added test for fetching chunk

electron/src/lite-node/api/account.ts

@@ -9,6 +9,7 @@ import {
   handleActiveChat,
   handleAddressGroupInvitesMessage,
   handleArbitraryDataFileList,
+  handleArbitraryDataFileMessage,
   handleArbitraryLatestTransaction,
   handleBlockDataMessage,
   handleGroupBansMessage,
@@ -34,6 +35,7 @@ import {
   createGetAddressGroupInvitesPayload,
   createGetAddressNamesPayload,
   createGetArbitraryDataFileListPayload,
+  createGetArbitraryDataFilePayload,
   createGetArbitraryLatestTransactionPayload,
   createGetBansPayload,
   createGetGroupInvitesPayload,
@@ -178,8 +180,20 @@ export async function getArbitraryResource(
         null
       )
     );
+    const dataFileList = handleArbitraryDataFileList(res2);
+    if (dataFileList.hashes?.length > 0) {
+      const res3: Buffer = await client.sendRequest(
+        MessageType.GET_ARBITRARY_DATA_FILE,
+        createGetArbitraryDataFilePayload(
+          dataFileList.signature,
+          dataFileList.hashes[0]
+        )
+      );
 
-    console.log('res22', handleArbitraryDataFileList(res2));
+      console.log('res333', handleArbitraryDataFileMessage(res3));
+    }
+
+    console.log('res22');
   }
   if (Array.isArray(data) && data.length > 0) {
     return data[0];

electron/src/lite-node/messages/handlers.ts

@@ -1151,3 +1151,34 @@ export function handleArbitraryDataFileList(buffer) {
     isRelayPossible,
   };
 }
+
+export function handleArbitraryDataFileMessage(buffer) {
+  let offset = 0;
+
+  if (buffer.length < 68) {
+    throw new Error(
+      `Invalid message length: got ${buffer.length}, expected at least 68`
+    );
+  }
+
+  const signature = buffer.subarray(offset, offset + 64);
+  offset += 64;
+
+  const dataLength = buffer.readInt32BE(offset);
+  offset += 4;
+
+  const remaining = buffer.length - offset;
+  if (remaining < dataLength) {
+    throw new Error(
+      `Data length mismatch: expected ${dataLength} bytes, but only ${remaining} bytes available`
+    );
+  }
+
+  const data = buffer.subarray(offset, offset + dataLength);
+
+  return {
+    signature,
+    dataLength,
+    data,
+  };
+}

electron/src/lite-node/protocol/messageTypes.ts

@@ -10,6 +10,8 @@ export enum MessageType {
   GET_SUPPLY = 74,
   LAST_BLOCK_HEIGHT = 75,
   GET_LAST_BLOCK_HEIGHT = 76,
+  ARBITRARY_DATA_FILE = 110,
+  GET_ARBITRARY_DATA_FILE = 111,
   ARBITRARY_DATA_FILE_LIST = 120,
   GET_ARBITRARY_DATA_FILE_LIST = 121,
   ARBITRARY_LATEST_TRANSACTION = 122,

electron/src/lite-node/protocol/payloads.ts

@@ -610,3 +610,19 @@ export function createGetArbitraryDataFileListPayload(
 
   return Buffer.concat(buffers);
 }
+
+export function createGetArbitraryDataFilePayload(signature, hash) {
+  if (signature.length !== 64) {
+    throw new Error(
+      `Invalid signature length: expected 64 bytes, got ${signature.length}`
+    );
+  }
+
+  if (hash.length !== 32) {
+    throw new Error(
+      `Invalid hash length: expected 32 bytes, got ${hash.length}`
+    );
+  }
+
+  return Buffer.concat([signature, hash]);
+}