如何通过Python使用GhostDriver处理警报？

Question

问题： GhostDriver
API尚不支持警报处理。目前有一种可接受的解决方法，即将您自己的javascript注入将处理警报并为您存储其文本的页面。

我在通过python webdriver绑定使用此解决方法时遇到了麻烦。这可能与我的新手对javascript的理解有关。

这是我尝试利用的变通方法的示例：https
:
//github.com/detro/ghostdriver/issues/20#issuecomment-15641983

我正在使用一个公开的站点来演示警报，以使其变得更加简单：http
:
//www.tizag.com/javascriptT/javascriptalert.php

这是我的代码：

from selenium import webdriver

button_xpath = "/html/body/table[3]/tbody/tr/td[2]/table/tbody/tr/td/div[4]/form/input"

js = """
(function () {
var lastAlert = undefined;
window.alert = function (message) {
    lastAlert = message;
};
window.getLastAlert = function () {
    var result = lastAlert;
    lastAlert = undefined;
    return result;
};
}());
"""

driver = webdriver.PhantomJS()
driver.get('http://www.tizag.com/javascriptT/javascriptalert.php')
driver.execute_script("window.alert = %s" % js)
driver.find_element_by_xpath(button_xpath).click()
#exception just occured
driver.execute_script("return window.getLastAlert && window.getLastAlert();")

例外是：

WebDriverException: Message: u'Error Message => \'Click failed: TypeError: \'undefined\' is not a function (evaluating \'alert(\'Are you sure you want to give us the deed to your house?\')\')\'\n caused by Request => {"headers":{"Accept":"application/json","Accept-Encoding":"identity","Connection":"close","Content-Length":"81","Content-Type":"application/json;charset=UTF-8","Host":"127.0.0.1:41752","User-Agent":"Python-urllib/2.7"},"httpVersion":"1.1","method":"POST","post":"{\\"sessionId\\": \\"0eaf7680-9897-11e2-b375-55b9cb6ceb0f\\", \\"id\\": \\":wdc:1364578560610\\"}","url":"/click","urlParsed":{"anchor":"","query":"","file":"click","directory":"/","path":"/click","relative":"/click","port":"","host":"","password":"","user":"","userInfo":"","authority":"","protocol":"","source":"/click","queryKey":{},"chunks":["click"]},"urlOriginal":"/session/0eaf7680-9897-11e2-b375-55b9cb6ceb0f/element/%3Awdc%3A1364578560610/click"}' ; Screenshot: available via screen

我是JS菜鸟。我希望有人可以指出正确的方向。

Answer 1

一个简单的解决方案是重写window.alert方法，以将参数输出到全局变量。

使用覆盖函数定义js注入变量：

js = """
window.alert = function(message) {
lastAlert = message;
}
"""

然后只需通过python中的execute_script调用传递js变量，如下所示：

driver.execute_script("%s" % js)

然后，当它们全部运行后，您可以对全局lastAlert执行返回：

driver.execute_script("return lastAlert")