(C# 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)
Chilkat.JsonObject jsonToken = new Chilkat.JsonObject();
jsonToken.LoadFile("qa_data/tokens/paypal.json");

// Build the Authorization request header field value.
Chilkat.StringBuilder sbAuth = 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.
Chilkat.Rest rest = new Chilkat.Rest();
bool bAutoReconnect = true;
bool success = await rest.ConnectAsync("api.sandbox.paypal.com",443,true,bAutoReconnect);
if (success != true) {
    Debug.WriteLine(rest.LastErrorText);
    return;
}

// ----------------------------------------------------------------------------------------------
// 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.
Chilkat.StringBuilder sbPath = new Chilkat.StringBuilder();
sbPath.Append("/v1/invoicing/invoices/invoice_id/qr-code");
int numReplacements = 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="}
Chilkat.StringBuilder sbJsonResponse = new Chilkat.StringBuilder();
success = await rest.FullRequestNoBodySbAsync("GET",sbPath.GetAsString(),sbJsonResponse);
if (success != true) {
    Debug.WriteLine(rest.LastErrorText);
    return;
}

Chilkat.JsonObject json = new Chilkat.JsonObject();
json.EmitCompact = false;
json.LoadSb(sbJsonResponse);

Debug.WriteLine("Response Status Code = " + Convert.ToString(rest.ResponseStatusCode));

// Did we get a 200 success response?
if (rest.ResponseStatusCode != 200) {
    Debug.WriteLine(json.Emit());
    Debug.WriteLine("Failed.");
    return;
}

// If the 200 response is received, the response body contains the PNG data.
// Save the PNG to a file.
Chilkat.BinData pngData = new Chilkat.BinData();
pngData.AppendEncoded(json.StringOf("image"),"base64");
success = pngData.WriteFile("qa_output/paypal_qr_code.png");
if (success == false) {
    Debug.WriteLine("Failed to save PNG file.");
    return;
}

Debug.WriteLine("Success.");