Ok for those not watching the discussion on #stratum on IRC, I believe we have a final protocol for mining resume which should not break any clients or pools.
It was decided that the parameters could include both the user agent and the session ID as the first and second parameters. If this fails cgminer/other clients should resort to sending blank set of parameters as previously.
The session Id, it was decided, would be encoded along with the notification message "mining.notify" as a member of the 3 deep array parameters returned for "result" by the pool.
See the following for an example of an initial connect followed by a reconnect.
[2013-02-25 10:30:58] SEND: {"id": 0, "method": "mining.subscribe", "params": ["cgminer/2.10.5"]}
[2013-02-25 10:30:58] RECVD: {"result": [[["mining.notify", "02000000b507a8fd1ea2b7d9cdec867086f6935228aba1540154f83930377ea5a2e37108"], ["mining.set_difficulty", "02000000b507a8fd1ea2b7d9cdec867086f6935228aba1540154f83930377ea5a2e371082"]], "02000000", 4], "id": 0, "error": null}
[2013-02-25 10:30:58] Pool 0 stratum session id: 02000000b507a8fd1ea2b7d9cdec867086f6935228aba1540154f83930377ea5a2e37108
[2013-02-25 10:30:58] Pool 0 confirmed mining.subscribe with extranonce1 02000000 extran2size 4
[2013-02-25 10:33:00] SEND: {"id": 2, "method": "mining.subscribe", "params": ["cgminer/2.10.5", "02000000b507a8fd1ea2b7d9cdec867086f6935228aba1540154f83930377ea5a2e37108"]}
[2013-02-25 10:33:00] RECVD: {"result": [[["mining.notify", "02000000c33cfaa37a964c2ba76c78b99dc170a1b1fe7a5fe025f72e89afba7fc6f23d0e"], ["mining.set_difficulty", "02000000c33cfaa37a964c2ba76c78b99dc170a1b1fe7a5fe025f72e89afba7fc6f23d0e2"]], "02000000", 4], "id": 2, "error": null}
[2013-02-25 10:33:00] Pool 0 stratum session id: 02000000c33cfaa37a964c2ba76c78b99dc170a1b1fe7a5fe025f72e89afba7fc6f23d0e
[2013-02-25 10:33:00] Pool 0 confirmed mining.subscribe with extranonce1 02000000 extran2size 4
Note the session ID has changed between the initial subscription and the resume, BUT the extranonce1 has remained the same. This tells the miner it can (re)submit shares before the disconnection.
Hopefully we will not need to revise this any further.
