[Discussion] Remove xucli addcurrency <currency> + removecurrency

[kilrau]

Abstract: How about we get rid of xucli addcurrency <currency> and just add a currency automatically when xucli addpair <base_currency> <quote_currency> contains a new currency? The same way xucli removepair <pair_id> would remove the currency if it's not used anywhere else.

Motivation: As @offerm just discovered, it's not too user-friendly to think of the step of adding a currency first before one is able to addpair for such. Others will too.

Pro: better UX, wouldn't need to change internals, wouldn't need a new listcurrencies call.
Alternative would be to get rid of the "currency" concept altogether.

PS: I would also want to straighten the the addpair call and command to:
xucli addpair <pair_id> add a trading pair in the format <base_currency>/<quote_currency> to be consistent with other <pair_id> commands. At the moment it's

xucli addpair btc ltc but
xucli removepair btc/ltc

Let's agree on sth first, not high prio obviously, see milestone.

[offerm]

Agree to the concept.
For ERC20 we need to provide also the token address so we need to see how to provide this extra info.

[kilrau]

Good point. Maybe:

xucli addpair <pair_id> [token addresses]
Description: add a trading pair in the format <base_currency>/<quote_currency> with additional [base_currency_token_address]/[quote_currency_token_address] for tokens.

Other calls can remain the same.

[erkarl]

I agree that skipping addcurrency would be a better UX for the end user, but we also need to provide the decimal_places and contract_address for ERC20 tokens. It feels like including those in the addpair call would make things even more complicated. Another option is to fetch this information from a local database/mapping (not sure about this either).

[kilrau]

Outdated stats on erc20 decimals distribution: ethereum/EIPs#724 (comment), so not 9X% with 18 decimals like I thought it would be.

I'd indeed want to automate fetching all additional info of a token address:

• How about fetching it from geth calling the decimals function of the given contract?
• For that we would need an additional check that geth and raiden are actually available before we allow adding contract addresses. Which they should be anyways but maybe not in the moment of adding a pair. Opinions?

[offerm]

I think it is valid to request raiden when adding an ERC20 token. Don't see a problem with that.

Also, as far as I recall, Raiden used to provide token information in their token API. This was removed in one of the latest version. We can ask them to put it in so we can query raiden and not geth/parity/infura/etc.

But I'm not sure we should touch this at all.... My question was not about the "how to add a pair" but more about - what is still missing in xud before an order can be issued for WETH/BTC. The answer is - "nothing".

My question now - what is missing in xud before a swap can be agreed between the maker and taker?

[sangaman]

We would also need to specify the swap client (between lnd and raiden for now). It seems more complicated and confusing to me to try to combine adding a currency and adding a trading pair into a single call. In terms of UX, this is something that has to be done rarely and only by administrators.

But I do agree that the cli command for add pair should use the ltc/btc format rather than ltc btc to be consistent.

[kilrau]

Not crucial at the moment, just like I said.

We can go with a manual addcurrency call specifying all these details including swap client for now. In the long run I would want to get rid of "currencies" altogether and just have pairs once we are able to fetch all info from underlying clients.

[kilrau]

ERC20 and also other token standards contain a name and symbol field. We could just read this directly from the full node (e.g. geth) and use it as ticker symbol for the currency instead of asking the user to enter it manually. User can confirm or alter this. Token addresses without name or symbol require the user to enter a ticker symbol name.

[offerm]

For this xud would need direct access to geth. Something that we don't have today. Better to ask `raiden` to add this to their token API.

…

On Wed, May 8, 2019 at 9:26 PM Kilian Rausch ⚡️ ***@***.***> wrote: ERC20 and also other token standards contain a name and symbol field. We could just read this directly from the full node (e.g. geth) and use it as ticker symbol for the currency instead of asking the user to enter it manually. User can confirm or alter this. Token addresses without name or symbol require the user to enter a ticker symbol name. — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#896 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/ACKDI4SIQKEKEBGPJ6FC63LPUMLOJANCNFSM4HGTCM5Q> .

[engwarrior]

Pls provide estimate for this task.

[kilrau]

This one needs further discussion if that's even possible @engwarrior