Supporting read() with fileinput?

Daniel Yoo dyoo at hkn.eecs.berkeley.edu
Tue Nov 25 22:11:12 CET 2003


Hi everyone,

I'm was wondering: would it be a good idea to have the FileInput class
support a read() method?  I found myself running into a small problem
while using xml.sax.parse in combination with fileinput.  Here's a
snippet that demonstrates the problem:

###
import xml.sax
import fileinput

xml.sax.parse(fileinput.input(), xml.sax.ContentHandler())
###

This doesn't work, because fileinput.input() isn't a file-like object:
it doesn't have read(), so it can't be converted into a nice InputSource.


But I thought it might be nice to have one, so I cooked up a quick
class to make it work:

###
class ByteStream:
    def __init__(self, f):
        self._buffer = []
        self._f = f

    def read(self, bytes):
        if not self._buffer: self._prime()
        next_block = self._buffer[:bytes]
        del self._buffer[:bytes]
        return ''.join(next_block)

    def _prime(self):
        self._buffer.extend(list(self._f.readline()))
###

And now I can get:

###
xml.sax.parse(ByteStream(fileinput.input()), xml.sax.ContentHandler())
###

to work.  But I'd rather make this solution a bit more permanent.
*grin* Would it be a good idea to add a read() method to FileInput to
make it more file-like?


Thanks!




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