feat(desktop): bundled renderer, modules and instance accounts (#3254)

fluxer_desktop/src/main/SelectedInstanceFetch.ts

@@ -0,0 +1,119 @@
+// SPDX-License-Identifier: AGPL-3.0-or-later
+
+import type {Buffer} from 'node:buffer';
+import type http from 'node:http';
+import {
+	DesktopOriginTrust,
+	type DesktopOutboundHTTP,
+	getDesktopOutboundHTTP,
+	readBoundedMessage,
+	readMessageContentLength,
+} from '@electron/main/DesktopOutboundHTTP';
+import {HttpStatus} from '@fluxer/constants/src/HttpConstants';
+
+const INSTANCE_RESPONSE_MAX_BYTES = 1024 * 1024;
+const INSTANCE_RESPONSE_MAX_CHUNKS = 1024;
+const INSTANCE_FETCH_TIMEOUT_MS = 15_000;
+
+const SELECTED_INSTANCE_SERVICE_NAME = 'desktop_selected_instance';
+const INSTANCE_RESPONSE_DESCRIPTION = 'Instance response';
+const RESET_CONTENT_STATUS = 205;
+
+interface SelectedInstanceFetchRequest {
+	readonly body?: Uint8Array | null;
+	readonly expectedOrigin: string;
+	readonly headers?: Readonly<Record<string, string>> | null;
+	readonly method?: string | null;
+	readonly signal?: AbortSignal | null;
+	readonly timeoutMs?: number | null;
+	readonly url: string;
+}
+
+interface DesktopInstanceResponse {
+	readonly body: Buffer | null;
+	readonly headers: http.IncomingHttpHeaders;
+	readonly ok: boolean;
+	readonly status: number;
+	readonly statusText: string;
+}
+
+class InstanceRedirectRefusedError extends Error {
+	public readonly status: number;
+
+	public constructor(url: string, status: number) {
+		super(`Instance request to ${url} was answered with an HTTP ${status} redirect, which is never followed`);
+		this.name = 'InstanceRedirectRefusedError';
+		this.status = status;
+	}
+}
+
+class InvalidInstanceTimeoutError extends RangeError {
+	public constructor(timeoutMs: number) {
+		super(`Instance request timeout ${timeoutMs} must be a positive safe integer`);
+		this.name = 'InvalidInstanceTimeoutError';
+	}
+}
+
+function hasNoBody(method: string, status: number): boolean {
+	if (method === 'HEAD') {
+		return true;
+	}
+	return status === HttpStatus.NO_CONTENT || status === RESET_CONTENT_STATUS || status === HttpStatus.NOT_MODIFIED;
+}
+
+export class DesktopSelectedInstanceClient {
+	private readonly outboundHTTP: DesktopOutboundHTTP;
+
+	public constructor(outboundHTTP: DesktopOutboundHTTP) {
+		this.outboundHTTP = outboundHTTP;
+	}
+
+	public async fetch(request: SelectedInstanceFetchRequest): Promise<DesktopInstanceResponse> {
+		const timeoutMs = request.timeoutMs ?? INSTANCE_FETCH_TIMEOUT_MS;
+		if (!Number.isSafeInteger(timeoutMs) || timeoutMs <= 0) {
+			throw new InvalidInstanceTimeoutError(timeoutMs);
+		}
+		const method = (request.method ?? 'GET').toUpperCase();
+		const message = await this.outboundHTTP.request({
+			body: request.body ?? null,
+			expectedOrigin: request.expectedOrigin,
+			headers: request.headers ?? null,
+			method,
+			originTrust: DesktopOriginTrust.BOUND,
+			serviceName: SELECTED_INSTANCE_SERVICE_NAME,
+			signal: request.signal ?? null,
+			timeoutMs,
+			url: request.url,
+		});
+		if (message.status >= 300 && message.status < 400) {
+			message.message.destroy();
+			throw new InstanceRedirectRefusedError(request.url, message.status);
+		}
+		let body: Buffer | null = null;
+		if (hasNoBody(method, message.status)) {
+			message.message.resume();
+		} else {
+			body = await readBoundedMessage({
+				declaredBytes: readMessageContentLength(message, INSTANCE_RESPONSE_DESCRIPTION),
+				description: INSTANCE_RESPONSE_DESCRIPTION,
+				maxBytes: INSTANCE_RESPONSE_MAX_BYTES,
+				maxChunks: INSTANCE_RESPONSE_MAX_CHUNKS,
+				message: message.message,
+			});
+		}
+		return {
+			body,
+			headers: message.headers,
+			ok: message.status >= 200 && message.status < 300,
+			status: message.status,
+			statusText: message.statusText,
+		};
+	}
+}
+
+let sharedSelectedInstanceClient: DesktopSelectedInstanceClient | null = null;
+
+export function getDesktopSelectedInstanceClient(): DesktopSelectedInstanceClient {
+	sharedSelectedInstanceClient ??= new DesktopSelectedInstanceClient(getDesktopOutboundHTTP());
+	return sharedSelectedInstanceClient;
+}