From 85e544dc8e57e2c92bda3eb719973f73e8ad9d1b Mon Sep 17 00:00:00 2001
From: softsimon <softsimon@protonmail.com>
Date: Wed, 22 Jun 2022 13:15:44 +0200
Subject: [PATCH] Adding missing Block Tip Hash API

---
 .../src/api/bitcoin/bitcoin-api-abstract-factory.ts    |  1 +
 backend/src/api/bitcoin/bitcoin-api.ts                 |  7 +++++++
 backend/src/api/bitcoin/esplora-api.ts                 |  5 +++++
 backend/src/index.ts                                   |  1 +
 backend/src/routes.ts                                  | 10 ++++++++++
 5 files changed, 24 insertions(+)

diff --git a/backend/src/api/bitcoin/bitcoin-api-abstract-factory.ts b/backend/src/api/bitcoin/bitcoin-api-abstract-factory.ts
index 71269da31..0c64a9d63 100644
--- a/backend/src/api/bitcoin/bitcoin-api-abstract-factory.ts
+++ b/backend/src/api/bitcoin/bitcoin-api-abstract-factory.ts
@@ -4,6 +4,7 @@ export interface AbstractBitcoinApi {
   $getRawMempool(): Promise<IEsploraApi.Transaction['txid'][]>;
   $getRawTransaction(txId: string, skipConversion?: boolean, addPrevout?: boolean, lazyPrevouts?: boolean): Promise<IEsploraApi.Transaction>;
   $getBlockHeightTip(): Promise<number>;
+  $getBlockHashTip(): Promise<string>;
   $getTxIdsForBlock(hash: string): Promise<string[]>;
   $getBlockHash(height: number): Promise<string>;
   $getBlockHeader(hash: string): Promise<string>;
diff --git a/backend/src/api/bitcoin/bitcoin-api.ts b/backend/src/api/bitcoin/bitcoin-api.ts
index 41671ede1..1ff8486f4 100644
--- a/backend/src/api/bitcoin/bitcoin-api.ts
+++ b/backend/src/api/bitcoin/bitcoin-api.ts
@@ -64,6 +64,13 @@ class BitcoinApi implements AbstractBitcoinApi {
       });
   }
 
+  $getBlockHashTip(): Promise<string> {
+    return this.bitcoindClient.getChainTips()
+      .then((result: IBitcoinApi.ChainTips[]) => {
+        return result.find(tip => tip.status === 'active')!.hash;
+      });
+  }
+
   $getTxIdsForBlock(hash: string): Promise<string[]> {
     return this.bitcoindClient.getBlock(hash, 1)
       .then((rpcBlock: IBitcoinApi.Block) => rpcBlock.tx);
diff --git a/backend/src/api/bitcoin/esplora-api.ts b/backend/src/api/bitcoin/esplora-api.ts
index d92bba1bf..fbed1c429 100644
--- a/backend/src/api/bitcoin/esplora-api.ts
+++ b/backend/src/api/bitcoin/esplora-api.ts
@@ -25,6 +25,11 @@ class ElectrsApi implements AbstractBitcoinApi {
       .then((response) => response.data);
   }
 
+  $getBlockHashTip(): Promise<string> {
+    return axios.get<string>(config.ESPLORA.REST_API_URL + '/blocks/tip/hash', this.axiosConfig)
+      .then((response) => response.data);
+  }
+
   $getTxIdsForBlock(hash: string): Promise<string[]> {
     return axios.get<string[]>(config.ESPLORA.REST_API_URL + '/block/' + hash + '/txids', this.axiosConfig)
       .then((response) => response.data);
diff --git a/backend/src/index.ts b/backend/src/index.ts
index 6bd8de841..c61a45c69 100644
--- a/backend/src/index.ts
+++ b/backend/src/index.ts
@@ -329,6 +329,7 @@ class Server {
         .get(config.MEMPOOL.API_URL_PREFIX + 'tx/:txId/outspends', routes.getTransactionOutspends)
         .get(config.MEMPOOL.API_URL_PREFIX + 'block/:hash/header', routes.getBlockHeader)
         .get(config.MEMPOOL.API_URL_PREFIX + 'blocks/tip/height', routes.getBlockTipHeight)
+        .get(config.MEMPOOL.API_URL_PREFIX + 'blocks/tip/hash', routes.getBlockTipHash)
         .get(config.MEMPOOL.API_URL_PREFIX + 'block/:hash/txs', routes.getBlockTransactions)
         .get(config.MEMPOOL.API_URL_PREFIX + 'block/:hash/txs/:index', routes.getBlockTransactions)
         .get(config.MEMPOOL.API_URL_PREFIX + 'block/:hash/txids', routes.getTxIdsForBlock)
diff --git a/backend/src/routes.ts b/backend/src/routes.ts
index 99f54a9f8..e8db4e25d 100644
--- a/backend/src/routes.ts
+++ b/backend/src/routes.ts
@@ -901,6 +901,16 @@ class Routes {
     }
   }
 
+  public async getBlockTipHash(req: Request, res: Response) {
+    try {
+      const result = await bitcoinApi.$getBlockHashTip();
+      res.setHeader('content-type', 'text/plain');
+      res.send(result);
+    } catch (e) {
+      res.status(500).send(e instanceof Error ? e.message : e);
+    }
+  }
+
   public async getTxIdsForBlock(req: Request, res: Response) {
     try {
       const result = await bitcoinApi.$getTxIdsForBlock(req.params.hash);