SingleFile/lib/single-file-background.js

(function () {
	'use strict';

	/*
	 * Copyright 2010-2020 Gildas Lormeau
	 * contact : gildas.lormeau <at> gmail.com
	 * 
	 * This file is part of SingleFile.
	 *
	 *   The code in this file is free software: you can redistribute it and/or 
	 *   modify it under the terms of the GNU Affero General Public License 
	 *   (GNU AGPL) as published by the Free Software Foundation, either version 3
	 *   of the License, or (at your option) any later version.
	 * 
	 *   The code in this file is distributed in the hope that it will be useful, 
	 *   but WITHOUT ANY WARRANTY; without even the implied warranty of 
	 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero 
	 *   General Public License for more details.
	 *
	 *   As additional permission under GNU AGPL version 3 section 7, you may 
	 *   distribute UNMODIFIED VERSIONS OF THIS file without the copy of the GNU 
	 *   AGPL normally required by section 4, provided you include this license 
	 *   notice and a URL through which recipients can access the Corresponding 
	 *   Source.
	 */

	/* global browser, XMLHttpRequest */

	const referrers = new Map();
	const REQUEST_ID_HEADER_NAME = "x-single-file-request-id";
	const MAX_CONTENT_SIZE = 8 * (1024 * 1024);

	browser.runtime.onMessage.addListener((message, sender) => {
		if (message.method && message.method.startsWith("singlefile.fetch")) {
			return new Promise(resolve => {
				onRequest(message, sender)
					.then(resolve)
					.catch(error => resolve({ error: error && error.toString() }));
			});
		}
	});

	async function onRequest(message, sender) {
		if (message.method == "singlefile.fetch") {
			try {
				const response = await fetchResource(message.url, { referrer: message.referrer, headers: message.headers });
				return sendResponse(sender.tab.id, message.requestId, response);
			} catch (error) {
				return sendResponse(sender.tab.id, message.requestId, { error: error.message, array: [] });
			}
		} else if (message.method == "singlefile.fetchFrame") {
			return browser.tabs.sendMessage(sender.tab.id, message);
		}
	}

	async function sendResponse(tabId, requestId, response) {
		for (let blockIndex = 0; blockIndex * MAX_CONTENT_SIZE <= response.array.length; blockIndex++) {
			const message = {
				method: "singlefile.fetchResponse",
				requestId,
				headers: response.headers,
				status: response.status,
				error: response.error
			};
			message.truncated = response.array.length > MAX_CONTENT_SIZE;
			if (message.truncated) {
				message.finished = (blockIndex + 1) * MAX_CONTENT_SIZE > response.array.length;
				message.array = response.array.slice(blockIndex * MAX_CONTENT_SIZE, (blockIndex + 1) * MAX_CONTENT_SIZE);
			} else {
				message.array = response.array;
			}
			await browser.tabs.sendMessage(tabId, message);
		}
		return {};
	}

	function fetchResource(url, options = {}, includeRequestId) {
		return new Promise((resolve, reject) => {
			const xhrRequest = new XMLHttpRequest();
			xhrRequest.withCredentials = true;
			xhrRequest.responseType = "arraybuffer";
			xhrRequest.onerror = event => reject(new Error(event.detail));
			xhrRequest.onreadystatechange = () => {
				if (xhrRequest.readyState == XMLHttpRequest.DONE) {
					if (xhrRequest.status || xhrRequest.response.byteLength) {
						if ((xhrRequest.status == 401 || xhrRequest.status == 403 || xhrRequest.status == 404) && !includeRequestId) {
							fetchResource(url, options, true)
								.then(resolve)
								.catch(reject);
						} else {
							resolve({
								arrayBuffer: xhrRequest.response,
								array: Array.from(new Uint8Array(xhrRequest.response)),
								headers: { "content-type": xhrRequest.getResponseHeader("Content-Type") },
								status: xhrRequest.status
							});
						}
					} else {
						reject(new Error("Empty response"));
					}
				}
			};
			xhrRequest.open("GET", url, true);
			if (options.headers) {
				for (const entry of Object.entries(options.headers)) {
					xhrRequest.setRequestHeader(entry[0], entry[1]);
				}
			}
			if (includeRequestId) {
				const randomId = String(Math.random()).substring(2);
				setReferrer(randomId, options.referrer);
				xhrRequest.setRequestHeader(REQUEST_ID_HEADER_NAME, randomId);
			}
			xhrRequest.send();
		});
	}

	function setReferrer(requestId, referrer) {
		referrers.set(requestId, referrer);
	}

	/*
	 * Copyright 2010-2020 Gildas Lormeau
	 * contact : gildas.lormeau <at> gmail.com
	 * 
	 * This file is part of SingleFile.
	 *
	 *   The code in this file is free software: you can redistribute it and/or 
	 *   modify it under the terms of the GNU Affero General Public License 
	 *   (GNU AGPL) as published by the Free Software Foundation, either version 3
	 *   of the License, or (at your option) any later version.
	 * 
	 *   The code in this file is distributed in the hope that it will be useful, 
	 *   but WITHOUT ANY WARRANTY; without even the implied warranty of 
	 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero 
	 *   General Public License for more details.
	 *
	 *   As additional permission under GNU AGPL version 3 section 7, you may 
	 *   distribute UNMODIFIED VERSIONS OF THIS file without the copy of the GNU 
	 *   AGPL normally required by section 4, provided you include this license 
	 *   notice and a URL through which recipients can access the Corresponding 
	 *   Source.
	 */

	/* global browser */

	browser.runtime.onMessage.addListener((message, sender) => {
		if (message.method == "singlefile.frameTree.initResponse" || message.method == "singlefile.frameTree.ackInitRequest") {
			browser.tabs.sendMessage(sender.tab.id, message, { frameId: 0 });
			return Promise.resolve({});
		}
	});

	/*
	 * Copyright 2010-2020 Gildas Lormeau
	 * contact : gildas.lormeau <at> gmail.com
	 * 
	 * This file is part of SingleFile.
	 *
	 *   The code in this file is free software: you can redistribute it and/or 
	 *   modify it under the terms of the GNU Affero General Public License 
	 *   (GNU AGPL) as published by the Free Software Foundation, either version 3
	 *   of the License, or (at your option) any later version.
	 * 
	 *   The code in this file is distributed in the hope that it will be useful, 
	 *   but WITHOUT ANY WARRANTY; without even the implied warranty of 
	 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero 
	 *   General Public License for more details.
	 *
	 *   As additional permission under GNU AGPL version 3 section 7, you may 
	 *   distribute UNMODIFIED VERSIONS OF THIS file without the copy of the GNU 
	 *   AGPL normally required by section 4, provided you include this license 
	 *   notice and a URL through which recipients can access the Corresponding 
	 *   Source.
	 */

	/* global browser, setTimeout, clearTimeout */

	const timeouts = new Map();

	browser.runtime.onMessage.addListener((message, sender) => {
		if (message.method == "singlefile.lazyTimeout.setTimeout") {
			let tabTimeouts = timeouts.get(sender.tab.id);
			let frameTimeouts;
			if (tabTimeouts) {
				frameTimeouts = tabTimeouts.get(sender.frameId);
				if (frameTimeouts) {
					const previousTimeoutId = frameTimeouts.get(message.type);
					if (previousTimeoutId) {
						clearTimeout(previousTimeoutId);
					}
				} else {
					frameTimeouts = new Map();
				}
			}
			const timeoutId = setTimeout(async () => {
				try {
					const tabTimeouts = timeouts.get(sender.tab.id);
					const frameTimeouts = tabTimeouts.get(sender.frameId);
					if (tabTimeouts && frameTimeouts) {
						deleteTimeout(frameTimeouts, message.type);
					}
					await browser.tabs.sendMessage(sender.tab.id, { method: "singlefile.lazyTimeout.onTimeout", type: message.type });
				} catch (error) {
					// ignored
				}
			}, message.delay);
			if (!tabTimeouts) {
				tabTimeouts = new Map();
				frameTimeouts = new Map();
				tabTimeouts.set(sender.frameId, frameTimeouts);
				timeouts.set(sender.tab.id, tabTimeouts);
			}
			frameTimeouts.set(message.type, timeoutId);
			return Promise.resolve({});
		}
		if (message.method == "singlefile.lazyTimeout.clearTimeout") {
			let tabTimeouts = timeouts.get(sender.tab.id);
			if (tabTimeouts) {
				const frameTimeouts = tabTimeouts.get(sender.frameId);
				if (frameTimeouts) {
					const timeoutId = frameTimeouts.get(message.type);
					if (timeoutId) {
						clearTimeout(timeoutId);
					}
					deleteTimeout(frameTimeouts, message.type);
				}
			}
			return Promise.resolve({});
		}
	});

	browser.tabs.onRemoved.addListener(tabId => timeouts.delete(tabId));

	function deleteTimeout(framesTimeouts, type) {
		framesTimeouts.delete(type);
	}

})();