gecko-dev/dom/manifest/Manifest.jsm

227 lines
6.4 KiB
JavaScript

/*
* Manifest.jsm is the top level api for managing installed web applications
* https://www.w3.org/TR/appmanifest/
*
* It is used to trigger the installation of a web application via .install()
* and to access the manifest data (including icons).
*
* TODO:
* - Trigger appropriate app installed events
*/
"use strict";
ChromeUtils.import("resource://gre/modules/XPCOMUtils.jsm");
const { ManifestObtainer } =
ChromeUtils.import("resource://gre/modules/ManifestObtainer.jsm", {});
const { ManifestIcons } =
ChromeUtils.import("resource://gre/modules/ManifestIcons.jsm", {});
ChromeUtils.defineModuleGetter(this, "OS",
"resource://gre/modules/osfile.jsm");
ChromeUtils.defineModuleGetter(this, "JSONFile",
"resource://gre/modules/JSONFile.jsm");
/**
* Generates an hash for the given string.
*
* @note The generated hash is returned in base64 form. Mind the fact base64
* is case-sensitive if you are going to reuse this code.
*/
function generateHash(aString) {
const cryptoHash = Cc["@mozilla.org/security/hash;1"]
.createInstance(Ci.nsICryptoHash);
cryptoHash.init(Ci.nsICryptoHash.MD5);
const stringStream = Cc["@mozilla.org/io/string-input-stream;1"]
.createInstance(Ci.nsIStringInputStream);
stringStream.data = aString;
cryptoHash.updateFromStream(stringStream, -1);
// base64 allows the '/' char, but we can't use it for filenames.
return cryptoHash.finish(true).replace(/\//g, "-");
}
/**
* Trims the query paramters from a url
*/
function stripQuery(url) {
return url.split("?")[0];
}
// Folder in which we store the manifest files
const MANIFESTS_DIR = OS.Path.join(OS.Constants.Path.profileDir, "manifests");
// We maintain a list of scopes for installed webmanifests so we can determine
// whether a given url is within the scope of a previously installed manifest
const MANIFESTS_FILE = "manifest-scopes.json";
/**
* Manifest object
*/
class Manifest {
constructor(browser, manifestUrl) {
this._manifestUrl = manifestUrl;
// The key for this is the manifests URL that is required to be unique.
// However arbitrary urls are not safe file paths so lets hash it.
const fileName = generateHash(manifestUrl) + ".json";
this._path = OS.Path.join(MANIFESTS_DIR, fileName);
this._browser = browser;
}
async initialise() {
this._store = new JSONFile({path: this._path, saveDelayMs: 100});
await this._store.load();
}
async prefetch(browser) {
const manifestData = await ManifestObtainer.browserObtainManifest(browser);
const icon = await ManifestIcons.browserFetchIcon(browser, manifestData, 192);
const data = {
installed: false,
manifest: manifestData,
cached_icon: icon
};
return data;
}
async install() {
const manifestData = await ManifestObtainer.browserObtainManifest(this._browser);
this._store.data = {
installed: true,
manifest: manifestData
};
Manifests.manifestInstalled(this);
this._store.saveSoon();
}
async icon(expectedSize) {
if ('cached_icon' in this._store.data) {
return this._store.data.cached_icon;
}
const icon = await ManifestIcons
.browserFetchIcon(this._browser, this._store.data.manifest, expectedSize);
// Cache the icon so future requests do not go over the network
this._store.data.cached_icon = icon;
this._store.saveSoon();
return icon;
}
get scope() {
const scope = this._store.data.manifest.scope ||
this._store.data.manifest.start_url;
return stripQuery(scope);
}
get name() {
return this._store.data.manifest.short_name ||
this._store.data.manifest.name ||
this._store.data.manifest.short_url;
}
get url() {
return this._manifestUrl;
}
get installed() {
return this._store.data && this._store.data.installed || false;
}
get start_url() {
return this._store.data.manifest.start_url;
}
get path() {
return this._path;
}
}
/*
* Manifests maintains the list of installed manifests
*/
var Manifests = {
async initialise () {
if (this.started) {
return this.started;
}
this.started = (async () => {
// Make sure the manifests have the folder needed to save into
await OS.File.makeDir(MANIFESTS_DIR, {ignoreExisting: true});
// Ensure any existing scope data we have about manifests is loaded
this._path = OS.Path.join(OS.Constants.Path.profileDir, MANIFESTS_FILE);
this._store = new JSONFile({path: this._path});
await this._store.load();
// If we dont have any existing data, initialise empty
if (!this._store.data.hasOwnProperty("scopes")) {
this._store.data.scopes = new Map();
}
// Cache the Manifest objects creates as they are references to files
// and we do not want multiple file handles
this.manifestObjs = {};
})();
return this.started;
},
// When a manifest is installed, we save its scope so we can determine if
// fiture visits fall within this manifests scope
manifestInstalled(manifest) {
this._store.data.scopes[manifest.scope] = manifest.url;
this._store.saveSoon();
},
// Given a url, find if it is within an installed manifests scope and if so
// return that manifests url
findManifestUrl(url) {
for (let scope in this._store.data.scopes) {
if (url.startsWith(scope)) {
return this._store.data.scopes[scope];
}
}
return null;
},
// Get the manifest given a url, or if not look for a manifest that is
// tied to the current page
async getManifest(browser, manifestUrl) {
// Ensure we have all started up
await this.initialise();
// If the client does not already know its manifestUrl, we take the
// url of the client and see if it matches the scope of any installed
// manifests
if (!manifestUrl) {
const url = stripQuery(browser.currentURI.spec);
manifestUrl = this.findManifestUrl(url);
}
// No matches so no manifest
if (manifestUrl === null) {
return null;
}
// If we have already created this manifest return cached
if (manifestUrl in this.manifestObjs) {
return this.manifestObjs[manifestUrl];
}
// Otherwise create a new manifest object
this.manifestObjs[manifestUrl] = new Manifest(browser, manifestUrl);
await this.manifestObjs[manifestUrl].initialise();
return this.manifestObjs[manifestUrl];
}
};
var EXPORTED_SYMBOLS = ["Manifests"]; // jshint ignore:line