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[英]How to insert content script in google chrome extension when page was changed via history.pushState?
[英]insert content script when page was changed by history.pushState and ajax call
我遇到了将内容脚本插入到由history.pushState和ajax调用更改的页面中的问题。 我在stackoverflow上找到了类似的主题 ,但该解决方案对我不起作用(该解决方案是使用chrome.webNavigation.onHistoryStateUpdated和“popstate”事件)。
这是我的清单的一个片段:
"content_scripts": [
{
"matches": ["https://vk.com/audios*", "https://vk.com/al_audio.php*"],
"js": ["jquery-2.1.4.min.js", "getListOfSongs.js"]
}
]
chrome.webNavigation.onHistoryStateUpdated仅当我导航到另一个页面时才有效,如果我按顺序多次导航到同一页面没有任何反应。 例如:它工作时
1)首次访问https://vk.com/audios * - 首页或重新加载
2)转到https://vk.com/some_other_page - ajax调用
3)转到https://vk.com/audios * - ajax电话
它不起作用
1)首次访问https://vk.com/audios * - 首页或重新加载
2)再次转到https://vk.com/audios * - ajax调用,此时内容脚本没有注入
3)再次转到https://vk.com/audios * - ajax调用,此时内容脚本没有注入,依此类推
每次我第二次点击同一页面时依次生成以下请求:
https://vk.com/al_audio.php?__query=audios *********&_ ref = left_nav&_smt = audio%3A2&al = -1&al_id = ********&_ rndVer = 60742
(请求参数可能有所不同)
在这种情况下, JQuery .ajaxComplete也不会捕获任何事件。
并且pushState不会触发“popstate”事件,因此我无法使用window.onpopstate事件
我可能会使用chrome.webNavigation.onDOMContentLoaded和chrome.webNavigation.onCompleted,但是当我重新加载页面时,这些事件发生的时间超过一次,因此脚本将被多次注入。
这种情况的最佳解决方案是什么?
我可以想到两种可能的方式:
1 - 使用计时器检查脚本是否仍在那里,如果没有,再添加一次......
2 - 检查ajax调用,如果他们的url与删除脚本的其中一个URL匹配,请再次添加脚本。
您的脚本(清单中定义的脚本)仍然存在,即使在ajax调用之后,它也不会再次运行(不确定历史推送器会发生什么)。 所以,我假设您需要读取一些元素或重新运行stript。 我假设您添加了附加html标记的脚本。
所以你需要的东西是读取元素或重新运行某些代码。
1 - 计时器方法 - 我为我希望添加到页面中某个目标元素的 任何元素 (不仅是脚本)创建了一个解决方案。
它使用计时器来检查目标元素是否存在。 当它找到目标元素时,它会添加我的。 然后调整计时器以检查我的元素是否仍然存在。 如果没有,请再次添加。
您只需要一次调用appendChildPersistent
,这将在您浏览时始终保持活动状态。
var timers = {}; //stores the setInterval ids
//this is the only method you need to call
//give your script an `id` (1)
//the child is your script, it can be anything JQuery.append can take
//toElem is the Jquery "SELECTOR" of the element to add your script into.
//I'm not sure what would happen if toElem were not a string.
//callback is a function to call after insertion if desired, optional.
appendChildPersistent = function(id, child, toElem, callback)
{
//wait for target element to appear
withLateElement(toElem, function(target)
{
target.append(child); //appends the element - your script
if (typeof callback !== 'undefined') callback(); //execute callback if any
//create a timer to constantly check if your script is still there
timers[id] = setInterval(function()
{
//if your script is not found, clear this timer and tries to add again
if (document.getElementById(id) === null)
{
clearInterval(timers[id]);
delete timers[id];
appendChildPersistent(id, child, toElem, callback);
}
},3000);
});
}
//this function waits for an element to appear on the page
//since you can't foresee when an ajax call will finish
//selector is the jquery selector of the target element
//doAction is what to do when the element is found
function withLateElement(selector, doAction)
{
//checks to see if this element is already being waited for
if (!(selector in timers))
{
//create a timer to check if the target element appeared
timers[selector] = setInterval(function(){
var elem = $(selector);
//checks if the element exists and is not undefined
if (elem.length >= 0)
{
if (typeof elem[0] !== 'undefined')
{
//stops searching for it and executes the action specified
clearInterval(timers[selector]);
delete timers[selector];
doAction(elem);
}
}
}, 2000);
}
}
(1)向脚本标记添加Id似乎不是问题: 为脚本标记提供ID
2 - 捕获ajax调用
一个选项是使用chrome.webRequest 。 但奇怪的是,这对我没用。 另一种选择如下。
对于这种情况,请检查此答案 ,并且不要忘记在那里阅读Chrome扩展程序的相关答案。 它只有在您遵循整个过程时才有效。 幸运的是,我今天测试了它并且效果很好:p
在这里,您要做的是更改XMLHttpRequest
方法open
并send
以在调用它们时检测(并且可能也获取参数)。
但是,在Google Extension中,绝对有必要在页面中插入stript (而不是注入内容脚本的后台页面或脚本,但是内容脚本会将一些代码注入到dom中 ,如下所示)。
var script = document.createElement('script');
script.textContent = actualCode; //actual code is the code you want to inject, the one that replaces the ajax methods
document.head.appendChild(script); //make sure document.head is already loaded before doing it
script.parentNode.removeChild(script); //I'm not sure why the original answer linked removes the script after that, but I kept doing it in my solution
这是至关重要的,因为扩展尝试创建一个隔离的环境,并且您在此环境中对XMLHttpRequest
所做的更改将不会参与。 (这就是JQuery.ajaxComplete似乎不起作用的原因,你需要在页面中注入一个脚本才能工作 - 看看这里 )
在这个纯JavaScript的解决方案中 ,您可以替换方法:
//enclosing the function in parentheses to avoid conflict with vars from the page scope
(function() {
var XHR = XMLHttpRequest.prototype;
// Store the orignal methods from the request
var open = XHR.open;
var send = XHR.send;
// Create your own methods to replace those
//this custom open stores the method requested (get or post) and the url of the request
XHR.open = function(method, url) {
this._method = method; //this field was invented here
this._url = url; //this field was invented here
return open.apply(this, arguments); //calls the original method without any change
//what I did here was only to capture the method and the url information
};
//this custom send adds an event listener that fires whenever a request is complete/loaded
XHR.send = function(postData) {
//add event listener that fires when request loads
this.addEventListener('load', function() {
//what you want to do when a request is finished
//check if your element is there and readd it if necessary
//if you know the exact request url, you can put an if here, but it's not necessary
addMyElementsToPage(); //your custom function to add elements
console.log("The method called in this request was: " + this._method);
console.log("The url of this request was: " + this._url);
console.log("The data retrieved is: " + this.responseText);
});
//call the original send method without any change
//so the page can continue it's execution
return send.apply(this, arguments);
//what we did here was to insert an interceptor of the success of a request and let the request continue normally
};
})();
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