PDF.co Web API – PDF To Image API – C# – Convert PDF To PNG From URL Asynchronously

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ByteScoutWebApiExample.csproj

      
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ByteScoutWebApiExample.sln

      

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Program.cs

      
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 https://app.pdf.co/documentation/api
		const String API_KEY = "***********************************";
		
		// 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();

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

			try
			{
				// URL for `PDF To PNG` API call
				string url = "https://api.pdf.co/v1/pdf/convert/to/png";

				// 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.
					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())
			{
				// Set API Key
                webClient.Headers.Add("x-api-key", API_KEY);
				
				string url = "https://api.pdf.co/v1/job/check?jobid=" + jobId;

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

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

    

packages.config

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

How to Convert PDF to PNG Async using PDF.co Web API in C#

In this tutorial, you will learn how to convert PDF to PNG from URL asynchronously in C-sharp(C#) using PDF.co web API. We will use a sample PDF in this demo. First, open your Visual Studio editor. You can also use your favourite editor in C-sharp(C#). Then enter the C-sharp(C#) sample code. You can get the sample code in PDF.co API docs.

Now install the Newtonsoft.Json. Right-click on the reference and select the Manage Nuggets package. Then look up for Newtonsoft.Json and install. After installing the Newtonsoft.Json, add your API key.

You can get the API key in your PDF.co dashboard. Next input the direct source file URL. Set Async to true. Once you’re done setting up the code, you may now run the program. Our program run successfully and returned the correct value.

Let’s check the folder to see the result.

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