add SSDP broadcast utility for connecting remote Bambu printers to a local slicer

mods/bambu/ssdp.js

@@ -0,0 +1,89 @@
+/**
+ * Utility to make a Bambu printer appear on the local subnet
+ * so that the Bambu Network Plugin can find it. The intended
+ * use case is where a printer is on another subnet but reachable
+ * directly (routable) and Bambu Studio / Orca Slicer can't find
+ * it because SSDP broadcasts do not cross subnets.
+ * 
+ * When this process is run from the command line, it should appear
+ * under the slicer Devices tab when "+" is selected.
+ */
+
+const [ name, host, serial ] = process.argv.slice(2);
+
+if (!(name && host && serial)) {
+    console.log('usage: ssdp [host] [serial-no]');
+    return process.exit(0);
+}
+
+console.log([
+    `Broadcasting Bambu Printer`,
+    `Name: ${name}`,
+    `Host: ${host}`,
+    `Serial: ${serial}`,
+].join('\n'));
+
+const dgram = require("dgram");
+
+// SSDP parameters
+const SSDP_ADDRESS = "239.255.255.250";
+const SSDP_PORT = 1900;
+
+// Create a UDP socket
+const socket = dgram.createSocket("udp4");
+
+// SSDP discovery message
+const ssdpMessage = `
+NOTIFY * HTTP/1.1
+HOST: ${SSDP_ADDRESS}:${SSDP_PORT}
+Server: UPnP/1.0
+Location: ${host}
+NT: urn:bambulab-com:device:3dprinter:1
+USN: ${serial}
+Cache-Control: max-age=1800
+DevModel.bambu.com: C11
+DevName.bambu.com: ${name}
+DevSignal.bambu.com: -66
+DevConnect.bambu.com: lan
+DevBind.bambu.com: free
+Devseclink.bambu.com: secure
+DevVersion.bambu.com: 01.07.00.00
+DevCap.bambu.com: 1`
+.trim().split('\n').join("\r\n") + "\r\n\r\n";
+
+function send(socket, addr, port) {
+
+    // Send the SSDP broadcast
+    socket.send(
+        ssdpMessage,
+        0,
+        ssdpMessage.length,
+        port,
+        addr,
+        (err) => {
+            if (err) {
+                console.error("Error sending SSDP broadcast:", err);
+            } else {
+                console.log(`>>>>>>>>>>>>>>>>> ${addr} : ${port}`);
+            }
+        }
+    );
+}
+
+socket.on("error", error => console.log({ error }));
+
+// Handle responses from devices
+socket.on("message", (msg, rinfo) => {
+    // console.log(`<<<<<<<<<<<<<<<<< ${rinfo.address} : ${rinfo.port}`);
+    // console.log(msg.toString().trim());
+    // console.log('<<<<<<<<<<<<<<<<<');
+});
+
+// Bind the socket and join the multicast group
+socket.bind(1900, () => {
+    socket.addMembership(SSDP_ADDRESS); // Join the SSDP multicast group
+    setInterval(() => send(socket, '239.255.255.250', 2021), 1000);
+    // setInterval(() => send(socket, '239.255.255.250', 1990), 2000);
+    // setInterval(() => send(socket, '255.255.255.255', 2021), 2000);
+});
+