[Grok-dev] Re: [Zope3-Users] save file to filesystem

kev mictlan.tecutli.0 at gmail.com
Wed Feb 27 19:39:01 EST 2008

thanks for the quick responce martijn. ive gotta better grasp of the
concepts now, but yea the implementation makes  my head spin a bit. i´ll
begin to investigate using what you´ve laid out here as  a guide. i´ve
joined the grok-dev list. 

El jue, 28-02-2008 a las 00:19 +0100, Martijn Faassen escribió:
> Hi there,
> I haven't had much experience with blobs yet (I hope to start working
> with this in the near future).
> >From my reading of the blobfile docs, I think the "File" object
> defined in it is *not* a schema field, such as the
> one you use from megrok.form. These things are different things
> altogether, even though they're both called file.
> blobfile tries to make its File object compatible with the file object
> stored by the zope.app.file package. This is the
> implementation of an object that *stores* the file data, not the field
> that appears in the schema. From my cursory browsing
> through z3c.blobfile it doesn't implement such a file field.
> So, concept involved:
> * the File field in a schema
> * the actual object that ends up on your Python object, a File object
> (altogether different, just same name). This stores your
>   file in some way, by default in the ZODB, but now we want to use the
> blob version.
> * the widget that displays this field in a form.
> I think unfortunately some custom work seems necessary to hook this
> up. megrok.form uses collective.namedfile for its file upload widget.
> Collective namedfile defines a field and widget for the file. Glancing
> at it, I don't think it's much code, but we do need:
> * a special 'BlobFile' field that stores the information in the ZODB
> * probably a BlobNamedFile storage object that subclasses from the
> existing blobfile File object, but adds a filename (which the named
> file bits need)
> * a new BlobNamedFileWidget widget  that subclasses NamedFileWidget
> and creates a BlobNamedFile instead of a
>   NamedFile. With a few tweaks to collective.namedfile we could make
> this widget subclass really minimal, just introducing
>   a file object factory in it or looking up some utility or adapter to
> configure it, but even without that, it's going to be short.
> I expect that all this is probably a bit intimidating for you to get
> done yourself, but luckily there's help. I think this might make for a
> good addition to megrok.form, which we're interested in expanding. I
> think it makes sense for us to add blob file support in there along
> the lines of what I sketched out above. Please join us in grok-dev and
> we'll try to work it out with you. To start this off, I've cc-ed it
> into that list as well as the developer of megrok.form.
> Regards,
> Martijn

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