javascript - Firefox 扩展可以自行卸载吗？

Question

我发现扩展A能够卸载扩展B:Uninstall/Remove Firefox Extension programmatically?

我想知道相同的方法是否也适用于卸载自身的扩展(例如，如果它感觉到有一个高级扩展取代了它)？以下代码是我对上述链接问题的答案的简单改编:

Components.utils.import("resource://gre/modules/AddonManager.jsm");
AddonManager.getAddonByID("supersedes-me@id", function(betteraddon) {
   if (betteraddon) {
      AddonManager.getAddonById("my-own@id", function(thisaddon) {
         if (!thisaddon) {
            // this Add-on not present? Should not happen ...
            return;
         }
         if (!(thisaddon.permissions & AddonManager.PERM_CAN_UNINSTALL)) {
            // Add-on cannot be uninstalled
            return;
         }
         thisaddon.uninstall();
         if (thisaddon.pendingOperations & AddonManager.PENDING_UNINSTALL) {
            // Need to restart to finish the uninstall.
            // Might ask the user to do just that. Or not ask and just do.
            // Or just wait until the browser is restarted by the user.
         }
      });
   }
});

这听起来很危险，因为自卸载插件至少正在等待从其自己的卸载返回调用......但这种做法真的那么危险吗？毕竟，现在卸载甚至是可撤消的，这意味着卸载的插件会“仍然存在”一段时间..？

Answer 1

是的，扩展程序可以使用 AddonManager.jsm 自行卸载。您可以获得Addon对象，使用 getAddonByID() ，其中有 uninstall()方法。换句话说，或多或少，你在问题中如何编码。

下面是一个可自行卸载的附加 SDK 扩展。安装后，它会短暂出现在 about:addons 中，但随后消失。从 .xpi 文件安装时，它会在控制台中生成以下输出:

uninstallself:My ID=@uninstallself
uninstallself:This add-on is being loaded for reason= install
uninstallself:Going to uninstall myself
uninstallself:This add-on is being unloaded for reason= uninstall
uninstallself:Called uninstall on myself

如果使用jpm run调用，它还会输出另外两行错误，表明无法删除文件。该文件是由 jpm run 创建的临时 .xpi 文件。

package.json:

{
    "title": "Test Self Uninstall",
    "name": "uninstallself",
    "version": "0.0.1",
    "description": "Test an add-on uninstalling itself",
    "main": "index.js",
    "author": "Makyen",
    "engines": {
        "firefox": ">=38.0a1",
        "fennec": ">=38.0a1"
    },
    "license": "MIT",
    "keywords": [
        "jetpack"
    ]
}

index.js:

/* Firefox Add-on SDK uninstall self */

const { AddonManager } = require("resource://gre/modules/AddonManager.jsm");
var self = require("sdk/self");
var myId = self.id;

var utils = require('sdk/window/utils');
activeWin = utils.getMostRecentBrowserWindow();
// Using activeWin.console.log() is needed to have output to the
// Browser Console when installed as an .xpi file.  In that case,
// console is mapped to dump(), which does not output to the console. 
// This is done to not polute the console from SDK add-ons that are
// logging information when they should not.  Using jpm run,
// console.log outputs to the Browser Console.

activeWin.console.log('My ID=' +myId);

exports.main = function (options) {
activeWin = utils.getMostRecentBrowserWindow();
    activeWin.console.log('This add-on is being loaded for reason=', options.loadReason);
};

exports.onUnload = function (reason) {
    activeWin.console.log('This add-on is being unloaded for reason=',reason);
};

AddonManager.getAddonByID(myId,addon => {
    if(addon && typeof addon.uninstall === 'function'){
        activeWin.console.log('Going to uninstall myself');
        addon.uninstall();
        activeWin.console.log('Called uninstall on myself');
    }
});