无铬-从网页中获取所有图像src

Question

我正在尝试使用无浏览器获取HTML页面中所有img标记的src值。我目前的实现如下所示：

async function run() {
    const chromeless = new Chromeless();
    let url = 'http://someurl/somepath.html';

    var allImgUrls = await chromeless
        .goto(url)
        .evaluate(() => document.getElementsByTagName('img'));

    var htmlContent = await chromeless
        .goto(url)
        .evaluate(() => document.documentElement.outerHTML );

    console.log(allImgUrls);

    await chromeless.end()
}

问题是，我没有在allImgUrls中获得img对象的任何值。

Answer 1

经过一些研究，我们发现我们可以采用这样的方法：

var imgSrcs = await chromeless
        .goto(url)
        .evaluate(() => {
            /// since document.querySelectorAll doesn't actually return an array but a Nodelist (similar to array)
            /// we call the map function from Array.prototype which is equivalent to [].map.call()
            const srcs = [].map.call(document.querySelectorAll('img'), img => img.src);
            return JSON.stringify(srcs);
        });