在内容和后台之间传递的Chrome扩展消息无效

本文介绍了在内容和后台之间传递的Chrome扩展消息无效的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述 background.js getPageDimension = function（）{ chrome.tabs.getSelected（null，function（tab） { chrome.tabs.sendMessage（tab.id，{message：DIMENSION}，function（response）{ if（response！= null）{ console.log（response。 x）; console.log（response.y）; console.log（response.w）; console.log（response.h）; } else { console.log（'Response is null'）; } }）; }）; }; content.js $ b $ pre $ chrome.runtime.onMessage.addListener（函数（msg，sender，sendResponse）{ if（msg .message&&（msg.message ==DIMENSION））{ var dimension = getPageDiemension（document.documentElement）; console.log（dimension.x）; console .log（dimension.y）; console.log（dimension.w）; console.log（dimension.h）; sendResponse（{x：dimension.x，y：dimension .y，w：dimension.w，h：dimension.h}）; } }）; getPageDiemension = function（currentDom）{ var dimension = new Object（）; dimension.x = 0; dimension.y = 0; dimension.w = currentDom.scrollWidth; dimension.h = currentDom.scrollHeight; 返回维度; $ / code> 所以我的目标是获得当前页面的全部高度和宽度活动标签。当我调试我的内容脚本时，我在 background.js 中获得了正确的响应，但是如果在未进行调试的情况下运行脚本，则会得到 undefined 在我的 background.js 中的回应。 这是我的文件中：c $ c> cotent.js all_frames：true，matches：[http：// * / *，https： // * / *，js：[content.js] }]， 请帮助我，我哪里错了？ 解决方案 问题 在你的代码中有两个小问题，我在发现一个错误之后发现它，因为它看起来很完美（当它完全不工作时）。 您正在使用不应使用的已弃用的 chrome.tabs.getSelected（...）方法。使用 chrome.tabs.query（{active：true，highlight：true}，...）。 在您的 chrome.runtime.onMessage 侦听器中，在内容脚本中，您在发送响应之前进行一些计算：这会使消息通道关闭，然后才能发送响应，并会导致 null 响应。 从官方文档： $ b 解决方案 现在您知道问题所在，您可以用 tabs.query（）替换旧的 tabs.getSelected（），然后添加一个 return true; 语句在您的内容脚本中的 runtime.onMessage 事件的处理程序中。解决方案如下，我也稍微减轻了一些代码。 您的 background.js ： getPageDimension = function（）{ chrome.tabs.query（{active：true，highlight：true}，function（tabs ）{ chrome.tabs.sendMessage（tabs [0] .id，{message：DIMENSION}，function（response）{ if（response！== null）console.log（'Response ：'，response）; else console.log（'Response is null'）; }）; }）; }; 您的 content.js ： chrome.runtime.onMessage.addListener（函数（msg，sender，sendResponse）{ if（msg.message&& amp; ;（msg.message ==DIMENSION））{ var dimension = getPageDiemension（document.documentElement）; console.log（'Dimension：'，dimension）; sendResponse ）; } 返回true; }）; $ b getPageDiemension = function（currentDom）{ return {x：0，y：0，w：currentDom.scrollWidth，h：currentDom.scrollHeight $ b $ h $>工作示例 $ b 你可以找到一个我为测试做的实例 HERE 。 文档链接 为了清楚起见，我将留下一些文档 chrome.tabs API chrome.tabs.query 方法 Chrome扩展消息传递 chrome.tabs.sendMessage 方法 chrome.runtime.onMessage 事件 I am developing a chrome extension, here are the main files:background.jsgetPageDimension = function (){ chrome.tabs.getSelected(null, function(tab) { chrome.tabs.sendMessage(tab.id, { message: "DIMENSION" }, function(response){ if (response != null) { console.log(response.x); console.log(response.y); console.log(response.w); console.log(response.h); }else{ console.log('Response is null'); } }); }); };content.jschrome.runtime.onMessage.addListener(function(msg, sender, sendResponse) { if (msg.message && (msg.message == "DIMENSION")) { var dimension = getPageDiemension(document.documentElement); console.log(dimension.x); console.log(dimension.y); console.log(dimension.w); console.log(dimension.h); sendResponse({x: dimension.x, y: dimension.y,w: dimension.w,h: dimension.h}); }});getPageDiemension = function(currentDom){ var dimension = new Object(); dimension.x = 0; dimension.y = 0; dimension.w = currentDom.scrollWidth; dimension.h = currentDom.scrollHeight; return dimension;}So my aim is to get the full height and width of page loaded in current active tab. When I debug my content script, I get the proper response in my background.js, but if run the script without debugging, I get an undefined response in my background.js.Here is the declaration of my cotent.js in my manifest.json file:"content_scripts": [{ "all_frames": true, "matches": [ "http://*/*", "https://*/*" ], "js": ["content.js"]}],Kindly help me, where am I going wrong?. Let me know if you need any further data. 解决方案 IssuesThere are two little problems in your code, which I found after a wile, since that it looks perfectly working (when it isn't at all).You're using the deprecated chrome.tabs.getSelected(...) method, which you should avoid. Use chrome.tabs.query({active: true, highlighted: true}, ...) instead.In your chrome.runtime.onMessage listener, in the content script, you are doing some calculations before sending the response: this makes the message channel close before you can send a response, and will result in a null response.Quoting from the official documentation:SolutionNow that you know what the problems are, you can easily replace the old tabs.getSelected() with tabs.query(), and add a return true; statement in the handler of the runtime.onMessage event in your content script. The solution is the following, I also lightened the code a bit.Your background.js:getPageDimension = function (){ chrome.tabs.query({active: true, highlighted: true}, function(tabs) { chrome.tabs.sendMessage(tabs[0].id, { message: "DIMENSION" }, function(response){ if (response !== null) console.log('Response:', response); else console.log('Response is null'); }); }); };Your content.js:chrome.runtime.onMessage.addListener(function(msg, sender, sendResponse) { if (msg.message && (msg.message == "DIMENSION")) { var dimension = getPageDiemension(document.documentElement); console.log('Dimension:', dimension); sendResponse(dimension); } return true;});getPageDiemension = function(currentDom){ return { x: 0, y: 0, w: currentDom.scrollWidth, h: currentDom.scrollHeight }}Working exampleYou can find a working example I made for testing HERE.Documentation linksJust for clarity, I'm leaving you some documentation links regarding the APIs involved in this extension that you may find helpful:chrome.tabs APIchrome.tabs.query methodChrome extension message passingchrome.tabs.sendMessage methodchrome.runtime.onMessage event 这篇关于在内容和后台之间传递的Chrome扩展消息无效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！