Proposal: implement custom TLV records for spontaneous payments #273
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| @@ -456,3 +456,12 @@ impl Default for ChannelConfig { | |||
| LdkChannelConfig::default().into() | |||
| } | |||
| } | |||
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| /// Custom TLV entry. | |||
| pub struct TlvEntry { | |||
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In the protocol the TLV entry is defined with a length
https://github.com/lightning/bolts/blob/master/01-messaging.md#type-length-value-format
Whats the reason of not including it here?
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I see that LDK is expecting type and value to set the tlv. I guess then the length is set by ldk when sending the message.
Maybe add a bit more info on the type and value describing the restrictions or characterizes of the props:
for example, for type:
type identifiers below 2^16 are reserved for use in this specification. type identifiers greater than or equal to 2^16 are available for custom records. (from the blip)
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In the protocol the TLV entry is defined with a length https://github.com/lightning/bolts/blob/master/01-messaging.md#type-length-value-format
Whats the reason of not including it here?
The length of the data buffer is used for that. I shall see if we can improve the representation, though
| @@ -490,8 +490,11 @@ pub(crate) fn do_channel_full_cycle<K: KVStore + Sync + Send, E: ElectrumApi>( | |||
| // Test spontaneous/keysend payments | |||
| println!("\nA send_spontaneous_payment"); | |||
| let keysend_amount_msat = 2500_000; | |||
| let keysend_payment_hash = | |||
| node_a.send_spontaneous_payment(keysend_amount_msat, node_b.node_id()).unwrap(); | |||
| let tlv1 = TlvEntry { r#type: 131073, value: vec![0x00, 0x11, 0x22, 0x33] }; | |||
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does this test validate that the counter-party node received the message?
| @@ -1222,7 +1222,7 @@ impl<K: KVStore + Sync + Send + 'static> Node<K> { | |||
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| /// Send a spontaneous, aka. "keysend", payment | |||
| pub fn send_spontaneous_payment( | |||
| &self, amount_msat: u64, node_id: PublicKey, | |||
| &self, amount_msat: u64, node_id: PublicKey, custom_tlvs: Vec<TlvEntry>, | |||
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are the custom_tlvs required in order to send a spontaneous payment?
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Not really required but may be useful. But I see the point, we'll probably take tnull's suggestion to base this change off PR 270; probably once it's merged
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Thanks for looking into this! While adding custom TLV support is stretching our 'keep API minimal' guidelines, I see that it can be of value for certain usecases.
I however agree with @jbesraa's question above regarding the optionality of custom TLVs. Rather than just adding it to the API method, could you base this entire PR off #270 and add it as a new SpontaneousPayment::send_with_custom_tlvs variant to and keep the default send method untouched?
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Is there a use for this people want in the immediate future aside from the messages thing? Is the podcast streaming sats thing using the messages field or are there other fields it uses? |
Yes, the main usecase is Podcasting 2.0: https://github.com/lightning/blips/blob/master/blip-0010.md |
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Ah, damn, that uses a different TLV than other messages, okay, fair enough, hard to capture that in a single API that isn't full-blown custom TLVs 😭 |
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should the |
A very simple implementation of custom TLV records for keysend requests.