Skip to content

lud-17 fallback scheme. #94

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
fiatjaf wants to merge 1 commit into
base: luds
Choose a base branch
from
Open

lud-17 fallback scheme. #94

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
10 changes: 10 additions & 0 deletions 17.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -26,6 +26,16 @@ This document defines that LNURLs will have the format of conventional URLs, wit

When `WALLET` sees a link or QR code like `lnurlw:domain.com/path` it should make a `GET` request to `https://domain.com/path`; and when it sees `lnurlp:examplennnnnnnn.onion/path` it should make a request to `http://examplennnnnnnn.onion/path`.

## Fallback scheme

To replace the [_Fallback scheme_ from LUD-01](01.md#fallback-scheme), wallets should also allow for `https://`-prefixed URLs when scanning QR codes and handle them just like they handle `lnurl1...` links today.

The idea is that the fallback scheme is expected to only be used in QR codes, never in links (the original intent of the fallback scheme was to be used in printed lnurl-withdraw vouchers, but this also applies to printed lnurl-pay QR codes like the [McDonald's ones](https://twitter.com/fiatjaf/status/1435251011527000066)).

If someone sees a QR code printed on a place, for example, they may know it's an LNURL thing and scan directly with their Lightning wallet, but they may also think it is a normal QR code or they don't even have a Lightning wallet, so they scan it and try to open it on their web browser. In that case the `SERVICE` may handle the request, check for the presence of `Accept: text/html` header and return a webpage with instructions.

This remains entirely optional and `SERVICE` should only use `https://` in printed QR codes if it is also willing to return a fallback HTML page.

@chill117 chill117 Oct 4, 2021

Copy link
Copy Markdown
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Does this advice refer only to the case where the URL is encoded directly as a QR code and not when encoded using bech32 (e.g. "lnurl1...") then encoded as QR code?

@fiatjaf fiatjaf Oct 4, 2021

Copy link
Copy Markdown
Collaborator Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Yes.


## Deployment

Once most wallets signal their intent to implement, everybody can implement support for the new scheme, but keep supporting the old way for many years to come. Then new apps can start to use the new scheme.