How to get image format when i get image via http request using nodejs

Question

I'm getting image via line api. when user send image to my bot, I will get it, and upload to aws s3 bucket: GET https://api.line.me/v2/bot/message/{messageId}/content

I got success image. I'm using file = fs.createWriteStream("file.jpg") and pipe(file). However, it will be fixed at file extension "jpg". For example, the file I get has the extension "gif", it will still save in the format "jpg".

So, how to get image format, if I know image format, i can use fs.createWriteStream to create file have the same format.

you want image format before uploading to s3 or after? – Aabid Jun 07 '18 at 10:41 — Aabid, Jun 07 '18 at 10:41
I want before uploading to s3 – Nam Lee Jun 07 '18 at 15:01 — Nam Lee, Jun 07 '18 at 15:01

score 0 · Answer 1 · answered Jun 11 '18 at 06:42

You can simply first read headers of image and you will get image format in it, according to image format can save it to s3 Bucket.

Here is the sample code.

request.head('https://www.google.com/images/branding/googlelogo/2x/googlelogo_color_272x92dp.png', function (err, res, body) {
    console.log('content-type:', res.headers['content-type']);
    console.log('content-length:', res.headers['content-length']);
    let filename = 'image.png' // according to content type
    request(uri).pipe(fs.createWriteStream(filename)).on('close', callback);
});

filename can be decided according to content-type

How to get image format when i get image via http request using nodejs

1 Answers1