Privacy Browser Android

I do not speak the language this is written in (perhaps French?). Can you please repost it in English?

Translation from deepl.com/translate :

The Webpage
https://media.interieur.gouv.fr/deplacement-covid-19/
generates a PDF file that you should be able to save in the phone memory. With privacy browser it cannot be saved because it signals "invalid url" in the file saving dialog box.

At a minimum, this will become possible with the release of Privacy WebView in the 4.x series. But it might be possible to extract this information from DOM storage somehow.

I have faced the same error in "Snapdrop" (https://github.com/RobinLinus/snapdrop).

I made some tests, too.

A lot of browsers in the F-Droid store seem to have similar problems with this type of download; in short, they can't download the files.

But... It works just fine with the Android versions of Firefox & Chrome.

Firefox and Chrome (and browsers based on them) can download blobs because they can walk the DOM tree and extract the blob. But Android's System WebView does not expose the DOM in the same way, so browsers that are based on WebView, like Privacy Browser and a number of other browsers on F-Droid, cannot download blobs.

I've saw some closed source wrappers able to download the blob not sure how, but the file name was some random string, with .bin extension (which can be fixed by renaming it to it's source name & extension).

https://fonts.google.com/icons is another good test site.

The google icons website you've provided, are obviously blobs. But when I tested my proton drive downloads, they're considered blobs too. But strangely they aren't.

For instance, there's a closed source chinese browser called Via was able to download proton drive files. When analysed the file url it shows as data instead of blob. Here's the url form
data:application/zip;base64,<some-long-data-string>==

Sounds like Proton Drive sometimes presents as data URLs and other times as blob URLs. Servers can choose to do things like that if they want to. It might depend on how the browser presents itself, like the User Agent or some other behavior.

I don't think it's sometimes. It's everytime, always has been data URL in proton. But PB's considering data as blob too. You can try data URLs on other wrappers, & then in PB to look into the difference.

Thinking about it a little bit more, when you download something from a blob (a storage location in the DOM accessed by JavaScript) it contains a data URL with the actual item. So, to be able to handle downloading of blobs you first must be able to walk the DOM to find the blob, then you must convert the data URL it contains into the file you want to save.

Privacy Browser Android already knows how to convert data URLs into files and save them. But because Android's WebView does not provide a built-in downloader, and because it does not expose the DOM in a way that is easy to walk to find the blob, that is the step where downloading blobs breaks down for browsers based on WebView.

There might be some way to walk the tree and extract the data URL from the blob using JavaScript injection. When I get around to looking deeply at this feature I am going to take the time to explore that. Otherwise, it will probably have to wait for the 4.x series.

Or, you know, you could always submit a feature request to Proton Drive to present their file downloads as actual https URLs (best, in my opinion), or as data URLs (second best) instead of wrapping them in a blob.

Their public forum is very pathetic actually. Neither do they have an issue tracker, nor their app in f-droid either. It's a shame they're been promoted as the no. 1 swiss service.