It’s often desired to quickly export data in a generic method that takes little coding. There are already some solutions for this. I didn’t like any however as they ignore many to many fields. One could argue a more robust system might be needed when handling more complex reports with gui sql query builders and such. Screw that here’s a hack to get the job 95% done.
I want to check off fields in Django Admin’s model list display. Then make an action to make a spreadsheet report, not some crap csv.
Here is my hack function to take a model and query set and spit out an .xls file
def admin_export_xls(request, app, model, qs=None):
""" Exports a model to xls.
qs: optional queryset if only exporting some data"""
mc = ContentType.objects.get(app_label=app, model=model).model_class()
wb = xlwt.Workbook()
ws = wb.add_sheet(unicode(mc._meta.verbose_name_plural))
#for i, f in enumerate(mc._meta.fields):
# ws.write(0,i, f.name)
# Lets get all fields names, even m2m
for i, field in enumerate(mc._meta.get_all_field_names()):
ws.write(0,i, field)
if not qs:
qs = mc.objects.all()
for ri, row in enumerate(qs):
for ci, f in enumerate(mc._meta.get_all_field_names()):
try:
# terrible way to detect m2m manager
if unicode(getattr(row, f))[1:51] == 'django.db.models.fields.related.ManyRelatedManager':
# If it's a M2M relationship, serialize it and throw it in one cell.
value = ""
for item in getattr(row, f).all():
value += unicode(item) + ", "
value = value[:-2]
ws.write(ri+1, ci, value)
else:
ws.write(ri+1, ci, unicode(getattr(row, f)))
except:
# happens when the m2m is has an appended _set. This is a hack that works sometimes, it sucks I know
try:
f += "_set"
value = ""
for item in getattr(row, f).all():
value += unicode(item) + ", "
value = value[:-2]
ws.write(ri+1, ci, value)
except:
ws.write(ri+1, ci, "")
fd, fn = tempfile.mkstemp()
os.close(fd)
wb.save(fn)
fh = open(fn, 'rb')
resp = fh.read()
fh.close()
response = HttpResponse(resp, mimetype='application/ms-excel')
response['Content-Disposition'] = 'attachment; filename=%s.xls' %
(unicode(mc._meta.verbose_name_plural),)
return response
That will serialize manytomany fields to comma separated fields all in one cell. Next in you need an admin aciton.
def export_selected_objects(modeladmin, request, queryset):
app = queryset[0]._meta.app_label
model = queryset[0]._meta.module_name
return admin_export_xls(request, app, model, queryset)
export_selected_objects.short_description = "Export selected items to XLS"
You can see I made mine global. It works on all models. For this to work well you need to make sure your unicode representations of your models are useful. The most common thing I run into are phone numbers. A person can have unlimited phone numbers. The end user will assume a report of people will include this. I make my number’s unicode something like “Cell: 555-555-5555”.
Of course this code isn’t perfect and there are many times a more robust solution will be needed. What if you want a report of companies with contacts at the company and phone numbers of each contact. At that point you need to generate a query that can get such data and that’s going to take some gross gui query builder program or custom reports by you the developer.
Technology Against You 