fix(arns): enforce undername limit

The ANTs provide the sorted array of records in resolution order. We are now enforcing the undername limits and returning a 402 to arns names that are not supported. Additional `X-ArNS-Limit` and `X-ArNS-Index` headers are added to indicate where the name/undername is in the list of records returned by the ANT.

package.json

@@ -8,7 +8,7 @@
     "url": "https://github.com/ar-io/ar-io-node"
   },
   "dependencies": {
-    "@ar.io/sdk": "^2.2.5",
+    "@ar.io/sdk": "^2.5.0-alpha.2",
     "@aws-lite/client": "^0.21.7",
     "@aws-lite/s3": "^0.1.21",
     "@clickhouse/client": "^1.3.0",

src/constants.ts

@@ -30,6 +30,8 @@ export const headerNames = {
   arnsResolvedId: 'X-ArNS-Resolved-Id',
   arnsProcessId: 'X-ArNS-Process-Id',
   arnsResolvedAt: 'X-ArNS-Resolved-At',
+  arnsLimit: 'X-ArNS-Limit',
+  arnsIndex: 'X-ArNS-Index',
 };
 
 export const DATA_PATH_REGEX =

src/middleware/arns.ts

@@ -20,7 +20,7 @@ import { asyncMiddleware } from 'middleware-async';
 
 import * as config from '../config.js';
 import { headerNames } from '../constants.js';
-import { sendNotFound } from '../routes/data/handlers.js';
+import { sendNotFound, sendPaymentRequired } from '../routes/data/handlers.js';
 import { DATA_PATH_REGEX } from '../constants.js';
 import { NameResolution, NameResolver } from '../types.js';
 import * as metrics from '../metrics.js';
@@ -90,20 +90,34 @@ export const createArnsMiddleware = ({
     };
 
     const start = Date.now();
-    const { resolvedId, ttl, processId, resolvedAt } =
+    const { resolvedId, ttl, processId, resolvedAt, limit, index } =
       await getArnsResolutionPromise().finally(() => {
         // remove from cache after resolution
         arnsRequestCache.del(arnsSubdomain);
       });
     metrics.arnsResolutionTime.observe(Date.now() - start);
+    // TODO: handle if undername is not supported based on undername limits and return a 402 error
     if (resolvedId === undefined) {
       sendNotFound(res);
       return;
     }
+
     res.header(headerNames.arnsResolvedId, resolvedId);
     res.header(headerNames.arnsTtlSeconds, ttl.toString());
     res.header(headerNames.arnsProcessId, processId);
     res.header(headerNames.arnsResolvedAt, resolvedAt.toString());
+    res.header(headerNames.arnsLimit, limit.toString());
+    res.header(headerNames.arnsIndex, index.toString());
+
+    // handle undername limit exceeded
+    if (index > limit) {
+      sendPaymentRequired(
+        res,
+        'ArNS undername limit exceeded. Purchase additional undernames to continue.',
+      );
+      return;
+    }
+
     // TODO: add a header for arns cache status
     res.header('Cache-Control', `public, max-age=${ttl}`);
     dataHandler(req, res, next);

src/resolution/composite-arns-resolver.ts

@@ -113,6 +113,8 @@ export class CompositeArNSResolver implements NameResolver {
         resolvedAt: undefined,
         ttl: undefined,
         processId: undefined,
+        limit: undefined,
+        index: undefined,
       }
     );
   }

src/resolution/on-demand-arns-resolver.ts

@@ -102,6 +102,8 @@ export class OnDemandArNSResolver implements NameResolver {
           resolvedAt: Date.now(),
           ttl: 300,
           processId: undefined,
+          limit: undefined,
+          index: undefined,
         };
       }
 
@@ -119,9 +121,19 @@ export class OnDemandArNSResolver implements NameResolver {
       const undername =
         name === baseName ? '@' : name.replace(`_${baseName}`, '');
 
-      const antRecord = await ant.getRecord({
-        undername,
-      });
+      // enforce the limit of undername resolution, the ant contract is responsible for returning names in the order they should be resolved
+      const antRecords = await ant.getRecords();
+
+      const nameIndex = antRecords.findIndex(
+        (record) => record.name === undername,
+      );
+
+      // validate the undername exists on the ant records
+      if (nameIndex === -1) {
+        throw new Error('Undername does not exist on the ant records');
+      }
+
+      const antRecord = antRecords[nameIndex];
 
       if (antRecord === undefined) {
         throw new Error('Invalid name, ant record for name not found');
@@ -139,6 +151,8 @@ export class OnDemandArNSResolver implements NameResolver {
         resolvedAt: Date.now(),
         processId: processId,
         ttl,
+        limit: arnsRecord.undernameLimit,
+        index: nameIndex,
       };
     } catch (error: any) {
       this.log.warn('Unable to resolve name:', {
@@ -154,6 +168,8 @@ export class OnDemandArNSResolver implements NameResolver {
       resolvedAt: undefined,
       ttl: undefined,
       processId: undefined,
+      limit: undefined,
+      index: undefined,
     };
   }
 }

src/resolution/trusted-gateway-arns-resolver.ts

@@ -56,6 +56,10 @@ export class TrustedGatewayArNSResolver implements NameResolver {
       const ttl =
         parseInt(response.headers[headerNames.arnsTtlSeconds.toLowerCase()]) ||
         DEFAULT_ARNS_TTL_SECONDS;
+      const limit =
+        parseInt(response.headers[headerNames.arnsLimit.toLowerCase()]) || 10;
+      const index =
+        parseInt(response.headers[headerNames.arnsIndex.toLowerCase()]) || 0;
       if (isValidDataId(resolvedId)) {
         this.log.info('Resolved name', { name, nameUrl, resolvedId, ttl });
         return {
@@ -64,13 +68,17 @@ export class TrustedGatewayArNSResolver implements NameResolver {
           resolvedAt: Date.now(),
           processId,
           ttl,
+          limit,
+          index,
         };
       } else {
         this.log.warn('Invalid resolved data ID', {
           name,
           nameUrl,
           resolvedId,
           ttl,
+          limit,
+          index,
         });
       }
     } catch (error: any) {
@@ -87,6 +95,8 @@ export class TrustedGatewayArNSResolver implements NameResolver {
       resolvedAt: undefined,
       ttl: undefined,
       processId: undefined,
+      limit: undefined,
+      index: undefined,
     };
   }
 }

src/routes/data/handlers.ts

@@ -331,6 +331,13 @@ export const sendNotFound = (res: Response) => {
   res.status(404).send('Not found');
 };
 
+export const sendPaymentRequired = (
+  res: Response,
+  text = 'Payment required',
+) => {
+  res.status(402).send(text);
+};
+
 // Data routes
 export const createRawDataHandler = ({
   log,

src/types.d.ts

@@ -603,6 +603,8 @@ export interface ValidNameResolution {
   resolvedAt: number;
   ttl: number;
   processId: string;
+  limit: number;
+  index: number;
 }
 
 // Name resolved, but is missing
@@ -612,6 +614,8 @@ export interface MissingNameResolution {
   resolvedAt: number;
   ttl: number;
   processId: undefined;
+  limit: undefined;
+  index: undefined;
 }
 
 // An error occured while resolving the name
@@ -621,6 +625,8 @@ export interface FailedNameResolution {
   resolvedAt: undefined;
   ttl: undefined;
   processId: undefined;
+  limit: undefined;
+  index: undefined;
 }
 
 type NameResolution =

yarn.lock

@@ -119,10 +119,10 @@
   dependencies:
     xss "^1.0.8"
 
-"@ar.io/sdk@^2.2.5":
-  version "2.3.2"
-  resolved "https://registry.yarnpkg.com/@ar.io/sdk/-/sdk-2.3.2.tgz#afac6c5cb38f517f53af6c9d70eeea9175fc70c4"
-  integrity sha512-O1BX951DzwRB3/9hc8O8PulxE84qe6wSN3ADqlJT4W0k9RcWLN/rbGMdSPaoN8dMgnxwtnIkXkHw6CG9Fu+V3g==
+"@ar.io/sdk@^2.5.0-alpha.2":
+  version "2.5.0-alpha.2"
+  resolved "https://registry.yarnpkg.com/@ar.io/sdk/-/sdk-2.5.0-alpha.2.tgz#dafa3649988691ac06c33afc53481c8b0b827a2f"
+  integrity sha512-vH8gF7P4qurGewYc38J2ari/o6Q7Hy9a6IGG8BLa96xzETxG8uCznw9widuuWxObCvzDp0DGIBxQPlrvsQxauA==
   dependencies:
     "@dha-team/arbundles" "^1.0.1"
     "@permaweb/aoconnect" "^0.0.57"