Hao's Thoughts

Ruby, Rails, Objective-C and everything else

Print to Label Printer Directly From Within Web Application

I’ve been helping a local store developing a Point of Sale (POS) system recently, and one of their requirements is printing price tag from within the product management interface. The first time I heard about this, I thought it was impossbile to have a web app to talk to a local printer. “There must be something like a client app, which installed on the client side, retriving the print jobs via a REST api and send it to the label printer.”, my initial thought leads me to start looking for Java Applet, which pretty much acts as a client app but residing in a web page.

After few google searches, I found a Java Applet named jZebra, which looks pretty much what I need, and it’s now moved to to QZ.

Download and install the free version of the software, now I have QZ-Tray as a broker who’s going to talk to the printer, the applet in the web page is going to communicate with QZ-Tray via WebSocket, it works like a magic, but there’re few pitfalls I need to mention here hoping it could help someone like me.

  • setup the label printer

QZ has provided a really great tutorial on how to setup the label printer, I tried to follow the instructions, but never succeeded. The thing is from within http://localhost:631/admin, you should not click “Add Printer”, while you should click “Find New Printers”, and follow the rest of the instructions from QZ. You may need to restart the QZ-Tray to pick up the changes.