如何使用爬虫抓取网站的所有内部网址？

Question

我想在 node.js 中使用爬虫来爬取网站中的所有链接（内部链接）并获取每个页面的标题，我在 npm crawler上看到了这个插件，如果我检查文档，则有以下示例：

var Crawler = require("crawler");

var c = new Crawler({
   maxConnections : 10,
   // This will be called for each crawled page
   callback : function (error, res, done) {
       if(error){
           console.log(error);
       }else{
           var $ = res.$;
           // $ is Cheerio by default
           //a lean implementation of core jQuery designed specifically for the server
           console.log($("title").text());
       }
       done();
   }
});

// Queue just one URL, with default callback
c.queue('http://balenol.com');

但我真正想要的是抓取网站中的所有内部网址，并且是内置在这个插件中还是需要单独编写？我在插件中没有看到任何选项可以访问站点中的所有链接，这可能吗？

Answer 1

以下代码段会抓取它找到的每个 URL 中的所有 URL。

const Crawler = require("crawler");

let obselete = []; // Array of what was crawled already

let c = new Crawler();

function crawlAllUrls(url) {
    console.log(`Crawling ${url}`);
    c.queue({
        uri: url,
        callback: function (err, res, done) {
            if (err) throw err;
            let $ = res.$;
            try {
                let urls = $("a");
                Object.keys(urls).forEach((item) => {
                    if (urls[item].type === 'tag') {
                        let href = urls[item].attribs.href;
                        if (href && !obselete.includes(href)) {
                            href = href.trim();
                            obselete.push(href);
                            // Slow down the
                            setTimeout(function() {
                                href.startsWith('http') ? crawlAllUrls(href) : crawlAllUrls(`${url}${href}`) // The latter might need extra code to test if its the same site and it is a full domain with no URI
                            }, 5000)

                        }
                    }
                });
            } catch (e) {
                console.error(`Encountered an error crawling ${url}. Aborting crawl.`);
                done()

            }
            done();
        }
    })
}

crawlAllUrls('https://github.com/evyatarmeged/');