89 lines
2.9 KiB
Markdown
89 lines
2.9 KiB
Markdown
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This signaling server defines a very simple protocol to allow the establishing
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of a WebRTC connection between clients and devices. It should only be used for
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development purposes or for very simple applications with no security, privacy
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or scalability requirements.
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Serious applications should build their own signaling server, implementing the
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protocol exactly as defined below (any modifications would likely require
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modifications to the client and/or device which will then not be maintained by
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the cuttlefish team).
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The signaling server MUST expose two (different) websocket endpoints:
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* wss://<addr>/register_device
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* wss://<addr>/connect_client
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Additional endpoints are allowed and are up to the specific applications.
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Extending the messages below with additional fields should be done with extreme
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care, prefixing the field names with an applciation specific word is strongly
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recommended. The same holds true for creating new message types.
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Devices connect to the *register_device* endpoint and send these types of
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messages:
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* {"message_type": "register", "device_id": <String>, "device_info": <Any>}
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* {"message_type": "forward", "client_id": <Integer>, "payload": <Any>}
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The server sends the device these types of messages:
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* {"message_type": "config", "ice_servers": <Array of IceServer dictionaries>,
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...}
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* {"message_type": "client_msg", "client_id": <Integer>, "payload": <Any>}
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* {"message_type": "client_disconnected", "client_id": <Integer>}
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* {"error": <String>}
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Clients connect to the *connect_client* endpoint and send these types of
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messages:
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* {"message_type": "connect", "device_id": <String>}
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* {"message_type": "forward", "payload": <Any>}
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The server sends the clients these types of messages:
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* {"message_type": "config", "ice_servers": <Array of IceServer dictionaries>,
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...}
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* {"message_type": "device_info", "device_info": <Any>}
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* {"message_type": "device_msg", "payload": <Any>}
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* {"error": <String>}
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A typical application flow looks like this:
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* **Device** connects to *register_device*
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* **Device** sends **register** message
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* **Server** sends **config** message to **Device**
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* **Client** connects to *connect_client*
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* **Client** sends **connect** message
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* **Server** sends **config** message to **Client**
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* **Server** sends **device_info** message to **Client**
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* **Client** sends **forward** message
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* **Server** sends **client_msg** message to **Device** (at this point the
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device knows about the client and cand send **forward** messages intended for
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it)
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* **Device** sends **forward** message
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* **Server** sends **device_msg** message to client
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* ...
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In an alternative flow, not supported by this implementation but allowed by the
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design, the **Client** connects first and only receives a **config** message
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from the **Server**, only after the **Device** has sent the **register** message
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the **Server** sends the **device_info** messaage to the **Client**.
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