fix: add websocket close handling (#17548)

resolves #17508 

Display an error in the UI that the websocket closed if the user is
still interacting with the dynamic parameters form

<img width="795" alt="Screenshot 2025-04-23 at 17 57 25"
src="https://github.com/user-attachments/assets/15362ddb-fe01-462e-8537-a48302c5c621"
/>

site/src/api/api.ts

@@ -1015,9 +1015,11 @@ class ApiMethods {
 		{
 			onMessage,
 			onError,
+			onClose,
 		}: {
 			onMessage: (response: TypesGen.DynamicParametersResponse) => void;
 			onError: (error: Error) => void;
+			onClose: () => void;
 		},
 	): WebSocket => {
 		const socket = createWebSocket(
@@ -1033,6 +1035,10 @@ class ApiMethods {
 			socket.close();
 		});
 
+		socket.addEventListener("close", () => {
+			onClose();
+		});
+
 		return socket;
 	};
 

site/src/pages/CreateWorkspacePage/CreateWorkspacePageExperimental.tsx

@@ -1,4 +1,4 @@
-import type { ApiErrorResponse } from "api/errors";
+import { type ApiErrorResponse, DetailedError } from "api/errors";
 import { checkAuthorization } from "api/queries/authCheck";
 import {
 	templateByName,
@@ -107,6 +107,15 @@ const CreateWorkspacePageExperimental: FC = () => {
 				onError: (error) => {
 					setWsError(error);
 				},
+				onClose: () => {
+					// There is no reason for the websocket to close while a user is on the page
+					setWsError(
+						new DetailedError(
+							"Websocket connection for dynamic parameters unexpectedly closed.",
+							"Refresh the page to reset the form.",
+						),
+					);
+				},
 			},
 		);
 
@@ -141,7 +150,7 @@ const CreateWorkspacePageExperimental: FC = () => {
 	} = useExternalAuth(realizedVersionId);
 
 	const isLoadingFormData =
-		ws.current?.readyState !== WebSocket.OPEN ||
+		ws.current?.readyState === WebSocket.CONNECTING ||
 		templateQuery.isLoading ||
 		permissionsQuery.isLoading;
 	const loadFormDataError = templateQuery.error ?? permissionsQuery.error;

site/src/pages/CreateWorkspacePage/CreateWorkspacePageViewExperimental.stories.tsx

@@ -0,0 +1,40 @@
+import type { Meta, StoryObj } from "@storybook/react";
+import { DetailedError } from "api/errors";
+import { chromatic } from "testHelpers/chromatic";
+import { MockTemplate, MockUser } from "testHelpers/entities";
+import { CreateWorkspacePageViewExperimental } from "./CreateWorkspacePageViewExperimental";
+
+const meta: Meta<typeof CreateWorkspacePageViewExperimental> = {
+	title: "Pages/CreateWorkspacePageViewExperimental",
+	parameters: { chromatic },
+	component: CreateWorkspacePageViewExperimental,
+	args: {
+		autofillParameters: [],
+		diagnostics: [],
+		defaultName: "",
+		defaultOwner: MockUser,
+		externalAuth: [],
+		externalAuthPollingState: "idle",
+		hasAllRequiredExternalAuth: true,
+		mode: "form",
+		parameters: [],
+		permissions: {
+			createWorkspaceForAny: true,
+		},
+		presets: [],
+		sendMessage: () => {},
+		template: MockTemplate,
+	},
+};
+
+export default meta;
+type Story = StoryObj<typeof CreateWorkspacePageViewExperimental>;
+
+export const WebsocketError: Story = {
+	args: {
+		error: new DetailedError(
+			"Websocket connection for dynamic parameters unexpectedly closed.",
+			"Refresh the page to reset the form.",
+		),
+	},
+};