writing \feff at the begining of a file

[MRAB]

Jean-Michel Pichavant wrote:
> Hello python world,
> 
> I'm trying to update the content of a $Microsoft$ VC2005 project files 
> using a python application.
> Since those files are XML data, I assumed I could easily do that.
> 
> My problem is that VC somehow thinks that the file is corrupted and 
> update the file like the following:
> 
> -<?xml version='1.0' encoding='UTF-8'?>
> +?<feff><?xml version="1.0" encoding="UTF-8"?>
> 
> 
> Actually, <feff> is displayed in a different color by vim, telling me 
> that this is some kind of special caracter code (I'm no familiar with 
> such thing).
> After googling that, I have a clue : could be some unicode caracter use 
> to indicate something ... well I don't know in fact ("UTF-8 files 
> sometimes start with a byte-order marker (BOM) to indicate that they are 
> encoded in UTF-8.").
> 
> My problem is however simplier : how do I add such character at the 
> begining of the file ?
> I tried
> 
> f = open('paf', w)
> f.write(u'\ufeff')
> 
> UnicodeEncodeError: 'ascii' codec can't encode character u'\ufeff' in 
> position 0: ordinal not in range(128)
> 
> The error may be explicit but I have no idea how to proceed further. Any 
> clue ?
> 
In Python 2 the default encoding is 'ascii'. What you want is 'utf-8'.

Use codecs.open() instead, with the 'utf-8-sig' encoding, which will
include the BOM.