Unable to serve base64 pngs

[a-digitalarcana]

I'm trying to serve a dynamically generated png file, but seem to be missing something. The data appears to be sent, but the browser (Chrome) just renders a broken image icon.

const express = require('express');
const app = express();
const port = 3000;

app.get('/', function(req, res) {
  res.send(`<img src="/png/"/>`);
});

app.get("/png/", function(req, res) {
  console.log("request img");
  const img = "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";
  //res.type('png');
  res.writeHead(200, {
    'Content-Type': 'image/png',
    'Content-Length': img.length
  });
  res.end(img); 
});

app.listen(port, function() {
  console.log(`listening on port ${port}!`)
});

[Douglas Wilson]

Unless I'm missing something, Chrome does not unbase64 responses. You need to do that on the server. Replace res.end(img) with res.end(Buffer.from(img, 'base64'))

[Douglas Wilson]

Also remove the content-length since it would no longer be the correct value.

[a-digitalarcana]

Ah, perfect.. that did the trick. I was confused because Chrome has no problem with data:image/png;base64,iVBORw0KGgo... directly in the url input field. Thanks!

[Douglas Wilson]

Yea, the data: URIs have special rules compared to http: or https: ones is all.