Http provider support multi (#2950)

* use queryStorageAt for multi storage queries

* fix lint

* e2e tests

* skip lints for api.spec.ts

* remove e2e test from PR

* do not decorate multi() if can not supported

* empty line

* update

Co-authored-by: Ian He <ian.he@centrality.ai>

packages/api/src/base/Decorate.ts

@@ -174,6 +174,13 @@ export abstract class Decorate<ApiType extends ApiTypes> extends Events {
     return this._rpcCore.provider.hasSubscriptions;
   }
 
+  /**
+   * @returns `true` if the API decorate multi-key queries
+   */
+  get supportMulti (): boolean {
+    return this._rpcCore.provider.hasSubscriptions || !!this._rpcCore.state.queryStorageAt;
+  }
+
   public injectMetadata (metadata: Metadata, fromEmpty?: boolean, registry?: Registry): void {
     const decoratedMeta = expandMetadata(registry || this.#registry, metadata);
 
@@ -300,10 +307,13 @@ export abstract class Decorate<ApiType extends ApiTypes> extends Events {
     }, input as DecoratedRpc<ApiType, RpcInterface>);
   }
 
+  // only be called if supportMulti is true
   protected _decorateMulti<ApiType extends ApiTypes> (decorateMethod: DecorateMethod<ApiType>): QueryableStorageMulti<ApiType> {
     // eslint-disable-next-line @typescript-eslint/no-unsafe-return
     return decorateMethod((calls: QueryableStorageMultiArg<ApiType>[]): Observable<Codec[]> =>
-      this._rpcCore.state.subscribeStorage(
+      (this.hasSubscriptions
+        ? this._rpcCore.state.subscribeStorage
+        : this._rpcCore.state.queryStorageAt)(
         calls.map((arg: QueryableStorageMultiArg<ApiType>) =>
           Array.isArray(arg)
             ? [arg[0].creator, ...arg.slice(1)]
@@ -403,8 +413,7 @@ export abstract class Decorate<ApiType extends ApiTypes> extends Events {
           this._retrieveMapKeysPaged(creator, opts)));
     }
 
-    // only support multi where subs are available
-    if (this.hasSubscriptions) {
+    if (this.supportMulti) {
       // When using double map storage function, user need to pass double map key as an array
       decorated.multi = decorateMethod((args: (Arg | Arg[])[]): Observable<Codec[]> =>
         this._retrieveMulti(args.map((arg) => [creator, arg])));
@@ -454,7 +463,10 @@ export abstract class Decorate<ApiType extends ApiTypes> extends Events {
       ...Array(Math.ceil(keys.length / PAGE_SIZE_VALS))
         .fill(0)
         .map((_, index): Observable<Codec[]> =>
-          this._rpcCore.state.subscribeStorage(keys.slice(index * PAGE_SIZE_VALS, (index * PAGE_SIZE_VALS) + PAGE_SIZE_VALS))
+          (this.hasSubscriptions
+            ? this._rpcCore.state.subscribeStorage
+            : this._rpcCore.state.queryStorageAt
+          )(keys.slice(index * PAGE_SIZE_VALS, (index * PAGE_SIZE_VALS) + PAGE_SIZE_VALS))
         )
     ).pipe(
       map((valsArr): Codec[] =>

packages/api/src/base/Init.ts

@@ -54,8 +54,12 @@ export abstract class Init<ApiType extends ApiTypes> extends Decorate<ApiType> {
 
     this._rpc = this._decorateRpc(this._rpcCore, this._decorateMethod);
     this._rx.rpc = this._decorateRpc(this._rpcCore, this._rxDecorateMethod);
-    this._queryMulti = this._decorateMulti(this._decorateMethod);
-    this._rx.queryMulti = this._decorateMulti(this._rxDecorateMethod);
+
+    if (this.supportMulti) {
+      this._queryMulti = this._decorateMulti(this._decorateMethod);
+      this._rx.queryMulti = this._decorateMulti(this._rxDecorateMethod);
+    }
+
     this._rx.signer = options.signer;
 
     this._rpcCore.setRegistrySwap((hash: string | Uint8Array) => this.getBlockRegistry(hash));