public async Task <IEnumerable <LabelConfidence> > Tags(byte[] image, ComputerVisionSettings settings)
{
using (var client = new HttpClient())
{
var apiKey = settings.ComputerVisionAPIKey;
var apiUri = settings.ComputerVisionUri;
if (String.IsNullOrEmpty(apiKey) || String.IsNullOrEmpty(apiUri))
{
logger.LogError("Please provide apiKey and URI to the Machine Learning WebService");
return(null);
}
client.DefaultRequestHeaders.Add("Ocp-Apim-Subscription-Key", apiKey);
string apiUriTag = $"{apiUri}/tag";
using (ByteArrayContent requestContent = new ByteArrayContent(image))
{
requestContent.Headers.ContentType = new MediaTypeHeaderValue("application/octet-stream");
var response = await client.PostAsync(apiUriTag, requestContent);
string contentString = await response.Content.ReadAsStringAsync();
if (!response.IsSuccessStatusCode)
{
logger.LogError($"The request failed with status code: {response.StatusCode}");
logger.LogDebug(response.Headers.ToString());
logger.LogDebug(contentString);
throw new Exception("Error in Cognitive Services response");
}
var visionApiResponse = JsonConvert.DeserializeObject <VisionApiResponse>(contentString);
var query = visionApiResponse.tags.AsQueryable();
if (query.Any(t => t.confidence > settings.Threshold))
{
query = query
.Where(t => t.confidence > settings.Threshold)
.OrderByDescending(t => t.confidence)
.Take(settings.MaxLength);
}
else
{
// In case we don't find any element matching threshold, we match only first one
query = query
.OrderByDescending(t => t.confidence)
.Take(1);
}
return(query.Select(t => new LabelConfidence()
{
Label = t.name, Probability = (float)t.confidence
}));
}
}
}
public ComputerVisionPrediction(IOptionsSnapshot <AppSettings> settings, IComputerVisionClient modelManagementClient)
{
this.computerVisionClient = modelManagementClient;
//TODO: move these settings to setting file
computerVisionSettings = new ComputerVisionSettings
{
ComputerVisionAPIKey = settings.Value.ComputerVision?.VisionAPIKey,
ComputerVisionUri = settings.Value.ComputerVision?.VisionUri,
Threshold = 0.85f,
MaxLength = 5
};
}
