Self-Signed Certificate Support in QZ Tray

[Mykhailo Zinchuk]

Dear QZ Tray Support,

I'm using QZ Tray with a Node.js app and connecting via secure WebSocket.The connection works without signing but fails with self-signed certificates, showing a 1006 - Session Closed error and:

Error: Unable to establish connection with QZ at deeper (/path/to/node_modules/qz-tray/qz-tray.js:113:40)

Does QZ Tray support self-signed certificates for secure WebSocket connections or i should use only paid certificate from your site? If so, can i buy only cert, without any plan?

Thank you, Mykhailo Zinchuk

[Lite Finocchiaro]

Mykhailo:

Does QZ Tray support self-signed certificates for secure WebSocket connections

Yes, but not all self-signed certificates are the same, and you also need the private key if you want signing to work.

Did you generate your self-signed cert and private key using the QZ-Tray client? If not, please try this method and let us know if it works:

https://qz.io/docs/signing#demo-keys

Cheers,

Lite Finocchiaro

VP, QZ Industries

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[Mykhailo Zinchuk]

Thank you for your quick answer. It worked.

Can you also maybe tell how to fix problem whil printing image? One time it was ok, and printed without spaces in letters. But all next times it looks like this:



I use node.js, 

and have such code. Tried different params like density, and other from your doc, but does not help. Printer is ok, cause with other lib it works fine(node-thermal-printer).

let config = qz.configs.create('ReceiptPrinter');

let data = [

{

type: 'raw',

format: 'image',

flavor: 'base64',

options: { language: 'escp', dotDensity: 'double' },

data: base64Image,

},

'\x0A' + '\x0A' + '\x0A' + '\x0A' + '\x0A' + '\x0A' + '\x0A',

'\x1B' + '\x69',

]; // after connection

await qz.print(config, data).catch((e) => console.error(e));

Thanks in advance!

чт, 22 трав. 2025 р. о 01:48 Lite Finocchiaro <lite.m.fi...@gmail.com> пише:

[Lite Finocchiaro]

Mykhailo:

Did you power cycle the printer before switching between QZ-Tray and node-thermal-printer? I ask this because we may achieve our raw image printing in different ways, and if there are conflicting ESC/POS commands, then this could give undesired results. 

Sometimes adding the "init" command before an ESC/POS command string can help clear any remaining configurations from previous prints, instead of turning the printer off and on.

https://qz.io/docs/raw#escpos

I also noticed that you use "ESCP" instead of "ESCPOS", but this should not make a difference in this particular case.

Here is a copy/paste of QZ-Tray logs of the raw image test from https://demo.qz.io to an Epson TM-T88V, along with picture results.

{"call":"print","params":{"printer":{"name":"88"},"options":{"bounds":null,"colorType":"color","copies":1,"density":0,"duplex":false,"fallbackDensity":null,"interpolation":"bicubic","jobName":null,"legacy":false,"margins":0,"orientation":null,"paperThickness":null,"printerTray":null,"rasterize":false,"rotation":0,"scaleContent":true,"size":null,"units":"in","forceRaw":false,"encoding":null,"spool":{}},"data":[{"type":"raw","format":"image","data":"https:\/\/demo.qz.io\/assets\/img\/image_sample_bw.png","options":{"language":"ESCPOS","x":"0","y":"0","dotDensity":"double","xmlTag":"v7:Image","pageWidth":"480","pageHeight":""}}]},"signature":"","timestamp":1748400788564,"uid":"8ekcd2","position":{"x":960,"y":523},"signAlgorithm":"SHA512"}

I think that if you power cycle your printer before doing the QZ-Tray method, you should get the desired results. If you do not, please send logs:

 From the QZ Tray Icon:
Advanced, Troubleshooting, Zip Logs (To Desktop)

 

Feel free to send them directly to me (off list) or to sup...@qz.io if they contain information that you do not wish to share publicly.

Cheers,

Lite