Split PDF From URL Asynchronously | VB.NET | PDF Splitting APIByteScout PDF Extractor SDK

Split PDF From URL Asynchronously | VB.NET | PDF Splitting API


Imports System.IO
Imports System.Net
Imports System.Threading
Imports Newtonsoft.Json
Imports Newtonsoft.Json.Linq

' Cloud API asynchronous "Split PDF" job example.
' Allows to avoid timeout errors when processing huge or scanned PDF documents.

Module Module1

    ' The authentication key (API Key).
    ' Get your own by registering at https://app.pdf.co/documentation/api
    Const API_KEY As String = "***********************************"

    ' Source PDF file to split
    Const SourceFileUrl As String = "https://bytescout-com.s3.amazonaws.com/files/demo-files/cloud-api/pdf-split/sample.pdf"
    ' Comma-separated list of page numbers (or ranges) to process. Example: '1,3-5,7-'.
    Const Pages As String = "1-2,3-"
    ' (!) Make asynchronous job
    Const Async As Boolean = True

    Sub Main()

        ' Create standard .NET web client instance
        Dim webClient As WebClient = New WebClient()

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

        ' Set JSON content type
        webClient.Headers.Add("Content-Type", "application/json")

        ' Prepare URL for `Split PDF` API call
        Dim url As String = "https://api.pdf.co/v1/pdf/split"

        ' Prepare requests params as JSON
        ' See documentation: https : //apidocs.pdf.co
        Dim parameters As New Dictionary(Of String, Object)
        parameters.Add("pages", Pages)
        parameters.Add("url", SourceFileUrl)
        parameters.Add("async", Async)

        ' Convert dictionary of params to JSON
        Dim jsonPayload As String = JsonConvert.SerializeObject(parameters)

            ' Execute POST request with JSON payload
            Dim response As String = webClient.UploadString(url, jsonPayload)

            ' 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 PDF 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.
                    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 PDF files
                        Dim part As Integer = 1
                        For Each token As JToken In resultFilesUrls

                            Dim resultFileUrl As String = token.ToString()
                            Dim localFileName As String = String.Format(".\part{0}.pdf", part)

                            webClient.DownloadFile(resultFileUrl, localFileName)

                            Console.WriteLine("Downloaded ""{0}"".", localFileName)
                            part = part + 1


                        Exit Do

                    ElseIf status = "working" Then

                        ' Pause for a few seconds


                        Exit Do

                    End If


            End If

        Catch ex As WebException
        End Try


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

    End Sub

    Function CheckJobStatus(jobId As String) As String

        Using webClient As WebClient = New WebClient()

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

            Dim url As String = "https://api.pdf.co/v1/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