0':
raise Error('line contains NULL byte')
self.parse_process_char(c)
self.parse_process_char('\0')
if self.state == START_RECORD:
break
fields = self.fields
self.fields = None
return fields
next = __next__
_dialect_registry = {}
def register_dialect(name, dialect='excel', **fmtparams):
if not isinstance(name, str):
raise TypeError('"name" must be a string')
dialect = Dialect.extend(dialect, fmtparams)
try:
Dialect.validate(dialect)
except Exception:
raise TypeError('dialect is invalid')
assert name not in _dialect_registry
_dialect_registry[name] = dialect
def unregister_dialect(name):
try:
_dialect_registry.pop(name)
except KeyError:
raise Error('"{name}" not a registered dialect'.format(name=name))
def get_dialect(name):
try:
return _dialect_registry[name]
except KeyError:
raise Error('Could not find dialect {0}'.format(name))
def list_dialects():
return list(_dialect_registry)
class Dialect():
"""Describe a CSV dialect.
This must be subclassed (see csv.excel). Valid attributes are:
delimiter, quotechar, escapechar, doublequote, skipinitialspace,
lineterminator, quoting, strict.
"""
_name = ""
_valid = False
# placeholders
delimiter = None
quotechar = None
escapechar = None
doublequote = None
skipinitialspace = None
lineterminator = None
quoting = None
strict = None
def __init__(self):
self.validate(self)
if self.__class__ != Dialect:
self._valid = True
@classmethod
def validate(cls, dialect):
dialect = cls.extend(dialect)
if not isinstance(dialect.quoting, int):
raise Error('"quoting" must be an integer')
if dialect.delimiter is None:
raise Error('delimiter must be set')
cls.validate_text(dialect, 'delimiter')
if dialect.lineterminator is None:
raise Error('lineterminator must be set')
if not isinstance(dialect.lineterminator, str):
raise Error('"lineterminator" must be a string')
if dialect.quoting not in [
QUOTE_NONE, QUOTE_MINIMAL, QUOTE_NONNUMERIC, QUOTE_ALL]:
raise Error('Invalid quoting specified')
if dialect.quoting != QUOTE_NONE:
if dialect.quotechar is None and dialect.escapechar is None:
raise Error('quotechar must be set if quoting enabled')
if dialect.quotechar is not None:
cls.validate_text(dialect, 'quotechar')
@staticmethod
def validate_text(dialect, attr):
val = getattr(dialect, attr)
if not isinstance(val, str):
if isinstance(val, bytes):
raise Error('"{0}" must be string, not bytes'.format(attr))
raise Error('"{0}" must be string, not {1}'.format(
attr, type(val).__name__))
if len(val) != 1:
raise Error('"{0}" must be a 1-character string'.format(attr))
@staticmethod
def defaults():
return {
'delimiter': ',',
'doublequote': True,
'escapechar': None,
'lineterminator': '\r\n',
'quotechar': '"',
'quoting': QUOTE_MINIMAL,
'skipinitialspace': False,
'strict': False,
'replace_nulls_with': None
}
@classmethod
def extend(cls, dialect, fmtparams=None):
if isinstance(dialect, str):
dialect = get_dialect(dialect)
if fmtparams is None:
return dialect
defaults = cls.defaults()
if any(param not in defaults for param in fmtparams):
raise TypeError('Invalid fmtparam')
specified = dict(
(attr, getattr(dialect, attr, None))
for attr in cls.defaults()
)
specified.update(fmtparams)
return type(str('ExtendedDialect'), (cls,), specified)
@classmethod
def combine(cls, dialect, fmtparams):
"""Create a new dialect with defaults and added parameters."""
dialect = cls.extend(dialect, fmtparams)
defaults = cls.defaults()
specified = dict(
(attr, getattr(dialect, attr, None))
for attr in defaults
if getattr(dialect, attr, None) is not None or
attr in ['quotechar', 'delimiter', 'lineterminator', 'quoting']
)
defaults.update(specified)
dialect = type(str('CombinedDialect'), (cls,), defaults)
cls.validate(dialect)
return dialect()
def __delattr__(self, attr):
if self._valid:
raise AttributeError('dialect is immutable.')
super().__delattr__(attr)
def __setattr__(self, attr, value):
if self._valid:
raise AttributeError('dialect is immutable.')
super().__setattr__(attr, value)
class Excel(Dialect):
"""Describe the usual properties of Excel-generated CSV files."""
delimiter = ','
quotechar = '"'
doublequote = True
skipinitialspace = False
lineterminator = '\r\n'
quoting = QUOTE_MINIMAL
register_dialect("excel", Excel)
class ExcelTab(Excel):
"""Describe the usual properties of Excel-generated TAB-delimited files."""
delimiter = '\t'
register_dialect("excel-tab", ExcelTab)
class UnixDialect(Dialect):
"""Describe the usual properties of Unix-generated CSV files."""
delimiter = ','
quotechar = '"'
doublequote = True
skipinitialspace = False
lineterminator = '\n'
quoting = QUOTE_ALL
register_dialect("unix", UnixDialect)
class DictReader():
def __init__(self, f, fieldnames=None, restkey=None, restval=None,
*args, **kwds):
self._fieldnames = fieldnames # list of keys for the dict
self.restkey = restkey # key to catch long rows
self.restval = restval # default value for short rows
self.dialect = kwds.get('dialect', "excel")
self.reader = Reader(f, self.dialect, *args, **kwds)
self.line_num = 0
def __iter__(self):
return self
@property
def fieldnames(self):
if self._fieldnames is None:
try:
self._fieldnames = next(self.reader)
except StopIteration:
pass
self.line_num = self.reader.line_num
return self._fieldnames
@fieldnames.setter
def fieldnames(self, value):
self._fieldnames = value
def __next__(self):
if self.line_num == 0:
# Used only for its side effect.
self.fieldnames
row = next(self.reader)
self.line_num = self.reader.line_num
# unlike the basic reader, we prefer not to return blanks,
# because we will typically wind up with a dict full of None
# values
while row == []:
row = next(self.reader)
d = dict(zip(self.fieldnames, row))
lf = len(self.fieldnames)
lr = len(row)
if lf < lr:
d[self.restkey] = row[lf:]
elif lf > lr:
for key in self.fieldnames[lr:]:
d[key] = self.restval
return d
next = __next__
class DictWriter():
def __init__(self, f, fieldnames, *args, **kwds):
self.fieldnames = fieldnames # list of keys for the dict
self.extrasaction = kwds.get('extrasaction', "raise")
self.restval = kwds.get('restval', "") # for writing short dicts
if self.extrasaction.lower() not in ("raise", "ignore"):
raise ValueError("extrasaction (%s) must be 'raise' or 'ignore'"
% self.extrasaction)
dialect = kwds.get('dialect', "excel")
self.writer = Writer(f, dialect, *args, **kwds)
def writeheader(self):
header = dict(zip(self.fieldnames, self.fieldnames))
self.writerow(header)
def _dict_to_list(self, rowdict):
if self.extrasaction == "raise":
wrong_fields = [k for k in rowdict if k not in self.fieldnames]
if wrong_fields:
raise ValueError("dict contains fields not in fieldnames: " +
", ".join([repr(x) for x in wrong_fields]))
return (rowdict.get(key, self.restval) for key in self.fieldnames)
def writerow(self, rowdict):
return self.writer.writerow(self._dict_to_list(rowdict))
def writerows(self, rowdicts):
return self.writer.writerows(map(self._dict_to_list, rowdicts))