Django snippets

import csv, StringIO

class UnicodeWriter(object):
    """
    Like UnicodeDictWriter, but takes lists rather than dictionaries.
    
    Usage example:
    
    fp = open('my-file.csv', 'wb')
    writer = UnicodeWriter(fp)
    writer.writerows([
        [u'Bob', 22, 7],
        [u'Sue', 28, 6],
        [u'Ben', 31, 8],
        # \xc3\x80 is LATIN CAPITAL LETTER A WITH MACRON
        ['\xc4\x80dam'.decode('utf8'), 11, 4],
    ])
    fp.close()
    """
    def __init__(self, f, dialect=csv.excel_tab, encoding="utf-16", **kwds):
        # Redirect output to a queue
        self.queue = StringIO.StringIO()
        self.writer = csv.writer(self.queue, dialect=dialect, **kwds)
        self.stream = f
        self.encoding = encoding
    
    def writerow(self, row):
        # Modified from original: now using unicode(s) to deal with e.g. ints
        self.writer.writerow([unicode(s).encode("utf-8") for s in row])
        # Fetch UTF-8 output from the queue ...
        data = self.queue.getvalue()
        data = data.decode("utf-8")
        # ... and reencode it into the target encoding
        data = data.encode(self.encoding)
        # write to the target stream
        self.stream.write(data)
        # empty queue
        self.queue.truncate(0)
    
    def writerows(self, rows):
        for row in rows:
            self.writerow(row)

class UnicodeDictWriter(UnicodeWriter):
    """
    A CSV writer that produces Excel-compatibly CSV files from unicode data.
    Uses UTF-16 and tabs as delimeters - it turns out this is the only way to
    get unicode data in to Excel using CSV.
    
    Usage example:
    
    fp = open('my-file.csv', 'wb')
    writer = UnicodeDictWriter(fp, ['name', 'age', 'shoesize'])
    writer.writerows([
        {'name': u'Bob', 'age': 22, 'shoesize': 7},
        {'name': u'Sue', 'age': 28, 'shoesize': 6},
        {'name': u'Ben', 'age': 31, 'shoesize': 8},
        # \xc3\x80 is LATIN CAPITAL LETTER A WITH MACRON
        {'name': '\xc4\x80dam'.decode('utf8'), 'age': 11, 'shoesize': 4},
    ])
    fp.close()
    
    Initially derived from http://docs.python.org/lib/csv-examples.html
    """
    
    def __init__(self, f, fields, dialect=csv.excel_tab,
            encoding="utf-16", **kwds):
        super(UnicodeDictWriter, self).__init__(f, dialect, encoding, **kwds)
        self.fields = fields
    
    def writerow(self, drow):
        row = [drow.get(field, '') for field in self.fields]
        super(UnicodeDictWriter, self).writerow(row)