feat: fetch node keys from subnet certificate

docs/generated/changelog.html

@@ -11,7 +11,13 @@ <h1>Agent-JS Changelog</h1>
 
     <section>
       <h2>Version x.x.x</h2>
-      <ul></ul>
+      <ul>
+        <li>
+          feat!: adds certificate logic to decode subnet and node key paths from the hashtree.
+          Changes the interface for `lookup_path` to allow returning a HashTree, but also constrains
+          `lookup` response to an ArrayBuffer using a new `lookupResultToBuffer` export
+        </li>
+      </ul>
       <h2>Version 0.19.3</h2>
       <ul>
         <li>fix: Principal JSON is compatible with @dfinity/utils jsonReviver helper</li>

packages/agent/src/agent/http/index.ts

@@ -27,6 +27,8 @@ import {
   SubmitRequestType,
 } from './types';
 import { AgentHTTPResponseError } from './errors';
+import { request } from '../../canisterStatus';
+import { SubnetStatus } from '../../certificate';
 
 export * from './transforms';
 export { Nonce, makeNonce } from './types';
@@ -178,6 +180,8 @@ export class HttpAgent implements Agent {
   private readonly _retryTimes; // Retry requests N times before erroring by default
   public readonly _isAgent = true;
 
+  #subnetKeys: Map<string, SubnetStatus> = new Map();
+
   constructor(options: HttpAgentOptions = {}) {
     if (options.source) {
       if (!(options.source instanceof HttpAgent)) {
@@ -575,6 +579,21 @@ export class HttpAgent implements Agent {
     this._identity = Promise.resolve(identity);
   }
 
+  public async fetchSubnetKeys(canisterId: Principal | string): Promise<any> {
+    const effectiveCanisterId: Principal = Principal.from(canisterId);
+    const response = await request({
+      canisterId: effectiveCanisterId,
+      paths: ['subnet'],
+      agent: this,
+    });
+
+    const subnetResponse = response.get('subnet');
+    if (subnetResponse && typeof subnetResponse === 'object' && 'nodeKeys' in subnetResponse) {
+      this.#subnetKeys.set(effectiveCanisterId.toText(), subnetResponse as SubnetStatus);
+    }
+    return subnetResponse;
+  }
+
   protected _transform(request: HttpAgentRequest): Promise<HttpAgentRequest> {
     let p = Promise.resolve(request);
 

packages/agent/src/canisterStatus/index.test.ts

@@ -188,6 +188,6 @@ describe('Canister Status utility', () => {
     expect(status.get('asdf' as unknown as Path)).toBe(null);
     // Expect undefined for unset value
     expect(status.get('test123')).toBe(undefined);
-    expect(consoleSpy).toBeCalledTimes(2);
+    expect(consoleSpy).toBeCalledTimes(3);
   });
 });

packages/agent/src/canisterStatus/index.ts

@@ -1,9 +1,13 @@
 /** @module CanisterStatus */
-
 import { Principal } from '@dfinity/principal';
 import { AgentError } from '../errors';
 import { HttpAgent } from '../agent/http';
-import { Certificate, CreateCertificateOptions } from '../certificate';
+import {
+  Certificate,
+  CreateCertificateOptions,
+  SubnetStatus,
+  lookupResultToBuffer,
+} from '../certificate';
 import { toHex } from '../utils/buffer';
 import * as Cbor from '../cbor';
 import { decodeLeb128, decodeTime } from '../utils/leb';
@@ -12,7 +16,15 @@ import { decodeLeb128, decodeTime } from '../utils/leb';
  * Types of an entry on the canisterStatus map.
  * An entry of null indicates that the request failed, due to lack of permissions or the result being missing.
  */
-export type Status = string | ArrayBuffer | Date | ArrayBuffer[] | Principal[] | bigint | null;
+export type Status =
+  | string
+  | ArrayBuffer
+  | Date
+  | ArrayBuffer[]
+  | Principal[]
+  | SubnetStatus
+  | bigint
+  | null;
 
 /**
  * Interface to define a custom path. Nested paths will be represented as individual buffers, and can be created from text using {@link TextEncoder}
@@ -98,7 +110,24 @@ export const request = async (options: {
           canisterId: canisterId,
         });
 
-        const data = cert.lookup(encodePath(uniquePaths[index], canisterId));
+        response.certificate;
+        const lookup = (cert: Certificate, path: Path) => {
+          if (path === 'subnet') {
+            const data = cert.cache_node_keys();
+            return {
+              path: path,
+              data,
+            };
+          } else {
+            return {
+              path: path,
+              data: lookupResultToBuffer(cert.lookup(encodePath(path, canisterId))),
+            };
+          }
+        };
+
+        // must pass in the rootKey if we have no delegation
+        const { path, data } = lookup(cert, uniquePaths[index]);
         if (!data) {
           // Typically, the cert lookup will throw
           console.warn(`Expected to find result for path ${path}, but instead found nothing.`);
@@ -121,6 +150,10 @@ export const request = async (options: {
               status.set(path, decodeHex(data));
               break;
             }
+            case 'subnet': {
+              status.set(path, data);
+              break;
+            }
             case 'candid': {
               status.set(path, new TextDecoder().decode(data));
               break;