Temporary files cause issue under Windows 7

[phaefele]

Seems that NamedTemporaryFiles under Windows are opened automatically. This causes issues when codec.open is then used to open the file in the IPython V3 code. I changed the code to use the following method as opposed to codecs_open in the save and get methods.

Am happy to integrate it in if need be.

Thanks for this work.

Regards
Paul

     def _codecs_open(self, filename, file_handle, mode='rb', encoding=None, errors='strict', buffering=1):
        # Copy of codecs.open
        if encoding is not None:
            if 'U' in mode:
                # No automatic conversion of '\n' is done on reading and writing
                mode = mode.strip().replace('U', '')
                if mode[:1] not in set('rwa'):
                    mode = 'r' + mode
            if 'b' not in mode:
                # Force opening of the file in binary mode
                mode = mode + 'b'
        try:
            file = open(filename, mode, buffering)
        except:
            file = file_handle
        if encoding is None:
            return file
        info = codecs.lookup(encoding)
        srw = codecs.StreamReaderWriter(file, info.streamreader, info.streamwriter, errors)
        # Add attributes to simplify introspection
        srw.encoding = encoding
        return srw

Save was changed as follows (get the same)

 def _save_notebook(self, path, nb):
        self.log.debug('_save_notebook: %s', locals())

        k = boto.s3.key.Key(self.bucket)
        k.key = self._path_to_s3_key(path)

        try:
            with tempfile.NamedTemporaryFile() as t:
                with self._codecs_open(t.name, t, mode='w', encoding='utf-8') as f:
                    # write tempfile with utf-8 encoding
                    nbformat.write(nb, f, version=nbformat.NO_CONVERT)
                    # upload as bytes (t's fp didn't advance)
                    t.seek(0)
                    k.set_contents_from_file(t)
        except Exception as e:
            raise web.HTTPError(400, u"Unexpected Error Writing Notebook: %s %s" % (path, e))

[graphaelli]

That seems like strange behavior but https://bugs.python.org/issue14243 and others suggest that some special handling is indeed necessary on windows. Can you please submit a pull request with code that works on windows and we can iterate from there?