latch=true publisher in rosjs

[rctoris]

Migrated from https://github.com/RobotWebTools/rosjs/issues/31

@jihoonl :
Can rosjs set Publisher(latch=True) ?

[rctoris]

I think the rosbridge protocol itself would have to be modified to support this.

[odestcj]

Can you elaborate? I thought this was an issue with the current implementation of rosbridge_server, not v2 of the protocol?

[rctoris]

Other direction -- to create a latched topic, the client has to specify it somewhere in the protocol. rosbridge has to be responsible for this since a client is never notified when someone subscribes to their topic.

[RainCT]

Hi jihoonl,

Not sure why you're referencing issue #1. Just to clarify, my (already merged) patch fixes latched subscribers, it has nothing to do with publishers.

[jihoonl]

Yeah I have just noticed that after referencing the pull request. I will just keep the reference to remind that latch subscription is now supported and only remaining thing is supporting latch publisher.

[jihoonl]

Resolved by the pull requests