Morteza Ziaeemehr Morteza Ziaeemehr - 6 months ago 107
Node.js Question

Nodejs - How to show qr-image result in view

I use

qr-image
plugin for Nodejs to generate a QR code and it works pretty good.

The problem is showing result image in ejs.

var express = require('express');
var router = express.Router();
var qr = require('qr-image');

router.get('/', function(req, res) {
var code = qr.image("text to show in qr", { type: 'png', ec_level: 'H', size: 10, margin: 0 });
res.type('png');
code.pipe(res);
// res.render('index', { title: 'QR Page', qr: code });
});


When i uncomment last line, nodejs crashs.
How to send
code
to view as a variable?

Update:

This code returns
[object Object]
in result page.

var code = qr.image("text to show in qr", { type: 'png', ec_level: 'H', size: 10, margin: 0 });
res.render('index', { title: 'QR Page', qr: code });


Also console.log(code) shows this:

{ _readableState:
{ highWaterMark: 16384,
buffer: [],
length: 0,
pipes: null,
pipesCount: 0,
flowing: false,
ended: false,
endEmitted: false,
reading: false,
calledRead: false,
sync: true,
needReadable: false,
emittedReadable: false,
readableListening: false,
objectMode: false,
defaultEncoding: 'utf8',
ranOut: false,
awaitDrain: 0,
readingMore: false,
decoder: null,
encoding: null },
readable: true,
domain: null,
_events: {},
_maxListeners: 10,
_read: [Function] }

Answer

You're trying to stuff a rendered image into a template engine; it's not going to work.

You should instead have an image tag in the template that points to a URL that responds with the image.

// Edit based on comment

router.get('/qr/:text', function(req,res){
   var code = qr.image(req.params.text, { type: 'png', ec_level: 'H', size: 10, margin: 0 });
   res.setHeader('Content-type', 'image/png');
   code.pipe(res);
}

Then in your html template, make an image tag with the src set to /qr/whatever text and you should be in good shape.