找不到Amazon S3映像。 必须推迟

Question

I have a meteor app where I upload an image to S3 via a node framework called knox.

It works well but when Im getting the success response from S3 with the link to the image I also want to show it to the user like this:

$("#thumbnail").attr("src", url);

However this generates a 404 not found in the console and the image is not showing. But if I put a delay for around 5-10s it works.

setTimeout(function() {
    $("#thumbnail").attr("src", url);
}, 10000);

Why do I get the URL from S3 before they are ready to show it? Is there a way I can wait until its ready before showing it to the user?

Answer 1

As nodejs is asynchronous (meaning that it does not wait until one request is finished before next one gets called) your url gets returned quicker than the image is uploaded, therefor you can't see the image. This could be fixed using callbacks.