Validator: one of several fields must be non-empty

[Jim Karsten]

This validator handles a case where at least one of several fields must be non-blank.

class IS_NOT_ALL_EMPTY(object):

"""Class representing a validator requiring at least one non-empty field in a set. """
def __init__(self, others,

error_message='Enter a value in at least one field'):
self.others = others
self.error_message = error_message

def __call__(self, value):

okay = (value, None)
error = (value, self.error_message)
# Return okay either the 'value', or one of self.others is not empty.
values = []
values.append(value)
values.extend(self.others)
empties = []
for v in values:

unused_v, empty = is_empty(v)
empties.append(empty)

# Example empties == [True, True, False]
# If one False exists, it's valid
if reduce(lambda x, y: x and y, empties):

return error

return okay

Usage:

db.define_table('contact',

Field('name', 'string'

requires=IS_NOT_ALL_EMPTY([request.vars.organization],

error_message='Enter a name or an organization'),

),
Field('organization', 'string',

requires=IS_NOT_ALL_EMPTY([request.vars.name],

error_message='Enter a name or an organization'),

))

Cheers,
Jim Karsten

[Anthony]

Cool. Maybe add a slice for this: http://www.web2pyslices.com/main/default/index

[pbreit]

Is there an ETA on Slices2?

[Bruno Rocha]

On Thu, Jun 9, 2011 at 8:29 PM, pbreit <pbreit...@gmail.com> wrote:

Is there an ETA on Slices2?

I've been working on designs and Martin Mulone in the mais app, but we both got busy woth other works, so it is frozen for a while.

Now the goal is to create a new web2pyslices which acts as a repository for apps, snippets and plugins, just like in rails where every project has a manifest file with a dependency list, than user can go to the command line and call the automatic installer (downloader-unpacker).

Thats on the way, but we do not have an ETA yet.

[David Marko]

This(or some modofication) could be part of web2py core, I think its quite general purpose validator ...

David

[Richard Vézina]

I found that all(empties) does the same of reduce(lambda x, y: x and y, empties)...

And I write this for the case when we want only one field to be filled for a group of fields passed to the validator :

class ONLY_ONE_CAN_BE_FILLED(object): 

    """Class representing a validator requiring at least one non-empty field in a set. """ 

    def __init__(

        self, 

        others, 

        error_message='Enter a value in at least one field'

        ): 

        self.others = others 

        self.error_message = error_message 

    def __call__(self, value): 

        okay = (value, None) 

        error = (value, self.error_message) 

        values = [] 

        values.append(value) 

        values.extend(self.others) 

        empties = [] 

        for v in values: 

            unused_v, empty = is_empty(v) 

            empties.append(empty) 

        if empties.count(False) == 1:

            return okay

        else:

            return error

Here how to use it :

requires=ONLY_ONE_CAN_BE_FILLED([request.vars.FIELD1,request.vars.FIELD2],error_message='Select only one field')

It's a bit counter intuitive to count the False, but since we only have is_empty()...

Richard