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Convert PDF To PNG From URL Asynchronously - C#

PDF to PNG sample in C# demonstrating ‘Convert PDF To PNG From URL Asynchronously’

using Newtonsoft.Json;
using Newtonsoft.Json.Linq;
using System;
using System.Collections.Generic;
using System.Net;
using System.Threading;

// Cloud API asynchronous "PDF To PNG" job example.
// Allows to avoid timeout errors when processing huge or scanned PDF documents.

namespace ByteScoutWebApiExample
	class Program
		// The authentication key (API Key).
		// Get your own by registering at
		const String API_KEY = "***********************************";
		// Source PDF file
        // You can also upload your own file into and use it as url. Check "Upload File" samples for code snippets:
		const string SourceFileUrl = @"";
		// 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();

			// Set API Key
			webClient.Headers.Add("x-api-key", API_KEY);

				// URL for `PDF To PNG` API call
				string url = "";

				// Prepare requests params as JSON
				Dictionary<string, object> parameters = new Dictionary<string, object>();
				parameters.Add("password", Password);
				parameters.Add("pages", Pages);
				parameters.Add("url", SourceFileUrl);
				parameters.Add("async", Async);

				// Convert dictionary of params to JSON
				string jsonPayload = JsonConvert.SerializeObject(parameters);

				// Execute POST request with JSON payload
				string response = webClient.UploadString(url, jsonPayload);

				// 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.
						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);
						else if (status == "working")
							// Pause for a few seconds
					while (true);
			catch (WebException e)


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

		static string CheckJobStatus(string jobId)
			using (WebClient webClient = new WebClient())
				// Set API Key
                webClient.Headers.Add("x-api-key", API_KEY);
				string url = "" + jobId;

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

				return Convert.ToString(json["status"]);
} Web API: the Web API with a set of tools for documents manipulation, data conversion, data extraction, splitting and merging of documents. Includes image recognition, built-in OCR, barcode generation and barcode decoders to decode bar codes from scans, pictures and pdf.

Get your API key here!

Download Source Code (.zip)

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