fix: maxlimit check to subscription event requests (#600)

* fix: maxLimit checks added to subscription requests

* docs(changeset): fix: maxLimit checks added to subscription message handler

---------

Co-authored-by: Ricardo Cabral <me@ricardocabral.io>

Author: saniddhyaDubey

.changeset/brown-bears-pay.md

@@ -0,0 +1,5 @@
+---
+"nostream": patch
+---
+
+fix: maxLimit checks added to subscription message handler

src/handlers/subscribe-message-handler.ts

@@ -116,6 +116,14 @@ export class SubscribeMessageHandler implements IMessageHandler, IAbortable {
       }
     }
 
+    const maxLimit = subscriptionLimits?.maxLimit ?? 0
+    if (maxLimit > 0) {
+      const hasExcessiveLimit = filters.some((filter) => filter.limit !== undefined && filter.limit > maxLimit)
+      if (hasExcessiveLimit) {
+        return `Limit too high: Filter limit must be less than or equal to ${maxLimit}`
+      }
+    }
+
     if (
       typeof subscriptionLimits?.maxSubscriptionIdLength === 'number' &&
       subscriptionId.length > subscriptionLimits.maxSubscriptionIdLength

test/unit/handlers/subscribe-message-handler.spec.ts

@@ -367,6 +367,23 @@ describe('SubscribeMessageHandler', () => {
       )
     })
 
+    it('returns reason if filter limit exceeds max limit', () => {
+      settingsFactory.returns({
+        limits: {
+          client: {
+            subscription: {
+              maxLimit: 50,
+            },
+          },
+        },
+      })
+      filters = [{ limit: 100 }]
+
+      expect((handler as any).canSubscribe(subscriptionId, filters)).to.equal(
+        'Limit too high: Filter limit must be less than or equal to 50',
+      )
+    })
+
     it('returns reason if subscription id is too long', () => {
       settingsFactory.returns({
         limits: {