Trouble downloading files in Google Apps Script web app after Chrome update

Question

I've had a Google Apps Script web app running for a bit over a year which gave users an option to download a csv file. It worked perfectly fine, although in the console it gave a warning about downloading from an iFrame being deprecated.

After updating Chrome, I now get the following error when trying to download:

Download is disallowed. The frame initiating or instantiating the download is sandboxed, but the flag ‘allow-downloads’ is not set. See https://www.chromestatus.com/feature/5706745674465280 for more details.

When following the above link, it provides the following information:

Chrome is planning on removing this capability - i.e. Chrome is going to block all downloads initiated from or instantiated in a sandboxed iframe by default. The embedder may add "allow-downloads" to the sandbox attributes list to opt in. This allows content providers to restrict malicious or abusive downloads.

How can I add "allow-downloads" to the sandbox attributes in the Google Apps Script environment? Alternatively, is there a workaround to enable downloading files?

Glandule

Answer 1

Update as of 07/29/2020:

The attribute "allow-downloads" has now been added to the sandbox attributes and there is no longer any issue downloading files.

Glandule

issuetracker.google.com/issues/157368720#comment76 – Spacetime

Yes, exactly. It is fixed right now, the iframe in GAS has been updated with allow-downloads flag – Sacrament

Answer 2

It is discussed here https://issuetracker.google.com/issues/157368720 that HtmlService.XFrameOptionsMode.ALLOWALL should set allow-downloads on GAS web app sandbox. We should watch this issue for changes.

Sacrament

var html = HtmlService.createTemplateFromFile('page') html.ssid = 'hellothere'; html.reportid = "0"; var new_html = html.evaluate().setXFrameOptionsMode(HtmlService.XFrameOptionsMode.ALLOWALL) IS THIS THE CORRECT SYNTAX? – Voss

Answer 3

Include sandbox="allow-downloads" in your iframe tag, which contains the code that is used for downloading the CSV file.

Tertiary

This is not possible in a Google Apps Script web app. – Saimon

Answer 4

There is one work around that I found if you have a download button, you can right click and open in a new tab. You have to rename the file but at least you can get it, until there is a fix.

Abb

please tell me how to do this. – Chancroid

I'm using sheets and creating a Json file. I just created a modal that retrieves the data to download, in my case its a JSON, Then turn it into a blob then a URL, then attach it to an anchor tag and display that in the modal. Right click and open in a new tab and the download comes through, just not the name of the file that was set. – Abb

Could you please reply to my question asked here. people there does not seem to understand the actual problem. link also I am unable to get the result if you could provide any solution there I would greatly appreciate. – Chancroid

Answer 5

iframe that embeds a webpage with sandbox attributes. You added allow-downloads to enable downloads from within the iframe, which is required to allow users to download content (such as reports) when the iframe is sandboxed.

<iframe width="100%" height="1068"
  src="url"
  frameborder="0" style="border: 0; border-radius: 24px" allowfullscreen
  sandbox="allow-storage-access-by-user-activation allow-scripts allow-same-origin allow-popups allow-popups-to-escape-sandbox allow-downloads"></iframe>

Delafuente

This does not provide an answer to the question. Once you have sufficient reputation you will be able to comment on any post; instead, provide answers that don't require clarification from the asker. - From Review – Sadism