def etag_response_processor(page, request, response):
    etag = page.etag(request)
    if etag is not None:
        response['ETag'] = '"' + etag + '"'
Response processor to set an etag header on outgoing responses.
dataset/ETHPy150Open feincms/feincms/feincms/module/page/processors.py/etag_response_processor