From c8651b1632315c13bb3eb8ecfa73063066192184 Mon Sep 17 00:00:00 2001
From: Abdul Azeem <sabdulazeem01@gmail.com>
Date: Thu, 7 Nov 2024 13:28:17 +0530
Subject: [PATCH 1/2] feat: Clear filtersMap when it reaches maximum entries
 allowed

The code changes in `api.ts` introduce a check to clear the `filtersMap` when it reaches the maximum number of entries allowed, as specified by the `maxEntriesAllowed` configuration value. This ensures that the `filtersMap` does not exceed the allowed size and prevents potential performance issues and DoS attacks
---
 src/api.ts    | 12 ++++++++++++
 src/config.ts |  2 ++
 2 files changed, 14 insertions(+)

diff --git a/src/api.ts b/src/api.ts
index 820c3677..a301ddb3 100755
--- a/src/api.ts
+++ b/src/api.ts
@@ -2799,6 +2799,10 @@ export const methods = {
       unsubscribe,
       type: Types.FilterTypes.block,
     }
+    if (filtersMap.size >= config.maxEntriesAllowed) {
+      filtersMap.clear()
+      console.log(`filtersMap cleared after ${config.maxEntriesAllowed} entries`)
+    }
     filtersMap.set(filterId.toString(), internalFilter)
 
     callback(null, filterId)
@@ -2833,6 +2837,10 @@ export const methods = {
       unsubscribe,
       type: Types.FilterTypes.pendingTransaction,
     }
+    if (filtersMap.size >= config.maxEntriesAllowed) {
+      filtersMap.clear()
+      console.log(`filtersMap cleared after ${config.maxEntriesAllowed} entries`)
+    }
     filtersMap.set(filterId.toString(), internalFilter)
 
     callback(null, filterId)
@@ -2934,6 +2942,10 @@ export const methods = {
       unsubscribe,
       type: Types.FilterTypes.log,
     }
+    if (filtersMap.size >= config.maxEntriesAllowed) {
+      filtersMap.clear()
+      console.log(`filtersMap cleared after ${config.maxEntriesAllowed} entries`)
+    }
     filtersMap.set(filterId.toString(), internalFilter)
 
     callback(null, filterId)
diff --git a/src/config.ts b/src/config.ts
index a633cf32..ae3e8be8 100644
--- a/src/config.ts
+++ b/src/config.ts
@@ -106,6 +106,7 @@ type Config = {
   }
   axiosTimeoutInMs: number
   enableBlacklistingIP: boolean
+  maxEntriesAllowed: number // maximum number of entries allowed for map to store
 }
 
 export type ServicePointTypes = 'aalg-warmup'
@@ -249,4 +250,5 @@ export const CONFIG: Config = {
   },
   axiosTimeoutInMs: 3000,
   enableBlacklistingIP: false,
+  maxEntriesAllowed: 10000,
 }

From 46ea364221d2eec6f284b98d4621ae5647b68dda Mon Sep 17 00:00:00 2001
From: Abdul Azeem <sabdulazeem01@gmail.com>
Date: Wed, 20 Nov 2024 14:21:58 +0300
Subject: [PATCH 2/2] feat: Implement removeOldestFilter to manage filtersMap
 size

---
 src/api.ts   | 10 ++++------
 src/utils.ts | 19 +++++++++++++++++++
 2 files changed, 23 insertions(+), 6 deletions(-)

diff --git a/src/api.ts b/src/api.ts
index a301ddb3..e8b394e8 100755
--- a/src/api.ts
+++ b/src/api.ts
@@ -27,6 +27,7 @@ import {
   getSyncTime,
   removeFromNodeList,
   sanitizeIpAndPort,
+  removeOldestFilter,
 } from './utils'
 import crypto from 'crypto'
 import { logEventEmitter } from './logger'
@@ -2800,8 +2801,7 @@ export const methods = {
       type: Types.FilterTypes.block,
     }
     if (filtersMap.size >= config.maxEntriesAllowed) {
-      filtersMap.clear()
-      console.log(`filtersMap cleared after ${config.maxEntriesAllowed} entries`)
+      removeOldestFilter(filtersMap)
     }
     filtersMap.set(filterId.toString(), internalFilter)
 
@@ -2838,8 +2838,7 @@ export const methods = {
       type: Types.FilterTypes.pendingTransaction,
     }
     if (filtersMap.size >= config.maxEntriesAllowed) {
-      filtersMap.clear()
-      console.log(`filtersMap cleared after ${config.maxEntriesAllowed} entries`)
+      removeOldestFilter(filtersMap)
     }
     filtersMap.set(filterId.toString(), internalFilter)
 
@@ -2943,8 +2942,7 @@ export const methods = {
       type: Types.FilterTypes.log,
     }
     if (filtersMap.size >= config.maxEntriesAllowed) {
-      filtersMap.clear()
-      console.log(`filtersMap cleared after ${config.maxEntriesAllowed} entries`)
+      removeOldestFilter(filtersMap)
     }
     filtersMap.set(filterId.toString(), internalFilter)
 
diff --git a/src/utils.ts b/src/utils.ts
index 38fda413..a60d10e0 100644
--- a/src/utils.ts
+++ b/src/utils.ts
@@ -29,6 +29,7 @@ import {
   OriginalTxData,
   AccountTypesData,
   Account2,
+  InternalFilter
 } from './types'
 import Sntp from '@hapi/sntp'
 import { randomBytes, createHash } from 'crypto'
@@ -1838,6 +1839,24 @@ export function sanitizeIpAndPort(ipPort: string): { isValid: boolean; error?: s
   return { isValid: true }
 }
 
+export function removeOldestFilter(filtersMap: Map<string, InternalFilter>): void {
+  let oldestKey: string | undefined;
+  let oldestTimestamp = Infinity;
+
+  // Iterate through the map to find the oldest entry
+  for (const [key, value] of filtersMap) {
+    if (value.filter.lastQueriedTimestamp < oldestTimestamp) {
+      oldestTimestamp = value.filter.lastQueriedTimestamp;
+      oldestKey = key;
+    }
+  }
+
+  // Remove the oldest entry
+  if (oldestKey !== undefined) {
+    filtersMap.delete(oldestKey);
+  }
+}
+
 class Semaphore {
   private queue: (() => void)[] = []
   private value: number