检测Chrome扩展内容脚本是否已被注入/内容脚本包含警卫 [英] detect if Chrome extension content script has been injected / content script include guard

问题描述

我想在更新标签时执行内容脚本功能。问题是，有时标签更新是ajax（没有页面重新加载），同时仍然改变页面的URL。因此，注入的旧内容脚本仍然存在于页面上。结果是内容脚本的多个实例被注入并在同一页面上运行。

因此，我正在寻找一种机制来注入内容脚本，内容脚本已被注入。任何想法？您可以尝试发送消息到内容脚本（ .com / extensions / messaging.htmlrel =noreferrer>消息传递）。如果内容脚本成功返回响应，则意味着内容脚本已经存在，否则返回空响应，您可以检查空响应并注入内容脚本。

  chrome.tabs.query（{active：true，currentWindow：true }，function（tabs）{
 chrome.tabs.sendMessage（tabs [0] .id，{greeting：hello}，function（response）{
 if（response）{
 console.log（Already there）; 
} 
 else {
 console.log（Not there，inject contentscript）; 
} 
}）; 
}）; 
  

ContentScript：

  chrome.runtime.onMessage.addListener（
函数（request，sender，sendResponse）{
 if（request.greeting ==hello）
 sendResponse（{message：hi}）; 
}）; 
  

I want to execute a content script function whenever a tab is updated. The problem is that, sometimes the tab update is ajax (without a page reload), while still changing the page's url. Therefore the old content script injected still exists on the page. The result is multiple instances of content script injected and running on the same page.

So, I'm looking for a mechanism to inject a content script, only if no same content script has been injected before. Any ideas?

解决方案

You can try sending a message to content script (Message Passing). If the content script successfully returns a response then it means that the content script is already there otherwise an empty response is returned, you can check for an empty response and inject the content script.

Background:

chrome.tabs.query({active: true, currentWindow: true}, function(tabs) {
    chrome.tabs.sendMessage(tabs[0].id, {greeting: "hello"}, function(response) {
        if (response) {
            console.log("Already there");
        }
        else {
            console.log("Not there, inject contentscript");
        }
    });
});

ContentScript:

chrome.runtime.onMessage.addListener(
    function(request, sender, sendResponse) {
        if (request.greeting == "hello")
            sendResponse({message: "hi"});
 });

这篇关于检测Chrome扩展内容脚本是否已被注入/内容脚本包含警卫的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！