from __future__ import absolute_import
import csv
import codecs
import cStringIO


class Echo(object):

  def write(self, value):
    return value

class UnicodeWriter:

  """
  A CSV writer which will write rows to CSV file "f",
  which is encoded in the given encoding.
  """

  def __init__(self, f, dialect=csv.excel, encoding="utf-8", **kwds):
    # Redirect output to a queue
    self.queue = cStringIO.StringIO()
    self.writer = csv.writer(self.queue, dialect=dialect, **kwds)
    self.stream = f
    self.encoder = codecs.getincrementalencoder(encoding)()

  def writerow(self, row):
    self.writer.writerow([handle_column(s) 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 = self.encoder.encode(data)
    # write to the target stream
    value = self.stream.write(data)
    # empty queue
    self.queue.truncate(0)
    return value

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

from django.views.generic import View
from django.http.response import StreamingHttpResponse

class ExampleView(View):
  headers=['一些','表頭']
  def get(self,request):
    result = [['第一行','數(shù)據(jù)1'],
         ['第二行','數(shù)據(jù)2']]
    echoer = Echo()
    writer = UnicodeWriter(echoer)
    def csv_itertor():
        yield codecs.BOM_UTF8
        yield writer.writerow(self.headers)
        for column in result:
          yield writer.writerow(column)

    response = StreamingHttpResponse(
      (row for row in csv_itertor()),
      content_type="text/csv;charset=utf-8")
    response['Content-Disposition'
         ] = 'attachment;filename="example.csv"'
    return response