nodejs - How to read and output jpg image?

Question

I've been trying to find an example of how to read a jpeg image and then show the image.

var http = require("http"), fs = require("fs");

http.createServer(function (req, res) {
    res.writeHead(
      200, 
      { "Content-Type": "text/html" }
    );

    fs.readFile("image.jpg", function (err, data) {
      if (err) throw err;
      res.write(data);
    });

    res.end();
}).listen(8124, "127.0.0.1");

console.log("Server running at http://127.0.0.1:8124/");

Tried the following code but I think the encoding needs to be set as buffer. Using console.log it outputs 'Object' for the data.

maerics · Accepted Answer · 2020-03-26 15:27:33Z

104

Here is how you can read the entire file contents, and if done successfully, start a webserver which displays the JPG image in response to every request:

var http = require('http')
var fs = require('fs')

fs.readFile('image.jpg', function(err, data) {
  if (err) throw err // Fail if the file can't be read.
  http.createServer(function(req, res) {
    res.writeHead(200, {'Content-Type': 'image/jpeg'})
    res.end(data) // Send the file data to the browser.
  }).listen(8124)
  console.log('Server running at http://localhost:8124/')
})

Note that the server is launched by the "readFile" callback function and the response header has Content-Type: image/jpeg.

[Edit] You could even embed the image in an HTML page directly by using an <img> with a data URI source. For example:

  res.writeHead(200, {'Content-Type': 'text/html'});
  res.write('<html><body><img src="data:image/jpeg;base64,')
  res.write(Buffer.from(data).toString('base64'));
  res.end('"/></body></html>');

edited Mar 26, 2020 at 15:27

answered Mar 2, 2012 at 22:33

maerics

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3 Comments

mesh Over a year ago

Is there a way to do it so lets say we read the jpeg data and put in the src attribute maybe through encoding it to base64?

mesh Over a year ago

Awesome! Just the solution I needed. Thanks for that second example.

Umair Ahmed Over a year ago

what about if we have multiple images ?

Sercan REYHANLI · Accepted Answer · 2019-01-01 19:35:32Z

1

Two things to keep in mind Content-Type and the Encoding

1) What if the file is css

if (/.(css)$/.test(path)) {
  res.writeHead(200, {'Content-Type': 'text/css'}); 
  res.write(data, 'utf8');
}

2) What if the file is jpg/png

if (/.(jpg)$/.test(path)) {
  res.writeHead(200, {'Content-Type': 'image/jpg'});
  res.end(data,'Base64');
}

Above one is just a sample code to explain the answer and not the exact code pattern.

edited Jan 1, 2019 at 19:35

Sercan REYHANLI

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answered Jan 18, 2018 at 14:32

user2248133

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