Tests for error handling

package-lock.json

@@ -7569,6 +7569,13 @@
         "n3": "^1.17.2"
       }
     },
+    "node_modules/@solid-notifications/types": {
+      "version": "0.1.2",
+      "resolved": "https://registry.npmjs.org/@solid-notifications/types/-/types-0.1.2.tgz",
+      "integrity": "sha512-0SP6XmOjFhqt/m4FFXnYh6slSiXMoheO3UpU7POSDStLSb6tLVAQLiy0hBKvNyGBLlftRObHWoBWlt2X/LhVRg==",
+      "dev": true,
+      "license": "MIT"
+    },
     "node_modules/@solid/access-control-policy": {
       "version": "0.1.3",
       "dev": true,
@@ -29628,6 +29635,7 @@
         "@ldo/cli": "^0.0.1-alpha.28",
         "@rdfjs/data-model": "^1.2.0",
         "@rdfjs/types": "^1.0.1",
+        "@solid-notifications/types": "^0.1.2",
         "@solid/community-server": "^7.1.3",
         "@types/jest": "^27.0.3",
         "cross-env": "^7.0.3",

packages/solid/package.json

@@ -29,6 +29,7 @@
     "@ldo/cli": "^0.0.1-alpha.28",
     "@rdfjs/data-model": "^1.2.0",
     "@rdfjs/types": "^1.0.1",
+    "@solid-notifications/types": "^0.1.2",
     "@solid/community-server": "^7.1.3",
     "@types/jest": "^27.0.3",
     "cross-env": "^7.0.3",

packages/solid/src/resource/Resource.ts

@@ -334,8 +334,7 @@ export abstract class Resource extends (EventEmitter as new () => TypedEmitter<{
    * ```
    */
   isSubscribedToNotifications(): boolean {
-    // TODO
-    throw new Error("Not Implemented");
+    return !!this.notificationSubscription;
   }
 
   /**
@@ -732,10 +731,13 @@ export abstract class Resource extends (EventEmitter as new () => TypedEmitter<{
   /**
    * TODO
    */
-  async subscribeToNotifications(): Promise<OpenSubscriptionResult> {
+  async subscribeToNotifications(
+    onNotificationError?: (err: Error) => void,
+  ): Promise<OpenSubscriptionResult> {
     this.notificationSubscription = new Websocket2023NotificationSubscription(
       this,
       this.onNotification.bind(this),
+      onNotificationError,
       this.context,
     );
     return await this.notificationSubscription.open();

packages/solid/src/resource/notifications/NotificationSubscription.ts

@@ -18,15 +18,18 @@ export type CloseSubscriptionResult =
 export abstract class NotificationSubscription {
   protected resource: Resource;
   protected onNotification: (message: NotificationMessage) => void;
+  protected onError?: (err: Error) => void;
   protected context: SolidLdoDatasetContext;
 
   constructor(
     resource: Resource,
     onNotification: (message: NotificationMessage) => void,
+    onError: ((err: Error) => void) | undefined,
     context: SolidLdoDatasetContext,
   ) {
     this.resource = resource;
     this.onNotification = onNotification;
+    this.onError = onError;
     this.context = context;
   }
 

packages/solid/src/resource/notifications/Websocket2023NotificationSubscription.ts

@@ -8,37 +8,35 @@ import { SubscriptionClient } from "@solid-notifications/subscription";
 import { WebSocket } from "ws";
 import { UnsupportedNotificationError } from "./results/NotificationErrors";
 import type { NotificationMessage } from "./NotificationMessage";
+import type { Resource } from "../Resource";
+import type { SolidLdoDatasetContext } from "../../SolidLdoDatasetContext";
+import type {
+  ChannelType,
+  NotificationChannel,
+} from "@solid-notifications/types";
 
 const CHANNEL_TYPE =
   "http://www.w3.org/ns/solid/notifications#WebSocketChannel2023";
 
 export class Websocket2023NotificationSubscription extends NotificationSubscription {
   private socket: WebSocket | undefined;
+  private createWebsocket: (address: string) => WebSocket;
+
+  constructor(
+    resource: Resource,
+    onNotification: (message: NotificationMessage) => void,
+    onError: ((err: Error) => void) | undefined,
+    context: SolidLdoDatasetContext,
+    createWebsocket?: (address: string) => WebSocket,
+  ) {
+    super(resource, onNotification, onError, context);
+    this.createWebsocket = createWebsocket ?? createWebsocketDefault;
+  }
 
   async open(): Promise<OpenSubscriptionResult> {
-    const client = new SubscriptionClient(this.context.fetch);
     try {
-      const notificationChannel = await client.subscribe(
-        this.resource.uri,
-        CHANNEL_TYPE,
-      );
-      return new Promise<OpenSubscriptionResult>((resolve) => {
-        this.socket = new WebSocket(notificationChannel.receiveFrom);
-        this.socket.onmessage = (message) => {
-          const messageData = message.data.toString();
-          // TODO uncompliant Pod error on misformatted message
-          this.onNotification(JSON.parse(messageData) as NotificationMessage);
-        };
-        this.socket.onerror = (err) =>
-          resolve(UnexpectedResourceError.fromThrown(this.resource.uri, err));
-        this.socket.onopen = () => {
-          resolve({
-            isError: false,
-            type: "subscribeToNotificationSuccess",
-            uri: this.resource.uri,
-          });
-        };
-      });
+      const notificationChannel = await this.discoverNotificationChannel();
+      return this.subscribeToWebsocket(notificationChannel);
     } catch (err) {
       if (
         err instanceof Error &&
@@ -50,6 +48,45 @@ export class Websocket2023NotificationSubscription extends NotificationSubscript
     }
   }
 
+  async discoverNotificationChannel(): Promise<NotificationChannel> {
+    const client = new SubscriptionClient(this.context.fetch);
+    return await client.subscribe(
+      this.resource.uri,
+      CHANNEL_TYPE as ChannelType,
+    );
+  }
+
+  async subscribeToWebsocket(
+    notificationChannel: NotificationChannel,
+  ): Promise<OpenSubscriptionResult> {
+    return new Promise<OpenSubscriptionResult>((resolve) => {
+      let didResolve = false;
+      this.socket = this.createWebsocket(
+        notificationChannel.receiveFrom as string,
+      );
+      this.socket.onmessage = (message) => {
+        const messageData = message.data.toString();
+        // TODO uncompliant Pod error on misformatted message
+        this.onNotification(JSON.parse(messageData) as NotificationMessage);
+      };
+      this.socket.onerror = (err) => {
+        if (!didResolve) {
+          resolve(UnexpectedResourceError.fromThrown(this.resource.uri, err));
+        } else {
+          this.onError?.(err.error);
+        }
+      };
+      this.socket.onopen = () => {
+        didResolve = true;
+        resolve({
+          isError: false,
+          type: "subscribeToNotificationSuccess",
+          uri: this.resource.uri,
+        });
+      };
+    });
+  }
+
   async close(): Promise<CloseSubscriptionResult> {
     this.socket?.terminate();
     return {
@@ -59,3 +96,7 @@ export class Websocket2023NotificationSubscription extends NotificationSubscript
     };
   }
 }
+
+function createWebsocketDefault(address: string) {
+  return new WebSocket(address);
+}

packages/solid/src/resource/notifications/results/NotificationErrors.ts

@@ -1,5 +1,5 @@
 import { ResourceError } from "../../../requester/results/error/ErrorResult";
 
 export class UnsupportedNotificationError extends ResourceError {
-  readonly type = "unexpectedResourceError" as const;
+  readonly type = "unsupportedNotificationError" as const;
 }

packages/solid/test/Integration.test.ts

@@ -2038,6 +2038,8 @@ describe("Integration", () => {
       const subscriptionResult = await resource.subscribeToNotifications();
       expect(subscriptionResult.type).toBe("subscribeToNotificationSuccess");
 
+      expect(resource.isSubscribedToNotifications()).toBe(true);
+
       await authFetch(SAMPLE_DATA_URI, {
         method: "PATCH",
         body: 'INSERT DATA { <http://example.org/#spiderman> <http://xmlns.com/foaf/0.1/name> "Peter Parker" . }',
@@ -2062,6 +2064,7 @@ describe("Integration", () => {
       expect(unsubscribeResponse.type).toBe(
         "unsubscribeFromNotificationSuccess",
       );
+      expect(resource.isSubscribedToNotifications()).toBe(false);
       await authFetch(SAMPLE_DATA_URI, {
         method: "PATCH",
         body: 'INSERT DATA { <http://example.org/#spiderman> <http://xmlns.com/foaf/0.1/name> "Miles Morales" . }',
@@ -2079,8 +2082,6 @@ describe("Integration", () => {
           literal("Miles Morales"),
         ).size,
       ).toBe(0);
-
-      await resource.unsubscribeFromNotifications();
     });
 
     it("handles notification when subscribed to a child that is deleted", async () => {
@@ -2191,5 +2192,38 @@ describe("Integration", () => {
 
       await testContainer.unsubscribeFromNotifications();
     });
+
+    it("returns an error when it cannot subscribe to a notification", async () => {
+      const resource = solidLdoDataset.getResource(SAMPLE_DATA_URI);
+
+      await app.stop();
+
+      const subscriptionResult = await resource.subscribeToNotifications();
+      expect(subscriptionResult.type).toBe("unexpectedResourceError");
+
+      await app.start();
+    });
+
+    it("returns an error when the server doesnt support websockets", async () => {
+      const resource = solidLdoDataset.getResource(SAMPLE_DATA_URI);
+
+      await app.stop();
+      const disabledWebsocketsApp = await createApp(
+        path.join(__dirname, "./configs/server-config-without-websocket.json"),
+      );
+      await disabledWebsocketsApp.start();
+
+      const subscriptionResult = await resource.subscribeToNotifications();
+      expect(subscriptionResult.type).toBe("unsupportedNotificationError");
+
+      await disabledWebsocketsApp.stop();
+      await app.start();
+    });
+
+    it("causes no problems when unsubscribing when not subscribed", async () => {
+      const resource = solidLdoDataset.getResource(SAMPLE_DATA_URI);
+      const result = await resource.unsubscribeFromNotifications();
+      expect(result.type).toBe("unsubscribeFromNotificationSuccess");
+    });
   });
 });

packages/solid/test/Websocket2023NotificationSubscription.test.ts

@@ -0,0 +1,57 @@
+import type { WebSocket, Event, ErrorEvent } from "ws";
+import { Websocket2023NotificationSubscription } from "../src/resource/notifications/Websocket2023NotificationSubscription";
+import type { SolidLdoDatasetContext } from "../src";
+import { Leaf } from "../src";
+import type { NotificationChannel } from "@solid-notifications/types";
+
+describe("Websocket2023NotificationSubscription", () => {
+  it("returns an error when websockets have an error", async () => {
+    const WebSocketMock: WebSocket = {} as WebSocket;
+    const onErrorMock = jest.fn();
+
+    const subscription = new Websocket2023NotificationSubscription(
+      new Leaf("https://example.com", {
+        fetch,
+      } as unknown as SolidLdoDatasetContext),
+      () => {},
+      onErrorMock,
+      {} as unknown as SolidLdoDatasetContext,
+      () => WebSocketMock,
+    );
+
+    const subPromise = subscription.subscribeToWebsocket({
+      receiveFrom: "http://example.com",
+    } as unknown as NotificationChannel);
+    WebSocketMock.onopen?.({} as Event);
+
+    const subscriptionResult = await subPromise;
+    expect(subscriptionResult.type).toBe("subscribeToNotificationSuccess");
+
+    WebSocketMock.onerror?.({ error: new Error("Test Error") } as ErrorEvent);
+
+    expect(onErrorMock).toHaveBeenCalled();
+  });
+
+  it("returns an error when websockets have an error at the beginning", async () => {
+    const WebSocketMock: WebSocket = {} as WebSocket;
+    const onErrorMock = jest.fn();
+
+    const subscription = new Websocket2023NotificationSubscription(
+      new Leaf("https://example.com", {
+        fetch,
+      } as unknown as SolidLdoDatasetContext),
+      () => {},
+      onErrorMock,
+      {} as unknown as SolidLdoDatasetContext,
+      () => WebSocketMock,
+    );
+
+    const subPromise = subscription.subscribeToWebsocket({
+      receiveFrom: "http://example.com",
+    } as unknown as NotificationChannel);
+    WebSocketMock.onerror?.({ error: new Error("Test Error") } as ErrorEvent);
+    const subscriptionResult = await subPromise;
+
+    expect(subscriptionResult.type).toBe("unexpectedResourceError");
+  });
+});

packages/solid/test/configs/server-config-without-websocket.json

@@ -0,0 +1,44 @@
+{
+  "@context": "https://linkedsoftwaredependencies.org/bundles/npm/@solid/community-server/^7.0.0/components/context.jsonld",
+  "import": [
+    "css:config/app/init/initialize-root.json",
+    "css:config/app/main/default.json",
+    "css:config/app/variables/default.json",
+    "css:config/http/handler/default.json",
+    "css:config/http/middleware/default.json",
+    "css:config/http/notifications/webhooks.json",
+    "css:config/http/server-factory/http.json",
+    "css:config/http/static/default.json",
+    "css:config/identity/access/public.json",
+    "css:config/identity/email/default.json",
+    "css:config/identity/handler/no-accounts.json",
+    "css:config/identity/oidc/default.json",
+    "css:config/identity/ownership/token.json",
+    "css:config/identity/pod/static.json",
+    "css:config/ldp/authentication/dpop-bearer.json",
+    "css:config/ldp/authorization/webacl.json",
+    "css:config/ldp/handler/default.json",
+    "css:config/ldp/metadata-parser/default.json",
+    "css:config/ldp/metadata-writer/default.json",
+    "css:config/ldp/modes/default.json",
+    "css:config/storage/backend/file.json",
+    "css:config/storage/key-value/resource-store.json",
+    "css:config/storage/location/root.json",
+    "css:config/storage/middleware/default.json",
+    "css:config/util/auxiliary/acl.json",
+    "css:config/util/identifiers/suffix.json",
+    "css:config/util/index/default.json",
+    "css:config/util/logging/winston.json",
+    "css:config/util/representation-conversion/default.json",
+    "css:config/util/resource-locker/file.json",
+    "css:config/util/variables/default.json"
+  ],
+  "@graph": [
+    {
+      "comment": [
+        "A Solid server that stores its resources on disk and uses WAC for authorization.",
+        "No registration and the root container is initialized to allow full access for everyone so make sure to change this."
+      ]
+    }
+  ]
+}

packages/solid/test/solidServer.helper.ts

@@ -14,7 +14,7 @@ export const WEB_ID =
 // Use an increased timeout, since the CSS server takes too much setup time.
 jest.setTimeout(40_000);
 
-export async function createApp(): Promise<App> {
+export async function createApp(customConfigPath?: string): Promise<App> {
   if (process.env.SERVER) {
     return {
       start: () => {},
@@ -28,7 +28,7 @@ export async function createApp(): Promise<App> {
       mainModulePath: resolveModulePath(""),
       typeChecking: false,
     },
-    config: resolveModulePath("config/file-root.json"),
+    config: customConfigPath ?? resolveModulePath("config/file-root.json"),
     variableBindings: {},
     shorthand: {
       port: 3_001,