Add CLN send via CLNRest

[ekzyis]

Describe the problem you're trying to solve

Looks like the CLNRest plugin we're already using to receive also supports spending:

Mhh, we might be able to pay using the CLNRest plugin we're already using. When you click on 'Try it!' here, it lists all available methods and pay, renepay and xpay are among them. 👀

-- https://stacker.news/items/910893

Describe the solution you'd like

Use CLNRest to spend from a CLN node.

Describe alternatives you've considered

No response

Additional context

No response

[Scroogey-SN]

I'm trying to extend the cln plugin to do this.

The config in index.js would need a second part with the pay parts (URL, rune for paying). I tried to glance from the nwc plugin how to make it so either part is optional. Even with requiredWithout: 'url' the validate: of the existing 'rune' fails (because empty). Is it supposed to validate an empty parameter when it's not required? Or do I need to extend the validation to allow empty?

How do you test making a bolt11 payment in dev? Buying CCs doesn't do that in dev.

[ekzyis]

The config in index.js would need a second part with the pay parts (URL, rune for paying).

I think you only need an additional rune since we can assume they are using the same URL for sending and receiving. That's also how it works with LNbits.

Even with requiredWithout: 'url' the validate: of the existing 'rune' fails (because empty). Is it supposed to validate an empty parameter when it's not required?

If you use requiredWithout: 'url' for a field, it is supposed to validate that this field was set (= required) if url is NOT set. So the rune for paying should be required if there's no rune for receiving and vice versa.

Btw, sorry for the confusing wallet config. I realized we didn't even document requiredWithout in wallets/README.md.

How do you test making a bolt11 payment in dev? Buying CCs doesn't do that in dev.

You can test a wallet by trying to zap with it

[Scroogey-SN]

When I add a runePay field and add the requiredWithout: it seems the .test() part of the 'rune' validate: gets evaluated even when I only fill in the runePay and leave rune empty, because I get an error "item is undefined" and the console shows a decodeRune() invokation.

However, if I replace the entire 'rune' validate: with string().length(64), it works when I only set runePay and leave rune empty.

I may misunderstand what the .test() clause does there. Why is it evaluated when rune is empty and not required?

--- a/wallets/cln/index.js
+++ b/wallets/cln/index.js
@@ -14,7 +14,6 @@ export const fields = [
     placeholder: '55.5.555.55:3010',
     hint: 'tor or clearnet',
     clear: true,
-    serverOnly: true,
     validate: string().socket()
   },
   {
@@ -33,6 +32,8 @@ export const fields = [
     hint: 'must be restricted to method=invoice',
     clear: true,
     serverOnly: true,
+    optional: 'for receiving',
+    requiredWithout: 'runePay',
     validate: string().matches(B64_URL_REGEX, { message: 'invalid rune' })
       .test({
         name: 'rune',
@@ -51,6 +52,20 @@ export const fields = [
           return true
         }
       })
+//  validate: string().length(64)
+//  validate: string().hexOrBase64()
+  },
+  {
+    name: 'runePay',
+    label: 'pay rune',
+    type: 'text',
+    placeholder: 'S34KtUW-6gqS_hD_9cc_PNhfF-NinZyBOCgr1aIrark9NCZtZXRob2Q9aW52b2ljZQ==',
+    hint: 'must allow method=pay',
+    clear: true,
+    clientOnly: true,
+    optional: 'for sending',
+    requiredWithout: 'rune',
+    validate: string().hexOrBase64()
   },
   {
     name: 'cert',

[ekzyis]

Why is it evaluated when rune is empty and not required?

We're using yup and it seems to always run test if it's defined, even if the value isn't set.

To avoid it failing if it's not set, we usually catch this case inside the test function.

Examples:

• NWC
• hex strings

But I think this is only limited to custom test functions. Built-in validators like .length don't seem to run when the value is not set.

Maybe there's a better way to deal with this instead of handling empty values inside test. Would be cool if we could mark something as .optional and then validation always succeeds if it's not set 🤔 But that's a different issue.