(Lianja) PayPal - Cancel Sent Invoice

Cancels a sent invoice, by ID, and, optionally, sends a notification about the cancellation to the payer, merchant, and Cc: emails.

Note: This example requires Chilkat v9.5.0.65 or greater.

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// Note: Requires Chilkat v9.5.0.65 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)
loJsonToken = createobject("CkJsonObject")
loJsonToken.LoadFile("qa_data/tokens/paypal.json")

// Build the Authorization request header field value.
loSbAuth = createobject("CkStringBuilder")
// token_type should be "Bearer"
loSbAuth.Append(loJsonToken.StringOf("token_type"))
loSbAuth.Append(" ")
loSbAuth.Append(loJsonToken.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.
loRest = createobject("CkRest")
llBAutoReconnect = .T.
llSuccess = loRest.Connect("api.sandbox.paypal.com",443,.T.,llBAutoReconnect)
if (llSuccess <> .T.) then
    ? loRest.LastErrorText
    release loJsonToken
    release loSbAuth
    release loRest
    return
endif

// ----------------------------------------------------------------------------------------------
// 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 the JSON request body containing the reminder information:
loJson = createobject("CkJsonObject")
loJson.EmitCompact = .F.
loJson.UpdateString("subject","Past due")
loJson.UpdateString("note","Canceling invoice")
loJson.UpdateBool("send_to_merchant",.T.)
loJson.UpdateBool("send_to_payer",.T.)
? loJson.Emit()

// The JSON created by the above code:

// 	{ 
// 	  "subject": "Past due",
// 	  "note": "Canceling invoice",
// 	  "send_to_merchant": true,
// 	  "send_to_payer": true
// 	}

// Build a path using a previously-sent invoice ID.
loSbPath = createobject("CkStringBuilder")
loSbPath.Append("/v1/invoicing/invoices/invoice_id/cancel")
lnNumReplacements = loSbPath.Replace("invoice_id","INV2-XPWZ-NUTQ-LNWB-P8NC")

loJson.EmitCompact = .T.
loSbRequestBody = createobject("CkStringBuilder")
loSbResponseBody = createobject("CkStringBuilder")

loRest.AddHeader("Content-Type","application/json")
loRest.AddHeader("Authorization",loSbAuth.GetAsString())
loJson.EmitSb(loSbRequestBody)

llSuccess = loRest.FullRequestSb("POST",loSbPath.GetAsString(),loSbRequestBody,loSbResponseBody)
if (llSuccess <> .T.) then
    ? loRest.LastErrorText
    release loJsonToken
    release loSbAuth
    release loRest
    release loJson
    release loSbPath
    release loSbRequestBody
    release loSbResponseBody
    return
endif

? "Response Status Code = " + str(loRest.ResponseStatusCode)

// In our testing, we received a 204 response, which is a success HTTP response code, but 
// differs from the PayPal REST API reference documentation, which states that a 202 response
// is expected.  I suspect an error in the PayPal documentation, or in the PayPal responder.
// Check for either 202 or 204..
// Did we get a 202 accepted response?
if ((loRest.ResponseStatusCode <> 202) and (loRest.ResponseStatusCode <> 204)) then
    ? loSbResponseBody.GetAsString()
    ? "Failed."
    release loJsonToken
    release loSbAuth
    release loRest
    release loJson
    release loSbPath
    release loSbRequestBody
    release loSbResponseBody
    return
endif

// The 202/204 response should be empty.  (Again, our experience differs from the online PayPal documentation..)
? "Success."


release loJsonToken
release loSbAuth
release loRest
release loJson
release loSbPath
release loSbRequestBody
release loSbResponseBody