PDF Text Search from Uploaded File Asynchronously - VB.NET
PDF Search Text sample in VB.NET demonstrating ‘PDF Text Search from Uploaded File Asynchronously’
Module1.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 PDF file
Const SourceFile As String = ".\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 = ""
' Search string.
Const SearchString As String = "\d{1,}\.\d\d" 'Regular expression To find numbers Like '100.00'
' Note: Do Not use `+` char in regex, but use `{1,}` instead.
' `+` char Is valid for URL And will Not be escaped, And it will become a space char on the server side.
' Enable regular expressions (Regex)
Const RegexSearch As Boolean = True
' (!) 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. MAKE UPLOADED PDF FILE SEARCHABLE
' Prepare URL for PDF text search API call.
' See documentation: https : //app.pdf.co/documentation/api/1.0/pdf/find.html
Dim url As String = "https://api.pdf.co/v1/pdf/find"
' Prepare requests params as JSON
' See documentation: https : //apidocs.pdf.co
Dim parameters As New Dictionary(Of String, Object)
parameters.Add("password", Password)
parameters.Add("pages", Pages)
parameters.Add("url", uploadedFileUrl)
parameters.Add("searchString", SearchString)
parameters.Add("regexSearch", RegexSearch)
parameters.Add("async", Async)
' Convert dictionary of params to JSON
Dim jsonPayload As String = JsonConvert.SerializeObject(parameters)
' 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 = json("jobId").ToString()
' URL of generated json file that will available after the job completion
Dim resultFileUrl = 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 = CheckJobStatus(jobId) ' Possible statuses: "working", "failed", "aborted", "success".
' Display timestamp and status (for demo purpose)
Console.WriteLine(DateTime.Now.ToLongTimeString() + ": " + status)
If (status = "success") Then
' Execute request
Dim respFileJson As String = webClient.DownloadString(resultFileUrl)
' Parse JSON response
Dim jsonFoundInformation As JArray = JArray.Parse(respFileJson)
' Display found information in console
For Each item As JToken In jsonFoundInformation
Console.WriteLine($"Found text {item("text")} at coordinates {item("left")}, {item("top")}")
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
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(ByVal jobId As String)
Using webClient As 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
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