I have created a binary field in my application and uploaded an xls file..  when downloading the file by clicking the binary field, the downloaded file extension is correct.. But when i download same file from the binary field using my code, it downloads with out any extension..
my code is :
return{
            'type' : 'ir.actions.act_url',
            'url' : '/web/content?model=res.company&field=my_binary_field&filename_field=my_file_name_field&id=' + str(company_id.id),
            'target': 'self',
        }
please help me to resolve