With ExpresJS or Node, Is there an easy way to read an external image into memory and serve it?

Question

With ExpresJS or Node, Is there an easy way to read an external image into memory and serve it?

I'm using an external service to create images. I'd like my users to be able to hit my API and ask for the image. Then my Express server would retrieve it from the external service, then serve it to the user. Sort of like a proxy I suppose, but not exactly.

Is there an easy way to do this, preferably one that doesn't involve downloading the image to the hard drive, then reading it back in and serving it?

Using the request library, I was able to come up with this:

var request = require("request");

exports.relayImage = function(req, res){
    request(req.params.url).pipe(res);
}

That seems to work. If there is a more efficient way to do this (meaning on server resources, not in terms of lines of code), speak up!

Thanks!

node.js
express

Answer 1

What you are doing is exactly what you should be doing, and is the most efficient method. Using pipe, the data is sent as it comes in, requiring no additional resources than are needed to buffer and transmit.

Also be mindful of content type and other response headers that you may want to relay. Finally, realize that you've effectively built an open proxy where anyone can request anything they want through your servers. This is a bit dangerous, so be sure to lock it down in your final application.

Answer 2

You should be able to use the http module to make a request to the external image service with a callback that returns the image as the response. It won't write to disk unless you explicitly tell it to.