Code change:
value MUST be less than or equal to the value provided by the application server. <ins> 6.3. A push message that has been stored by the push service can be replaced with new content.  If the user agent is offline during the time that the push messages are sent, updating a push message avoids the situation where obsolete or redundant messages are sent to the user agent. Only push messages that have been assigned a topic can be updated.  A push message with a topic replaces any outstanding push message with an identical topic. A push message topic is a string.  A topic is carried in a Topic header field.  A topic is used to correlate push messages sent to the same subscription, it does not convey any other semantics. The grammar for the Topic header field uses the "token" and "quoted- string" rules defined in RFC7230. Any double quotes from the "quoted-string" form are removed before comparing topics for equality. For use with this protocol, the Topic header field MUST be restricted to no more than 32 characters from the URL- and filename-safe base64 set [RFC4648].  A push service that receives a request with a Token header field that does not meet these constraints SHOULD return an HTTP 400 (Bad Request) status code to an application server. A push message request creates a new push message resource, but simultaneously deletes any existing message resource that has a matching topic.  In effect, the information that is stored for the push message is updated, but a new resource is created to avoid problems with in flight acknowledgments for the old message.  The push service MAY suppress acknowledgement receipts for the replaced message. This mechanism doesn't allow for stored push messages to be deleted. An application server can remove a push message using a DELETE request to the push message URL. A push message with a topic that has a zero or absent time-to-live will cause a stored message with the same topic to be removed as well as not being stored itself, but the push service will attempt to forward the updated message to the user agent. A push message with a topic that is not shared by an outstanding message to the same subscription is stored or delivered as normal. The value of the Topic header field MUST NOT be forwarded to user agents.  Its value is not encrypted or authenticated. </ins> 7. A user agent requests the delivery of new push messages by making a

Related discussion:
text: Updated based on feedback from NAME Note that I haven't changed the name. Not sure that we have consensus on that yet.
Conversation starts : How does the PS know that AS can accept more receipts, and how does it know a receipt has been accepted by the AS ?
Two-Pipe model a la mode de TIP? URL
NAME started on HTTPbis
Costin : we discussed my concerns on flow control for push promises, and I think it's reasonable to have them addressed either as part of http2 or as a separate document. I'm closing this issue for webpush since it's no longer actionable - NAME - re-open if you want to track for "futures". I'll tag appropriately. +1 - we discussed my concerns on flow control for push promises, and I think it's reasonable to have them addressed either as part of http2 or as a separate document. Other than that I think it's reasonable and stable base - extensions and features can be added on top of it. Costin Richard Maher wrote: >
+1 But I'm not sure we can support the mode that Martin described, so I think we may take advantage of "PS MAY return a new receipt subscription if it is unable to reuse". Buffering and flow control are complicated - the choice is between dropping receipts or sending them to a different DC. I haven't checked, but I think there is no guarantee on saving receipts if AS doesn't have enough ingress capacity. One question for HTTP/2 experts: I assumed the receipt promises are subject to normal 'max concurrent streams' ( and this will be the main mechanism to do flow control/balancing from PS to AS). However I see rfc7540: ... " Note: The client never sends a frame with the END_STREAM flag for a server push." How does the PS know that AS can accept more receipts, and how does it know a receipt has been accepted by the AS ? Costin Brian Raymor wrote: >