PDF Compress

/*jshint esversion: 6 */

var https = require("https");
var path = require("path");
var fs = require("fs");

// `request` module is required for file upload.
// Use "npm install request" command to install.
var request = require("request");

// The authentication key (API Key).
// Get your own by registering at https://app.pdf.co
const API_KEY = "***********************************";


// Source PDF file
const SourceFile = "./sample.pdf";
// PDF document password. Leave empty for unprotected documents.
const Password = "";
// Destination PDF file name
const DestinationFile = "./result.pdf";


// 1. RETRIEVE PRESIGNED URL TO UPLOAD FILE.
getPresignedUrl(API_KEY, SourceFile)
  .then(([uploadUrl, uploadedFileUrl]) => {
      // 2. UPLOAD THE FILE TO CLOUD.
      uploadFile(API_KEY, SourceFile, uploadUrl)
          .then(() => {
              // 3. COMPRESS UPLOADED PDF FILE
              compressPDF(API_KEY, uploadedFileUrl, Password, DestinationFile);
          })
          .catch(e => {
              console.log(e);
          });
  })
  .catch(e => {
      console.log(e);
  });


function getPresignedUrl(apiKey, localFile) {
  return new Promise(resolve => {
      // Prepare request to `Get Presigned URL` API endpoint
      let queryPath = `/v1/file/upload/get-presigned-url?contenttype=application/octet-stream&name=${path.basename(SourceFile)}`;
      let reqOptions = {
          host: "api.pdf.co",
          path: encodeURI(queryPath),
          headers: { "x-api-key": API_KEY }
      };
      // Send request
      https.get(reqOptions, (response) => {
          response.on("data", (d) => {
              let data = JSON.parse(d);
              if (data.error == false) {
                  // Return presigned url we received
                  resolve([data.presignedUrl, data.url]);
              }
              else {
                  // Service reported error
                  console.log("getPresignedUrl(): " + data.message);
              }
          });
      })
          .on("error", (e) => {
              // Request error
              console.log("getPresignedUrl(): " + e);
          });
  });
}

function uploadFile(apiKey, localFile, uploadUrl) {
  return new Promise(resolve => {
      fs.readFile(SourceFile, (err, data) => {
          request({
              method: "PUT",
              url: uploadUrl,
              body: data,
              headers: {
                  "Content-Type": "application/octet-stream"
              }
          }, (err, res, body) => {
              if (!err) {
                  resolve();
              }
              else {
                  console.log("uploadFile() request error: " + e);
              }
          });
      });
  });
}

function compressPDF(apiKey, uploadedFileUrl, password, destinationFile) {
  // Prepare request to `Compress PDF` API endpoint
  var queryPath = `/v2/pdf/compress`;

  // JSON payload for api request
  var jsonPayload = JSON.stringify({
      name: path.basename(destinationFile), password: password, url: uploadedFileUrl, async: true
  });

  var reqOptions = {
      host: "api.pdf.co",
      method: "POST",
      path: queryPath,
      headers: {
          "x-api-key": apiKey,
          "Content-Type": "application/json",
          "Content-Length": Buffer.byteLength(jsonPayload, 'utf8')
      }
  };
  // Send request
  var postRequest = https.request(reqOptions, (response) => {
      response.on("data", (d) => {
          response.setEncoding("utf8");

          // Parse JSON response
          let data = JSON.parse(d);
          console.log(`Job #${data.jobId} has been created!`);

          if (data.error == false) {
              checkIfJobIsCompleted(data.jobId, data.url, destinationFile);
          }
          else {
              // Service reported error
              console.log("readBarcodes(): " + data.message);
          }
      });
  })
      .on("error", (e) => {
          // Request error
          console.log("readBarcodes(): " + e);
      });

  // Write request data
  postRequest.write(jsonPayload);
  postRequest.end();
}

function checkIfJobIsCompleted(jobId, resultFileUrl, destinationFile) {
  let queryPath = `/v1/job/check`;

  // JSON payload for api request
  let jsonPayload = JSON.stringify({
      jobid: jobId
  });

  let reqOptions = {
      host: "api.pdf.co",
      path: queryPath,
      method: "POST",
      headers: {
          "x-api-key": API_KEY,
          "Content-Type": "application/json",
          "Content-Length": Buffer.byteLength(jsonPayload, 'utf8')
      }
  };

  // Send request
  var postRequest = https.request(reqOptions, (response) => {
      response.on("data", (d) => {
          response.setEncoding("utf8");

          // Parse JSON response
          let data = JSON.parse(d);
          console.log(`Checking Job #${jobId}, Status: ${data.status}, Time: ${new Date().toLocaleString()}`);

          if (data.status == "working") {
              // Check again after 3 seconds
              setTimeout(function () { checkIfJobIsCompleted(jobId, resultFileUrl, destinationFile); }, 3000);
          }
          else if (data.status == "success") {
              // Download PDF file
              var file = fs.createWriteStream(destinationFile);
              https.get(resultFileUrl, (response2) => {
                  response2.pipe(file)
                      .on("close", () => {
                          console.log(`Generated PDF file saved as "${destinationFile}" file.`);
                      });
              });
          }
          else {
              console.log(`Operation ended with status: "${data.status}".`);
          }
      })
  });

  // Write request data
  postRequest.write(jsonPayload);
  postRequest.end();
}