问题
I am trying to use chrome extension to get some data from web of science. In one step, I want to create a new tab and wait until it loaded. So I add a webNavigation Listener after creating the tab. I found the listener works well only for some websites. If I use the target url (web of science) as the code below, I won't get the alert window. But if I use the target "https://stackoverflow.com/questions/ask", it gives the alert successfully. Why this happens? Could anyone advice the reason to me? Really thankful to it.
background.js
chrome.browserAction.onClicked.addListener(function(tab) {
chrome.tabs.query({active: true, currentWindow: true}, function(tabs) {
var activeTab = tabs[0];
tabId = activeTab.id;
chrome.tabs.sendMessage(tabId, {"message": "clicked_browser_action"});
});
});
var link = 'https://apps.webofknowledge.com/OneClickSearch.do?product=UA&search_mode=OneClickSearch&excludeEventConfig=ExcludeIfFromFullRecPage&SID=7ENVgUT3nRKp41VVlhe&field=AU&value=Leroux,%20E.'; // failed in this url
//var link = 'https://stackoverflow.com/questions/ask'; //success in this url
function listener1(){
chrome.webNavigation.onCompleted.removeListener(listener1);
chrome.tabs.sendMessage(tabId, {"message": "to content"});
alert('listener succeed');
}
chrome.runtime.onMessage.addListener(
function(request, sender, sendResponse) {
if (request.joke == 'content initial'){
chrome.tabs.create({ url: link });
chrome.tabs.query({active: true, currentWindow: true}, function(tabs) {
var activeTab = tabs[0];
tabId = activeTab.id;
});
//alert(link);
chrome.webNavigation.onCompleted.addListener(listener1, {url: [{urlMatches : link}]});
}
}
)
content.js
chrome.runtime.onMessage.addListener(
function(request, sender, sendResponse) {
if( request.message === "clicked_browser_action" ) {
console.log('content initial');
chrome.runtime.sendMessage({joke: 'content initial'}, function(response) {
});
}
}
)
manifest.json
{
"manifest_version": 2,
"name": "citation",
"version": "1",
"background": {
"scripts": ["background.js"],
"persistent": false
},
"browser_action": {},
"content_scripts": [{
"matches": ["<all_urls>"],
"run_at": "document_idle",
"js": ["content.js"]
}],
"permissions": [
"downloads",
"webNavigation",
"tabs",
"<all_urls>"
]
}
回答1:
The main problem is that urlMatches
is a regular expression in RE2 syntax as you can see in the documentation so various special symbols in the URL like ?
are interpreted differently. Solution: use urlEquals
or other literal string comparisons.
There are other problems:
- The API is asynchronous so the tabs are created and queried later in the future in no predictable sequence. Solution: use the callback of create().
- All tabs are reported in webNavigation listener, not just the active one, so theoretically there's a problem of two identical URLs being reported in different tabs. Also the API filtering parameter cannot handle URLs with
#hash
part Solution: remember the tab id you want to monitor in a variable and compare it in the listener, and explicitly strip #hash part in the filter. - The site may redirect the final URL of the page so it may not get reported due to your filter. Solution: specify only the host name in the filter.
- The tab that sends you messages or performs navigation may be inactive. Solution: use the tab id in the listener's parameters.
chrome.browserAction.onClicked.addListener(tab => {
chrome.tabs.sendMessage(tab.id, {message: 'clicked_browser_action'});
});
var link = '...............';
chrome.runtime.onMessage.addListener((msg, sender, sendResponse) => {
if (msg.joke === 'content initial') {
chrome.tabs.create({url: link}, tab => {
chrome.webNavigation.onCompleted.addListener(function onCompleted(info) {
if (info.tabId === tab.id && info.frameId === 0) {
chrome.webNavigation.onCompleted.removeListener(onCompleted);
chrome.tabs.sendMessage(tab.id, {message: 'to content'});
console.log('listener succeeded');
}
}, {
url: [{urlPrefix: new URL(link).origin + '/'}],
});
});
}
});
Notes:
- Avoid declaring
content_scripts
in manifest.json for all URLs if you only need processing on demand. Use programmatic injection in such cases. - Instead of alert() use the proper debugging in devtools like breakpoints or
console.log()
of the background page (more info).
来源:https://stackoverflow.com/questions/57314419/why-webnavigation-listener-failed-for-some-websites