Host and connect

Host and connect

🚦 The icon in the chat header

One glyph and one word, always there, so you never have to open Setup to know where you stand:

⚪	offline	nothing running
🟡	starting	a host or a connect is being opened
🟢	hosting	this window is serving a room
🔵	connected	a client, with its device
🟠	reconnecting	the link dropped and it is trying again
🔴	lost	the link went away and nothing is retrying

The transcript still says what happened ("Disconnected: …", "Paired with …"); the header says where you stand now, and a line above the message box carries anything the app needs to say — tap it to copy it. A red icon is worth a look at Stop: pressing it and hosting again is the fastest reset.

⚡ In a hurry

cthrone host                 # on the device that serves (port 8080)
cthrone connect 192.168.1.5  # on the other one

The host prints its address. Compare the six-digit code on both screens, accept on the host, and type.

flowchart LR
    H["🟢 cthrone host<br/>prints an address"] -->|"websocket · NATS · Bluetooth"| C["🔵 cthrone connect"]
    C --> K["🔢 six-digit code<br/>on both screens"]
    K -->|✅ accept on the host| M["💬 type"]
    K -->|❌ refuse| X["🚫 no session"]

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The default transport needs nothing but the two binaries: one device hosts, the other connects.

On the device that hosts

cthrone host

It serves on port 8080 on every interface, over https/wss by default. Useful flags:

Flag	What it does
-p, --port	the port (default 8080)
--host	bind one interface instead of every one
--name	the device name the peer sees, and the name a scan reports
--no-tls	plaintext ws:// — only for a v0.6.0 peer or a network you trust

A host is a room: every device that joins sees the messages of every other, with the sender named. There is no pairing of two devices in private.

On the device that connects

cthrone connect 192.168.1.20

or, if you scanned first, the address the scan printed. The client dials wss:// and pins the host's self-signed certificate on first contact.

What happens on first contact

1. Both screens show a six-digit code, derived from the two ephemeral keys.
2. The host asks whether to accept the device; the code is what you compare.
3. Answer Accept, and the device's key is pinned under its name. Answer Refuse — or let the question expire — and nothing is recorded.

The code is the whole defence against a machine in the middle, and it only works if the two numbers match. Pairing and peers covers what is stored and how to undo it.

Finding the host

cthrone scan              # walks the /24 the default route uses
cthrone scan --subnet 192.168.1.0/24
cthrone scan --all-subnets

A scan reports devices that announce themselves and hosts that answer on the chat port. It cannot cross a subnet, a NAT or a router that isolates its clients — a device on another Wi-Fi of the same modem is found after it has been connected to once, because the host then also announces itself to that address by unicast. See Finding devices across networks, and NATS when the network isolates its own clients.

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