Django csv export

Question

I have the following csv export function to export model information in csv file. But I am trying to figure out how to show outputs from functions in the model. So the csv export function shows all the fields in the model (fields in the table) but not outputs from functions in the model..

So if I have the following:

def avg_tag(self, obj):
    bids = Bid.objects.active(user=obj.user.id)
    return bids.aggregate(average_price=Avg('list_price'))['average_price']

in the model

It does not get the output from that function.

Here is the csv export function action:

def export_select_fields_csv_action(description="Export selected objects",
                     fields=None, exclude=None, header=True):
def export_as_csv(modeladmin, request, queryset):
    """
    Generic csv export admin action.
    based on http://djangosnippets.org/snippets/1697/
    """
    opts = modeladmin.model._meta
    field_names = [field.name for field in opts.fields]
    labels = []
    if exclude:
        field_names = [v for v in field_names if v not in exclude]
    elif fields:
        field_names = [k for k, v in fields if k in field_names]
        labels = [v for k, v in fields if k in field_names]

    response = HttpResponse(mimetype='text/csv')
    response['Content-Disposition'] = ('attachment; filename=%s.csv'
        % unicode(opts).replace('.', '_'))

    writer = csv.writer(response)
    if header:
        if labels:
            writer.writerow(labels)
        else:
            writer.writerow(field_names)
    for obj in queryset:
        writer.writerow([unicode(getattr(obj, field)).encode('utf-8')
            for field in field_names])
    return response
export_as_csv.short_description = description
return export_as_csv

How can I change the function above so that the outputs from functions in the model are outputted in the csv? Thanks!

Aidan Ewen · Answer 1 · 2013-02-22T21:34:18.807

1

I guess edit the bit where you loop through the queryset and just add it on the end -

for obj in queryset:
    writer.writerow([unicode(getattr(obj, field)).encode('utf-8')
        for field in field_names] + "," + obj.avg_tag())

You can do something similar to add the heading you want -

if header:
    if labels:
        writer.writerow(labels + "," + "Average Tag")
    else:
        writer.writerow(field_names + "," + "Average Tag"))

UPDATE

It's going to be a bit difficult getting fields and methods because you'll find that there are lots of methods on your model which you didn't define (and you probably don't want in your csv). There's no easy way of differentiating which you want and which you don't.

Have a play with the following to see what's in there -

import inspect
obj = modeladmin.model()
methods = [a for a in dir(modeladmin.model) if inspect.ismethod(getattr(obj, a))]
for method in methods:
    print str(method)

I certainly can't see an elegant way of doing this (or in fact anyway) - I think you're going to have to actually specify each method.

edited Feb 22 '13 at 21:34

answered Feb 22 '13 at 19:27

Aidan Ewen

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Gah! Beat me to the punch :) – Brandon Taylor Feb 22 '13 at 19:28
@Brandon - am I playing dirty posting in stages? ;) – Aidan Ewen Feb 22 '13 at 19:33
Haha. Not at all. I've just been on a Stack Overflow rampage of late. – Brandon Taylor Feb 22 '13 at 19:34
Yeah me too. Think I'm about to get busy again though - so probably won't be me racing you to the post for a bit.. – Aidan Ewen Feb 22 '13 at 20:19
what if I want to do this for all the functions in the model not only avg_tag? I want to pass in a field name that could be an actual field or a function name. How can I output the value for that entity that could be an actual field or function? thanks. – Chris Hansen Feb 22 '13 at 20:21
See: http://stackoverflow.com/questions/191010/how-to-get-a-complete-list-of-objects-methods-and-attributes – Brandon Taylor Feb 22 '13 at 20:24
I can't see an easy way of doing this - I've added an update anyway. – Aidan Ewen Feb 22 '13 at 21:34

Django csv export

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