How to send image in C# to a Flask Server that is decoded by OpenCV?

问题

Here is part of my Flask API in Python:

image_data = flask.request.get_data() # image_data's data type
string image_vector = numpy.frombuffer(image_data, dtype=numpy.uint8) 
image = cv2.imdecode(image_vector, cv2.IMREAD_COLOR)

How would I send a image that I encoded like below, in C#:

        ResultString = "Loading...";
        var surface = SKSurface.Create(new SKImageInfo((int)canvasView.CanvasSize.Width,
                                        (int)canvasView.CanvasSize.Height));
        var canvas = surface.Canvas;
        canvas.Clear();

        foreach (SKPath path in completedPaths)
            canvas.DrawPath(path, paint);

        foreach (SKPath path in inProgressPaths.Values)
            canvas.DrawPath(path, paint);

        canvas.Flush();

        var snap = surface.Snapshot();
        var pngImage = snap.Encode(SKEncodedImageFormat.Png, 100);
        AnalyerResults analyerResults = mathclient.AnalyzeWork(pngImage);
        try { ResultString = analyerResults.message; } catch { ResultString = "Error..."; }

How would I send the image to in C# to be able to be received and decoded like shown in part of my API? I already tried:

HttpClient client = await GetClient();
var result = await client.PostAsync(Url + "analyzer", new ByteArrayContent(pngImage.ToArray()));
return JsonConvert.DeserializeObject<AnalyerResults>(await result.Content.ReadAsStringAsync());

I also tried:

var client = new RestClient(Url + "analyzer");
client.Timeout = -1;
var request = new RestRequest(Method.POST);
request.AddHeader("Content-Type", "image/png");
request.AddParameter("image/png", pngImage, ParameterType.RequestBody);
IRestResponse response = client.Execute(request);
return JsonConvert.DeserializeObject<AnalyerResults>(response.Content);

However in both the content returned null. This question is related to How to Replicate this Postman Request which has a Binary Content Body and contains a .PNG File in C#?.

来源：https://stackoverflow.com/questions/62708339/how-to-send-image-in-c-sharp-to-a-flask-server-that-is-decoded-by-opencv

标签

python

.net

OpenCV

Flask