26

用户点击此链接：

<span onclick="slow_function_that_fills_the_panel(); $('#panel').show();">

现在我正在模拟 phantomjs 中的点击：

page.evaluate(
  function() { $("#panel").click(); }
);
console.log('SUCCESS');
phantom.exit();

在慢速函数结束执行并且 DIV 变得可见之前，幻象退出。如何实现等待？

4

4 回答 4

26

这是 Cyber​​maxs 的回答：

function waitFor ($config) {
    $config._start = $config._start || new Date();

    if ($config.timeout && new Date - $config._start > $config.timeout) {
        if ($config.error) $config.error();
        if ($config.debug) console.log('timedout ' + (new Date - $config._start) + 'ms');
        return;
    }

    if ($config.check()) {
        if ($config.debug) console.log('success ' + (new Date - $config._start) + 'ms');
        return $config.success();
    }

    setTimeout(waitFor, $config.interval || 0, $config);
}

使用示例：

waitFor({
    debug: true,  // optional
    interval: 0,  // optional
    timeout: 1000,  // optional
    check: function () {
        return page.evaluate(function() {
            return $('#thediv').is(':visible');
        });
    },
    success: function () {
        // we have what we want
    },
    error: function () {} // optional
});

使用配置变量时会更容易一些。

于 2013-09-28T18:44:01.290 回答
15

默认情况下，PhantomJS 是异步运行的，这会导致您在上面描述的问题（脚本在您的结果准备好之前完成）

但是，没有什么可以阻止您以同步方式使用它。

只需phantom.page.sendEvent('mousemove')在while循环中使用。这将继续循环通过事件泵，直到 webkit 引擎加载您的页面或处理任何必要的浏览器事件。

var page = require('webpage').create();

// Step 1: View item
page.open('http://localhost/item3324.php');
do { phantom.page.sendEvent('mousemove'); } while (page.loading);
page.render('step1-viewitem.png');

// Step 2: Add to cart
page.evaluate(function() {$('#add-to-cart').click(); });
do { phantom.page.sendEvent('mousemove'); } while (page.loading);
page.render('step2-viewcart.png');

// Step 3: Confirm contents
page.evaluate(function() {$('#confirm-cart').click(); });
do { phantom.page.sendEvent('mousemove'); } while (page.loading);
page.render('step3-confirm.png');

请注意，page.loading也可以是任何其他布尔条件，例如：

do { phantom.page.sendEvent('mousemove'); } 
while (page.evaluate(function() {return $("#panel").is(":visible");}));

我在处理triflejs.org项目（幻象的 Internet Explorer 版本）试图模拟trifle.wait(ms)对 PhantomJS 环境内部的调用时发现了这种方法。

于 2015-03-12T13:22:09.853 回答
8

My approach for this scenario is to wait until "something" is done or true. I highly suggest you to test waitfor.js.

demo.html

<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
    <script src="http://code.jquery.com/jquery-1.9.1.js"></script>
    <title>Test</title>
</head>
<body id="body">

    <div id="thediv">Hello World !</div>

    <script type="text/javascript">
        $('#thediv').hide();
        setTimeout(function () {
            $('#thediv').show();
        }, 3000);

    </script>
</body>
</html>

demoscript.js

var page = require('webpage').create();
var system = require('system');

function waitFor(testFx, onReady, timeOutMillis) {
    var maxtimeOutMillis = timeOutMillis ? timeOutMillis : 5000, //< Default Max Timout is 5s
        start = new Date().getTime(),
        condition = false,
        interval = setInterval(function () {
            if ((new Date().getTime() - start < maxtimeOutMillis) && !condition) {
                // If not time-out yet and condition not yet fulfilled
                condition = (typeof (testFx) === "string" ? eval(testFx) : testFx()); //< defensive code
            } else {
                if (!condition) {
                    // If condition still not fulfilled (timeout but condition is 'false')
                    //console.log("'waitFor()' timeout");
                    typeof (onReady) === "string" ? eval(onReady) : onReady();
                    clearInterval(interval);
                    //phantom.exit(1);
                } else {
                    // Condition fulfilled (timeout and/or condition is 'true')
                    console.log("'waitFor()' finished in " + (new Date().getTime() - start) + "ms.");
                    typeof (onReady) === "string" ? eval(onReady) : onReady(); //< Do what it's supposed to do once the condition is fulfilled
                    clearInterval(interval); //< Stop this interval
                }
            }
        }, 500); //< repeat check every 500ms
};

if (system.args.length != 1) {
    console.log('invalid call');
    phantom.exit(1);
} else {
    //adapt the url to your context
    page.open('http://localhost:40772/demo.html', function (status) {
        if (status !== 'success') {
            console.log('Unable to load the address!');
            phantom.exit();
        } else {
            waitFor(
                function () {
                    return page.evaluate(function () {
                        return $('#thediv').is(':visible');
                    });
                },
                function () {
                    page.render('page.png');
                    phantom.exit();
                }, 5000);
        }
    });
}

This script evaluate $('#thediv').is(':visible')(classic Jquery code) every 500 ms to check if the div is visible.

于 2013-05-29T08:34:37.787 回答
1

在 page.evaluate() 中，使用self.loading属性来测试完成度......

var fs = require('fs');
path = '/path/to/file.html';
address = 'http://google.com';    

page.open(address, function (status) {
    if (status !== 'success') {
        console.log('Unable to access page');
    } else {
        var p = page.evaluate(function () {
            if(!self.loading){ // ah, such beauty
              return document.documentElement.outerHTML;
            }
        });
    fs.write(path, p, 'w');
    }
    phantom.exit();
});
于 2015-09-30T22:07:27.587 回答