ryam4u / rawprintinghttpserver

A Windows application which serve HTTP protocol to send binary data from browser (javascript) to client local printer

Raw Printing HTTP Server

Simple HTTP Server to send binary data from browser (javascript) to client local or network printer. It supports ESC/POS codes and works well with Generic/Text Only Driver. It supports all browser that has XHR implementation.

How It Works

      Cloud (API)
  
           ↓   send Print Document (Base64 String)

        Browser
        
           ↓   Relay the print document
           
Raw Printing HTTP Server

           ↓   Convert Base64 to byte array then send

Local or Network Printer

Installation

• Download the zip package here
• Extract the zip package
• Run setup.exe
• Follow the steps
• Run Raw Printing HTTP Server from Start (Auto start whenever user sign in)

Configurations

Config file will be in %PROGRAMDATA%\lockerace\RawPrintingHTTPServer named config.json. parameters :

• allowedDomains: string[] => list of allowed origin domains (please include protocol & port)
• port: int => port number to listen (default: 9100)

example :

{
    "allowedDomains": [
        "http://localhost:4200",
        "http://localhost:3000"
    ],
    "port": 9100
}

Endpoints :

• GET / => view current status of the server and remove already allowed domains via GUI response :

  • type: html

• GET /printers => list all printers available at current machine. HTTP request header origin must be within allowed domains.

  response :

  • type: json
  • values:
    • machineName: string => NetBIOS resolved computer name
    • printers: string[] => list of printer names installed locally
  • example : { "machineName" : "Somebody-PC", "printers" : ["Microsoft XPS Document Writer", "Fax"] }

• GET /permissions => check whether origin allowed to print

  response :

  • type: json
  • values:
    • allowed: boolean => whether origin allowed to print or not
  • example : { "allowed": true }

• GET /permissions => ask local user permission to allow requested domain to print

  query parameters :

  • h: string (required) => domain origin that will be allowed to print which include protocol & port (URI encoded). e.g.: http%3A%2F%2Flocalhost%3A4200

  response :

  • type: html
  • description: dialog with 2 buttons, allow and block

• POST / => send print job information to printer

  accept: json

  body parameters :

  • printer: string (required) => printer name
  • data: string (required) => base64 encoded binary data
  • id: string (required) => document id/print job name

  response :

  • type: json
  • values:
    • success: boolean => print job sent status
    • data: string => document id/print job name if success or error message if failed

  example : { "printer": "LX-300+", "data": "SGVsbG8gV29ybGQh", "id": "Test Document" }

Notes

• For network printer, you must install it locally first (drivers & authentication)
• You can use esc-pos-encoder to generate binary data (works with either Node.js or browser)

Usage

Angular + esc-pos-encoder:

@Component({
  selector: 'app-root',
  template: `
      <div *ngIf="message">{{message}}</div>
      <button (click)="print()">Print</button>
  `})
class AppComponent {
  message: string;
  constructor(private http: HttpClient) {}
  print() {
    // Generate the document to print
    let encoder = new EscPosEncoder();
    let result = encoder
      .initialize()
      .text('The quick brown fox jumps over the lazy dog')
      .newline()
      .encode();
    let docId = 'Test Document';
    
    // Convert UInt8Array to base64 string
    let buf = Buffer.from(result.buffer);
    let binData = buf.toString('base64');
    
    // Send print job to printer
    this.http.post('http://localhost:9100', {printer: 'LX-300', data: binData, id: docId})
      .subscribe((response) => {
        if (response.success) {
          this.message = 'Print job sent successfully';
        } else {
          this.message = response.data;
        }
      }, (err) => {
        // If failed, ask for print permission
        let winOpt = 'toolbar=no,location=no,directories=no,status=no,menubar=no,scrollbars=yes,resizable=yes,width=400,height=300,top=0,left=0';
        window.open('http://localhost:9100/permissions?h=http%3A%2F%2Flocalhost%3A4200', 'Ask Permission', winOpt);
      });
  }
}

Credits

Michael Davies