*Wip* Run proxy app through electron

src/proxy/nativemessage.ts

@@ -0,0 +1,84 @@
+/* tslint:disable:no-console */
+import IPC from './ipc';
+
+// Mostly based on the example from MDN,
+// https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/Native_messaging
+export default class NativeMessage {
+    ipc: IPC;
+
+    constructor(ipc: IPC) {
+        this.ipc = ipc;
+    }
+
+    send(message: object) {
+        const messageBuffer = Buffer.from(JSON.stringify(message));
+
+        const headerBuffer = Buffer.alloc(4);
+        headerBuffer.writeUInt32LE(messageBuffer.length, 0);
+
+        process.stdout.write(Buffer.concat([headerBuffer, messageBuffer]));
+    }
+
+    listen() {
+        let payloadSize: number = null;
+
+        // A queue to store the chunks as we read them from stdin.
+        // This queue can be flushed when `payloadSize` data has been read
+        const chunks: any = [];
+
+        // Only read the size once for each payload
+        const sizeHasBeenRead = () => Boolean(payloadSize);
+
+        // All the data has been read, reset everything for the next message
+        const flushChunksQueue = () => {
+            payloadSize = null;
+            chunks.splice(0);
+        };
+
+        const processData = () => {
+            // Create one big buffer with all all the chunks
+            const stringData = Buffer.concat(chunks);
+            console.error(stringData);
+
+            // The browser will emit the size as a header of the payload,
+            // if it hasn't been read yet, do it.
+            // The next time we'll need to read the payload size is when all of the data
+            // of the current payload has been read (ie. data.length >= payloadSize + 4)
+            if (!sizeHasBeenRead()) {
+                payloadSize = stringData.readUInt32LE(0);
+            }
+
+            // If the data we have read so far is >= to the size advertised in the header,
+            // it means we have all of the data sent.
+            // We add 4 here because that's the size of the bytes that old the payloadSize
+            if (stringData.length >= payloadSize + 4) {
+                // Remove the header
+                const contentWithoutSize = stringData
+                    .slice(4, payloadSize + 4)
+                    .toString();
+
+                // Reset the read size and the queued chunks
+                flushChunksQueue();
+
+                const json = JSON.parse(contentWithoutSize);
+
+                // Forward to desktop application
+                this.ipc.send(json);
+            }
+        };
+
+        process.stdin.on('readable', () => {
+            // A temporary variable holding the nodejs.Buffer of each
+            // chunk of data read off stdin
+            let chunk = null;
+
+            // Read all of the available data
+            // tslint:disable-next-line:no-conditional-assignment
+            while ((chunk = process.stdin.read()) !== null) {
+                chunks.push(chunk);
+            }
+
+            processData();
+        });
+    }
+}