Allow forcing a file to download instead of opening in the browser

Feature request

Is your feature request related to a problem? Please describe.

I have json files uploaded in supabase storage and I provide presigned links to them in <a> tags in my webapp. Currently, when users click on these links, they are navigated to the json file, which displays in the browser. I would prefer clicking on the link to instead pop up a “Download file” prompt and leave the user on the same page (i.e. don’t navigate away), so that downloading json files behaves the same as downloading other files.

Describe the solution you’d like

I think there are 2 options that might make sense:

1. Accept a Content-Disposition header when uploading a file to storage-api (pass it through to the S3/File backends similar to the Content-Type header)
2. Allow a Content-Disposition header to be provided when creating a presigned url, that header is then included in the response when a client follows the presigned url
   1. This option is similar to how the AWS SDK allows you to override a variety of different headers for presigned urls, see the Overriding Response Header Values heading in the docs

Describe alternatives you’ve considered

1. Using the download attribute on anchor tags (<a>) doesn’t work, because my webapp is on a different domain/origin than the storage-api/kong (which is on a supabase.co subdomain).
2. You can get around the above same-origin limitation by downloading as a blob: URL, but that’s clunky and slow and restrictive. Source: https://stackoverflow.com/a/49500465
3. I could upload files with a bogus content type (e.g. application/octet-stream), so they would be served back with the same content type header and the browser wouldn’t think it could open it directly. But, this seems hacky.

[thebengeu]

Thanks for the detailed feature request. I think that it might make sense to support both options, just like how the AWS SDK does. I’d probably be able to get to this in early April.

[fenos]

PR is up - this feature will land shortly! 🎉