I'm doing some work with WebDAV representations in Zope 2, among other
things, and I'm trying to see if we should use zope.filerepresentation
as the central abstraction for file read/write operations.
However, I find myself lacking a couple of things:
1) A way for an IReadFile to return the file's MIME (content) type
(for the Content-Type, for example) and an optional filename (for the
Conent-Disposition header, for example)
2) A way for an IWriteFile to be told about the MIME type and encoding
of the data it is consuming. I know that IFileFactory() contains this,
but data is not always going to be written to a new file, so setting
this from the factory won't work.
3) I see this comment:
# TODO: We will add ILargeReadFile and ILargeWriteFile to efficiently
# handle large data.
But it seems this was never implemented. I need a way for the
IWriteFile.write() to be passed a file-like object (in fact, there's not
really any clear notion of what the 'data' parameter is, but I assume
it's meant to be a str object), and for IReadFile.read() to return a
file stream iterator of some kind instead of the full raw data.
I see two options here:
- add a new plone.filerepresentation that extends these interfaces
- commit some changes to zope.filerepresentation and make a new
release of this
Since zope.filerepresentation is really *just* interfaces, #2 seems
best. Any objections?
Here's an initial take on the interfaces:
"""Provide read access to file data
"""Return the file data as a str
"""Return the data length
"""Provide efficient read access to file data
"""Get the content/MIME type of the file as a string in the form
'major/minor'. Return None if this is not known.
"""Get the intended file name for this file. Return None if this
is not known.
"""Return an iterable of the file data
"""Update the file data
def writeFile(data, contentType=None, encoding=None):
"""Update the file data.
data is a file-like object containing input data
contentType is the content/MIME type of the data as a string in
the form 'major/minor'. It may be None if unknown.
encoding is the encoding of the string. It may be None
This should be 100% backwards compatible. The downside is that people
will need to implement both write() and writeFile() / read() and
getIterator() to support both str based and stream based reading and
writing, but that's easily addressed with a StringIO.
And of course, nothing in the ZTK will actually use these new
interfaces, but that could come later. ;)
Author of `Professional Plone Development`, a book for developers who
want to work with Plone. See http://martinaspeli.net/plone-book
Zope-Dev maillist - Zope-Dev@zope.org
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