Improve URI monero_wallet standard by allowing optional <txid> string

[SamsungGalaxyPlayer]

Current Monero URI documentation: https://github.com/monero-project/monero/wiki/URI-Formatting#wallet-definition-scheme

There is a Monero gift card project that could benefit from including txids in the URI, now that scan_txid is available.

Proposal

At a minimum, a monero_wallet URI requires one of seed or (view_key,address). Additional parameters are useful to enable spending ( seed enables spends; view_key without spend_key does not) and for efficiency purposes.

Parameter	Type	Requires	Description
address	String	view_key	Main (95-character) address.
spend_key	Hex String	address, view_key	Private spend key of a wallet.
view_key	Hex String	address, absence of seed	Private view key of a wallet. If a view_key is provided but a spend_key is not provided, then the wallet will be view-only.
seed	String	Absence of view_key	URL encoded mnemonic seed to restore a deterministic wallet.
height	Long	Absence of txid	Block height when the wallet was created or first received funds. Only one height may be provided.
txid	String	Absence of height	Transaction ID(s) to scan. Multiple transaction IDs can be provided if separated by a semicolon ;.

Example 1:

monero_wallet:address=467iotZU5tvG26k2xdZWkJ7gwATFVhfbuV3yDoWx5jHoPwxEi4f5BuJQwkP6GpCb1sZvUVB7nbSkgEuW8NKrh9KKRRga5qz?spend_key=029c559cd7669f14e91fd835144916009f8697ab5ac5c7f7c06e1ff869c17b0b&view_key=afaf646edbff3d3bcee8efd3383ffe5d20c947040f74e1110b70ca0fbb0ef90d&txid=715d7f44aa641d562ea649d14152f10f84f5fd087caf637295b963cbcbb05a0e

Example 2:

monero_wallet:address=58Bj65FCpfpULRXyf7mmsY1vB4qiW8qQ8X99tw783rSggPjmvUcRHycaXUQfSwMVpuUj6FWDr4fNHFYyo7f1XdtsJsXAJ1Y&spend_key=75ca1b95ee9dd8bbf059da64c6750fd500731f8775389ce089d516d46108fc05&view_key=c59b3e3182d9c665d0f3a1776a28301410283ab6ff6a9bd3abc7a5bb37758f03&txid=f8477b831a028f07d5638157afc0fbf0897066b4caa29dc48f885fba79cec814;bd20081e0d1abf05b275bcc06bc7e315bc03c57870e247c82c8a45b30f4d1b34;cdbed9b4b2f56de7cce9255610d0cae702aefb36f9a4ff15698ea448f29f6188

Example 3:

monero_wallet:address=467iotZU5tvG26k2xdZWkJ7gwATFVhfbuV3yDoWx5jHoPwxEi4f5BuJQwkP6GpCb1sZvUVB7nbSkgEuW8NKrh9KKRRga5qz?seed=python%20runway%20gossip%20lymph%20hills%20karate%20ruined%20innocent%20ought%20dual%20shipped%20shipped%20sushi%20pyramid%20guys%20entrance%20obedient%20natural%20kiwi%20wobbly%20vixen%20wipeout%20template%20typist%20innocent&height=12345676

Legacy and Inconsistencies

• The Monero documentation previously referred to both mnemonic_seed and seed as interchangeable. Good wallet code should accept either seed or mnemonic_seed for the seed parameter.
• The Monero documentation previously indicated that address= was not required if the address was provided directly after monero_wallet:. Good wallet code should account for this possibility.

Context/Use

There is a desire to use Monero "gift cards" with a small preloaded value on them. In situations where these cards are loaded in a single transaction, wallets can easily and near-instantly scan specific txids, for then sweeping into another seed automatically.

If only a restore height is specified, then scanning can take minutes or hours.

Scanning a monero_wallet URI with specific txids signals to the wallet that the only funds in this seed are from these specific txids.

This field serves 2 purposes:

1. Specifying txids for significantly faster scanning.
2. Indicating to wallets that this seed is for single-use only, and can be discarded (swept) once scanned.

Questions

• Should we allow multiple txids, or just 1?: Multiple ones supported with semicolon
• Should we allow specifying both a txid and block height? What use-case would this be for, and how should a wallet handle this? No, this will not be allowed in the standard.

Changelog

• 2022-12-29: Added semicolons for multi-txid support and added notes about required components. Added section to the proposal that covers legacy and inconsistencies.
• 2023-02-21: Fix typo

[plowsof]

Some great use cases for scan_tx (insta syncing a one-time-use gift wallet with 1 input -> to be transferred to the users own wallet via magic - ideally from a trusted node)

Sidenote: theres a bit of a bug with scan_tx where duplicates can be scanned and appear in your history list as amount "0" - probably causes issues elsewhere, jberman has a PR fixing it here monero-project/monero#8566

[plowsof]

1 txid , or a list separated by commas is easy to work with. proof of concept here https://github.com/plowsof/redeem_gift_poc

edit* this pull request to add multiple recipients to a payment uri uses ";" so for consistency txid should also monero-project/monero#8665

[SamsungGalaxyPlayer]

I believe it's ready for final review now @luigi1111

[SamsungGalaxyPlayer]

@luigi1111 Cake Wallet is implementing the URI standard as written above, which deviates somewhat from the listed version in the wiki.

[luigi1111]

Should the wiki be updated?

[plowsof]

to get this moving along, this needs to be a pull request to the actual wiki, then it can be reviewed conveniently before merging. thanks @SamsungGalaxyPlayer for this 🥇 ( @ofrnxmr (?) pointed out that connecting to a node as --trusted-daemon reduces network usage. in my PoC i found it reduced the time to claim a gift card from 18s to around 8s~ )

[SamsungGalaxyPlayer]

@plowsof how can I open a pull request for the wiki? I haven't done that before

[plowsof]

@SamsungGalaxyPlayer sorry, the feature does not exist, removes foot from mouth will ask around what the best course of action here is

[plowsof]

@SamsungGalaxyPlayer a suggestion was to make a PR to https://github.com/monero-project/meta/tree/master/api (adding a file called something like uri_formatting.md inside the api folder) because we can't make PRs/review @ the wiki

[SamsungGalaxyPlayer]

Well Cake is going forward with the standard above. If Core wants to update the wiki page to match this, only they can edit that page as far as I understand @luigi1111 @plowsof

[luigi1111]

https://github.com/monero-project/monero/wiki/URI-Formatting/_history isn't only Core, but I don't know off-hand how to do it (for non-maintainers).

[selsta]

We locked the wiki because people would add nonsense / malicious links.

[SamsungGalaxyPlayer]

I will re-open with changes. Our devs have advised me, and I've learned more about URIs in the process.