PactAzureFunction.cs

public static class ProviderMock
{
  [FunctionName("providerMock")]
  public static async Task<IActionResult> Run(
      [HttpTrigger(AuthorizationLevel.Function, Route = "{*route}")] HttpRequest req,
      string route)
  {
    var requestBody = new MemoryStream();
    await req.Body.CopyToAsync(requestBody);
    requestBody.Seek(0, SeekOrigin.Begin);
    var request = new Core.Transport.Http.HttpRequest
    {
      Method = new HttpMethod(req.Method),
      Path = route,
      Query = req.QueryString.Value,
      Body = PactDefinition.PayloadFormat.Deserialize(requestBody)
    };

    if (req.Headers.Any())
    {
      request.Headers = request.Headers ?? new Dictionary<string, string>();
      foreach (var header in req.Headers)
      {
        request.Headers[header.Key] = header.Value;
      }
    }

    Core.Transport.Http.HttpResponse response;
    try
    {
      var interaction = PactDefinition.Pact.GetMatchingInteraction(request, PactDefinition.TransportMatchers);
      if (request.Body is JObject jsonBody && interaction.RequestType != typeof(JObject))
      {
        request.Body = PactDefinition.PayloadFormat.Deserialize(jsonBody, interaction.RequestType);
      }

      response = (Core.Transport.Http.HttpResponse)interaction.Respond(request, PactDefinition.TransportMatchers);
    }
    catch (Exception ex)
    {
      return new NotFoundObjectResult("Getting a response from the pact failed for this request. Exception: " + Environment.NewLine + ex);
    }

    if (response.Headers != null)
    {
      foreach (var header in response.Headers)
      {
        req.HttpContext.Response.Headers.Add(header.Key, header.Value);
      }
    }

    if (response.Body != null)
    {
      var memoryStream = new MemoryStream();
      PactDefinition.PayloadFormat.Serialize(response.Body,memoryStream);

      return new FileContentResult(memoryStream.ToArray(),
        string.IsNullOrEmpty(PactDefinition.PayloadFormat.MimeType)
        ? "application/octet-stream" 
        :  PactDefinition.PayloadFormat.MimeType);
    }
    else
    {
      return new StatusCodeResult((int)response.Status);
    }
  }
}