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Chrome onMessage侦听器始终发送“未定义”响应

[英]Chrome onMessage listener always sends 'undefined' response

 原文  2014-10-08 00:44:03  6   1    javascript/ google-chrome/ selenium/ google-chrome-extension/ browser-extension

问题描述

I have made the most basic chrome extension that could use message passing. 我做了可以使用消息传递的最基本的chrome扩展。 The extension should listen for messages from a website ( localhost:8080/* here) and always respond "Bye". 该扩展程序应侦听来自网站的消息（此处为localhost:8080/* ），并始终响应“再见”。 In the test selenium opens a locally served page with chrome which tries to send a message to the extension and then throws the response on the console: 在测试中，硒打开一个带有chrome的本地服务页面，该页面尝试向扩展发送消息，然后在控制台上抛出响应： 

$ tree -I node_modules
.
├── extension
│   ├── background.js
│   └── manifest.json
├── package.json
└── test
    ├── index.html
    └── selenium-test.js

2 directories, 5 files

background.js background.js 

chrome.runtime.onMessage.addListener(
    function (req, sender, sendResp) {
        sendResp('Bye');
    });

manifest.json 的manifest.json 

{
    "name": "chrome-test",
    "version": "0.1",
    "manifest_version": 2,
    "key": "pcoogjpilcclcmejpkmbifdbihomlgec",
    "description": "Test extension.",
    "app": {
    "background": {
        "scripts": ["background.js"],
        "persistent": true
    }
    },
    "externally_connectable": {
    "matches": [
        "http://localhost:8080/*"
    ],
    "accepts_tls_channel_id": false
    },
    "permissions": [
    "http://localhost:8080/*"
    ]
}

package.json 的package.json 

{
    "name": "chrome-test",
    "version": "0.0.5",
    "description": "Chrome API sucks.",
    "keywords": [ "" ],
    "author": "Chris Perivolaropoulos",
    "contributors": [],
    "dependencies": {
    "selenium-webdriver": "*",
    "mocha": "*",
    "chai": "*"
    },
    "scripts": {
    "test": "mocha test/selenium-test.js"
    }
}

index.html 的index.html 

<html>
  <head>
    <title>Test page</title>
  </head>
  <body>
    <h1>Test page</h1>
    <div id="echo"></div>
    <script type="text/javascript">
      chrome.runtime.sendMessage('pcoogjpilcclcmejpkmbifdbihomlgec', 'hello',
      function (msg) {
      console.log("Received! " + msg);
      });
    </script>
  </body>
</html>

selenium-test.js 硒test.js 

var assert = require('chai').assert,
    test = require('selenium-webdriver/testing'),
    webdriver = require('selenium-webdriver'),
    chromedriver = require('selenium-webdriver/chrome');

// @param extensions: string of unpacked extension path to install.
function chrome_driver(extension) {
    var logperfs = new webdriver.logging.Preferences(),
            opts = new chromedriver.Options().
                addArguments("--load-extension=" + extension ||
                                         '../extension');

    logperfs.setLevel(webdriver.logging.Type.BROWSER,
                                        webdriver.logging.Level.ALL);

    var chrome = new webdriver.Builder().
                withCapabilities(webdriver.Capabilities.chrome()).
                setChromeOptions(opts).
                setLoggingPrefs(logperfs).
                build();

    chrome.manage().timeouts().pageLoadTimeout(5000);
    return chrome;
}

function browser_logs(driver, callback) {
    driver.manage().logs().
        get(webdriver.logging.Type.BROWSER).then(callback);
}

test.describe('Test', function() {
    var chrome;
    this.timeout(10000);

    test.before(function() {
        chrome = chrome_driver("extension");
    });

    test.it("Test messages", function () {
        chrome.get("http://localhost:8080/test/index.html").then(function () {
            browser_logs(chrome, function (entries) {
                entries.forEach(function (e) {console.log("BrowserLog: " + e.message);});
                assert.equal(entries.pop().message,
                                         "hello", "Bus not echoing.");
            });
        });
    });

    test.after(function() {
        chrome.quit();
    });
});

To run a test first run a local http server 要运行测试，请首先运行本地http服务器 

$ python -m SimpleHTTPServer 8080
Serving HTTP on 0.0.0.0 port 8080 ...

and from another console run the tests 并从另一个控制台运行测试 

$ npm test

> chrome-test@0.0.5 test /path/to/project
> mocha test/selenium-test.js



  Test
BrowserLog: http://localhost:8080/test/index.html 11:15 Received! undefined
[2K[0G    1) Test messages


  0 passing (1s)
  1 failing

  1) Test Test messages:

      Bus not echoing.
      + expected - actual

      +hello
      -http://localhost:8080/test/index.html 11:15 Receviced! undefined

      at /path/to/project/test/selenium-test.js:43:12
      at /path/to/project/node_modules/selenium-webdriver/lib/goog/base.js:1582:15
      at webdriver.promise.ControlFlow.runInNewFrame_ (/path/to/project/node_modules/selenium-webdriver/lib/webdriver/promise.js:1640:20)
      at notify (/path/to/project/node_modules/selenium-webdriver/lib/webdriver/promise.js:444:12)
      at notifyAll (/path/to/project/node_modules/selenium-webdriver/lib/webdriver/promise.js:422:7)
      at resolve (/path/to/project/node_modules/selenium-webdriver/lib/webdriver/promise.js:400:7)
      at fulfill (/path/to/project/node_modules/selenium-webdriver/lib/webdriver/promise.js:512:5)
      at Object.webdriver.promise.asap (/path/to/project/node_modules/selenium-webdriver/lib/webdriver/promise.js:758:5)
      at webdriver.promise.ControlFlow.runInNewFrame_ (/path/to/project/node_modules/selenium-webdriver/lib/webdriver/promise.js:1651:25)
      at notify (/path/to/project/node_modules/selenium-webdriver/lib/webdriver/promise.js:444:12)
      at notifyAll (/path/to/project/node_modules/selenium-webdriver/lib/webdriver/promise.js:422:7)
      at resolve (/path/to/project/node_modules/selenium-webdriver/lib/webdriver/promise.js:400:7)
      at fulfill (/path/to/project/node_modules/selenium-webdriver/lib/webdriver/promise.js:512:5)
      at Object.webdriver.promise.asap (/path/to/project/node_modules/selenium-webdriver/lib/webdriver/promise.js:758:5)
      at webdriver.promise.ControlFlow.runInNewFrame_ (/path/to/project/node_modules/selenium-webdriver/lib/webdriver/promise.js:1651:25)
      at notify (/path/to/project/node_modules/selenium-webdriver/lib/webdriver/promise.js:444:12)
      at notifyAll (/path/to/project/node_modules/selenium-webdriver/lib/webdriver/promise.js:422:7)
      at resolve (/path/to/project/node_modules/selenium-webdriver/lib/webdriver/promise.js:400:7)
      at fulfill (/path/to/project/node_modules/selenium-webdriver/lib/webdriver/promise.js:512:5)
      at /path/to/project/node_modules/selenium-webdriver/lib/webdriver/promise.js:1507:10
      at /path/to/project/node_modules/selenium-webdriver/lib/goog/base.js:1582:15
      at webdriver.promise.ControlFlow.runInNewFrame_ (/path/to/project/node_modules/selenium-webdriver/lib/webdriver/promise.js:1640:20)
      at notify (/path/to/project/node_modules/selenium-webdriver/lib/webdriver/promise.js:444:12)
      at notifyAll (/path/to/project/node_modules/selenium-webdriver/lib/webdriver/promise.js:422:7)
      at resolve (/path/to/project/node_modules/selenium-webdriver/lib/webdriver/promise.js:400:7)
      at fulfill (/path/to/project/node_modules/selenium-webdriver/lib/webdriver/promise.js:512:5)
      at /path/to/project/node_modules/selenium-webdriver/lib/goog/base.js:1582:15
      at webdriver.promise.ControlFlow.runInNewFrame_ (/path/to/project/node_modules/selenium-webdriver/lib/webdriver/promise.js:1640:20)
      at notify (/path/to/project/node_modules/selenium-webdriver/lib/webdriver/promise.js:444:12)
      at notifyAll (/path/to/project/node_modules/selenium-webdriver/lib/webdriver/promise.js:422:7)
      at resolve (/path/to/project/node_modules/selenium-webdriver/lib/webdriver/promise.js:400:7)
      at fulfill (/path/to/project/node_modules/selenium-webdriver/lib/webdriver/promise.js:512:5)
      at /path/to/project/node_modules/selenium-webdriver/lib/webdriver/promise.js:703:49
      at /path/to/project/node_modules/selenium-webdriver/lib/webdriver/http/http.js:96:5
      at IncomingMessage.<anonymous> (/path/to/project/node_modules/selenium-webdriver/http/index.js:131:7)
      at IncomingMessage.emit (events.js:117:20)
      at _stream_readable.js:943:16
      at process._tickCallback (node.js:419:13)
  ==== async task ====
  WebDriver.manage().logs().get(browser)
      at webdriver.WebDriver.schedule (/path/to/project/node_modules/selenium-webdriver/lib/webdriver/webdriver.js:302:15)
      at webdriver.WebDriver.Logs.get (/path/to/project/node_modules/selenium-webdriver/lib/webdriver/webdriver.js:1380:23)
      at browser_logs (/path/to/project/test/selenium-test.js:28:3)
      at /path/to/project/test/selenium-test.js:41:4
      at /path/to/project/node_modules/selenium-webdriver/lib/goog/base.js:1582:15
      at webdriver.promise.ControlFlow.runInNewFrame_ (/path/to/project/node_modules/selenium-webdriver/lib/webdriver/promise.js:1640:20)
      at notify (/path/to/project/node_modules/selenium-webdriver/lib/webdriver/promise.js:444:12)
      at notifyAll (/path/to/project/node_modules/selenium-webdriver/lib/webdriver/promise.js:422:7)
      at resolve (/path/to/project/node_modules/selenium-webdriver/lib/webdriver/promise.js:400:7)
      at fulfill (/path/to/project/node_modules/selenium-webdriver/lib/webdriver/promise.js:512:5)
      at Object.webdriver.promise.asap (/path/to/project/node_modules/selenium-webdriver/lib/webdriver/promise.js:758:5)
      at webdriver.promise.ControlFlow.runInNewFrame_ (/path/to/project/node_modules/selenium-webdriver/lib/webdriver/promise.js:1651:25)
      at notify (/path/to/project/node_modules/selenium-webdriver/lib/webdriver/promise.js:444:12)
      at notifyAll (/path/to/project/node_modules/selenium-webdriver/lib/webdriver/promise.js:422:7)
      at resolve (/path/to/project/node_modules/selenium-webdriver/lib/webdriver/promise.js:400:7)
      at fulfill (/path/to/project/node_modules/selenium-webdriver/lib/webdriver/promise.js:512:5)
      at /path/to/project/node_modules/selenium-webdriver/lib/webdriver/promise.js:1507:10
      at /path/to/project/node_modules/selenium-webdriver/lib/goog/base.js:1582:15
      at webdriver.promise.ControlFlow.runInNewFrame_ (/path/to/project/node_modules/selenium-webdriver/lib/webdriver/promise.js:1640:20)
      at notify (/path/to/project/node_modules/selenium-webdriver/lib/webdriver/promise.js:444:12)
      at notifyAll (/path/to/project/node_modules/selenium-webdriver/lib/webdriver/promise.js:422:7)
      at resolve (/path/to/project/node_modules/selenium-webdriver/lib/webdriver/promise.js:400:7)
      at fulfill (/path/to/project/node_modules/selenium-webdriver/lib/webdriver/promise.js:512:5)
      at /path/to/project/node_modules/selenium-webdriver/lib/goog/base.js:1582:15
      at webdriver.promise.ControlFlow.runInNewFrame_ (/path/to/project/node_modules/selenium-webdriver/lib/webdriver/promise.js:1640:20)
      at notify (/path/to/project/node_modules/selenium-webdriver/lib/webdriver/promise.js:444:12)
      at notifyAll (/path/to/project/node_modules/selenium-webdriver/lib/webdriver/promise.js:422:7)
      at resolve (/path/to/project/node_modules/selenium-webdriver/lib/webdriver/promise.js:400:7)
      at fulfill (/path/to/project/node_modules/selenium-webdriver/lib/webdriver/promise.js:512:5)
      at /path/to/project/node_modules/selenium-webdriver/lib/webdriver/promise.js:703:49
      at /path/to/project/node_modules/selenium-webdriver/lib/webdriver/http/http.js:96:5
      at IncomingMessage.<anonymous> (/path/to/project/node_modules/selenium-webdriver/http/index.js:131:7)
      at IncomingMessage.emit (events.js:117:20)
      at _stream_readable.js:943:16
      at process._tickCallback (node.js:419:13)
  ==== async task ====
      at Context.ret (/path/to/project/node_modules/selenium-webdriver/testing/index.js:132:12)
      at Test.Runnable.run (/path/to/project/node_modules/mocha/lib/runnable.js:216:15)
      at Runner.runTest (/path/to/project/node_modules/mocha/lib/runner.js:373:10)
      at /path/to/project/node_modules/mocha/lib/runner.js:451:12
      at next (/path/to/project/node_modules/mocha/lib/runner.js:298:14)
      at /path/to/project/node_modules/mocha/lib/runner.js:308:7
      at next (/path/to/project/node_modules/mocha/lib/runner.js:246:23)
      at Object._onImmediate (/path/to/project/node_modules/mocha/lib/runner.js:275:5)
      at processImmediate [as _immediateCallback] (timers.js:345:15)



npm ERR! Test failed.  See above for more details.

The extension always responds undefined instead of 'Bye' as instructed in background.js . 该扩展始终响应undefined而不是按照background.js中的指示'Bye' 。

1 个解决方案

解决方案1
 2 已采纳  2014-10-08 10:31:37

Wrong event. 错误的事件。

Messages sent from webpages via externally_connectable are considered external messages. 从网页发送的消息经由externally_connectable被认为是外部的消息。 Therefore, your background script should look like this : 因此，您的背景脚本应如下所示 ： 

chrome.runtime.onMessageExternal.addListener(
  function (req, sender, sendResp) {
    sendResp('Bye');
  }
);

You get the impression that the listener sends an undefined response, because the callback of sendMessage is called in one of two cases: 您会感觉到侦听器发送了未定义的响应，因为在以下两种情况之一中调用了sendMessage的回调：

  • A listener actually called sendResponse . 侦听器实际上称为sendResponse 。 Then the argument is set to that response. 然后将参数设置为该响应。
  • There was an error sending the message. 发送消息时出错。 Then the argument is undefined and chrome.runtime.lastError is set. 然后undefined参数，并设置了chrome.runtime.lastError 。

You are hitting the second case - as there was no listener for the appropriate event. 您正在碰第二种情况-因为没有监听适当事件的人。

Now, a separate question is whether the webpage context even gets access to chrome.runtime.lastError .. 现在，另一个问题是网页上下文是否甚至可以访问chrome.runtime.lastError ..

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