func NewImageAPI(trainingDir string) *ImageAPI {
// Creates a drawing channel and scores map
drawingChan := make(chan classifier.Drawing)
scores := make(map[string]float64)
// Do the 'training'
go classifier.ReadDrawings(trainingDir, drawingChan)
for drawing := range drawingChan {
score := classifier.TrainFromDrawings(drawing)
scores[drawing.Classification] = score
}
return &ImageAPI{
Scores: scores,
}
}
func (api *ImageAPI) classifyHandler(w http.ResponseWriter, r *http.Request) {
w.Header().Set("Access-Control-Allow-Origin", "*")
w.Header().Set("Content-Type", "application/json")
imageEncoded := r.FormValue("image")
reader := base64.NewDecoder(
base64.StdEncoding, strings.NewReader(imageEncoded))
image, err := jpeg.Decode(reader)
if err != nil {
http.Error(w, err.Error(), 500)
return
}
result := classifier.TrainFromDrawings(
classifier.Drawing{Image: image})
closestClassification := ""
closestDistance := math.Inf(0)
// Loop through and find the best classification
for classification, score := range api.Scores {
if distance := math.Abs(result - score); distance < closestDistance {
closestClassification = classification
closestDistance = distance
}
}
jsonBytes, err := json.Marshal(struct {
Classification string `json:",omitempty"`
Distance float64 `json:",omitempty"`
}{closestClassification, closestDistance})
if err != nil {
log.Println(err)
http.Error(w, err.Error(), 500)
return
}
fmt.Fprintf(w, string(jsonBytes))
}