gecko-dev/dom/manifest/ManifestObtainer.jsm

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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/.
*/
/*
* ManifestObtainer is an implementation of:
* http://w3c.github.io/manifest/#obtaining
*
* Exposes 2 public method:
*
* .contentObtainManifest(aContent) - used in content process
* .browserObtainManifest(aBrowser) - used in browser/parent process
*
* both return a promise. If successful, you get back a manifest object.
*
* Import it with URL:
* 'chrome://global/content/manifestMessages.js'
*
* e10s IPC message from this components are handled by:
* dom/ipc/manifestMessages.js
*
* Which is injected into every browser instance via browser.js.
*
* exported ManifestObtainer
*/
/*globals Components, Task, PromiseMessage, XPCOMUtils, ManifestProcessor, BrowserUtils*/
"use strict";
const {
utils: Cu,
classes: Cc,
interfaces: Ci
} = Components;
Cu.import("resource://gre/modules/Task.jsm");
Cu.import("resource://gre/modules/PromiseMessage.jsm");
Cu.import("resource://gre/modules/XPCOMUtils.jsm");
Cu.import("resource://gre/modules/ManifestProcessor.jsm");
XPCOMUtils.defineLazyModuleGetter(this, "BrowserUtils", // jshint ignore:line
"resource://gre/modules/BrowserUtils.jsm");
this.ManifestObtainer = { // jshint ignore:line
/**
* Public interface for obtaining a web manifest from a XUL browser, to use
* on the parent process.
* @param {XULBrowser} The browser to check for the manifest.
* @return {Promise<Object>} The processed manifest.
*/
browserObtainManifest: Task.async(function* (aBrowser) {
const msgKey = "DOM:ManifestObtainer:Obtain";
if (!isXULBrowser(aBrowser)) {
throw new TypeError("Invalid input. Expected XUL browser.");
}
const mm = aBrowser.messageManager;
const {data: {success, result}} = yield PromiseMessage.send(mm, msgKey);
if (!success) {
const error = toError(result);
throw error;
}
return result;
}),
/**
* Public interface for obtaining a web manifest from a XUL browser.
* @param {Window} The content Window from which to extract the manifest.
* @return {Promise<Object>} The processed manifest.
*/
contentObtainManifest: Task.async(function* (aContent) {
if (!aContent || isXULBrowser(aContent)) {
throw new TypeError("Invalid input. Expected a DOM Window.");
}
let manifest;
try {
manifest = yield fetchManifest(aContent);
} catch (err) {
throw err;
}
return manifest;
}
)};
function toError(aErrorClone) {
let error;
switch (aErrorClone.name) {
case "TypeError":
error = new TypeError();
break;
default:
error = new Error();
}
Object.getOwnPropertyNames(aErrorClone)
.forEach(name => error[name] = aErrorClone[name]);
return error;
}
function isXULBrowser(aBrowser) {
if (!aBrowser || !aBrowser.namespaceURI || !aBrowser.localName) {
return false;
}
const XUL = "http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul";
return (aBrowser.namespaceURI === XUL && aBrowser.localName === "browser");
}
/**
* Asynchronously processes the result of response after having fetched
* a manifest.
* @param {Response} aResp Response from fetch().
* @param {Window} aContentWindow The content window.
* @return {Promise<Object>} The processed manifest.
*/
const processResponse = Task.async(function* (aResp, aContentWindow) {
const badStatus = aResp.status < 200 || aResp.status >= 300;
if (aResp.type === "error" || badStatus) {
const msg =
`Fetch error: ${aResp.status} - ${aResp.statusText} at ${aResp.url}`;
throw new Error(msg);
}
const text = yield aResp.text();
const args = {
jsonText: text,
manifestURL: aResp.url,
docURL: aContentWindow.location.href
};
const manifest = ManifestProcessor.process(args);
return manifest;
});
/**
* Asynchronously fetches a web manifest.
* @param {Window} a The content Window from where to extract the manifest.
* @return {Promise<Object>}
*/
const fetchManifest = Task.async(function* (aWindow) {
if (!aWindow || aWindow.top !== aWindow) {
let msg = "Window must be a top-level browsing context.";
throw new Error(msg);
}
const elem = aWindow.document.querySelector("link[rel~='manifest']");
if (!elem || !elem.getAttribute("href")) {
let msg = `No manifest to fetch at ${aWindow.location}`;
throw new Error(msg);
}
// Throws on malformed URLs
const manifestURL = new aWindow.URL(elem.href, elem.baseURI);
const reqInit = {
mode: "cors"
};
if (elem.crossOrigin === "use-credentials") {
reqInit.credentials = "include";
}
const request = new aWindow.Request(manifestURL, reqInit);
request.overrideContentPolicyType(Ci.nsIContentPolicy.TYPE_WEB_MANIFEST);
let response;
try {
response = yield aWindow.fetch(request);
} catch (err) {
throw err;
}
const manifest = yield processResponse(response, aWindow);
return manifest;
});
this.EXPORTED_SYMBOLS = ["ManifestObtainer"]; // jshint ignore:line