• Overview
  • Compatibility
  • References
• Usage
  • Prerequisites
  • Adding the Libraries to Your Project
  • Loading the Signing Key
  • Creating the OAuth Authorization Header
  • Signing HTTP Client Request Objects
  • Integrating with OpenAPI Generator API Client Libraries

Zero dependency library for generating a Mastercard API compliant OAuth signature.

This library requires a .NET Framework implementing .NET Standard 1.3.

Assemblies are strong-named as per Strong naming and .NET libraries. The SN key is available here: Identity.snk.

• OAuth 1.0a specification
• Body hash extension for non application/x-www-form-urlencoded payloads

Before using this library, you will need to set up a project in the Mastercard Developers Portal.

As part of this set up, you'll receive credentials for your app:

• A consumer key (displayed on the Mastercard Developer Portal)
• A private request signing key (matching the public certificate displayed on the Mastercard Developer Portal)

Install-Package Mastercard.Developer.OAuth1Signer.Core
Install-Package Mastercard.Developer.OAuth1Signer.RestSharp

dotnet add package Mastercard.Developer.OAuth1Signer.Core
dotnet add package Mastercard.Developer.OAuth1Signer.RestSharp

A System.Security.Cryptography.RSA key object can be created by calling the AuthenticationUtils.LoadSigningKey method:

var signingKey = AuthenticationUtils.LoadSigningKey(
                        "<insert PKCS#12 key file path>", 
                        "<insert key alias>", 
                        "<insert key password>");

The method that does all the heavy lifting is OAuth.GetAuthorizationHeader, in the Mastercard.Developer.OAuth1Signer.Core package. You can call into it directly and as long as you provide the correct parameters, it will return a string that you can add into your request's Authorization header.

var consumerKey = "<insert consumer key>";
var uri = "https://sandbox.api.mastercard.com/service";
var method = "POST";
var payload = "Hello world!";
var encoding = Encoding.UTF8;
var authHeader = OAuth.GetAuthorizationHeader(uri, method, payload, encoding, consumerKey, signingKey);

Alternatively, you can use helper classes for some of the commonly used HTTP clients.

These classes will modify the provided request object in-place and will add the correct Authorization header. Once instantiated with a consumer key and private key, these objects can be reused.

Usage briefly described below, but you can also refer to the test project for examples.

• System.Net.Http.HttpClient
• RestSharp Portable

The NetHttpClientSigner class is located in the Mastercard.Developer.OAuth1Signer.Core package.

Usage:

var baseUri = new Uri("https://api.mastercard.com/");
var httpClient = new HttpClient(new RequestSignerHandler(consumerKey, signingKey)) { BaseAddress = baseUri };
var postTask = httpClient.PostAsync(new Uri("/service", UriKind.Relative), new StringContent("{\"foo\":\"bår\"}");
// (...)

internal class RequestSignerHandler : HttpClientHandler
{
    private readonly NetHttpClientSigner signer;

    public RequestSignerHandler(string consumerKey, RSA signingKey)
    {
        signer = new NetHttpClientSigner(consumerKey, signingKey);
    }

    protected override Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
    {
        signer.Sign(request);
        return base.SendAsync(request, cancellationToken);
    }
}

The RestSharpSigner class is located in the Mastercard.Developer.OAuth1Signer.RestSharp package.

Usage:

var baseUri = new Uri("https://api.mastercard.com/");
var request = new RestRequest
{
    Method = Method.POST,
    Resource = "/service",
    Parameters =
    {
        new Parameter { Type = ParameterType.RequestBody, Encoding = Encoding.UTF8, Value = "{\"foo\":\"bår\"}"} // "application/json; charset=utf-8"
    }
};
var signer = new RestSharpSigner(consumerKey, signingKey);
signer.Sign(baseUri, request);

OpenAPI Generator generates API client libraries from OpenAPI Specs. It provides generators and library templates for supporting multiple languages and frameworks.

This project provides you with some authenticator classes you can use when configuring your API client. These classes will take care of adding the correct Authorization header before sending the request.

Generators currently supported:

• csharp (targetFramework v5.0)

Client libraries can be generated using the following command:

java -jar openapi-generator-cli.jar generate -i openapi-spec.yaml -g csharp -c config.json -o out

config.json:

{ "targetFramework": "v5.0" }

See also:

• OpenAPI Generator (executable)
• CONFIG OPTIONS for csharp

RestSharpOAuth1Authenticator is located in the Mastercard.Developer.OAuth1Signer.RestSharp package.

var config = Configuration.Default;
config.BasePath = "https://sandbox.api.mastercard.com";
config.ApiClient.RestClient.Authenticator = new RestSharpOAuth1Authenticator(ConsumerKey, signingKey, new Uri(config.BasePath));
var serviceApi = new ServiceApi(config);
// ...