我写了一个chrome扩展,popup js会发消息给后台,后台会把消息重定向到content script,经过一些网络请求,结果应该返回给后台,然后popup js。
下面是我的一些简化代码。
弹出js
$('.porintButton').click(function() {
switch (this.id) {
case 'learningPointButton':
chrome.runtime.sendMessage({ action: 'learning' }, callback);
processResult();
break;
}
return true;
});
后台js
chrome.runtime.onMessage.addListener((request, sender, sendResponse) => {
chrome.tabs.query({ active: true, currentWindow: true }, function (tabs) {
chrome.tabs.sendMessage(tabs[0].id, request, response => {
if (chrome.runtime.lastError) {
// If I click learningPointButton, the line will excute, and log 'ERROR: {message: "Could not establish connection. Receiving end does not exist."}'
console.log('ERROR: ', chrome.runtime.lastError);
} else {
console.log('The Content Script got the following Message: ' + JSON.stringify(response));
sendResponse(response);
}
});
});
return true;
});
内容脚本
chrome.runtime.onMessage.addListener(async (request, sender, sendResponse) => {
console.info('contentscript', request, sender);
switch (request.action) {
case 'learning':
// this simulate network async request, will not work,
setTimeout(() => {
sendResponse({ action: request.action, result: 'ok' });
}, 0);
// this works
// sendResponse({ action: request.action, result: 'ok' });
break;
}
// I have read https://developer.chrome.com/extensions/messaging#simple and return true here
return true;
});
如果我将消息隧道更改为 the Long-lived connections , 它会起作用,为什么?
最佳答案
@wOxxO 谢谢,你是对的。
我使用 Promise 风格重写了代码,现在它可以工作了。
我重写的代码是这样的。
chrome.runtime.onMessage.addListener((request, sender, sendResponse) => {
console.info('contentscript', request, sender);
switch (request.action) {
case 'learning':
Promise.all([doLearning(), doLearning(), doLearning()])
.then(unusedData => {
return getScore();
})
.then(scores => {
console.info(scores);
sendResponse({ action: request.action, result: 'ok', scores: scores });
})
.catch(e => {
console.error(e);
sendResponse({ action: request.action, result: 'error', message: e });
});
break;
case 'score':
getScore().then(scores => {
console.info(scores);
sendResponse({ action: request.action, result: 'ok', scores: scores });
}).catch(e => {
console.error(e);
sendResponse({ action: request.action, result: 'error', message: e });
});
break;
}
return true;
});
而且我可以直接从弹出窗口向内容脚本发送消息。
关于javascript - 内容脚本向后台发送响应时获取 "Could not establish connection. Receiving end does not exist.",我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/47066984/