refactor(chat): implement new error handling utilities and streamline interrupt request processing in NewChatPage for improved performance and maintainability

surfsense_web/lib/chat/chat-request-errors.ts

@@ -0,0 +1,89 @@
+export async function toHttpResponseError(
+	response: Response
+): Promise<Error & { errorCode?: string }> {
+	const statusDefaultCode =
+		response.status === 409
+			? "THREAD_BUSY"
+			: response.status === 429
+				? "RATE_LIMITED"
+				: response.status === 401 || response.status === 403
+					? "AUTH_EXPIRED"
+					: "SERVER_ERROR";
+
+	let rawBody = "";
+	try {
+		rawBody = await response.text();
+	} catch {
+		// noop
+	}
+
+	let parsedBody: Record<string, unknown> | null = null;
+	if (rawBody) {
+		try {
+			const parsed = JSON.parse(rawBody);
+			if (typeof parsed === "object" && parsed !== null) {
+				parsedBody = parsed as Record<string, unknown>;
+			}
+		} catch {
+			// noop
+		}
+	}
+
+	const detail = parsedBody?.detail;
+	const detailObject =
+		typeof detail === "object" && detail !== null ? (detail as Record<string, unknown>) : null;
+	const detailMessage = typeof detail === "string" ? detail : undefined;
+	const topLevelMessage =
+		typeof parsedBody?.message === "string" ? (parsedBody.message as string) : undefined;
+	const detailNestedMessage =
+		typeof detailObject?.message === "string" ? (detailObject.message as string) : undefined;
+
+	const topLevelCode =
+		typeof parsedBody?.errorCode === "string"
+			? parsedBody.errorCode
+			: typeof parsedBody?.error_code === "string"
+				? parsedBody.error_code
+				: undefined;
+	const detailCode =
+		typeof detailObject?.errorCode === "string"
+			? detailObject.errorCode
+			: typeof detailObject?.error_code === "string"
+				? detailObject.error_code
+				: undefined;
+
+	const errorCode = detailCode ?? topLevelCode ?? statusDefaultCode;
+	const message =
+		detailNestedMessage ??
+		detailMessage ??
+		topLevelMessage ??
+		`Backend error: ${response.status}`;
+
+	return Object.assign(new Error(message), { errorCode });
+}
+
+export function tagPreAcceptSendFailure(error: unknown): unknown {
+	if (error instanceof Error) {
+		const withCode = error as Error & { errorCode?: string; code?: string };
+		const existingCode = withCode.errorCode ?? withCode.code;
+		const passthroughCodes = new Set([
+			"PREMIUM_QUOTA_EXHAUSTED",
+			"THREAD_BUSY",
+			"AUTH_EXPIRED",
+			"UNAUTHORIZED",
+			"RATE_LIMITED",
+			"NETWORK_ERROR",
+			"STREAM_PARSE_ERROR",
+			"TOOL_EXECUTION_ERROR",
+			"PERSIST_MESSAGE_FAILED",
+			"SERVER_ERROR",
+		]);
+		if (existingCode && passthroughCodes.has(existingCode)) {
+			return Object.assign(error, { errorCode: existingCode });
+		}
+		return Object.assign(error, { errorCode: "SEND_FAILED_PRE_ACCEPT" });
+	}
+
+	return Object.assign(new Error("Failed to send message before stream acceptance"), {
+		errorCode: "SEND_FAILED_PRE_ACCEPT",
+	});
+}