How to make file upload facultative with Deform and Colander?

Question

I would like to render a form containing a sequence of files, representing different images of a product. Providing files should be facultative, so the form should validate even in the absence of files. How can I do this ?

Here is the colander schema I use:

    import colander
    import deform
    from deform import Form
    from deform import ValidationFailure
    from deform.interfaces import FileUploadTempStore 


    tmpstore = FileUploadTempStore()

    class Image(colander.Schema):
        image = colander.SchemaNode(
            deform.FileData(),
            widget=deform.widget.FileUploadWidget(tmpstore)
            ) 

    class Images(colander.SequenceSchema):
        images = Image()

    class ProductSchema(colander.Schema):
        completename = colander.SchemaNode(colander.String(), title="Complete Name")

        description = colander.SchemaNode(colander.String(), 
                                 widget = deform.widget.TextAreaWidget())

        images = Images()


    schema = ProductSchema()
    form = Form(schema, buttons=("submit", ))

I tried to add a 'missing' argument like:

image = colander.SchemaNode(
        deform.FileData(),
        missing = ???
        widget=deform.widget.FileUploadWidget(tmpstore)
        )

I think I get something functional when

missing={'filename': None, 'uid':None}

But I'm really not sure it's the correct way to do it...

Thanks !

@Sentinel - Why *better*? This is a totally good question for SO, as those on Django and other framework... What was the point you were trying to do? (Honest question, I'm just trying to understand the logic) — mac, Jul 03 '11 at 15:44
@mac: if it's a good question, why don't you upvote it ? ;-) — ascobol, Jul 03 '11 at 15:49
@ascobol - +1 because you asked for it, but since I don't know anything about pylons, it's difficult for me to tell if you did your research well before posting the question (maybe there are a trillions other identical questions phrased differently on SO?). — mac, Jul 03 '11 at 15:53
@Sentinel: Mailing lists suck. They are often much slower than sites like SO, you often have to sign up first (and then receive mails about crap you don't care about), ... — ThiefMaster, Jul 04 '11 at 08:29

score 5 · Accepted Answer · answered Jul 04 '11 at 08:14

5

You might try "missing = colander.null".

answered Jul 04 '11 at 08:14

Chris McDonough

2,479
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How to make file upload facultative with Deform and Colander?

1 Answers1