Handle CLOSED message from relays

.eslintrc.cjs

@@ -16,7 +16,10 @@ const config = {
       plugins: ["@typescript-eslint"],
       extends: ["eslint:recommended", "plugin:@typescript-eslint/recommended", "prettier"],
       rules: {
-        "@typescript-eslint/no-unused-vars": ["warn", { argsIgnorePattern: "^_" }],
+        "@typescript-eslint/no-unused-vars": [
+          "warn",
+          { argsIgnorePattern: "^_", varsIgnorePattern: "^_" },
+        ],
       },
     },
   ],

packages/kernel/src/nostr.spec.ts

@@ -42,6 +42,21 @@ describe("parseR2CMessage", () => {
     expect(subId).toBe("sub_id");
   });
 
+  test("parses CLOSED message", () => {
+    const closedJSON = `["CLOSED", "sub_id", "reason"]`;
+
+    const parsed = parseR2CMessage(closedJSON);
+    if (parsed === undefined) {
+      fail("parsing failed unexpectedly");
+    }
+    if (parsed[0] !== "CLOSED") {
+      fail(`unexpected message type: ${parsed[0]}`);
+    }
+    const [, subId, reason] = parsed;
+    expect(subId).toBe("sub_id");
+    expect(reason).toBe("reason");
+  });
+
   test("parses NOTICE message", () => {
     const noticeJSON = `["NOTICE", "error!"]`;
 
@@ -94,6 +109,19 @@ describe("parseR2CMessage", () => {
     }
   });
 
+  test("fails on malformed CLOSED message", () => {
+    const malformedClosedJSON = [
+      `["CLOSED"]`,
+      `["CLOSED", 42]`,
+      `["CLOSED", null]`,
+      `["CLOSED", "sub_id", null]`,
+    ];
+
+    for (const msgJSON of malformedClosedJSON) {
+      expect(parseR2CMessage(msgJSON)).toBeUndefined();
+    }
+  });
+
   test("fails on malformed NOTICE message", () => {
     const malformedNoticeJSON = [`["NOTICE"]`];
 

packages/kernel/src/nostr.ts

@@ -104,15 +104,18 @@ export type C2RMessageType = C2RMessage[0];
 // relay to client messages
 type R2CEvent = [type: "EVENT", subId: string, event: NostrEvent];
 type R2CEose = [type: "EOSE", subId: string];
+type R2CClosed = [type: "CLOSED", subId: string, message: string];
 type R2CNotice = [type: "NOTICE", notice: string];
 
-export type R2CMessage = R2CEvent | R2CEose | R2CNotice;
+export type R2CMessage = R2CEvent | R2CEose | R2CClosed | R2CNotice;
 export type R2CMessageType = R2CMessage[0];
 
 export type R2CSubMessage = R2CEvent | R2CEose;
 export type R2CSubMessageType = R2CSubMessage[0];
 
-const msgTypeNames: string[] = ["EVENT", "EOSE", "NOTICE", "OK", "AUTH", "COUNT"];
+const supportedR2CMsgTypes: R2CMessageType[] = ["EVENT", "EOSE", "CLOSED", "NOTICE"];
+const isSupportedR2CMsgType = (s: string): s is R2CMessageType =>
+  (supportedR2CMsgTypes as string[]).includes(s);
 
 export const parseR2CMessage = (rawMsg: string): R2CMessage | undefined => {
   let parsed: unknown;
@@ -129,12 +132,8 @@ export const parseR2CMessage = (rawMsg: string): R2CMessage | undefined => {
   }
 
   const msgType = parsed[0] as string;
-  if (!msgTypeNames.includes(msgType)) {
-    console.error("unknown R2C message type:", parsed[0]);
-    return undefined;
-  }
-  if (msgType === "OK" || msgType === "AUTH" || msgType === "COUNT") {
-    console.warn("ignoring R2C OK/AUTH/COUNT message");
+  if (!isSupportedR2CMsgType(msgType)) {
+    console.error("unsupported R2C message type:", parsed[0]);
     return undefined;
   }
   switch (msgType) {
@@ -161,6 +160,13 @@ export const parseR2CMessage = (rawMsg: string): R2CMessage | undefined => {
       }
       return parsed as R2CEose;
     }
+    case "CLOSED": {
+      if (parsed.length !== 3 || typeof parsed[1] !== "string" || typeof parsed[2] !== "string") {
+        console.error("malformed R2C CLOSED");
+        return undefined;
+      }
+      return parsed as R2CClosed;
+    }
     case "NOTICE": {
       if (parsed.length !== 2) {
         console.error("malformed R2C NOTICE");

packages/nostr-fetch/src/fetcherBackend.spec.ts

@@ -1,4 +1,8 @@
-import { FetchTillEoseOptions, NostrFetcherBackend } from "@nostr-fetch/kernel/fetcherBackend";
+import {
+  FetchTillEoseOptions,
+  NostrFetcherBackend,
+  isFetchTillEoseFailedSignal,
+} from "@nostr-fetch/kernel/fetcherBackend";
 import { setupMockRelayServer } from "@nostr-fetch/testutil/mockRelayServer";
 import { DefaultFetcherBackend } from "./fetcherBackend";
 
@@ -57,6 +61,25 @@ describe("DefaultFetcherBackend", () => {
       await expect(wsServer).toReceiveMessage(["CLOSE", "test"]);
     });
 
+    test("handles subscription close by relay w/ CLOSED message", async () => {
+      setupMockRelayServer(wsServer, [{ type: "closed", message: "invalid: malformed filter" }]);
+
+      await backend.ensureRelays([url], { connectTimeoutMs: 1000 });
+      const iter = backend.fetchTillEose(url, {}, defaultOpts);
+      try {
+        for await (const _ of iter) {
+          // do nothing
+        }
+        expect.unreachable("should throw FetchTillEoseFailedSignal");
+      } catch (err) {
+        if (isFetchTillEoseFailedSignal(err)) {
+          expect(err.message).toMatch("invalid: malformed filter");
+        } else {
+          expect.unreachable("should throw FetchTillEoseFailedSignal");
+        }
+      }
+    });
+
     test("aborts subscription on NOTICE", async () => {
       setupMockRelayServer(wsServer, [
         { type: "events", eventsSpec: { content: "test", n: 9 } },

packages/nostr-fetch/src/fetcherBackend.ts

@@ -121,6 +121,11 @@ export class DefaultFetcherBackend implements NostrFetcherBackend {
         tx.close();
       }
     });
+    sub.on("closed", (msg) => {
+      tx.error(
+        new FetchTillEoseFailedSignal(`subscription (id: ${sub.subId}) closed by relay: ${msg}`),
+      );
+    });
 
     // common process to close subscription
     const closeSub = () => {

packages/nostr-fetch/src/relay.spec.ts

@@ -6,6 +6,7 @@ import type {
   RelayDisconnectCb,
   RelayErrorCb,
   RelayNoticeCb,
+  SubClosedCb,
   SubEoseCb,
   SubEventCb,
   WSCloseEvent,
@@ -149,13 +150,15 @@ describe("Relay", () => {
     let spyCbs: {
       event: SubEventCb;
       eose: SubEoseCb;
+      closed: SubClosedCb;
     };
 
     beforeEach(() => {
       server = new WS(rurl, { jsonProtocol: true });
       spyCbs = {
         event: vi.fn((_) => {}),
         eose: vi.fn((_) => {}),
+        closed: vi.fn((_) => {}),
       };
     });
     afterEach(() => {
@@ -177,6 +180,7 @@ describe("Relay", () => {
       sub.on("event", spyCbs.event);
       sub.on("eose", spyCbs.eose);
       sub.on("eose", () => waitEose.resolve());
+      sub.on("closed", spyCbs.closed);
 
       sub.req();
       await expect(server).toReceiveMessage(["REQ", "normal", {}]);
@@ -189,6 +193,34 @@ describe("Relay", () => {
       // mock relay sends: 5 EVENTs then EOSE
       expect(spyCbs.event).toBeCalledTimes(5);
       expect(spyCbs.eose).toBeCalledTimes(1);
+      expect(spyCbs.closed).not.toBeCalled();
+    });
+
+    test("CLOSED by relay", async () => {
+      const r = initRelay(rurl, { connectTimeoutMs: 5000 });
+      setupMockRelayServer(server, [{ type: "closed", message: "closed by relay" }]);
+
+      await r.connect();
+
+      const waitClosed = new Deferred<void>();
+
+      const sub = r.prepareSub([{}], {
+        skipVerification: false,
+        abortSubBeforeEoseTimeoutMs: 1000,
+        subId: "malformed_sub",
+      });
+      sub.on("event", spyCbs.event);
+      sub.on("eose", spyCbs.eose);
+      sub.on("closed", spyCbs.closed);
+      sub.on("closed", () => waitClosed.resolve());
+
+      sub.req();
+      await waitClosed.promise;
+
+      expect(spyCbs.closed).toBeCalledTimes(1);
+      expect(spyCbs.closed).toBeCalledWith("closed by relay");
+      expect(spyCbs.event).not.toBeCalled();
+      expect(spyCbs.eose).not.toBeCalled();
     });
 
     test("aborts before EOSE if relay doesn't return events for a while", async () => {

packages/nostr-fetch/src/relay.ts

@@ -113,6 +113,11 @@ class RelayImpl implements Relay {
           this.forwardToSub(subId, (sub) => sub._forwardEose());
           break;
         }
+        case "CLOSED": {
+          const [, subId, msg] = parsed;
+          this.forwardToSub(subId, (sub) => sub._forwardClosed(msg));
+          break;
+        }
         case "NOTICE": {
           const [, notice] = parsed;
           this.#listeners.notice.forEach((cb) => cb(notice));
@@ -213,10 +218,12 @@ type EoseEventPayload = {
 
 export type SubEventCb = Callback<NostrEvent>;
 export type SubEoseCb = Callback<EoseEventPayload>;
+export type SubClosedCb = Callback<string>;
 
 export type SubEventCbTypes = {
   event: SubEventCb;
   eose: SubEoseCb;
+  closed: SubClosedCb;
 };
 
 export type SubEventTypes = keyof SubEventCbTypes;
@@ -248,6 +255,7 @@ class RelaySubscription implements Subscription {
   #listeners: SubListenersTable = {
     event: new Set(),
     eose: new Set(),
+    closed: new Set(),
   };
 
   #abortSubTimer: NodeJS.Timeout | undefined;
@@ -315,4 +323,12 @@ class RelaySubscription implements Subscription {
     }
     this.#listeners.eose.forEach((cb) => cb({ aborted: false }));
   }
+
+  _forwardClosed(msg: string) {
+    this.#listeners.closed.forEach((cb) => cb(msg));
+
+    // subscription has been closed by the relay -> clean up things
+    this.#clearListeners();
+    this.#relay._removeSub(this.#subId);
+  }
 }

packages/testutil/src/mockRelayServer.ts

@@ -16,6 +16,10 @@ type MockRelaySubResponseAction =
       eventsSpec: FakeEventsSpec;
       intervalMs?: number;
     }
+  | {
+      type: "closed";
+      message: string;
+    }
   | {
       type: "notice";
       notice: string;
@@ -31,6 +35,7 @@ type MockRelaySubResponseScenario = MockRelaySubResponseAction[];
 
 const r2cEventMsg = (subId: string, ev: NostrEvent) => JSON.stringify(["EVENT", subId, ev]);
 const r2cEoseMsg = (subId: string) => JSON.stringify(["EOSE", subId]);
+const r2cClosedMsg = (subId: string, message: string) => JSON.stringify(["CLOSED", subId, message]);
 const r2cNoticeMsg = (notice: string) => JSON.stringify(["NOTICE", notice]);
 
 // play the "subscription response scenario" on subscription request
@@ -41,6 +46,7 @@ const playSubScenario = async (
   subId: string,
 ) => {
   for (const action of scenario) {
+    console.log("playSubScenario", action);
     switch (action.type) {
       case "events":
         for (const ev of generateFakeEvents(action.eventsSpec)) {
@@ -52,6 +58,10 @@ const playSubScenario = async (
         }
         break;
 
+      case "closed":
+        socket.send(r2cClosedMsg(subId, action.message));
+        break;
+
       case "notice":
         socket.send(r2cNoticeMsg(action.notice));
         break;