Add retried fetch and connection check

plugin/package-lock.json

@@ -18,6 +18,7 @@
 				"esbuild-sass-plugin": "^3.3.1",
 				"eslint": "9.17.0",
 				"eslint-plugin-unused-imports": "^4.1.4",
+				"fetch-retry": "^6.0.0",
 				"obsidian": "1.7.2",
 				"openapi-fetch": "0.13.3",
 				"openapi-typescript": "7.4.4",
@@ -2012,6 +2013,13 @@
 				"reusify": "^1.0.4"
 			}
 		},
+		"node_modules/fetch-retry": {
+			"version": "6.0.0",
+			"resolved": "https://registry.npmjs.org/fetch-retry/-/fetch-retry-6.0.0.tgz",
+			"integrity": "sha512-BUFj1aMubgib37I3v4q78fYo63Po7t4HUPTpQ6/QE6yK6cIQrP+W43FYToeTEyg5m2Y7eFUtijUuAv/PDlWuag==",
+			"dev": true,
+			"license": "MIT"
+		},
 		"node_modules/file-entry-cache": {
 			"version": "8.0.0",
 			"resolved": "https://registry.npmjs.org/file-entry-cache/-/file-entry-cache-8.0.0.tgz",

plugin/package.json

@@ -19,6 +19,7 @@
 		"dayjs": "^1.11.13",
 		"esbuild": "0.24.0",
 		"esbuild-plugin-wasm-pack": "^1.1.0",
+		"esbuild-sass-plugin": "^3.3.1",
 		"eslint": "9.17.0",
 		"eslint-plugin-unused-imports": "^4.1.4",
 		"obsidian": "1.7.2",
@@ -28,6 +29,6 @@
 		"tslib": "2.4.0",
 		"typescript": "5.7.2",
 		"typescript-eslint": "8.18.0",
-		"esbuild-sass-plugin": "^3.3.1"
+		"fetch-retry": "^6.0.0"
 	}
 }

plugin/src/services/sync-service.ts

@@ -11,7 +11,12 @@ import type {
 	VaultUpdateId,
 } from "src/database/document-metadata";
 import { Logger } from "src/tracing/logger.js";
+import { retriedFetch } from "src/utils/retried-fetch.js";
 
+export interface CheckConnectionResult {
+	isSuccessful: boolean;
+	message: string;
+}
 export class SyncService {
 	private client: Client<paths>;
 
@@ -272,9 +277,32 @@ export class SyncService {
 		return response.data;
 	}
 
+	public async checkConnection(): Promise<CheckConnectionResult> {
+		try {
+			const result = await this.ping();
+			if (result.isAuthenticated) {
+				return {
+					isSuccessful: true,
+					message: `Successfully connected to server (version: ${result.serverVersion}) and authenticated.`,
+				};
+			}
+
+			return {
+				isSuccessful: false,
+				message: `Successfully connected to server (version: ${result.serverVersion}) but failed to authenticate.`,
+			};
+		} catch (e) {
+			return {
+				isSuccessful: false,
+				message: `Failed to connect to server: ${e}`,
+			};
+		}
+	}
+
 	private createClient(settings: SyncSettings): void {
 		this.client = createClient<paths>({
 			baseUrl: settings.remoteUri,
+			fetch: retriedFetch,
 		});
 	}
 }

plugin/src/utils/retried-fetch.ts

@@ -0,0 +1,41 @@
+import * as fetchRetryFactory from "fetch-retry";
+import { Logger } from "src/tracing/logger";
+
+const fetchWithRetry = fetchRetryFactory.default(fetch);
+
+export async function retriedFetch(
+	input: RequestInfo | URL,
+	init: RequestInit = {}
+): Promise<Response> {
+	return fetchWithRetry(input, {
+		...init,
+		retryOn: function (attempt, error, response) {
+			// retry on any network error, or 4xx or 5xx status codes
+			if (error !== null || !response || response.status >= 500) {
+				Logger.getInstance().warn(
+					`Retrying fetch attempt ${attempt} for ${getUrlFromInput(
+						input
+					)}`
+				);
+
+				return true;
+			}
+			return false;
+		},
+		retries: 6,
+		retryDelay: function (attempt) {
+			Logger;
+			return Math.pow(1.5, attempt) * 500;
+		},
+	});
+}
+
+function getUrlFromInput(input: RequestInfo | URL): string {
+	if (input instanceof URL) {
+		return input.href;
+	}
+	if (typeof input === "string") {
+		return input;
+	}
+	return input.url;
+}