Question

我认为如果devtool can list都创建了IndexedDB，那么应该有一个API来检索它们？？

任何人都知道如何在firefox SDK的帮助下获取名单列表？

Answer 1

我确实深入研究了代码并查看了源代码。遗憾的是，没有任何方便的API可以从一个主机中提取所有数据库。

他们这样做的方法是潜伏在用户个人资料文件夹中，查看.sqlite的所有文件夹和文件，并对每个.sqlite进行sql查询（如果有正在进行的事务，多次）查询并要求数据库名称

它降低了代码的和平性

// striped down version of: https://dxr.mozilla.org/mozilla-central/source/devtools/server/actors/storage.js

/* 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/. */

"use strict";

const {async} = require("resource://gre/modules/devtools/async-utils");
const { setTimeout } = require("sdk/timers");
const promise = require("sdk/core/promise");

// A RegExp for characters that cannot appear in a file/directory name. This is
// used to sanitize the host name for indexed db to lookup whether the file is
// present in <profileDir>/storage/default/ location
const illegalFileNameCharacters = [
  "[",
  // Control characters \001 to \036
  "\\x00-\\x24",
  // Special characters
  "/:*?\\\"<>|\\\\",
  "]"
].join("");
const ILLEGAL_CHAR_REGEX = new RegExp(illegalFileNameCharacters, "g");

var OS = require("resource://gre/modules/osfile.jsm").OS;
var Sqlite = require("resource://gre/modules/Sqlite.jsm");

/**
 * An async method equivalent to setTimeout but using Promises
 *
 * @param {number} time
 *        The wait time in milliseconds.
 */
function sleep(time) {
  let deferred = promise.defer();

  setTimeout(() => {
    deferred.resolve(null);
  }, time);

  return deferred.promise;
}

var indexedDBHelpers = {

  /**
   * Fetches all the databases and their metadata for the given `host`.
   */
  getDBNamesForHost: async(function*(host) {
    let sanitizedHost = indexedDBHelpers.getSanitizedHost(host);
    let directory = OS.Path.join(OS.Constants.Path.profileDir, "storage",
                                 "default", sanitizedHost, "idb");

    let exists = yield OS.File.exists(directory);
    if (!exists && host.startsWith("about:")) {
      // try for moz-safe-about directory
      sanitizedHost = indexedDBHelpers.getSanitizedHost("moz-safe-" + host);
      directory = OS.Path.join(OS.Constants.Path.profileDir, "storage",
                               "permanent", sanitizedHost, "idb");
      exists = yield OS.File.exists(directory);
    }
    if (!exists) {
      return [];
    }

    let names = [];
    let dirIterator = new OS.File.DirectoryIterator(directory);
    try {
      yield dirIterator.forEach(file => {
        // Skip directories.
        if (file.isDir) {
          return null;
        }

        // Skip any non-sqlite files.
        if (!file.name.endsWith(".sqlite")) {
          return null;
        }

        return indexedDBHelpers.getNameFromDatabaseFile(file.path).then(name => {
          if (name) {
            names.push(name);
          }
          return null;
        });
      });
    } finally {
      dirIterator.close();
    }
    return names;
  }),

  /**
   * Removes any illegal characters from the host name to make it a valid file
   * name.
   */
  getSanitizedHost: function(host) {
    return host.replace(ILLEGAL_CHAR_REGEX, "+");
  },

  /**
   * Retrieves the proper indexed db database name from the provided .sqlite
   * file location.
   */
  getNameFromDatabaseFile: async(function*(path) {
    let connection = null;
    let retryCount = 0;

    // Content pages might be having an open transaction for the same indexed db
    // which this sqlite file belongs to. In that case, sqlite.openConnection
    // will throw. Thus we retey for some time to see if lock is removed.
    while (!connection && retryCount++ < 25) {
      try {
        connection = yield Sqlite.openConnection({ path: path });
      } catch (ex) {
        // Continuously retrying is overkill. Waiting for 100ms before next try
        yield sleep(100);
      }
    }

    if (!connection) {
      return null;
    }

    let rows = yield connection.execute("SELECT name FROM database");
    if (rows.length != 1) {
      return null;
    }

    let name = rows[0].getResultByName("name");

    yield connection.close();

    return name;
  })

};

module.exports = indexedDBHelpers.getDBNamesForHost;

如果有人想要使用它，那么这就是你如何使用它

var getDBNamesForHost = require("./getDBNamesForHost");

getDBNamesForHost("http://example.com").then(names => {
  console.log(names);
});

如果有人要构建一个添加indexedDB.mozGetDatabaseNames以与indexedDB.webkitGetDatabaseNames相同的方式工作的插件，那就太酷了。我不这样做......如果你愿意的话会留给你。将是一个格斗开发工具;）

列出firefox插件中一个主机的所有indexeddb

1 个答案: