Add beforeRequest decorator for ui sdk (#1983)

src/ui/libs/schematic-sdk/decorator.ts

@@ -0,0 +1,66 @@
+import type {SdkConfig} from '@gravity-ui/sdk';
+import {CancellablePromise} from '@gravity-ui/sdk';
+
+const CANCEL_REQUEST_EVENT = 'sdk_cancel_request';
+
+type ConcurrentId = string | undefined;
+
+class SdkEvent extends EventTarget {
+    cancelRequest(concurrentId: ConcurrentId) {
+        this.dispatchEvent(new CustomEvent(CANCEL_REQUEST_EVENT, {detail: {concurrentId}}));
+    }
+}
+const instance = new SdkEvent();
+
+function subscribeCancelRequest(cb: (concurrentId: ConcurrentId) => void) {
+    function subscribe(event: Event) {
+        const customEvent = event as CustomEvent<{concurrentId: ConcurrentId}>;
+        cb(customEvent.detail.concurrentId);
+    }
+    instance.addEventListener(CANCEL_REQUEST_EVENT, subscribe);
+    function unsubscribe() {
+        instance.removeEventListener(CANCEL_REQUEST_EVENT, subscribe);
+    }
+    return unsubscribe;
+}
+
+export function emitCancelRequest(concurrentId: ConcurrentId) {
+    instance.cancelRequest(concurrentId);
+}
+
+export function initBeforeRequestDecorator(
+    beforeRequest: () => Promise<unknown>,
+): SdkConfig['decorator'] {
+    return (sdkActionFunc) =>
+        (...sdkActionFuncArgs) => {
+            const requestOptions = sdkActionFuncArgs[1];
+            const concurrentId = requestOptions?.concurrentId;
+            let cancelled = false;
+            let actionPromise: ReturnType<typeof sdkActionFunc>;
+            let unsubscribe: ReturnType<typeof subscribeCancelRequest>;
+            if (concurrentId) {
+                unsubscribe = subscribeCancelRequest((emittedConcurrentId) => {
+                    if (emittedConcurrentId === concurrentId) {
+                        cancelled = true;
+                    }
+                });
+            }
+            return new CancellablePromise(
+                beforeRequest().then(() => {
+                    unsubscribe?.();
+                    actionPromise = sdkActionFunc(...sdkActionFuncArgs);
+                    if (cancelled) {
+                        actionPromise.cancel();
+                    }
+                    return actionPromise;
+                }),
+                () => {
+                    unsubscribe?.();
+                    actionPromise?.cancel();
+                    cancelled = true;
+                },
+            ).finally(() => {
+                unsubscribe?.();
+            });
+        };
+}

src/ui/libs/schematic-sdk/index.ts

@@ -19,6 +19,7 @@ import {DL} from '../../constants';
 import {registry} from '../../registry';
 import Utils from '../../utils';
 
+import {emitCancelRequest} from './decorator';
 import type {OperationError, SdkError} from './parse-error';
 import {handleRequestError, isOperationError, isSdkError} from './parse-error';
 
@@ -60,6 +61,7 @@ const sdkConfig: SdkConfig = {
             },
         };
     },
+    // decorator: initBeforeRequestDecorator(...),
 };
 
 export const initSdk = () => {
@@ -97,8 +99,15 @@ export const initSdk = () => {
     return sdk;
 };
 
+// TODO: return object with sdk and cancelRequest
 export const getSdk = () => {
     return registry.libs.schematicSdk.get() as DatalensSdk<{
         root: typeof schema;
     }>;
 };
+
+// Use it instead of sdk.cancelRequest
+export function cancelRequest(concurrentId: string) {
+    emitCancelRequest(concurrentId);
+    getSdk().cancelRequest(concurrentId);
+}