[APLO-99] Support a `browser-end:false` option on a `SUBSCRIBE` frame to allow a Queue browser to wait for new messages instead of closing the subscription

• Type: New Feature
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.0-beta6
• Component/s: apollo-broker, apollo-stomp
• Assignee: Hiram R. Chirino
• Reporter: Hiram R. Chirino
• Created: 05/Dec/11 23:25
• Updated: 05/Dec/11 23:42
• Resolved: 05/Dec/11 23:42

Description

A normal subscription on a queue will consume messages so that no other
subscription will get a copy of the message. If you want to browse all the
messages on a queue in a non-destructive fashion, you can create browsing
subscription. Browsing subscriptions also works with durable subscriptions
since they are backed by a queue. To make a a browsing subscription, just add the
`browser:true` header to the `SUBSCRIBE` frame. For example:

SUBSCRIBE
id:mysub
browser:true
destination:/queue/foo

^@

Once the broker sends a browsing subscription the last message in the queue,
it will send the subscription a special "end of browse" message to indicate
browsing has completed and that the subscription should not expect any more
messages. The "end of browse" message will have a `browser:end` header set.
Example:

MESSAGE
subscription:mysub
destination:
message-id:
browser:end

^@

If you want the browsing subscription to remain active and continue to
listen for message once the last message on the queue is reached, you
should add the `browser-end:false` header to the `SUBSCRIBE` frame. When
the `browser-end:false` header is added the subscription will not be
sent the "end of browse" message previously described.