3.3.10. Demo - API Caching using Cache-Control Directives

• Requirements

  • Visual studio code

  • node.js

  • source code from github

    • 1.clone repository

      git clone https://github.com/acloudfan/REST-API-Course.git
      cd REST-API-CACHEING/
      npm install

• 程式碼解析

  • 1.API provider 設定max-age

    • 當cache expired前, browser的請求都不會到backend, 因此counter不會增加

    • cache

      app.get('/cachetest', function (req, res) {
        // Set the headers
        res.header('Cache-Control', 'public, max-age='+MAX_AGE);
      
        // Increment the counter
        counter++
        console.log('recvd ' + counter)
      
        // Response data
        data = {
            value: "Hello Cache !!!",
            counter: counter
      };
        res.send(JSON.stringify(data));
      });

  • 2.Client 設定no-cache

    • 會取得新的資料

      $.ajax(
                {
                    type:'GET',
                    url: "http://localhost:3000/cachetest" ,
                    headers: {"Cache-Control" : "no-cache"},
                    data: "{}",
                    contentType: "application/json; charset=utf-8",
                    dataType:  "json",
                    success: success ,
                    error: function (msg, url, line) {
                        alert('error '+msg+ "    "+url+"    "+line)
                    }
                })