抓取 reddit 帖子和评论

Question

我正在尝试使用 Node.js 和 Cheerio 抓取 Reddit 帖子和评论，但没有得到预期的结果。以下是我的设置和我面临的问题的简要概述。

设置：

Node.js：v14.17.0

Cheerio：v1.0.0-rc.10

请求-承诺：v4.2.6

代码：

const rp = require('request-promise');
const cheerio = require('cheerio');

const url = 'https://www.reddit.com/r/javascript/';


rp(url)
  .then(html => {
    const $ = cheerio.load(html);

    let posts = [];

    $('div.Post').each((i, element) => {
      let title = $(element).find('h3').text();

      let commentsLink = $(element).find('a[data-click-id="comments"]').attr('href');

      posts.push({ title, commentsLink });
    });

    console.log(posts);
  })
  .catch(err => {
    console.error(err);
  });

Answer 1

如果您使用代码查看从网站检索的内容，您会发现 Reddit 正在阻止您的请求。

您需要评估页面上的动态内容，并且至少看起来是一个浏览器。您可以使用 Puppeteer 来完成此操作。

const puppeteer = require('puppeteer');

(async () => {
  const browser = await puppeteer.launch();
  const page = await browser.newPage();

  await page.setUserAgent('Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/83.0.4103.116 Safari/537.36');
  
  await page.goto('https://www.reddit.com/r/javascript/');
  
  await page.waitForSelector('h1');

  const data = await page.evaluate(() => {
    // Get all articles on page.
    //
    // ! Without pagination there will just be the top three articles.
    //
    const articles = Array.from(document.querySelectorAll('article'));
    // Extract content from each article.
    //
    // ! You can get some text but it's just a summary of the article, not full content.
    //
    const content = articles.map(article => {
        return {
            title: article.querySelector('a').innerText
        }
    });

    return content;
  });
  
  console.log(data);
  
  await browser.close();
})();

输出示例：

[
  { title: 'WTF Wednesday (June 19, 2024)' },
  {
    title: 'Your /r/javascript recap for the week of June 10 - June 16, 2024'
  },
  { title: 'Announcing TypeScript 5.5' }
]