Google Chrome扩展程序中的同步通话

Question

我正在使用Google Chrome扩展程序,该扩展程序必须阻止/重定向某些传出请求.为此,我使用了chrome.webRequest.onBeforeRequest监听器.要决定是否阻止请求,我需要一些有关选项卡请求的信息.我可以使用它chrome.tabs.get(integer tabId, function callback),但回调是异步的,这意味着它可以在从onBeforeRequest侦听器返回值后调用.

chrome.webRequest.onBeforeRequest.addListener(function(details){
 chrome.tabs.get(details.tabId, function(tab){
  // get info from tab
 }); 
 // based on info from tab return redirect or not
}), {
 urls: ["<all_urls>"],
 types: ["main_frame"]
}, ["blocking"]);

有没有办法同步通话？或许还有一些其他选择.

Answer 1

Stack Overflow上的另一个答案建议跟踪监听器功能之外的选项卡,这完全避免了这个问题.

示例代码:

/* 
 * --------------------------------------------------
 * Keep list of tabs outside of request callback
 * --------------------------------------------------
 */
var tabs = {};

// Get all existing tabs
chrome.tabs.query({}, function(results) {
    results.forEach(function(tab) {
        tabs[tab.id] = tab;
    });
});

// Create tab event listeners
function onUpdatedListener(tabId, changeInfo, tab) {
    tabs[tab.id] = tab;
}
function onRemovedListener(tabId) {
    delete tabs[tabId];
}

// Subscribe to tab events
chrome.tabs.onUpdated.addListener(onUpdatedListener);
chrome.tabs.onRemoved.addListener(onRemovedListener);

/* 
 * --------------------------------------------------
 * Request callback
 * --------------------------------------------------
 */
// Create request event listener
function onBeforeRequestListener(details) {
    // *** Remember that tabId can be set to -1 ***
    var tab = tabs[details.tabId];

    // Respond to tab information
}

// Subscribe to request event
chrome.webRequest.onBeforeRequest.addListener(onBeforeRequestListener, {
    urls: ["<all_urls>"],
    types: ["main_frame"]
}, ["blocking"]);