Convert SpreadSheets to CSV files with Python and pyuno

Using the OORunner class that we developed last week we'll now create a Python class for converting spreadsheets into CSV files. The converter supports any type of input spreadsheet that is supported by OpenOffice.

When run the program takes pairs of input and output files, for example:

$ python file1.xls file1.csv file2.ods file2.csv

Each input file is a spreadsheet and it is converted into the corresponding output file as a CSV file.

The meat of the operation happens in the convert function from the SSConverter class. The first thing it does is start OpenOffice running using the OORunner class. It then converts the input and output file names to URLs and uses the desktop object returned by OORunner to create and load a document object. Converting the spreadsheet to a CSV file is merely a matter of saving the document to the output URL. The source code for the SSConverter class follows:

# Convert spreadsheet to CSV file.
# Based on:
#   PyODConverter (Python OpenDocument Converter) v1.0.0 - 2008-05-05
#   Copyright (C) 2008 Mirko Nasato <[email protected]>
#   Licensed under the GNU LGPL v2.1 - or any later version.

import os
import ooutils

import uno
from import ErrorCodeIOException

class SSConverter:
    Spreadsheet converter class.
    Converts spreadsheets to CSV files.

    def __init__(self, oorunner=None):
        self.desktop  = None
        self.oorunner = None

    def convert(self, inputFile, outputFile):
        Convert the input file (a spreadsheet) to a CSV file.

        # Start openoffice if needed.
        if not self.desktop:
            if not self.oorunner:
                self.oorunner = ooutils.OORunner()

            self.desktop = self.oorunner.connect()

        inputUrl  = uno.systemPathToFileUrl(os.path.abspath(inputFile))
        outputUrl = uno.systemPathToFileUrl(os.path.abspath(outputFile))
        document  = self.desktop.loadComponentFromURL(inputUrl, "_blank", 0, ooutils.oo_properties(Hidden=True))

            # Additional property option:
            #   FilterOptions="59,34,0,1"
            #     59 - Field separator (semicolon), this is the ascii value.
            #     34 - Text delimiter (double quote), this is the ascii value.
            #      0 - Character set (system).
            #      1 - First line number to export.
            # For more information see:
            document.storeToURL(outputUrl, ooutils.oo_properties(FilterName="Text - txt - csv (StarCalc)"))

if __name__ == "__main__":
    from sys import argv
    from os.path import isfile

    if len(argv) == 2  and  argv[1] == '--shutdown':
        if len(argv) < 3  or  len(argv) % 2 != 1:
            print "USAGE:"
            print "  python %s INPUT-FILE OUTPUT-FILE INPUT-FILE OUTPUT-FILE..." % argv[0]
            print "OR"
            print "  python %s --shutdown" % argv[0]
        if not isfile(argv[1]):
            print "File not found: %s" % argv[1]

            i = 1
            converter = SSConverter()

            while i+1 < len(argv):
                print '%s => %s' % (argv[i], argv[i+1])
                converter.convert(argv[i], argv[i+1])
                i += 2

        except ErrorCodeIOException, exception:
            print "ERROR! ErrorCodeIOException %d" % exception.ErrCode

As with OORunner, this code is based on PyODConverter. Next week we'll write a converter function that creates the CSV file automatically from the corresponding spreadsheet if the CSV file does not exist. In addition it will re-create the CSV file if the spreadsheet is newer than the CSV file. This way you can essentially use spreadsheets and CSV files interchangeably in your code.


Mitch Frazier is an embedded systems programmer at Emerson Electric Co. Mitch has been a contributor to and a friend of Linux Journal since the early 2000s.

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