src/qbe/django_qbe/exports.py

   1 # -*- coding: utf-8 -*-
   2 import codecs
   3 import csv
   4 from StringIO import StringIO
   5 from odf.opendocument import OpenDocumentSpreadsheet
   6 from odf.style import Style, TextProperties, TableColumnProperties
   7 from odf.text import P
   8 from odf.table import Table, TableRow, TableCell
   9
  10 from django.http import HttpResponse
  11 from django.utils.datastructures import SortedDict
  12
  13 __all__ = ("formats", )
  14
  15
  16 class FormatsException(Exception):
  17     pass
  18
  19
  20 class Formats(SortedDict):
  21
  22     def add(self, format):
  23         parent = self
  24
  25         def decorator(func):
  26             if callable(func):
  27                 parent.update({format: func})
  28             else:
  29                 raise FormatsException("func is not a function.")
  30
  31         return decorator
  32
  33
  34 formats = Formats()
  35
  36
  37 # Taken from http://docs.python.org/library/csv.html#csv-examples
  38 class UnicodeWriter(object):
  39     """
  40     A CSV writer which will write rows to CSV file "f",
  41     which is encoded in the given encoding.
  42     """
  43
  44     def __init__(self, f, dialect=csv.excel_tab, encoding="utf-8", **kwds):
  45         # Redirect output to a queue
  46         self.queue = StringIO()
  47         self.writer = csv.writer(self.queue, dialect=dialect, **kwds)
  48         self.stream = f
  49         self.encoder = codecs.getincrementalencoder(encoding)()
  50
  51     def writerow(self, row):
  52         self.writer.writerow([unicode(s).encode("utf-8") for s in row])
  53         # Fetch UTF-8 output from the queue ...
  54         data = self.queue.getvalue()
  55         data = data.decode("utf-8")
  56         # ... and reencode it into the target encoding
  57         data = self.encoder.encode(data)
  58         # write to the target stream
  59         self.stream.write(data)
  60         # empty queue
  61         self.queue.truncate(0)
  62
  63     def writerows(self, rows):
  64         for row in rows:
  65             self.writerow(row)
  66
  67
  68 def txt(msg):
  69     text = msg
  70     if msg is not None and not isinstance(msg, unicode):
  71         text = unicode (msg, "utf-8")
  72     return text
  73
  74
  75 def base_export(labels, results, dialect=csv.excel_tab):
  76     output = StringIO()
  77     w = UnicodeWriter(output, dialect=dialect)
  78     w.writerow(labels)
  79     for row in results:
  80         w.writerow(row)
  81     output.seek(0)
  82     return output.read()
  83
  84
  85 @formats.add("csv")
  86 def csv_format(labels, results):
  87     output = base_export(labels, results, dialect=csv.excel)
  88     mimetype = "text/csv"
  89     response = HttpResponse(output, mimetype=mimetype)
  90     response['Content-Disposition'] = 'attachment; filename=export.csv'
  91     return response
  92
  93
  94 @formats.add("ods")
  95 def ods_format(labels, results):
  96     doc = OpenDocumentSpreadsheet()
  97     style = Style(name="Large number", family="table-cell")
  98     style.addElement(TextProperties(fontfamily="Arial", fontsize="15pt"))
  99     doc.styles.addElement(style)
 100     widewidth = Style(name="co1", family="table-column")
 101     widewidth.addElement(TableColumnProperties(columnwidth="2.8cm", breakbefore="auto"))
 102     doc.automaticstyles.addElement(widewidth)
 103
 104     table = Table()
 105     if len (labels) > 0:
 106         tr = TableRow ()
 107         table.addElement (tr)
 108         for item in labels:
 109             tc = TableCell ()
 110             tr.addElement (tc)
 111             p = P(stylename = style, text = txt(item))
 112             tc.addElement (p)
 113
 114     for line in results:
 115         tr = TableRow ()
 116         table.addElement (tr)
 117         for item in line:
 118             tc = TableCell ()
 119             tr.addElement (tc)
 120             p = P (stylename = style, text = txt(item))
 121             tc.addElement (p)
 122
 123     doc.spreadsheet.addElement(table)
 124     buffer = StringIO ()
 125     doc.write(buffer)
 126
 127     mimetype = "application/vnd.oasis.opendocument.spreadsheet"
 128     response = HttpResponse(buffer.getvalue(), mimetype=mimetype)
 129     response['Content-Disposition'] = 'attachment; filename=export.ods'
 130     return response
 131
 132
 133 @formats.add("xls")
 134 def xls_format(labels, results):
 135     output = base_export(labels, results)
 136     mimetype = "application/vnd.ms-excel"
 137     response = HttpResponse(output, mimetype=mimetype)
 138     response['Content-Disposition'] = 'attachment; filename=export.xls'
 139     return response