ByteScout Cloud API Server – PDF To Image API – C# – Convert PDF To PNG From URL Asynchronously

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Program.cs

      
using System;
using System.IO;
using System.Net;
using Newtonsoft.Json.Linq;
using System.Threading;

// Please NOTE: In this sample we're assuming Cloud Api Server is hosted at "https://localhost". 
// If it's not then please replace this with with your hosting url.

// Cloud API asynchronous "PDF To PNG" job example.
// Allows to avoid timeout errors when processing huge or scanned PDF documents.
namespace ByteScoutWebApiExample
{
	class Program
	{
		// Source PDF file
		const string SourceFileUrl = @"https://bytescout-com.s3.amazonaws.com/files/demo-files/cloud-api/pdf-to-image/sample.pdf";
		// Comma-separated list of page indices (or ranges) to process. Leave empty for all pages. Example: '0,2-5,7-'.
		const string Pages = "";
		// PDF document password. Leave empty for unprotected documents.
		const string Password = "";
		// (!) Make asynchronous job
		const bool Async = true;

		static void Main(string[] args)
		{
			// Create standard .NET web client instance
			WebClient webClient = new WebClient();

			try
			{
				// Prepare URL for `PDF To PNG` API call
				string query = Uri.EscapeUriString(string.Format(
					"https://localhost/pdf/convert/to/png?password={0}&pages={1}&url={2}&async={3}",
					Password,
					Pages,
					SourceFileUrl,
					Async));

				// Execute request
				string response = webClient.DownloadString(query);

				// Parse JSON response
				JObject json = JObject.Parse(response);

				if (json["error"].ToObject<bool>() == false)
				{
					// Asynchronous job ID
					string jobId = json["jobId"].ToString();
					// URL of generated JSON file available after the job completion; it will contain URLs of result PNG files.
					string resultJsonFileUrl = json["url"].ToString();

					// Check the job status in a loop. 
					// If you don't want to pause the main thread you can rework the code 
					// to use a separate thread for the status checking and completion.
					do
					{
						string status = CheckJobStatus(jobId); // Possible statuses: "working", "failed", "aborted", "success".

						// Display timestamp and status (for demo purposes)
						Console.WriteLine(DateTime.Now.ToLongTimeString() + ": " + status);

						if (status == "success")
						{
							// Download JSON file as string
							string jsonFileString = webClient.DownloadString(resultJsonFileUrl);

							JArray resultFilesUrls = JArray.Parse(jsonFileString);

							// Download generated PNG files
							int page = 1;
							foreach (JToken token in resultFilesUrls)
							{
								string resultFileUrl = token.ToString();
								string localFileName = String.Format(@".\page{0}.png", page);

								webClient.DownloadFile(resultFileUrl, localFileName);

								Console.WriteLine("Downloaded \"{0}\".", localFileName);
								page++;
							}
							break;
						}
						else if (status == "working")
						{
							// Pause for a few seconds
							Thread.Sleep(3000);
						}
						else
						{
							Console.WriteLine(status);
							break;
						}
					}
					while (true);
				}
				else
				{
					Console.WriteLine(json["message"].ToString());
				}
			}
			catch (WebException e)
			{
				Console.WriteLine(e.ToString());
			}

			webClient.Dispose();

			Console.WriteLine();
			Console.WriteLine("Press any key...");
			Console.ReadKey();
		}

		static string CheckJobStatus(string jobId)
		{
			using (WebClient webClient = new WebClient())
			{
				string url = "https://localhost/job/check?jobid=" + jobId;

				string response = webClient.DownloadString(url);
				JObject json = JObject.Parse(response);

				return Convert.ToString(json["status"]);
			}
		}
	}
}

    

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packages.config

      
<?xml version="1.0" encoding="utf-8"?>
<packages>
  <package id="Newtonsoft.Json" version="10.0.3" targetFramework="net40" />
</packages>
    

ON-PREMISE OFFLINE SDK

60 Day Free Trial or Visit ByteScout Cloud API Server Home Page

Explore ByteScout Cloud API Server Documentation

Explore Samples

Sign Up for ByteScout Cloud API Server Online Training

ON-DEMAND REST WEB API

Get Your API Key

Explore Web API Docs

Explore Web API Samples

ON-PREMISE OFFLINE SDK

60 Day Free Trial or Visit ByteScout Cloud API Server Home Page

Explore ByteScout Cloud API Server Documentation

Explore Samples

Sign Up for ByteScout Cloud API Server Online Training

ON-DEMAND REST WEB API

Get Your API Key

Explore Web API Docs

Explore Web API Samples