bluetooth

BlueZ: adapter power, discovery, connected, paired and discovered devices, and pairing prompts.

list {
    items = mantle.bluetooth:map(function(bluetooth)
        return bluetooth.connected_devices
    end),
    key = function(device) return device.mac end,
    each = function(device)
        local battery = device.battery and string.format(" %d%%", device.battery) or ""
        return rect {
            on_click = function() mantle.bluetooth:disconnect(device.mac) end,
            children = { text { content = device.name .. battery } },
        }
    end,
}

State

mantle.bluetooth:get() returns BluetoothState, nil before the first push. A field marked ? may be absent.

ConnectedDevice

DeviceAction

What the shell is doing to a device, as its busy.

One of "pairing", "connecting", "disconnecting".

DeviceCategory

A device’s kind, read from its BlueZ class of device.

DiscoveredDevice

PairedDevice

PairingKind

What a pairing_request asks; see PairingRequest.kind.

One of "confirm", "authorize", "service", "display", "pin_entry", "passkey_entry".

PairingRequest

What the pairing agent is asking the user.

Actions

Call each as mantle.bluetooth:<action>(arguments...); ? marks an argument you may omit.

Backend

BlueZ on the system bus.

How do I…

Pair a new device

Scan, pair a discovered device, then answer the pairing_request it raises. A "display" request only shows a code to type on the device. Confirm, authorize and service requests take a yes or no; a yes within 750 ms of the prompt appearing is ignored. For "pin_entry" or "passkey_entry", submit a masked field with name = request.id .. "/" .. request.mac. The PIN must have 1–16 ASCII letters or digits; a passkey must have 1–6 digits (0–999999). A stale id or device is refused. Use No to decline an entry request. The typed value never enters Lua:

local function answer(accept)
    return function()
        local bluetooth = mantle.bluetooth:get()
        local request = bluetooth and bluetooth.pairing_request
        if request then
            mantle.bluetooth:answer_pairing(request.mac, accept)
        end
    end
end

local function button(label, on_click, visible)
    return rect { padding = 4, on_click = on_click, visible = visible, children = { text { content = label } } }
end

return column {
    spacing = 6,
    children = {
        button("Scan", function() mantle.bluetooth:start_discovery() end),
        list {
            items = mantle.bluetooth:map(function(bluetooth)
                return bluetooth.discovered_devices
            end),
            key = function(device) return device.mac end,
            each = function(device)
                return button(device.name ~= "" and device.name or device.mac, function()
                    mantle.bluetooth:pair(device.mac)
                end)
            end,
        },
        text {
            content = mantle.bluetooth:map(function(bluetooth)
                local request = bluetooth.pairing_request
                if request == nil then
                    return ""
                end
                return string.format("%s (%s) %s", request.name, request.kind, request.code or "")
            end, ""),
        },
        row {
            visible = mantle.bluetooth:map(function(bluetooth)
                local request = bluetooth.pairing_request
                return request ~= nil and
                    (request.kind == "confirm" or request.kind == "authorize" or request.kind == "service")
            end, false),
            spacing = 6,
            children = { button("Yes", answer(true)), button("No", answer(false)) },
        },
        textfield {
            visible = mantle.bluetooth:map(function(bluetooth)
                local request = bluetooth.pairing_request
                return request ~= nil and (request.kind == "pin_entry" or request.kind == "passkey_entry")
            end, false),
            width = "fill",
            height = 28,
            placeholder = "PIN or passkey",
            accessible_name = "Bluetooth PIN or passkey",
            secure_submit = mantle.bluetooth:map(function(bluetooth)
                local request = bluetooth.pairing_request
                if request and (request.kind == "pin_entry" or request.kind == "passkey_entry") then
                    return { capability = "bluetooth", action = "pair", name = request.id .. "/" .. request.mac }
                end
            end),
        },
        button("No", answer(false), mantle.bluetooth:map(function(bluetooth)
            local request = bluetooth.pairing_request
            return request ~= nil and (request.kind == "pin_entry" or request.kind == "passkey_entry")
        end, false)),
    },
}

Gotchas

Source: supervisor/src/capabilities/bluetooth/