PDF Info Reader

package com.company;

import com.google.gson.JsonElement;
import com.google.gson.JsonObject;
import com.google.gson.JsonParser;
import okhttp3.*;

import java.io.*;
import java.net.*;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.Map;

public class Main
{
  // The authentication key (API Key).
  // Get your own by registering at https://app.pdf.co
  final static String API_KEY = "***********************************";

  // Source file name
  final static Path SourceFile = Paths.get(".\\sample.pdf");


  public static void main(String[] args) throws IOException
  {
      // Create HTTP client instance
      OkHttpClient webClient = new OkHttpClient();

      // 1. RETRIEVE THE PRESIGNED URL TO UPLOAD THE FILE.
      // * If you already have a direct file URL, skip to the step 3.

      // Prepare URL for `Get Presigned URL` API call
      String query = String.format(
              "https://api.pdf.co/v1/file/upload/get-presigned-url?contenttype=application/octet-stream&name=%s",
              SourceFile.getFileName());

      // Prepare request
      Request request = new Request.Builder()
              .url(query)
              .addHeader("x-api-key", API_KEY) // (!) Set API Key
              .build();
      // Execute request
      Response response = webClient.newCall(request).execute();

      if (response.code() == 200)
      {
          // Parse JSON response
          JsonObject json = new JsonParser().parse(response.body().string()).getAsJsonObject();

          boolean error = json.get("error").getAsBoolean();
          if (!error)
          {
              // Get URL to use for the file upload
              String uploadUrl = json.get("presignedUrl").getAsString();
              // Get URL of uploaded file to use with later API calls
              String uploadedFileUrl = json.get("url").getAsString();

              // 2. UPLOAD THE FILE TO CLOUD.

              if (uploadFile(webClient, uploadUrl, SourceFile.toFile()))
              {
                  // 3. GET INFORMATION FROM UPLOADED FILE

                  getPdfInfo(webClient, uploadedFileUrl);
              }
          }
          else
          {
              // Display service reported error
              System.out.println(json.get("message").getAsString());
          }
      }
      else
      {
          // Display request error
          System.out.println(response.code() + " " + response.message());
      }
  }

  public static void getPdfInfo(OkHttpClient webClient, String uploadedFileUrl) throws IOException {
      // Prepare URL for `PDF Info` API call
      String query = "https://api.pdf.co/v1/pdf/info";

      // Make correctly escaped (encoded) URL
      URL url = null;
      try
      {
          url = new URI(null, query, null).toURL();
      }
      catch (URISyntaxException e)
      {
          e.printStackTrace();
      }

      // Create JSON payload
  String jsonPayload = String.format("{\"url\": \"%s\"}",
              uploadedFileUrl);

      // Prepare request body
      RequestBody body = RequestBody.create(MediaType.parse("application/json"), jsonPayload);
      
      // Prepare request
      Request request = new Request.Builder()
          .url(url)
          .addHeader("x-api-key", API_KEY) // (!) Set API Key
          .addHeader("Content-Type", "application/json")
          .post(body)
          .build();
      
      // Execute request
      Response response = webClient.newCall(request).execute();
      

      if (response.code() == 200)
      {
          // Parse JSON response
          JsonObject json = new JsonParser().parse(response.body().string()).getAsJsonObject();

          boolean error = json.get("error").getAsBoolean();
          if (!error)
          {
              // Display PDF document information
              JsonObject info = (JsonObject) json.get("info");
              for (Map.Entry<String, JsonElement> entry : info.entrySet())
              {
                  System.out.println(entry.getKey() + ": " + entry.getValue());
              }
          }
          else
          {
              // Display service reported error
              System.out.println(json.get("message").getAsString());
          }
      }
      else
      {
          // Display request error
          System.out.println(response.code() + " " + response.message());
      }
  }

  public static boolean uploadFile(OkHttpClient webClient, String url, File sourceFile) throws IOException
  {
      // Prepare request body
      RequestBody body = RequestBody.create(MediaType.parse("application/octet-stream"), sourceFile);

      // Prepare request
      Request request = new Request.Builder()
              .url(url)
              .addHeader("x-api-key", API_KEY) // (!) Set API Key
              .addHeader("content-type", "application/octet-stream")
              .put(body)
              .build();

      // Execute request
      Response response = webClient.newCall(request).execute();

      return (response.code() == 200);
  }
}