feat: make transaction optional in reverse claim endpoint (#771)

BoltzExchange · Jan 8, 2025 · 3ed922d · 3ed922d
1 parent a32ed36
commit 3ed922d
Show file tree

Hide file tree

Showing 5 changed files with 342 additions and 258 deletions.
diff --git a/lib/api/v2/routers/SwapRouter.ts b/lib/api/v2/routers/SwapRouter.ts
@@ -919,7 +919,7 @@ class SwapRouter extends RouterBase {
      *   schemas:
      *     ReverseClaimRequest:
      *       type: object
-     *       required: ["preimage", "pubNonce", "transaction", "index"]
+     *       required: ["preimage"]
      *       properties:
      *         preimage:
      *           type: string
@@ -939,7 +939,7 @@ class SwapRouter extends RouterBase {
      * @openapi
      * /swap/reverse/{id}/claim:
      *   post:
-     *     description: Requests a partial signature for a cooperative Reverse Swap claim transaction
+     *     description: Requests a partial signature for a cooperative Reverse Swap claim transaction. To settle the invoice, but not claim the onchain HTLC (eg to create a batched claim in the future), only the preimage is required. If no transaction is provided, an empty object is returned as response.
      *     tags: [Reverse]
      *     parameters:
      *       - in: path
@@ -1948,25 +1948,42 @@ class SwapRouter extends RouterBase {
       req.body,
       [
         { name: 'id', type: 'string', optional: params.id !== undefined },
-        { name: 'index', type: 'number' },
         { name: 'preimage', type: 'string', hex: true },
-        { name: 'pubNonce', type: 'string', hex: true },
-        { name: 'transaction', type: 'string', hex: true },
+        { name: 'index', type: 'number', optional: true },
+        { name: 'pubNonce', type: 'string', hex: true, optional: true },
+        { name: 'transaction', type: 'string', hex: true, optional: true },
       ],
     );
 
+    const toSignParams = [pubNonce, index, transaction];
+    const allDefined = toSignParams.every((param) => param !== undefined);
+    const allUndefined = toSignParams.every((param) => param === undefined);
+
+    if (!allDefined && !allUndefined) {
+      throw 'pubNonce, index and transaction must be all set or all undefined';
+    }
+
     const sig = await this.service.musigSigner.signReverseSwapClaim(
       params.id || id,
       preimage,
-      pubNonce,
-      transaction,
-      index,
+      allDefined
+        ? {
+            index,
+            theirNonce: pubNonce,
+            rawTransaction: transaction,
+          }
+        : undefined,
     );
 
-    successResponse(res, {
-      pubNonce: getHexString(sig.pubNonce),
-      partialSignature: getHexString(sig.signature),
-    });
+    successResponse(
+      res,
+      sig !== undefined
+        ? {
+            pubNonce: getHexString(sig.pubNonce),
+            partialSignature: getHexString(sig.signature),
+          }
+        : {},
+    );
   };
 
   private getChain = async (req: Request, res: Response) => {

diff --git a/lib/service/cooperative/MusigSigner.ts b/lib/service/cooperative/MusigSigner.ts
@@ -109,10 +109,12 @@ class MusigSigner {
   public signReverseSwapClaim = (
     swapId: string,
     preimage: Buffer,
-    theirNonce: Buffer,
-    rawTransaction: Buffer,
-    index: number,
-  ): Promise<PartialSignature> => {
+    toSign?: {
+      theirNonce: Buffer;
+      rawTransaction: Buffer;
+      index: number;
+    },
+  ): Promise<PartialSignature | undefined> => {
     return this.lock.acquire(
       MusigSigner.reverseSwapClaimSignatureLock,
       async () => {
@@ -154,6 +156,13 @@ class MusigSigner {
               await this.nursery.settleReverseSwapInvoice(swap, preimage);
             }
 
+            if (toSign === undefined) {
+              this.logger.debug(
+                `No transaction to sign for claim of Reverse Swap ${swap.id}`,
+              );
+              return undefined;
+            }
+
             this.logger.debug(
               `Creating partial signature for claim of Reverse Swap ${swap.id}`,
             );
@@ -175,9 +184,9 @@ class MusigSigner {
               swapTree,
               swap.keyIndex!,
               getHexBuffer(swap.claimPublicKey!),
-              theirNonce,
-              rawTransaction,
-              index,
+              toSign.theirNonce,
+              toSign.rawTransaction,
+              toSign.index,
             );
           },
         );

diff --git a/swagger-spec.json b/swagger-spec.json
@@ -1465,7 +1465,7 @@
     },
     "/swap/reverse/{id}/claim": {
       "post": {
-        "description": "Requests a partial signature for a cooperative Reverse Swap claim transaction",
+        "description": "Requests a partial signature for a cooperative Reverse Swap claim transaction. To settle the invoice, but not claim the onchain HTLC (eg to create a batched claim in the future), only the preimage is required. If no transaction is provided, an empty object is returned as response.",
         "tags": [
           "Reverse"
         ],
@@ -2648,10 +2648,7 @@
       "ReverseClaimRequest": {
         "type": "object",
         "required": [
-          "preimage",
-          "pubNonce",
-          "transaction",
-          "index"
+          "preimage"
         ],
         "properties": {
           "preimage": {