// A list of: { // id: number; // path: string; // } where [id] is the [connectionId] (internal to Chrome) and [path] is the // OS' name for the device (e.g. "COM4"). interface Connection { id: string; path: string; } let connections: Connection[] = []; // A list of "ports", i.e. connected clients (such as web pages). Multiple web // pages can connect to our service: they all receive the same data. let ports = []; interface Message { type: string; data: string; id: string; } function byPath(path: string): Connection[] { return connections.filter((x) => x.path == path); } function byId(id: string): Connection[] { return connections.filter((x) => x.id == id); } function onReceive(data, id: string) { if (ports.length == 0) return; let view = new DataView(data); let decoder = new TextDecoder("utf-8"); let decodedString = decoder.decode(view); ports.forEach(port => port.postMessage(<Message>{ type: "serial", data: decodedString, id: id, })); } function findNewDevices() { chrome.serial.getDevices(function (serialPorts) { serialPorts.forEach(function (serialPort) { if (byPath(serialPort.path).length == 0 && serialPort.displayName == "mbed Serial Port") { chrome.serial.connect(serialPort.path, { bitrate: 115200 }, function (info) { // In case the [connect] operation takes more than five seconds... if (info && byPath(serialPort.path).length == 0) connections.push({ id: info.connectionId, path: serialPort.path }); }); } }); }); } function main() { // Register new clients in the [ports] global variable. chrome.runtime.onConnectExternal.addListener(function (port) { if (/^(micro:bit|touchdevelop|yelm|pxt|codemicrobit|codethemicrobit|pxt.microbit.org)$/.test(port.name)) { ports.push(port); port.onDisconnect.addListener(function () { ports = ports.filter(function (x) { return x != port }); }); } }); // When receiving data for one of the connections that we're tracking, forward // it to all connected clients. chrome.serial.onReceive.addListener(function (info) { if (byId(info.connectionId).length > 0) onReceive(info.data, info.connectionId); }); // When it looks like we've been disconnected, drop the corresponding // connection object from the [connections] global variable. chrome.serial.onReceiveError.addListener(function (info) { if (info.error == "system_error" || info.error == "disconnected" || info.error == "device_lost") connections = connections.filter((x) => x.id != info.connectionId); }); // Probe serial connections at regular intervals. In case we find an mbed port // we haven't yet connected to, connect to it. setInterval(findNewDevices, 5000); findNewDevices(); } document.addEventListener("DOMContentLoaded", main);