feat: await fetchRootKey calls while making API calls

move fetchRootKey calls from constructor to API calls

BREAKING CHANGE:

packages/agent/src/actor.ts

@@ -531,9 +531,6 @@ function _createActorMethod(
       const ecid = effectiveCanisterId !== undefined ? Principal.from(effectiveCanisterId) : cid;
       const arg = IDL.encode(func.argTypes, args);
 
-      if (agent.rootKey == null)
-        throw new AgentError('Agent root key not initialized before making call');
-
       const { requestId, response, requestDetails } = await agent.call(cid, {
         methodName,
         arg,
@@ -545,7 +542,7 @@ function _createActorMethod(
         const cert = (response.body as v3ResponseBody).certificate;
         certificate = await Certificate.create({
           certificate: bufFromBufLike(cert),
-          rootKey: agent.rootKey,
+          rootKey: await agent.getRootKey(),
           canisterId: Principal.from(canisterId),
           blsVerify,
         });

packages/agent/src/agent/api.ts

@@ -147,7 +147,12 @@ export interface SubmitResponse {
  * An Agent able to make calls and queries to a Replica.
  */
 export interface Agent {
-  readonly rootKey: ArrayBuffer | null;
+  /**
+   * Returns the root key of the network. This is used to verify the authenticity of
+   * responses from the network.
+   */
+  getRootKey(): Promise<ArrayBuffer>;
+
   /**
    * Returns the principal ID associated with this agent (by default). It only shows
    * the principal of the default identity in the agent, which is the principal used

packages/agent/src/agent/http/http.test.ts

@@ -800,10 +800,9 @@ test('retry requests that fail due to a network failure', async () => {
   const agent = new HttpAgent({
     host: HTTP_AGENT_HOST,
     fetch: mockFetch,
+    rootKey: new Uint8Array(32),
   });
 
-  agent.rootKey = new Uint8Array(32);
-
   try {
     await agent.call(Principal.managementCanister(), {
       methodName: 'test',

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

@@ -150,6 +150,14 @@ export interface HttpAgentOptions {
    * Alternate root key to use for verifying certificates. If not provided, the default IC root key will be used.
    */
   rootKey?: ArrayBuffer;
+
+  /**
+   * Whether the agent should fetch the root key from the network. Defaults to false.
+   *
+   * WARNING!!! Do not enable this in production environments,
+   * as it can be used as an attack vector by malicious nodes.
+   */
+  shouldFetchRootKey?: boolean;
 }
 
 function getDefaultFetch(): typeof fetch {
@@ -245,19 +253,21 @@ other computations so that this class can stay as simple as possible while
 allowing extensions.
  */
 export class HttpAgent implements Agent {
-  public rootKey: ArrayBuffer;
   #identity: Promise<Identity> | null;
   readonly #fetch: typeof fetch;
   readonly #fetchOptions?: Record<string, unknown>;
   readonly #callOptions?: Record<string, unknown>;
   #timeDiffMsecs = 0;
   readonly host: URL;
   readonly #credentials: string | undefined;
-  #rootKeyFetched = false;
   readonly #retryTimes; // Retry requests N times before erroring by default
   #backoffStrategy: BackoffStrategyFactory;
   readonly #maxIngressExpiryInMinutes: number;
 
+  #rootKey: ArrayBuffer;
+  readonly #shouldFetchRootKey: boolean;
+  #fetchRootKeyPromise: Promise<ArrayBuffer> | null = null;
+
   // Public signature to help with type checking.
   public readonly _isAgent = true;
   public config: HttpAgentOptions = {};
@@ -288,7 +298,11 @@ export class HttpAgent implements Agent {
     this.#fetch = options.fetch || getDefaultFetch() || fetch.bind(global);
     this.#fetchOptions = options.fetchOptions;
     this.#callOptions = options.callOptions;
-    this.rootKey = options.rootKey ? options.rootKey : fromHex(IC_ROOT_KEY);
+
+    this.#rootKey = options.rootKey ?? fromHex(IC_ROOT_KEY);
+    this.#shouldFetchRootKey = options.shouldFetchRootKey ?? false;
+    // kick off the fetchRootKey process asynchronously, if needed
+    (async () => await this.fetchRootKey())();
 
     const host = determineHost(options.host);
     this.host = new URL(host);
@@ -354,16 +368,9 @@ export class HttpAgent implements Agent {
     return new this({ ...options });
   }
 
-  public static async create(
-    options: HttpAgentOptions & { shouldFetchRootKey?: boolean } = {
-      shouldFetchRootKey: false,
-    },
-  ): Promise<HttpAgent> {
+  public static async create(options: HttpAgentOptions = {}): Promise<HttpAgent> {
     const agent = HttpAgent.createSync(options);
     const initPromises: Promise<ArrayBuffer | void>[] = [agent.syncTime()];
-    if (agent.host.toString() !== 'https://icp-api.io' && options.shouldFetchRootKey) {
-      initPromises.push(agent.fetchRootKey());
-    }
     await Promise.all(initPromises);
     return agent;
   }
@@ -437,7 +444,7 @@ export class HttpAgent implements Agent {
   ): Promise<SubmitResponse> {
     // TODO - restore this value
     const callSync = options.callSync ?? true;
-    const id = await (identity !== undefined ? await identity : await this.#identity);
+    const id = identity !== undefined ? await identity : await this.#identity;
     if (!id) {
       throw new IdentityInvalidError(
         "This identity has expired due this application's security policy. Please refresh your authentication.",
@@ -1125,14 +1132,27 @@ export class HttpAgent implements Agent {
     return cbor.decode(await response.arrayBuffer());
   }
 
+  async getRootKey(): Promise<ArrayBuffer> {
+    return this.fetchRootKey();
+  }
+
   public async fetchRootKey(): Promise<ArrayBuffer> {
-    if (!this.#rootKeyFetched) {
-      const status = await this.status();
-      // Hex-encoded version of the replica root key
-      this.rootKey = (status as JsonObject & { root_key: ArrayBuffer }).root_key;
-      this.#rootKeyFetched = true;
+    if (!this.#shouldFetchRootKey) {
+      return this.#rootKey;
+    }
+
+    if (this.#fetchRootKeyPromise === null) {
+      this.#fetchRootKeyPromise = this.#fetchRootKey();
     }
-    return this.rootKey;
+
+    return await this.#fetchRootKeyPromise;
+  }
+
+  async #fetchRootKey(): Promise<ArrayBuffer> {
+    const status = await this.status();
+    // Hex-encoded version of the replica root key
+    this.#rootKey = (status as JsonObject & { root_key: ArrayBuffer }).root_key;
+    return this.#rootKey;
   }
 
   public invalidateIdentity(): void {

packages/agent/src/agent/proxy.ts

@@ -158,7 +158,8 @@ export class ProxyStubAgent {
 export class ProxyAgent implements Agent {
   private _nextId = 0;
   private _pendingCalls = new Map<number, [(resolve: any) => void, (reject: any) => void]>();
-  public rootKey = null;
+
+  #fetchRootKeyPromise: Promise<ArrayBuffer> | null = null;
 
   constructor(private _backend: (msg: ProxyMessage) => void) {}
 
@@ -241,10 +242,20 @@ export class ProxyAgent implements Agent {
     });
   }
 
+  async getRootKey(): Promise<ArrayBuffer> {
+    return this.fetchRootKey();
+  }
+
   public async fetchRootKey(): Promise<ArrayBuffer> {
+    if (this.#fetchRootKeyPromise === null) {
+      this.#fetchRootKeyPromise = this.#fetchRootKey();
+    }
+
+    return await this.#fetchRootKeyPromise;
+  }
+
+  async #fetchRootKey(): Promise<ArrayBuffer> {
     // Hex-encoded version of the replica root key
-    const rootKey = ((await this.status()) as any).root_key;
-    this.rootKey = rootKey;
-    return rootKey;
+    return ((await this.status()) as any).root_key;
   }
 }

packages/agent/src/canisterStatus/index.ts

@@ -147,13 +147,13 @@ export const request = async (options: {
         });
         const cert = await Certificate.create({
           certificate: response.certificate,
-          rootKey: agent.rootKey,
+          rootKey: await agent.getRootKey(),
           canisterId: canisterId,
         });
 
-        const lookup = (cert: Certificate, path: Path) => {
+        const lookup = async (cert: Certificate, path: Path) => {
           if (path === 'subnet') {
-            const data = fetchNodeKeys(response.certificate, canisterId, agent.rootKey);
+            const data = fetchNodeKeys(response.certificate, canisterId, await agent.getRootKey());
             return {
               path: path,
               data,
@@ -167,7 +167,7 @@ export const request = async (options: {
         };
 
         // must pass in the rootKey if we have no delegation
-        const { path, data } = lookup(cert, uniquePaths[index]);
+        const { path, data } = await 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.`);

packages/agent/src/polling/index.ts

@@ -92,10 +92,9 @@ export async function pollForResponse(
   }
 
   const state = await agent.readState(canisterId, { paths: [path] }, undefined, currentRequest);
-  if (agent.rootKey == null) throw new Error('Agent root key not initialized before polling');
   const cert = await Certificate.create({
     certificate: state.certificate,
-    rootKey: agent.rootKey,
+    rootKey: await agent.getRootKey(),
     canisterId: canisterId,
     blsVerify,
   });