From 8a508b4d15594484e459b742620fc29a66d3e2e7 Mon Sep 17 00:00:00 2001
From: Tanuj Soni <tanuj@shardeum.org>
Date: Wed, 25 Sep 2024 19:21:23 +0530
Subject: [PATCH] Add /tx-digest-hash endpoint to fetch last x tx digests

---
 src/Config.ts                       |  2 ++
 src/txDigester/api.ts               | 28 +++++++++++++++++++++++++++-
 src/txDigester/txDigestFunctions.ts |  7 +++++++
 src/txDigester/txDigests.ts         | 16 +++++++++++++++-
 4 files changed, 51 insertions(+), 2 deletions(-)

diff --git a/src/Config.ts b/src/Config.ts
index 49bb21a2..a7135134 100644
--- a/src/Config.ts
+++ b/src/Config.ts
@@ -61,6 +61,7 @@ export interface Config {
     MAX_ORIGINAL_TXS_PER_REQUEST: number
     MAX_CYCLES_PER_REQUEST: number
     MAX_BETWEEN_CYCLES_PER_REQUEST: number
+    MAX_DIGESTS_PER_REQUEST: number
   }
   cycleRecordsCache: {
     enabled: boolean
@@ -157,6 +158,7 @@ let config: Config = {
     MAX_ORIGINAL_TXS_PER_REQUEST: 100,
     MAX_CYCLES_PER_REQUEST: 100,
     MAX_BETWEEN_CYCLES_PER_REQUEST: 100,
+    MAX_DIGESTS_PER_REQUEST: 100,
   },
   cycleRecordsCache: {
     enabled: false,
diff --git a/src/txDigester/api.ts b/src/txDigester/api.ts
index 79189940..f320eeb4 100644
--- a/src/txDigester/api.ts
+++ b/src/txDigester/api.ts
@@ -1,6 +1,8 @@
 import { FastifyInstance, FastifyRequest } from 'fastify'
 import { Server, IncomingMessage, ServerResponse } from 'http'
-import { getTxDigestsForACycleRange } from './txDigestFunctions'
+import { getLatestTxDigests, getTxDigestsForACycleRange } from './txDigestFunctions'
+import { config } from '../Config'
+import * as Utils from '../Utils'
 
 type GetTxDigestsRequest = FastifyRequest<{
   Querystring: {
@@ -8,6 +10,9 @@ type GetTxDigestsRequest = FastifyRequest<{
     cycleEnd: number
   }
 }>
+type GetLatestTxDigestsRequest = FastifyRequest<{
+  Params: { count: string }
+}>
 
 /* To-Do: Add LRU cache for the tx-digests */
 export function registerRoutes(server: FastifyInstance<Server, IncomingMessage, ServerResponse>): void {
@@ -34,4 +39,25 @@ export function registerRoutes(server: FastifyInstance<Server, IncomingMessage,
     console.log('Fetched Tx digests', txDigests)
     reply.send(txDigests)
   })
+  
+  server.get('/api/tx-digest-hash/:count', async (_request: GetLatestTxDigestsRequest, reply) => {
+    const err = Utils.validateTypes(_request.params, { count: 's' })
+    if (err) {
+      reply.send({ success: false, error: err })
+      return
+    }
+    let count: number = parseInt(_request.params.count)
+    if (count <= 0 || Number.isNaN(count)) {
+      reply.send({ success: false, error: `Invalid count` })
+      return
+    }
+    if (count > config.REQUEST_LIMIT.MAX_DIGESTS_PER_REQUEST) {
+      count = config.REQUEST_LIMIT.MAX_DIGESTS_PER_REQUEST
+    }
+    
+    console.log(`Fetching latest ${count} tx digests`)
+    const txDigests = await getLatestTxDigests(count)
+    console.log('Fetched Tx digests', txDigests)
+    reply.send(txDigests)
+  })
 }
diff --git a/src/txDigester/txDigestFunctions.ts b/src/txDigester/txDigestFunctions.ts
index 5438bda4..1fa53445 100644
--- a/src/txDigester/txDigestFunctions.ts
+++ b/src/txDigester/txDigestFunctions.ts
@@ -102,3 +102,10 @@ export const getTxDigestsForACycleRange = async (
   const txDigests: txDigest.TransactionDigest[] = await txDigest.queryByCycleRange(cycleStart, cycleEnd)
   return txDigests
 }
+
+export const getLatestTxDigests = async (
+  count: number
+): Promise<txDigest.TransactionDigest[]> => {
+  const txDigests: txDigest.TransactionDigest[] = await txDigest.queryLatestTxDigests(count)
+  return txDigests
+}
diff --git a/src/txDigester/txDigests.ts b/src/txDigester/txDigests.ts
index 6c895e62..cb2ed515 100644
--- a/src/txDigester/txDigests.ts
+++ b/src/txDigester/txDigests.ts
@@ -79,7 +79,21 @@ export async function queryByCycleRange(startCycle: number, endCycle: number): P
     }
     return txDigests || []
   } catch (e) {
-    console.error(e)
+    console.error('Error fetching txDigests from DB: ', e)
+    return []
+  }
+}
+
+export async function queryLatestTxDigests(count: number): Promise<TransactionDigest[]> {
+  try {
+    const sql = `SELECT * FROM txDigests ORDER BY cycleEnd DESC LIMIT ?`
+    const txDigests = (await db.all(digesterDatabase, sql, [count])) as TransactionDigest[]
+    if (config.VERBOSE) {
+      console.log('Latest Tx Digests', txDigests)
+    }
+    return txDigests || []
+  } catch (e) {
+    console.error('Error fetching latest tx digests from DB: ', e)
     return []
   }
 }