如何检查是否有来自浏览器的待处理请求（Ajax 及其变体）

Question

我处理的一些网站有大量的 ajax 请求。我计划在单击断言元素之前等待 Ajax 请求完成。目前我使用

try {
    if (driver instanceof JavascriptExecutor) {
        JavascriptExecutor jsDriver = (JavascriptExecutor)driver;

        for (int i = 0; i< timeoutInSeconds; i++) 
        {
            Object numberOfAjaxConnections = jsDriver.executeScript("return jQuery.active");
            // return should be a number
            if (numberOfAjaxConnections instanceof Long) {
                Long n = (Long)numberOfAjaxConnections;
                System.out.println("Number of active jquery ajax calls: " + n);
                if (n.longValue() == 0L)  break;
            }
            Thread.sleep(1000);
        }
    }
    else {
       System.out.println("Web driver: " + driver + " cannot execute javascript");
    }
}
catch (InterruptedException e) {
    System.out.println(e);
}

但它适用于 Ajax 请求，但不适用于任何具有 jQuery 库变体的类似请求。

注意：

document.readyState == 'complete'

它不适用于 Ajax 请求或任何其他类似的替代方案。

测试都不是由我编写的，也不属于单个 webapp。所以我无法编辑 webapp。

Answer 1

我找到了答案，它适用于我检查过的少数 Ajax 和非 ajax 网站。在这个补丁之后，我不再需要对 ajax 繁重的页面进行隐式等待，LeGac 在他的一个 cmets 中指出了以下代码。

public static void checkPendingRequests(FirefoxDriver driver) {
    int timeoutInSeconds = 5;
    try {
        if (driver instanceof JavascriptExecutor) {
            JavascriptExecutor jsDriver = (JavascriptExecutor)driver;

            for (int i = 0; i< timeoutInSeconds; i++) 
            {
                Object numberOfAjaxConnections = jsDriver.executeScript("return window.openHTTPs");
                // return should be a number
                if (numberOfAjaxConnections instanceof Long) {
                    Long n = (Long)numberOfAjaxConnections;
                    System.out.println("Number of active calls: " + n);
                    if (n.longValue() == 0L)  break;
                } else{
                    // If it's not a number, the page might have been freshly loaded indicating the monkey
                    // patch is replaced or we haven't yet done the patch.
                    monkeyPatchXMLHttpRequest(driver);
                }
                Thread.sleep(1000);
            }
        }
        else {
           System.out.println("Web driver: " + driver + " cannot execute javascript");
        }
    }
    catch (InterruptedException e) {
        System.out.println(e);
    }    
}



public static void monkeyPatchXMLHttpRequest(FirefoxDriver driver) {
    try {
        if (driver instanceof JavascriptExecutor) {
            JavascriptExecutor jsDriver = (JavascriptExecutor)driver;
            Object numberOfAjaxConnections = jsDriver.executeScript("return window.openHTTPs");
            if (numberOfAjaxConnections instanceof Long) {
                return;
            }
            String script = "  (function() {" +
                "var oldOpen = XMLHttpRequest.prototype.open;" +
                "window.openHTTPs = 0;" +
                "XMLHttpRequest.prototype.open = function(method, url, async, user, pass) {" +
                "window.openHTTPs++;" +
                "this.addEventListener('readystatechange', function() {" +
                "if(this.readyState == 4) {" +
                "window.openHTTPs--;" +
                "}" +
                "}, false);" +
                "oldOpen.call(this, method, url, async, user, pass);" +
                "}" +
                "})();";
            jsDriver.executeScript(script);
        }
        else {
           System.out.println("Web driver: " + driver + " cannot execute javascript");
        }
    }
    catch (Exception e) {
        System.out.println(e);
    }
}

每一步之后你都需要调用

checkPendingRequests(driver);

Answer 2

这行不通？ http://api.jquery.com/ajaxstop/

$(document).ajaxStop(function() {
    // Do stuff here...    
});

Answer 3

如果使用JSONP请求，需要enable the active handling:

jQuery.ajaxPrefilter(function( options ) {
    options.global = true;
});

---

我认为active 的使用是正确的，但可能您使用的方式可能会在instanceof 条件下返回false。

（可选）see another way to wait for jQuery ajax calls using active in Selenium tests：

browser.wait_for_condition("selenium.browserbot.getCurrentWindow().jQuery.active === 0;", '30000')

Answer 4

根据我们对 cme​​ts 的讨论，这可能对您有用。

使用prototype.js：

var ACTIVE_REQUESTS = 0; // GLOBAL

ACTIVE_REQUESTS++
new Ajax.Request('/your/url', {
  onSuccess: function(response) {
    ACTIVE_REQUESTS--;
    // Handle the response content...
  }
}));

console.log("there are " + ACTIVE_REQUESTS + " open AJAX requests pending");

使用纯脚本：

interValRef = 0;

interValRef = setInterval("checkState();",100)

function checkState(){
    if(document.readyState == 'complete'){
        clearInterval(interValRef);
        myFunc();
    }
}

来源：Check Pending AJAX requests or HTTP GET/POST request