add support for lnurl comments

.gitignore

@@ -6,6 +6,7 @@ target/
 .env
 .fedimint-test-dir
 .test
+.idea
 
 # These are backup files generated by rustfmt
 **/*.rs.bk

migrations/2024-05-02-213721_add_lnurlp_comments/down.sql

@@ -0,0 +1 @@
+ALTER TABLE "invoice" DROP COLUMN "lnurlp_comment";

migrations/2024-05-02-213721_add_lnurlp_comments/up.sql

@@ -0,0 +1 @@
+ALTER TABLE "invoice" ADD COLUMN "lnurlp_comment" VARCHAR(100);

src/invoice.rs

@@ -146,6 +146,7 @@ async fn notify_user(
                 "bolt11": invoice.bolt11,
                 "preimage": invoice.preimage,
                 "zap_request": zap.as_ref().map(|z| z.request.clone()),
+                "lnurlp_comment": invoice.lnurlp_comment
             })
             .to_string(),
             None,

src/lnurlp.rs

@@ -37,7 +37,7 @@ pub async fn well_known_lnurlp(
         max_sendable: Amount { msats: MAX_AMOUNT },
         min_sendable: Amount { msats: MIN_AMOUNT },
         metadata: calc_metadata(&name, &state.domain_no_http()),
-        comment_allowed: None,
+        comment_allowed: Some(MAX_COMMENT_LEN),
         tag: LnurlType::PayRequest,
         status: LnurlStatus::Ok,
         nostr_pubkey: Some(state.nostr_sk.public_key()),
@@ -49,6 +49,7 @@ pub async fn well_known_lnurlp(
 
 const MAX_AMOUNT: u64 = 100_000_000 * 1_000; // 1 BTC
 const MIN_AMOUNT: u64 = 5_000; // 5 sats
+const MAX_COMMENT_LEN: i32 = 100;
 
 pub async fn lnurl_callback(
     state: &State,
@@ -86,6 +87,12 @@ pub async fn lnurl_callback(
         return Err(anyhow::anyhow!("Invalid nostr event"));
     }
 
+    if let Some(comment) = params.comment.as_ref() {
+        if comment.len() > MAX_COMMENT_LEN as usize {
+            return Err(anyhow::anyhow!("Comment too long"))
+        }
+    }
+
     let federation_id = FederationId::from_str(&user.federation_id)
         .map_err(|e| anyhow::anyhow!("Internal error: Invalid federation_id: {e}"))?;
 
@@ -134,6 +141,7 @@ pub async fn lnurl_callback(
         bolt11: pr.to_string(),
         amount: amount_msats as i64,
         state: InvoiceState::Pending as i32,
+        lnurlp_comment: params.comment
     };
 
     let created_invoice = state.db.insert_new_invoice(new_invoice)?;

src/models/invoice.rs

@@ -19,6 +19,7 @@ pub struct Invoice {
     pub bolt11: String,
     pub amount: i64,
     pub state: i32,
+    pub lnurlp_comment: Option<String>
 }
 
 impl Invoice {
@@ -74,6 +75,7 @@ pub struct NewInvoice {
     pub bolt11: String,
     pub amount: i64,
     pub state: i32,
+    pub lnurlp_comment: Option<String>
 }
 
 impl NewInvoice {

src/models/schema.rs

@@ -33,6 +33,8 @@ diesel::table! {
         bolt11 -> Varchar,
         amount -> Int8,
         state -> Int4,
+        #[max_length = 100]
+        lnurlp_comment -> Nullable<Varchar>,
     }
 }