ByteScout Cloud API Server - PDF To Image API - VB.NET - Convert PDF To JPEG From URL Asynchronously - ByteScout

ByteScout Cloud API Server – PDF To Image API – VB.NET – Convert PDF To JPEG From URL Asynchronously

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How to convert PDF to JPEG from URL asynchronously for PDF to image API in VB.NET and ByteScout Cloud API Server

Step-by-step tutorial:How to convert PDF to JPEG from URL asynchronously to have PDF to image API in VB.NET

The sample source codes on this page will show you how to create PDF to image API in VB.NET. ByteScout Cloud API Server was designed to assist PDF to image API in VB.NET. ByteScout Cloud API Server is the ready to use Web API Server that can be deployed in less than 30 minutes into your own in-house server or into private cloud server. Can store data on in-house local server based storage or in Amazon AWS S3 bucket. Processing data solely on the server using buil-in ByteScout powered engine, no cloud services are used to process your data!.

If you want to speed up the application’s code writing then VB.NET code samples for VB.NET developers help to implement using ByteScout Cloud API Server. Open your VB.NET project and simply copy & paste the code and then run your app! Enjoy writing a code with ready-to-use sample VB.NET codes to add PDF to image API functions using ByteScout Cloud API Server in VB.NET.

Trial version of ByteScout is available for free download from our website. This and other source code samples for VB.NET and other programming languages are available.

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Module1.vb
      
Imports System.IO Imports System.Net Imports System.Threading Imports Newtonsoft.Json.Linq ' 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 JPEG" job example. ' Allows to avoid timeout errors when processing huge or scanned PDF documents. Module Module1 ' Source PDF file Const SourceFileUrl As String = "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 Pages As String = "" ' PDF document password. Leave empty for unprotected documents. Const Password As String = "" ' (!) Make asynchronous job Const Async As Boolean = True Sub Main() ' Create standard .NET web client instance Dim webClient As WebClient = New WebClient() ' Prepare URL for `PDF To JPEG` API call Dim query As String = Uri.EscapeUriString(String.Format( "https://localhost/pdf/convert/to/jpg?password={0}&pages={1}&url={2}&async={3}", Password, Pages, SourceFileUrl, Async)) Try ' Execute request Dim response As String = webClient.DownloadString(query) ' Parse JSON response Dim json As JObject = JObject.Parse(response) If json("error").ToObject(Of Boolean) = False Then ' Asynchronous job ID Dim jobId As String = json("jobId").ToString() ' URL of generated JSON file available after the job completion; it will contain URLs of result JPEG files. Dim resultJsonFileUrl As String = 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 Dim status As String = CheckJobStatus(jobId) ' Possible statuses: "working", "failed", "aborted", "success". ' Display timestamp and status (for demo purposes) Console.WriteLine(DateTime.Now.ToLongTimeString() + ": " + status) If status = "success" Then ' Download JSON file as string Dim jsonFileString As String = webClient.DownloadString(resultJsonFileUrl) Dim resultFilesUrls As JArray = JArray.Parse(jsonFileString) ' Download generated JPEG files Dim page As Integer = 1 For Each token As JToken In resultFilesUrls Dim resultFileUrl As String = token.ToString() Dim localFileName As String = String.Format(".\page{0}.jpg", page) webClient.DownloadFile(resultFileUrl, localFileName) Console.WriteLine("Downloaded ""{0}"".", localFileName) page = page + 1 Next Exit Do ElseIf status = "working" Then ' Pause for a few seconds Thread.Sleep(3000) Else Console.WriteLine(status) Exit Do End If Loop Else Console.WriteLine(json("message").ToString()) End If Catch ex As WebException Console.WriteLine(ex.ToString()) End Try webClient.Dispose() Console.WriteLine() Console.WriteLine("Press any key...") Console.ReadKey() End Sub Function CheckJobStatus(jobId As String) As String Using webClient As WebClient = New WebClient() Dim url As String = "https://localhost/job/check?jobid=" + jobId Dim response As String = webClient.DownloadString(url) Dim json As JObject = JObject.Parse(response) Return Convert.ToString(json("status")) End Using End Function End Module

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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

VIDEO

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

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