Infinit loop with the moderate-images example about functions-samples HOT 3 CLOSED

Hi,

After digging a little bit, it seems that functions.storage.object().onChange(event is causing the infinite loop.
Since it is listening to all changes of the storage and our function is uploading a new image at the end. It probably triggers an onchange event and here we go again?

EDIT: I did a small trick, it's not clean but it stops the infinite loop waiting for a better fix.
I've added optimized: true in the metadata:

    // Uploading the Blurred image.
    metadata.blurred: true;
    return bucket.upload(tempLocalFile, {
      destination: filePath,
      metadata: {metadata: metadata} // Keeping custom metadata.
    });

And then I checked on the onChange(event) if the image is already blurred or not:

if (object.metadata.blurred) {
    return console.log("Already blurred");
  }

Works fine, I have a log "Already blurred" and then it stops.

from functions-samples.

The trick is nice indeed :) (good way to use metadatas)

But normally the function does not run in a loop. The issue is that in your code it seems you have removed the Cloud Vision API call (this is what stops the loop) and you are always blurring the image (you were just testing this I guess).

In the original sample we first check if the image is offensive and, if it is, we blur it. The function gets called again on the new blurred image but - because it's been blurred - the image is not detected as being offensive on the second check and this ends the loop.

By the way be careful when using metadata because the users can set them from the client (when you upload the image) and they could use that to bypass the image check on the function. You can avoid that by using some special security rules to forbid setting the metadata from the client though.

from functions-samples.

Thanks for your tips! I was not aware of metadata risk :)

from functions-samples.