Export csv with web2py

In controller, forxample default.py:

def export_csv():
  
    animals = db().select(db.purchase_type.ALL)
    fname='hello.csv'
  
    return dict(animals1=animals, fname=fname)

In view: view/default folder:
make flie export_csv.csv:

{{
import cStringIO
stream=cStringIO.StringIO()
animals1.export_to_csv_file(stream)
response.headers['Content-Type']='application/vnd.ms-excel'
response.headers['Content-disposition']='attachment;filename='+fname
response.write(stream.getvalue(), escape=False)
}} 

Save to system file?, simple:
f = open('hello.csv', 'w')
f.write(stream.getvalue())
f.close()

Enjoy!

Download of a file-like python object in web2py

Copy from:http://thadeusb.com/weblog/2010/1/17/download_of_a_filelike_python_object_in_web2py

Here are a couple of ways to expose any python file-like object as download-able in a web2py controller.
You might want to do this if you have a generated pdf report, or allowing an export of the sites content.
From your controller, you can stream a large file by using the stream function of the response object.

return response.stream(filelikeobject, chunk_size=64*1024)

You might also want to set the content type of what you are returning, as well as a new disposition (filename).

def export():
    from gluon.contenttype import contenttype
    response.headers['Content-Type'] = contenttype('.csv')
    response.headers['Content-disposition'] = 'attachment; filename=%s_database.csv' % (
        request.now
    )
    import csv, cStringIO
    s = cStringIO.StringIO()
    db.export_to_csv_file(s, delimiter=',', quotechar='"', quoting=csv.QUOTE_NONNUMERIC)
    return s.getvalue()