Usage#

Use Case 1: server-side render all traffic#

• Implementation 1: forward all traffic to service.prerender.cloud
  • This is the default implementation of our libraries and so service.prerender.cloud has a 3 minute cache to help mitigate the time cost of prerendering a request
• Implementation 2: forward all traffic to service.prerender.cloud but use a local cache
  • This is the recommended implementation because it's quick to implement and high performance (because you're not adding the round trip cost to service.prerender.cloud to 100% of your requests), and easy to do with our Node middleware but more involved for Apache, Nginx, and others
• Implementation 3: build all HTML in a batch process instead of forwarding traffic to service.prerender.cloud
  • This is the most cost effective and performant implementation but the most challenging.
    • use implementation 2 and crawl the pages with a user-agent that would trigger the prerender
    • or curl service.prerender.cloud/http://example.com > my-prerendered-page.html

Use Case 2: server-side render bot traffic only#

• Same as use case 1 but restricted to certain user-agents (not recommended due to potential cloaking penalties and the fact that HTTP caches become low value since user-agents are high cardinality)

Use Case 3: Scrape meta or open graph tags of a JavaScript app#

• Use any HTTP library in any language to do something like:

  const fetch = require("fetch").fetchUrl;
  const fs = require("fs");
  const cheerio = require("cheerio");
  
  const urlsToParse = ["https://www.prerender.cloud"];
  
  const options = {
    headers: {
      // put your token here or you'll be rate limited
      "x-prerender-token": ""
    }
  };
  
  function fetchUrl(url) {
    return new Promise(function(res, rej) {
      fetch(
        `http://service.prerender.cloud/${url}`,
        options,
        (error, meta, body) => {
          if (error) {
            console.error("error fetching", url, error);
            return null;
          }
  
          let parsed = cheerio.load(body.toString());
  
          return res([url, parsed("meta").toArray().map(m => m.attribs)]);
        }
      );
    });
  }
  
  Promise.all(urlsToParse.map(fetchUrl)).then(urls => {
    fs.writeFile("urlsMeta.json", JSON.stringify(urls));
  });