index.js

/*
Barcode Generator
(c) 2021 Patricio Díaz 
Adapted from  https://github.com/metafloor/bwip-js to use Express.js
*/
const express = require("express");
const bwipjs = require('bwip-js');

const { PNG2JPG } = require("./utils");

const app = express();
app.use(express.static('public'));

// app.get('/live', (req, res) => {
//     res.sendFile(path.join(__dirname + '/example/live.html'));
// });

app.get("/", (req, res) => {
    let parameters = req.query;

    if (!req.query.bcid || !req.query.text) {
        return res
            .status(404)
            .contentType('text/plain')
            .end('BarcodeGenerator: Missing bcid or text parameter', 'utf8');
    }

    // parameters from this project
    const base64 = parameters.base64 ? parameters.base64.trim().toLowerCase() == 'true' : false;
    delete parameters.base64;

    const format = parameters.format ? parameters.format.toLowerCase() : 'png';
    delete parameters.format;

    // parameters from bwip-js project
    // set some defaults
    parameters.bcid = parameters.bcid.toLowerCase();
    parameters.backgroundcolor = parameters.backgroundcolor ? parameters.backgroundcolor : 'FFFFFF';
    parameters.padding = parameters.padding ? parameters.padding : 1;
    parameters.guardwhitespace = true;
    parameters.paddingwidth = parameters.paddingwidth != undefined ? parameters.paddingwidth : 1;
    parameters.paddingheight = parameters.paddingheight != undefined ? parameters.paddingheight : 1;

    bwipjs.toBuffer(parameters, async(error, img) => {
        if (error) {
            return res
                .status(500)
                .contentType('text/plain')
                .send(`BarcodeGenerator: ${error.message}`);
        } // if (error) ... 

        let r0;
        let contentType;
        try {
            // convert to desired image format if needed
            switch (format) {
                case "jpg":
                    r0 = await PNG2JPG(img);
                    contentType = "image/jpg";
                    break;
                case "png":
                default:
                    r0 = img;
                    contentType = "image/png";
            } // switch ...

            // return base64 encoded if requested
            if (base64) {
                contentType = "text/plain"
            }

            res.status(200).contentType(contentType).send(base64 ? r0.toString("base64") : r0);

        } catch (error) {
            console.log("When rendering code: ", error);
            res.status(500)
                .contentType('text/plain')
                .send(`BarcodeGenerator: ${error.message}`);
        }
    }); // bwipjs.toBuffer ...

}); // app.get("/", ...

const server = app.listen(process.env.EXPRESS_PORT || 3000, () => {
    console.log("barcode-generator is listening on port", server.address().port);
});