unicodecsv.py

"""
Copyright 2010 Jeremy Dunck. All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are
permitted provided that the following conditions are met:

   1. Redistributions of source code must retain the above copyright notice, this list of
      conditions and the following disclaimer.

   2. Redistributions in binary form must reproduce the above copyright notice, this list
      of conditions and the following disclaimer in the documentation and/or other materials
      provided with the distribution.

THIS SOFTWARE IS PROVIDED BY JEREMY DUNCK ``AS IS'' AND ANY EXPRESS OR IMPLIED
WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL JEREMY DUNCK OR
CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

The views and conclusions contained in the software and documentation are those of the
authors and should not be interpreted as representing official policies, either expressed
or implied, of Jeremy Dunck.
"""

# -*- coding: utf-8 -*-
import csv
import numbers
import sys

from itertools import izip

pass_throughs = [
    'register_dialect',
    'unregister_dialect',
    'get_dialect',
    'list_dialects',
    'field_size_limit',
    'Dialect',
    'excel',
    'excel_tab',
    'Sniffer',
    'QUOTE_ALL',
    'QUOTE_MINIMAL',
    'QUOTE_NONNUMERIC',
    'QUOTE_NONE',
    'Error'
]
__all__ = [
    'reader',
    'writer',
    'DictReader',
    'DictWriter',
] + pass_throughs

for prop in pass_throughs:
    globals()[prop] = getattr(csv, prop)


def _stringify(s, encoding, errors):
    if s is None:
        return ''
    if isinstance(s, unicode):
        return s.encode(encoding, errors)
    elif isinstance(s, numbers.Number):
        pass  # let csv.QUOTE_NONNUMERIC do its thing.
    elif not isinstance(s, str):
        s = str(s)
    return s


def _stringify_list(l, encoding, errors='strict'):
    try:
        return [_stringify(s, encoding, errors) for s in iter(l)]
    except TypeError as e:
        raise csv.Error(str(e))


def _unicodify(s, encoding):
    if s is None:
        return None
    if isinstance(s, (unicode, int, float)):
        return s
    elif isinstance(s, str):
        return s.decode(encoding)
    return s


class UnicodeWriter(object):
    """
    >>> import unicodecsv
    >>> from cStringIO import StringIO
    >>> f = StringIO()
    >>> w = unicodecsv.writer(f, encoding='utf-8')
    >>> f.seek(0)
    >>> r = unicodecsv.reader(f, encoding='utf-8')
    """
    def __init__(self, f, dialect=csv.excel, encoding='utf-8', errors='strict',
                 *args, **kwds):
        self.encoding = encoding
        self.writer = csv.writer(f, dialect, *args, **kwds)
        self.encoding_errors = errors

    def writerow(self, row):
        return self.writer.writerow(
                _stringify_list(row, self.encoding, self.encoding_errors))

    def writerows(self, rows):
        for row in rows:
            self.writerow(row)

    @property
    def dialect(self):
        return self.writer.dialect
writer = UnicodeWriter


class UnicodeReader(object):
    def __init__(self, f, dialect=None, encoding='utf-8', errors='strict',
                 **kwds):

        format_params = ['delimiter', 'doublequote', 'escapechar',
                         'lineterminator', 'quotechar', 'quoting',
                         'skipinitialspace']

        if dialect is None:
            if not any([kwd_name in format_params
                        for kwd_name in kwds.keys()]):
                dialect = csv.excel
        self.reader = csv.reader(f, dialect, **kwds)
        self.encoding = encoding
        self.encoding_errors = errors
        self._parse_numerics = bool(
            self.dialect.quoting & csv.QUOTE_NONNUMERIC)

    def next(self):
        row = self.reader.next()
        encoding = self.encoding
        encoding_errors = self.encoding_errors
        unicode_ = unicode
        if self._parse_numerics:
            float_ = float
            return [(value if isinstance(value, float_) else
                    unicode_(value, encoding, encoding_errors))
                    for value in row]
        else:
            return [unicode_(value, encoding, encoding_errors)
                    for value in row]

    def __iter__(self):
        return self

    @property
    def dialect(self):
        return self.reader.dialect

    @property
    def line_num(self):
        return self.reader.line_num
reader = UnicodeReader


class DictWriter(csv.DictWriter):
    """
    >>> from cStringIO import StringIO
    >>> f = StringIO()
    >>> f.seek(0)
    """
    def __init__(self, csvfile, fieldnames, restval='',
                 extrasaction='raise', dialect='excel', encoding='utf-8',
                 errors='strict', *args, **kwds):
        self.encoding = encoding
        csv.DictWriter.__init__(self, csvfile, fieldnames, restval,
                                extrasaction, dialect, *args, **kwds)
        self.writer = UnicodeWriter(csvfile, dialect, encoding=encoding,
                                    errors=errors, *args, **kwds)
        self.encoding_errors = errors

    def writeheader(self):
        header = dict(zip(self.fieldnames, self.fieldnames))
        self.writerow(header)


class DictReader(csv.DictReader):
    """
    >>> from cStringIO import StringIO
    >>> f = StringIO()
    >>> w = DictWriter(f, fieldnames=['name', 'place'])
    >>> w.writerow({'name': 'Cary Grant', 'place': 'hollywood'})
    >>> f.seek(0)
    >>> r = DictReader(f, fieldnames=['name', 'place'])
    >>> print r.next() == {'name': 'Cary Grant', 'place': 'hollywood'}
    True
    """
    def __init__(self, csvfile, fieldnames=None, restkey=None, restval=None,
                 dialect='excel', encoding='utf-8', errors='strict', *args,
                 **kwds):
        if fieldnames is not None:
            fieldnames = _stringify_list(fieldnames, encoding)
        csv.DictReader.__init__(self, csvfile, fieldnames, restkey, restval,
                                dialect, *args, **kwds)
        self.reader = UnicodeReader(csvfile, dialect, encoding=encoding,
                                    errors=errors, *args, **kwds)
        if fieldnames is None and not hasattr(csv.DictReader, 'fieldnames'):
            # Python 2.5 fieldnames workaround.
            # See http://bugs.python.org/issue3436
            reader = UnicodeReader(csvfile, dialect, encoding=encoding,
                                   *args, **kwds)
            self.fieldnames = _stringify_list(reader.next(), reader.encoding)

        if self.fieldnames is not None:
            self.unicode_fieldnames = [_unicodify(f, encoding) for f in
                                       self.fieldnames]
        else:
            self.unicode_fieldnames = []

        self.unicode_restkey = _unicodify(restkey, encoding)

    def next(self):
        row = csv.DictReader.next(self)
        result = dict((uni_key, row[str_key]) for (str_key, uni_key) in
                      izip(self.fieldnames, self.unicode_fieldnames))
        rest = row.get(self.restkey)
        if rest:
            result[self.unicode_restkey] = rest
        return result