Python ftplib UnicodeEncodeError when trying to upload an XML with unicode content

Question

I am trying to upload an XML with unicode content to a FTP server using ftplib, but getting the following exception when I try to upload the using storbinary method. The XML data is properly encoded to unicode (utf-8), I have made sure of that, I am not sure as to why storbinary is trying to encode it to 'ascii' while uploading. Can anyone please help?


--> 429         ftp.storbinary("STOR file.xml", xml)
    430 
    431     def run(self):

/usr/lib/python2.7/ftplib.pyc in storbinary(self, cmd, fp, blocksize, callback, rest)
    463             buf = fp.read(blocksize)
    464             if not buf: break
--> 465             conn.sendall(buf)
    466             if callback: callback(buf)
    467         conn.close()

/usr/lib/python2.7/socket.pyc in meth(name, self, *args)
    222 
    223 def meth(name,self,*args):
--> 224     return getattr(self._sock,name)(*args)
    225 
    226 for _m in _socketmethods:

UnicodeEncodeError: 'ascii' codec can't encode character u'\xae' in position 3368: ordinal not in range(128)

It looks like it's a unicode object, so it's not encoded at all. — Cairnarvon
Is xml a file object? If not, use StringIO to create a file-like object from your xml string. — Austin Phillips
@AustinPhillips:Yes, I build the XML and use the StringIO object to pass it on to ftplib. — asp
@Cairnarvon: I did not understand what you meant, the string I write to the StringIO instance is an unicode instance, and just make sure about the encoding, I even tried adding a ".encode("utf-8")" to the string before writing to the StringIO object. — asp
@asp Please provide a minimal example showing the generation of the unicode string. — Austin Phillips

jfs jfs · Accepted Answer · 2013-02-24T11:17:32

You should pass a file opened in a binary mode to ftp.storbinary(). For example, if you want to upload a Unicode string as a filename file:

import io

assert isinstance(unicode_string, unicode)
file = io.BytesIO(unicode_string.encode("utf-8"))
ftp.storbinary("STOR filename", file)

If unicode_string contains xml; make sure that the character encoding used in the xml declaration is consistent with the encoding you use to store the file.

Python ftplib UnicodeEncodeError when trying to upload an XML with unicode content

2 Answers