feat: add nip11 limitation fields for created_at, default_limit, and restricted_writes

Author: a-khushal

src/handlers/request-handlers/root-request-handler.ts

@@ -21,6 +21,19 @@ export const rootRequestHandler = (request: Request, response: Response, next: N
     paymentsUrl.pathname = '/invoices'
 
     const content = settings.limits?.event?.content
+    const eventLimits = settings.limits?.event
+    const createdAtLimits = eventLimits?.createdAt
+    const hasAdmissionRestriction =
+      settings.payments?.enabled === true &&
+      Boolean(settings.payments?.feeSchedules?.admission?.some((feeSchedule) => feeSchedule.enabled))
+    const hasWriteRestriction =
+      hasAdmissionRestriction ||
+      (eventLimits?.eventId?.minLeadingZeroBits ?? 0) > 0 ||
+      (eventLimits?.pubkey?.minLeadingZeroBits ?? 0) > 0 ||
+      (eventLimits?.pubkey?.whitelist?.length ?? 0) > 0 ||
+      (eventLimits?.pubkey?.blacklist?.length ?? 0) > 0 ||
+      (eventLimits?.kind?.whitelist?.length ?? 0) > 0 ||
+      (eventLimits?.kind?.blacklist?.length ?? 0) > 0
 
     const pubkey = rawPubkey.startsWith('npub1') ? fromBech32(rawPubkey) : rawPubkey
     const self = rawSelf?.startsWith('npub1') ? fromBech32(rawSelf) : rawSelf
@@ -49,9 +62,13 @@ export const rootRequestHandler = (request: Request, response: Response, next: N
         max_content_length: Array.isArray(content)
           ? content[0].maxLength // best guess since we have per-kind limits
           : content?.maxLength,
-        min_pow_difficulty: settings.limits?.event?.eventId?.minLeadingZeroBits,
+        min_pow_difficulty: eventLimits?.eventId?.minLeadingZeroBits,
         auth_required: false,
         payment_required: settings.payments?.enabled,
+        created_at_lower_limit: createdAtLimits?.maxNegativeDelta,
+        created_at_upper_limit: createdAtLimits?.maxPositiveDelta,
+        default_limit: 500,
+        restricted_writes: hasWriteRestriction,
       },
       payments_url: paymentsUrl.toString(),
       fees: Object.getOwnPropertyNames(settings.payments.feeSchedules).reduce(

test/unit/handlers/request-handlers/root-request-handler.spec.ts

@@ -124,6 +124,43 @@ describe('rootRequestHandler', () => {
       expect(doc.self).to.equal('f'.repeat(64))
       expect(doc.terms_of_service).to.equal('https://relay.example.com/terms')
     })
+
+    it('includes NIP-11 limitation created_at and default_limit fields', () => {
+      createSettingsStub.returns({
+        ...baseSettings,
+        limits: {
+          ...baseSettings.limits,
+          event: {
+            ...baseSettings.limits.event,
+            createdAt: {
+              maxNegativeDelta: 86400,
+              maxPositiveDelta: 300,
+            },
+          },
+        },
+      })
+
+      rootRequestHandler(req, res, next)
+
+      const doc = res.send.firstCall.args[0]
+      expect(doc.limitation.created_at_lower_limit).to.equal(86400)
+      expect(doc.limitation.created_at_upper_limit).to.equal(300)
+      expect(doc.limitation.default_limit).to.equal(500)
+    })
+
+    it('sets limitation.restricted_writes based on active write restrictions', () => {
+      rootRequestHandler(req, res, next)
+      const defaultDoc = res.send.firstCall.args[0]
+      expect(defaultDoc.limitation.restricted_writes).to.equal(false)
+
+      res.send.resetHistory()
+      createSettingsStub.returns(settingsWithFee)
+
+      rootRequestHandler(req, res, next)
+
+      const restrictedDoc = res.send.firstCall.args[0]
+      expect(restrictedDoc.limitation.restricted_writes).to.equal(true)
+    })
   })
 
   describe('when serving HTML', () => {