Monitor Featre: The ability to synchronize student and teacher screens (screen share)

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(the teacher's screen can be displayed in real time for all students (acceptable delay TBD)

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To accomplish this we have several options:

• Special Chrome Plugin (usually requires an internet hosted site to host the relay)
• Tab Sharing (will be limited to tab based sharing within a browser) using the tab API
• Use RTCPeerConnection and getUserMedia with the chromeMediaSource constraint.

I believe we can utilize the RTCPeerConnection to do the screen sharing. I need to quickly evaluate how to host the services for STUN and TURN and ICE, if they are needed.

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I think we can get away without needing STUN, TURN, and ICE for the purposes of sharing within a local network. I need to verify this. I'll start using the simpl1/screencast demo. It's only on a local connection, so I'll jimmy this to work with any connected peer.

I spent some time looking at PeerJS and SimpleWebRTC. PeerJS looks pretty good. We can definitely use it for file sharing.

We are going to need a secure endpoint serving https. I'll need to generate self signed certs.

[truedat101]

Here are some alternative approaches. I may decide it is easier to stick with tab sharing: http://www.html5rocks.com/en/tutorials/streaming/screenshare/

to get the point across. See the above for more details.

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I need to come up with something that can be viewed on HTML5 ... I'd prefer not requiring special players and not with enormous network load. Thinking.

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Ok, so number 1 choice in the solution here using webrtc is too difficult at the moment for a number of reasons, starting with the set up, and then the web socket security. I need to spend some time reading those specs and review a sensible approach to signaling. I think I can leverage socket.io (which I have in my setup). Todo later.

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To quickly get off the ground, there are three options:

1) windows: tightvnc 2) Linux: novnc + x11vnc (this is what openstack uses) 3) guacamole:

See: http://jorgenmodin.net/index_html/archive/2010/11/30/novnc-vnc-screen-sharing-in-the-web-browser

[truedat101]

I'm using x11vnc (on linux) + novnc.

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A couple things on the setup:

x11vnc MUST have a password, or else you'll be insecure, and remote connection doesn't pass through. Do:

• x11vnc -storepasswd
• then run it: x11vnc -rfbauth ~/.vnc/passwd

noVNC has some special configuration as well:

• Generate a self signed cert (ok, this isn't secure): openssl req -new -x509 -days 365 -nodes -out self.pem -keyout self.pem
• /utils/launch.sh --cert self.pem vnc 192.168.1.13:5900

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Note, the final URL you get is : http://192.168.1.13:6080/vnc.html?host=mintyfresh&port=6080

It will have a hostname supplied. I don't know whether that makes a difference, probably for security, though we aren't running a proper DNS.

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So just need to make this a configuration option in the epochedu, to substitute the teacher IP address

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Also, will need to script the startup. For a windows-based demo system, I'll need to provide an alternate setup. For now, I'll only be supporting this linux demo system.

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This is a new feature, it's not what we thought. #1 is the screen sharing. This one is more like a security camera ... it will cycle through screens of each student's screen.

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Above is the feature in a nutshell. Left out is the detail about how the screens rotate. They just switch on the screen between users. Somehow we need to update the text to display which user.

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I've completed the base monitor app feature. Need to just add the dialog for setting a timeout.

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This is officially done. The GUI took a lot longer than expected to just get the dialog + input going. There is some bizarre quirk I suspect with jqmodal and caching of data in the input fields. Fixed a bug with the handling of "teacher" nick so that a teacher is skipped in the process of doing session monitor (don't monitor yourself). Good news with this approach is the plug doesn't do all the work, it's the browser.

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The only thing that was left was cleaning up the sharing and the monitoring dialog. Done.