(Visual Basic 6.0) 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 ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

' 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 ChilkatJsonObject
success = jsonToken.LoadFile("qa_data/tokens/paypal.json")

' Build the Authorization request header field value.
Dim sbAuth As New ChilkatStringBuilder
' token_type should be "Bearer"
success = sbAuth.Append(jsonToken.StringOf("token_type"))
success = sbAuth.Append(" ")
success = 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 ChilkatRest
Dim bAutoReconnect As Long
bAutoReconnect = 1
Dim success As Long
success = rest.Connect("api.sandbox.paypal.com",443,1,bAutoReconnect)
If (success <> 1) Then
    Debug.Print 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 ChilkatStringBuilder
success = sbPath.Append("/v1/invoicing/invoices/invoice_id/qr-code")
Dim numReplacements As Long
numReplacements = sbPath.Replace("invoice_id","INV2-ZG2H-HKAW-PMWU-N6ZR")

success = rest.AddHeader("Authorization",sbAuth.GetAsString())
' A 500x500 image results in a PNG file of approx. 4K bytes in size.
success = rest.AddQueryParam("width","500")
success = rest.AddQueryParam("height","500")
success = 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 ChilkatStringBuilder
success = rest.FullRequestNoBodySb("GET",sbPath.GetAsString(),sbJsonResponse)
If (success <> 1) Then
    Debug.Print rest.LastErrorText
    Exit Sub
End If

Dim json As New ChilkatJsonObject
json.EmitCompact = 0
success = json.LoadSb(sbJsonResponse)

Debug.Print "Response Status Code = " & rest.ResponseStatusCode

' Did we get a 200 success response?
If (rest.ResponseStatusCode <> 200) Then
    Debug.Print json.Emit()
    Debug.Print "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 ChilkatBinData
success = pngData.AppendEncoded(json.StringOf("image"),"base64")
success = pngData.WriteFile("qa_output/paypal_qr_code.png")
If (success = 0) Then
    Debug.Print "Failed to save PNG file."
    Exit Sub
End If

Debug.Print "Success."