api!: make QR code type for proxy not specific to SOCKS5

[link2xt]

No description provided.

[link2xt]

Second commit makes it possible to scan ss:// QR codes in addition to https://t.me/socks.
We can also add socks5:// QR code support.

http:// and https:// are currently parsed as URL. We can start scanning them as proxy as well, but currently they are a different QR code type that shows this on Android, offering to open URL in a browser:

Advantage of this would be that everything that can be set as a proxy is scanned as a QR proxy type.

[r10s]

lgtm, did not test, however.

once merged, we should file issues to support the new format

[r10s]

nice! i thought about that format already when doing #5895, however, regarded the idea as a minor because of some lack of understanding of Cow-strings :)

[r10s]

http:// and https:// are currently parsed as URL. We can start scanning them as proxy as well, but currently they are a different QR code type that shows this on Android, offering to open URL in a browser

i do not understand. URLs in QR codes are often just URLs that the user should open in a browser, the QR code is mostly there to avoid typing.

do you mean that it is common to have QR codes that just contain a URL that should be used as a proxy then? are they detectable by some format (eg. IP address)?

[link2xt]

http:// and https:// are currently parsed as URL. We can start scanning them as proxy as well, but currently they are a different QR code type that shows this on Android, offering to open URL in a browser

i do not understand. URLs in QR codes are often just URLs that the user should open in a browser, the QR code is mostly there to avoid typing.

do you mean that it is common to have QR codes that just contain a URL that should be used as a proxy then? are they detectable by some format (eg. IP address)?

@adbenitez wants to use QR codes as the primary interface to add proxies into the list in deltachat/deltachat-android#3292
Then pasting an URL manually is still possible, it is just no different from "paste from clipboard" in the QR code scanner.

This could work if all possible proxy URLs are scanned as Proxy type and all proxy URLs can be given to dc_set_config_from_qr() to start using this proxy.

Since users likely use Delta Chat as the QR code scanner app for HTTPS URLs in advertisements and bills, we can still offer "Open" action for Proxy QR codes that have URL starting with "http://" or "https://".

[link2xt]

Maybe I should put the URL into text2 and drop the "protocol". Proxy QR code is first of all an URL that can be used as a proxy, but nothing prevents offering to open it in a browser.

[link2xt]

do you mean that it is common to have QR codes that just contain a URL that should be used as a proxy then? are they detectable by some format (eg. IP address)?

I now detect them by not having a query and a path. So URL https://delta.chat/en/blog is definitely not a proxy, but https://delta.chat may be so it is parsed as a proxy. UI may still want to offer opening proxy QR codes in the browser if they start with https:// or http:// e.g. if they are parsed from the main screen and not from the proxy configuration screen.

[link2xt]

Now QR codes must have a port to be recognized as a proxy, so https://delta.chat is an URL, but https://delta.chat:443 is a proxy.