[Zope3-dev] Re: zope.filerepresentation.interfaces.IWriteFile

[Ignas Mikalajunas]

> Philipp von Weitershausen wrote:
> > Christian Theune wrote:
> >> Hi,
> >>
> >> as I stumbled over this recently, I'd like to bring this up for
> >> discussion:
> >>
> >> There is an interface called IWriteFile in the module
> >> zope.filerepresentation.interfaces.
> >>
> >> It defines one method "write(data)" with the doc string:
> >>
> >> "Update the file data"
> >>
> >> There are some problems I have with this:
> >>
> >> a) The interface is yet another interface for doing a file-like object.
> >> How many of those are around?
> >
> > Oh, which others are there?
>
> Humm. Looks like it's only that one =).
>
> >> b) It *seems intended* not to be really file-like but that "update the
> >> file data" means: writing to this will replace all previous data
> >
> > Yes.
>
> Too bad. :/
>
> >> c) The doc string is IMHO underspecified (I asked 3 other developers in
> >> the office. One of them said "it will replace the data on the second
> >> call", one said "it will append data like the file object", the third
> >> wasn't sure but was in favor of appending data)
> >>
> >> This interface is used only in very few places in Zope.
> >
> > FTP and HTTP PUT.
>
> Yup. That's what I saw.
>
> >> I'm not sure what to do now, but I think something needs to be changed.
> >> Here are some options:
> >>
> >> - Make the doc string more explicit. (That should happen anyway)
> >> - Keep the current behavior.
> >
> > I think we'll have to :(. There have been lots of documented uses of
> > filerepresentation
> >
> >> - Change the current behavior and make write() act like Python's
> >>   file.write()
> >
> > Perhaps in a new interface?
>
> We probably have to. But to be honest? I totally understand every
> programmer that will ask us "WTF?!?". Does anybody see a better way out
> of that situation without deprecating anything again?
>
> Christian

SchoolTool is using this infrastructure for it's RESTive views. And
yes the interface could get improved a bit. The file.write() method
could be more simmilar to IFileFactory.__call__ as else one has to
assume that updates to a file are not going to change the encoding as
the encoding from an HTTP PUT request is ignored (which got us a few
times when users were uploading ICal ics files with a different
encoding so we had to work around it with a custom view for updates).

Ignas