(VB.NET UWP/WinRT) PayPal Generate QR Code

Generates a QR code for an invoice, by ID.

The QR code is a PNG image in Base64-encoded format that corresponds to the invoice ID.

Note: A QR code can only be generated for an invoice that has been both created and sent.

See also Generate QR Code

Chilkat Universal Windows Platform (UWP) / WinRT Downloads Chilkat for the Universal Windows Platform (UWP)

' Note: Requires Chilkat v9.5.0.64 or greater.

' This requires the Chilkat API to have been previously unlocked.
' See Global Unlock Sample for sample code.

' Load our previously obtained access token. (see PayPal OAuth2 Access Token)
Dim jsonToken As New Chilkat.JsonObject
jsonToken.LoadFile("qa_data/tokens/paypal.json")

' Build the Authorization request header field value.
Dim sbAuth As New Chilkat.StringBuilder
' token_type should be "Bearer"
sbAuth.Append(jsonToken.StringOf("token_type"))
sbAuth.Append(" ")
sbAuth.Append(jsonToken.StringOf("access_token"))

' Make the initial connection.
' A single REST object, once connected, can be used for many PayPal REST API calls.
' The auto-reconnect indicates that if the already-established HTTPS connection is closed,
' then it will be automatically re-established as needed.
Dim rest As New Chilkat.Rest
Dim bAutoReconnect As Boolean = True
Dim success As Boolean = Await rest.ConnectAsync("api.sandbox.paypal.com",443,True,bAutoReconnect)
If (success <> True) Then
    Debug.WriteLine(rest.LastErrorText)
    Exit Sub
End If


' ----------------------------------------------------------------------------------------------
' The code above this comment could be placed inside a function/subroutine within the application
' because the connection does not need to be made for every request.  Once the connection is made
' the app may send many requests..
' ----------------------------------------------------------------------------------------------

' Build a path using an invoice ID.
Dim sbPath As New Chilkat.StringBuilder
sbPath.Append("/v1/invoicing/invoices/invoice_id/qr-code")
Dim numReplacements As Integer = sbPath.Replace("invoice_id","INV2-ZG2H-HKAW-PMWU-N6ZR")

rest.AddHeader("Authorization",sbAuth.GetAsString())
' A 500x500 image results in a PNG file of approx. 4K bytes in size.
rest.AddQueryParam("width","500")
rest.AddQueryParam("height","500")
rest.AddQueryParam("action","pay")

' Send the GET request and get the PNG image data as base64.
' A successful JSON response looks like this:
' {"image":"iVBORw0KGgoAA....AASUVORK5CYII="}
Dim sbJsonResponse As New Chilkat.StringBuilder
success = Await rest.FullRequestNoBodySbAsync("GET",sbPath.GetAsString(),sbJsonResponse)
If (success <> True) Then
    Debug.WriteLine(rest.LastErrorText)
    Exit Sub
End If


Dim json As New Chilkat.JsonObject
json.EmitCompact = False
json.LoadSb(sbJsonResponse)

Debug.WriteLine("Response Status Code = " & rest.ResponseStatusCode)

' Did we get a 200 success response?
If (rest.ResponseStatusCode <> 200) Then
    Debug.WriteLine(json.Emit())
    Debug.WriteLine("Failed.")
    Exit Sub
End If


' If the 200 response is received, the response body contains the PNG data.
' Save the PNG to a file.
Dim pngData As New Chilkat.BinData
pngData.AppendEncoded(json.StringOf("image"),"base64")
success = pngData.WriteFile("qa_output/paypal_qr_code.png")
If (success = False) Then
    Debug.WriteLine("Failed to save PNG file.")
    Exit Sub
End If


Debug.WriteLine("Success.")