Can i use HtmlUnit to listen for resource loading events?

问题

I'm trying to use HtmlUnit to detect resources (scripts, images, stylesheets, etc) that fail to load on a webpage.

I've tried

new WebConnectionWrapper(webClient) {
    @Override
    public WebResponse getResponse(WebRequest request) throws IOException {
        WebResponse response;
        response = super.getResponse(request);
        System.out.println(response.getStatusCode());
        return response;
    }
};

to no avail. It doesn't seem to handle CSS, images or JS, despite HtmlUnit logging:

statusCode=[404] contentType=[text/html] File: /resources/style.css

For reference, here's the file I'm loading:

<!DOCTYPE html>
<html>
    <head>
        <title>Test</title>
        <script type='text/javascript'>
            var xhr = new XMLHttpRequest();
            xhr.open("get", "someBadLink", true);
            xhr.send();
        </script>
        <link href="/resources/style.css" rel="stylesheet"/>
    </head>

    <body>
        <img src="bad_image.png">
    Cool.
    </body>
</html>

Is there any way to use HtmlUnit to detect the AJAX resource, CSS script and image that all 404?

回答1:

For AJAX, you have to wait as hinted here.
HtmlUnit doesn't automatically loads HtmlLink and HtmlImage, for performance reasons.
Please find below snippet that will print all. You can use .getByXPath() to get list of all elements.

public static void main(String[] args) throws Exception {
    try (final WebClient webClient = new WebClient()) {

        new WebConnectionWrapper(webClient) {
            @Override
            public WebResponse getResponse(WebRequest request) throws IOException {
              WebResponse response = super.getResponse(request);
              System.out.println(request.getUrl());
              System.out.println(response.getStatusCode());
              return response;
            }
        };

        String url = "http://localhost/test.html";
        HtmlPage page = webClient.getPage(url);

        // to wait for AJAX
        webClient.waitForBackgroundJavaScript(3000);

        // to forcibly load the link
        HtmlLink link = page.getFirstByXPath("//link");
        link.getWebResponse(true);

        // to forcibly load the image
        HtmlImage image = page.getFirstByXPath("//img");
        image.getImageReader();
    }
}

来源：https://stackoverflow.com/questions/31253688/can-i-use-htmlunit-to-listen-for-resource-loading-events

标签

java

htmlunit

headless-browser