add NPROC for communication with updater

lib/nproc.js

@@ -0,0 +1,85 @@
+const net = require('net');
+// TODO: must change to read by env
+const API_KEY = Buffer.from('AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA');
+
+function frame(msgType, topicStr, bodyBuf) {
+  const topic = Buffer.from(topicStr);
+  const payloadLen = 1 + 2 + 4 + topic.length + bodyBuf.length;
+  const totalBytes = payloadLen + 32;
+
+  const buf = Buffer.alloc(4 + payloadLen + 32);
+  buf.writeUInt32BE(totalBytes, 0);
+  buf.writeUInt8(msgType, 4);
+  buf.writeUInt16BE(topic.length, 5);
+  buf.writeUInt32BE(bodyBuf.length, 7);
+  topic.copy(buf, 11);
+  bodyBuf.copy(buf, 11 + topic.length);
+  API_KEY.copy(buf, 4 + payloadLen);
+  return buf;
+}
+
+class NprocClient {
+
+  MESSAGE_TYPE = {
+    SUB: 1,
+    UNSUB: 2,
+    PUB: 3,
+    PING: 4
+  };
+
+  constructor(
+    addr,
+    onConnect,
+    onClose
+  ){
+    let _addr = addr.toString().split(":");
+
+    let host = _addr[0];
+    let port = parseInt(_addr[1]);
+
+    this.client = net.createConnection({
+      host: host,
+      port: port
+    }, () => onConnect());
+    this.history = [];
+    this.acc = Buffer.alloc(0);
+    this.client.on('data', chunk => {
+      this.acc = Buffer.concat([this.acc, chunk]);
+      while(this.acc.length >= 4){
+        const total = this.acc.readUInt32BE(0);
+        if (this.acc.length < 4 + total) break;
+        const frm = this.acc.subarray(0, 4 + total);
+        this.acc = this.acc.subarray(4 + total);
+
+        const msgType = frm.readUInt8(4);
+        const topicLen = frm.readUInt16BE(5);
+        const bodyLen = frm.readUInt32BE(7);
+        const topic = frm.subarray(11, 11 + topicLen).toString();
+        const body = frm.subarray(11 + topicLen, 11 + topicLen + bodyLen);
+
+        let res = {
+          msgType, topic, body: body.toString()
+        };
+        console.log(`get msg! ${JSON.stringify(res)}`);
+
+        this.history.push(res);
+      }
+    });
+    this.client.on('close', () => onClose());
+  }
+
+  subscribe(topic){
+    this.client.write(frame(this.MESSAGE_TYPE.SUB, topic, Buffer.alloc(0)));
+  }
+
+  publish(topic, payload){
+    this.client.write(frame(this.MESSAGE_TYPE.PUB, topic, Buffer.from(JSON.stringify(payload))));
+  }
+
+  // TODO: unsub
+  // TODO: ping
+}
+
+module.exports = {
+  NprocClient
+};