gecko-dev/dom/manifest/ManifestProcessor.jsm

/* 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/. */
/*
 * ManifestProcessor
 * Implementation of processing algorithms from:
 * http://www.w3.org/2008/webapps/manifest/
 *
 * Creates manifest processor that lets you process a JSON file
 * or individual parts of a manifest object. A manifest is just a
 * standard JS object that has been cleaned up.
 *
 *   .process({jsonText,manifestURL,docURL});
 *
 * Depends on ImageObjectProcessor to process things like
 * icons and splash_screens.
 *
 * TODO: The constructor should accept the UA's supported orientations.
 * TODO: The constructor should accept the UA's supported display modes.
 * TODO: hook up developer tools to console. (1086997).
 */
/* globals Components, ValueExtractor, ImageObjectProcessor, ConsoleAPI*/
"use strict";

const {XPCOMUtils} = ChromeUtils.import("resource://gre/modules/XPCOMUtils.jsm");
XPCOMUtils.defineLazyGlobalGetters(this, ["URL"]);
const displayModes = new Set(["fullscreen", "standalone", "minimal-ui",
  "browser",
]);
const orientationTypes = new Set(["any", "natural", "landscape", "portrait",
  "portrait-primary", "portrait-secondary", "landscape-primary",
  "landscape-secondary",
]);
const textDirections = new Set(["ltr", "rtl", "auto"]);

const {ConsoleAPI} = ChromeUtils.import("resource://gre/modules/Console.jsm");
const {Services} = ChromeUtils.import("resource://gre/modules/Services.jsm");
// ValueExtractor is used by the various processors to get values
// from the manifest and to report errors.
const {ValueExtractor} = ChromeUtils.import("resource://gre/modules/ValueExtractor.jsm");
// ImageObjectProcessor is used to process things like icons and images
const {ImageObjectProcessor} = ChromeUtils.import("resource://gre/modules/ImageObjectProcessor.jsm");

var ManifestProcessor = { // jshint ignore:line
  get defaultDisplayMode() {
    return "browser";
  },
  get displayModes() {
    return displayModes;
  },
  get orientationTypes() {
    return orientationTypes;
  },
  get textDirections() {
    return textDirections;
  },
  // process() method processes JSON text into a clean manifest
  // that conforms with the W3C specification. Takes an object
  // expecting the following dictionary items:
  //  * jsonText: the JSON string to be processed.
  //  * manifestURL: the URL of the manifest, to resolve URLs.
  //  * docURL: the URL of the owner doc, for security checks
  process({
    jsonText,
    manifestURL: aManifestURL,
    docURL: aDocURL,
  }) {
    const domBundle = Services.strings.createBundle("chrome://global/locale/dom/dom.properties");

    const console = new ConsoleAPI({
      prefix: "Web Manifest",
    });
    const manifestURL = new URL(aManifestURL);
    const docURL = new URL(aDocURL);
    let rawManifest = {};
    try {
      rawManifest = JSON.parse(jsonText);
    } catch (e) {}
    if (typeof rawManifest !== "object" || rawManifest === null) {
      console.warn(domBundle.GetStringFromName("ManifestShouldBeObject"));
      rawManifest = {};
    }
    const extractor = new ValueExtractor(console, domBundle);
    const imgObjProcessor = new ImageObjectProcessor(console, extractor);
    const processedManifest = {
      "dir": processDirMember.call(this),
      "lang": processLangMember(),
      "start_url": processStartURLMember(),
      "display": processDisplayMember.call(this),
      "orientation": processOrientationMember.call(this),
      "name": processNameMember(),
      "icons": imgObjProcessor.process(
        rawManifest, manifestURL, "icons"
      ),
      "short_name": processShortNameMember(),
      "theme_color": processThemeColorMember(),
      "background_color": processBackgroundColorMember(),
    };
    processedManifest.scope = processScopeMember();
    return processedManifest;

    function processDirMember() {
      const spec = {
        objectName: "manifest",
        object: rawManifest,
        property: "dir",
        expectedType: "string",
        trim: true,
      };
      const value = extractor.extractValue(spec);
      if (this.textDirections.has(value)) {
        return value;
      }
      return "auto";
    }

    function processNameMember() {
      const spec = {
        objectName: "manifest",
        object: rawManifest,
        property: "name",
        expectedType: "string",
        trim: true,
      };
      return extractor.extractValue(spec);
    }

    function processShortNameMember() {
      const spec = {
        objectName: "manifest",
        object: rawManifest,
        property: "short_name",
        expectedType: "string",
        trim: true,
      };
      return extractor.extractValue(spec);
    }

    function processOrientationMember() {
      const spec = {
        objectName: "manifest",
        object: rawManifest,
        property: "orientation",
        expectedType: "string",
        trim: true,
      };
      const value = extractor.extractValue(spec);
      if (value && typeof value === "string" && this.orientationTypes.has(value.toLowerCase())) {
        return value.toLowerCase();
      }
      return undefined;
    }

    function processDisplayMember() {
      const spec = {
        objectName: "manifest",
        object: rawManifest,
        property: "display",
        expectedType: "string",
        trim: true,
      };
      const value = extractor.extractValue(spec);
      if (value && typeof value === "string" && displayModes.has(value.toLowerCase())) {
        return value.toLowerCase();
      }
      return this.defaultDisplayMode;
    }

    function processScopeMember() {
      const spec = {
        objectName: "manifest",
        object: rawManifest,
        property: "scope",
        expectedType: "string",
        trim: false,
      };
      let scopeURL;
      const startURL = new URL(processedManifest.start_url);
      const value = extractor.extractValue(spec);
      if (value === undefined || value === "") {
        return undefined;
      }
      try {
        scopeURL = new URL(value, manifestURL);
      } catch (e) {
        console.warn(domBundle.GetStringFromName("ManifestScopeURLInvalid"));
        return undefined;
      }
      if (scopeURL.origin !== docURL.origin) {
        console.warn(domBundle.GetStringFromName("ManifestScopeNotSameOrigin"));
        return undefined;
      }
      // If start URL is not within scope of scope URL:
      let isSameOrigin = startURL && startURL.origin !== scopeURL.origin;
      if (isSameOrigin || !startURL.pathname.startsWith(scopeURL.pathname)) {
        console.warn(domBundle.GetStringFromName("ManifestStartURLOutsideScope"));
        return undefined;
      }
      return scopeURL.href;
    }

    function processStartURLMember() {
      const spec = {
        objectName: "manifest",
        object: rawManifest,
        property: "start_url",
        expectedType: "string",
        trim: false,
      };
      let result = new URL(docURL).href;
      const value = extractor.extractValue(spec);
      if (value === undefined || value === "") {
        return result;
      }
      let potentialResult;
      try {
        potentialResult = new URL(value, manifestURL);
      } catch (e) {
        console.warn(domBundle.GetStringFromName("ManifestStartURLInvalid"));
        return result;
      }
      if (potentialResult.origin !== docURL.origin) {
        console.warn(domBundle.GetStringFromName("ManifestStartURLShouldBeSameOrigin"));
      } else {
        result = potentialResult.href;
      }
      return result;
    }

    function processThemeColorMember() {
      const spec = {
        objectName: "manifest",
        object: rawManifest,
        property: "theme_color",
        expectedType: "string",
        trim: true,
      };
      return extractor.extractColorValue(spec);
    }

    function processBackgroundColorMember() {
      const spec = {
        objectName: "manifest",
        object: rawManifest,
        property: "background_color",
        expectedType: "string",
        trim: true,
      };
      return extractor.extractColorValue(spec);
    }

    function processLangMember() {
      const spec = {
        objectName: "manifest",
        object: rawManifest,
        property: "lang",
        expectedType: "string", trim: true,
      };
      let tag = extractor.extractValue(spec);
      // TODO: Check if tag is structurally valid.
      //       Cannot do this because we don't support Intl API on Android.
      //       https://bugzilla.mozilla.org/show_bug.cgi?id=864843
      //       https://github.com/tc39/ecma402/issues/5
      // TODO: perform canonicalization on the tag.
      //       Can't do this today because there is no direct means to
      //       access canonicalization algorithms through Intl API.
      //       https://github.com/tc39/ecma402/issues/5
      return tag;
    }
  },
};
var EXPORTED_SYMBOLS = ["ManifestProcessor"]; // jshint ignore:line