feat: create type-safe API object for Headscale

app/server/headscale/api/error.ts

@@ -0,0 +1,143 @@
+import { data } from 'react-router';
+import { errors } from 'undici';
+
+// Represents an error that occurred during a response
+// Thrown when status codes are >= 400
+export default class ResponseError extends Error {
+	status: number;
+	response: string;
+	responseObject?: Record<string, unknown>;
+
+	constructor(status: number, response: string, requestUrl: string) {
+		super(`${requestUrl}: status ${status} - ${response}`);
+		this.name = 'ResponseError';
+		this.status = status;
+		this.response = response;
+
+		try {
+			// Try to parse the response as JSON to get a response object
+			this.responseObject = JSON.parse(response);
+		} catch {}
+	}
+}
+
+function isNodeNetworkError(error: unknown): error is NodeJS.ErrnoException {
+	if (typeof error !== 'object' || error === null) {
+		return false;
+	}
+
+	const keys = Object.keys(error as Record<string, unknown>);
+	return keys.includes('code') && keys.includes('errno');
+}
+
+export function friendlyError(givenError: unknown) {
+	let error: unknown = givenError;
+	if (error instanceof AggregateError) {
+		error = error.errors[0];
+	}
+
+	switch (true) {
+		case error instanceof errors.BodyTimeoutError:
+		case error instanceof errors.ConnectTimeoutError:
+		case error instanceof errors.HeadersTimeoutError:
+			return data('Timed out waiting for a response from the Headscale API', {
+				statusText: 'Request Timeout',
+				status: 408,
+			});
+
+		case error instanceof errors.SocketError:
+		case error instanceof errors.SecureProxyConnectionError:
+		case error instanceof errors.ClientClosedError:
+		case error instanceof errors.ClientDestroyedError:
+		case error instanceof errors.RequestAbortedError:
+			return data('The Headscale API is not reachable', {
+				statusText: 'Service Unavailable',
+				status: 503,
+			});
+
+		case error instanceof errors.InvalidArgumentError:
+		case error instanceof errors.InvalidReturnValueError:
+		case error instanceof errors.NotSupportedError:
+			return data('Unable to make a request (this is most likely a bug)', {
+				statusText: 'Internal Server Error',
+				status: 500,
+			});
+
+		case error instanceof errors.HeadersOverflowError:
+		case error instanceof errors.RequestContentLengthMismatchError:
+		case error instanceof errors.ResponseContentLengthMismatchError:
+		case error instanceof errors.ResponseExceededMaxSizeError:
+			return data('The Headscale API returned a malformed response', {
+				statusText: 'Bad Gateway',
+				status: 502,
+			});
+
+		case isNodeNetworkError(error):
+			if (error.code === 'ECONNREFUSED') {
+				return data('The Headscale API is not reachable', {
+					statusText: 'Service Unavailable',
+					status: 503,
+				});
+			}
+
+			if (error.code === 'ENOTFOUND') {
+				return data('The Headscale API is not reachable', {
+					statusText: 'Service Unavailable',
+					status: 503,
+				});
+			}
+
+			if (error.code === 'EAI_AGAIN') {
+				return data('The Headscale API is not reachable', {
+					statusText: 'Service Unavailable',
+					status: 503,
+				});
+			}
+
+			if (error.code === 'ETIMEDOUT') {
+				return data('Timed out waiting for a response from the Headscale API', {
+					statusText: 'Request Timeout',
+					status: 408,
+				});
+			}
+
+			if (error.code === 'ECONNRESET') {
+				return data('The Headscale API is not reachable', {
+					statusText: 'Service Unavailable',
+					status: 503,
+				});
+			}
+
+			if (error.code === 'EPIPE') {
+				return data('The Headscale API is not reachable', {
+					statusText: 'Service Unavailable',
+					status: 503,
+				});
+			}
+
+			if (error.code === 'ENETUNREACH') {
+				return data('The Headscale API is not reachable', {
+					statusText: 'Service Unavailable',
+					status: 503,
+				});
+			}
+
+			if (error.code === 'ENETRESET') {
+				return data('The Headscale API is not reachable', {
+					statusText: 'Service Unavailable',
+					status: 503,
+				});
+			}
+
+			return data('The Headscale API is not reachable', {
+				statusText: 'Service Unavailable',
+				status: 503,
+			});
+
+		default:
+			return data((error as Error).message ?? 'An unknown error occurred', {
+				statusText: 'Internal Server Error',
+				status: 500,
+			});
+	}
+}