Initial DDC release

internal/server/respond.go

@@ -0,0 +1,47 @@
+package server
+
+import (
+	"encoding/json"
+	"errors"
+	"net/http"
+
+	"ddc/internal/diskspace"
+	"ddc/internal/files"
+	"ddc/internal/jobs"
+	"ddc/internal/preferences"
+)
+
+func writeJSON(writer http.ResponseWriter, status int, payload any) {
+	writer.Header().Set("Content-Type", "application/json; charset=utf-8")
+	writer.WriteHeader(status)
+	json.NewEncoder(writer).Encode(payload)
+}
+
+func writeError(writer http.ResponseWriter, status int, message string) {
+	writeJSON(writer, status, map[string]string{"error": message})
+}
+
+func writeFailure(writer http.ResponseWriter, err error) {
+	writeError(writer, statusFor(err), err.Error())
+}
+
+func decodeJSON(request *http.Request, target any) error {
+	decoder := json.NewDecoder(request.Body)
+	decoder.DisallowUnknownFields()
+	return decoder.Decode(target)
+}
+
+func statusFor(err error) int {
+	switch {
+	case errors.Is(err, jobs.ErrJobNotFound):
+		return http.StatusNotFound
+	case errors.Is(err, jobs.ErrJobBusy), errors.Is(err, files.ErrDestinationExists):
+		return http.StatusConflict
+	case errors.Is(err, jobs.ErrInvalidRequest), errors.Is(err, preferences.ErrInvalid):
+		return http.StatusBadRequest
+	case errors.Is(err, diskspace.ErrInsufficientSpace):
+		return http.StatusInsufficientStorage
+	default:
+		return http.StatusInternalServerError
+	}
+}