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Read EAN 13 | VB.NET
Module1.vb:
VB
Imports System.IO Imports System.Net Imports System.Threading Imports Newtonsoft.Json Imports Newtonsoft.Json.Linq Module Module1 ' The authentication key (API Key). ' Get your own by registering at https://app.pdf.co Const API_KEY As String = "*********************************" ' Source file name Const SourceFile As String = ".\EAN13.png" ' Comma-separated list of barcode types to search. ' See valid barcode types in the documentation https://apidocs.pdf.co Const BarcodeTypes As String = "EAN13" ' Comma-separated list of page indices (or ranges) to process. Leave empty for all pages. Example: '0,2-5,7-'. Const Pages As String = "" ' (!) 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) ' 1. RETRIEVE THE PRESIGNED URL TO UPLOAD THE FILE. ' * If you already have a direct file URL, skip to the step 3. ' Prepare URL for `Get Presigned URL` API call Dim query As String = Uri.EscapeUriString(String.Format( "https://api.pdf.co/v1/file/upload/get-presigned-url?contenttype=application/octet-stream&name={0}", Path.GetFileName(SourceFile))) 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 ' Get URL to use for the file upload Dim uploadUrl As String = json("presignedUrl").ToString() ' Get URL of uploaded file to use with later API calls Dim uploadedFileUrl As String = json("url").ToString() ' 2. UPLOAD THE FILE TO CLOUD. webClient.Headers.Add("content-type", "application/octet-stream") webClient.UploadFile(uploadUrl, "PUT", SourceFile) ' You can use UploadData() instead if your file is byte array or Stream ' Set JSON content type webClient.Headers.Add("Content-Type", "application/json") ' 3. READ BARCODES FROM UPLOADED FILE ' Prepare URL for `Barcode Reader` API call Dim url As String = "https://api.pdf.co/v1/barcode/read/from/url" ' Prepare requests params as JSON ' See documentation: https : //apidocs.pdf.co Dim parameters As New Dictionary(Of String, Object) parameters.Add("types", BarcodeTypes) parameters.Add("pages", Pages) parameters.Add("url", uploadedFileUrl) parameters.Add("async", Async) ' Convert dictionary of params to JSON Dim jsonPayload As String = JsonConvert.SerializeObject(parameters) Try ' Execute POST request with JSON payload response = webClient.UploadString(url, jsonPayload) ' Parse JSON response json = 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 with decoded barcodes that will available after the job completion Dim resultFileUrl 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 generated JSON results file as string Dim jsonFileString As String = webClient.DownloadString(resultFileUrl) Dim jsonFoundBarcodes As JArray = JArray.Parse(jsonFileString) ' Display found barcodes in console For Each token As JToken In jsonFoundBarcodes Console.WriteLine("Found barcode:") Console.WriteLine(" Type: " + token("TypeName").ToString()) Console.WriteLine(" Value: " + token("Value").ToString()) Console.WriteLine(" Document Page Index: " + token("Page").ToString()) Console.WriteLine(" Rectangle: " + token("Rect").ToString()) Console.WriteLine(" Confidence: " + token("Confidence").ToString()) Console.WriteLine() 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 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 ''' <summary> ''' Check Job Status ''' </summary> 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