Express: Write binary image data to response

[honza]

This doesn't seem to work.

app.get('/image.jpg', function(req, res) {
    res.contentType('image/jpeg');
    res.end(data);
});

It returns a 200 but the response is empty. Thoughts? Thanks

[tj]

ah, i think i know what it is. try res.contentType('jpeg'). the reason we have that special-case for a field, is that it does:

return this.header('Content-Type', mime.lookup(type));

so lookup() for 'image/jpeg', or any canonical mime type passed will become the default of "application/octet-stream"

i'll fix this though so you can pass a valid mime type to it

[tj]

nvm it'll have to stay as-is I suppose, since even foo/barcould technically be a file path. i'd use res.header() directly, contentType is used in res.sendfile() etc that guess the content type based on the file's path, though it would be nice if contentType was a short-hand

[honza]

Where does the mime package come from? None of the above propositions worked for me. To give you a bit more info, I'm trying to convert an image and serve it on the fly (i.e. without the need to save it to disk first).

[honza]

I figured it out!

This line:

res.end(data);

needs to have the encoding parameter set:

res.end(data, 'binary');

This worked! Thanks!

[tj]

weird :s you shouldn't have to do that if you have a buffer

[emanueleliardo]

You can use res.send() instead of res.end() as suggested by expressjs documentation

res.contentType('image/jpeg');
res.send(data);