Add Command printer

src/client.ts

@@ -6,6 +6,7 @@ import Printer from './device/printer';
 import ConsolePrinterDriver from './printer-driver/console';
 import FilesystemPrinterDriver from './printer-driver/filesystem-printer';
 // import EscposPrinter from './printer-driver/escpos';
+import CommandPrinterDriver from './printer-driver/command-printer';
 // import StarPrinterDriver from './printer-driver/star';
 
 const readFile = promisify(fs.readFile);
@@ -101,6 +102,10 @@ export default async (
     // case 'escpos':
     //   printerDriver = new EscposPrinter();
     //   break;
+    case 'command':
+      // Example configuration for Command printer which uses a python script
+      printerDriver = new CommandPrinterDriver("python3", ['../python_print/main.py']);
+      break;
     // case 'star':
     //   printerDriver = new StarPrinterDriver();
     //   break;

src/printer-driver/command-printer.ts

@@ -0,0 +1,71 @@
+import { PrinterDriverInterface, PrintingResult } from '.';
+import fs from 'fs';
+import os from 'os';
+import path from 'path';
+import bitmapify from '../decoder/parser/bitmapify';
+import { spawn } from 'child_process';
+
+/**
+ * This class implements a spawning mechanism to print via any command / executable
+ * by providing the path to the created bitmap file. This can be used for example
+ * to print via a python script.
+ */
+export default class CommandPrinterDriver implements PrinterDriverInterface {
+
+  /**
+   * The Parameters that will be passed on to the command
+   */
+  parameters: [string];
+
+  /**
+   * The command to be executed
+   */
+  command: string;
+
+  constructor(command:string, parameters:[string] ){
+    this.parameters = parameters;
+    this.command = command;
+  }
+
+  /**
+   * @param buffer A Buffer object containing raw data encapsultated
+   * @returns The path to the created bitmap file.
+   */
+  createImageFileFromBuffer(buffer: Buffer){
+    const tempDir = path.join(os.tmpdir(), 'sirius-client');
+    fs.mkdirSync(tempDir, { recursive: true });
+
+    const randomName = Math.random().toString(36);
+    const tempFile = path.join(tempDir, randomName + '.bmp');
+
+    const bitmap = bitmapify(buffer);
+    fs.writeFileSync(tempFile, bitmap);
+    console.log(`Written: ${tempFile}`);
+    return tempFile;
+  }
+
+  async print(buffer: Buffer): Promise<PrintingResult> {
+    return new Promise<void>(resolve => {
+      const imageFile = this.createImageFileFromBuffer(buffer);
+      const commandParams = [...this.parameters];
+      commandParams.push(imageFile);
+      const process = spawn(this.command, commandParams);
+
+      process.stdout.on('data', function (data) {
+        console.log('Pipe data from command ...');
+        console.log(data.toString());
+      });
+      process.on('error', function (...args) {
+        console.log('Command error', args);
+      });
+      process.on('exit', function (code, signal) {
+          console.log('Command exit', code, signal);
+      });
+      process.on('close', function (code, signal) {
+          console.log('Command close', code, signal);
+          resolve();          
+      });
+
+    });
+  }
+}