Initial commit

json.go

@@ -0,0 +1,66 @@
+package jsrest
+
+import (
+	"encoding/json"
+	"errors"
+	"net/http"
+
+	"github.com/gopatchy/metadata"
+	"github.com/vfaronov/httpheader"
+)
+
+var ErrUnsupportedContentType = errors.New("unsupported Content-Type")
+
+func Read(r *http.Request, obj any) error {
+	contentType, _ := httpheader.ContentType(r.Header)
+
+	switch contentType {
+	case "":
+		fallthrough
+	case "application/json":
+		break
+
+	default:
+		return Errorf(ErrUnsupportedMediaType, "Content-Type: %s", contentType)
+	}
+
+	dec := json.NewDecoder(r.Body)
+	dec.DisallowUnknownFields()
+
+	err := dec.Decode(obj)
+	if err != nil {
+		return Errorf(ErrBadRequest, "decode JSON request body failed (%w)", err)
+	}
+
+	return nil
+}
+
+func Write(w http.ResponseWriter, obj any) error {
+	m := metadata.GetMetadata(obj)
+
+	w.Header().Set("Content-Type", "application/json")
+	httpheader.SetETag(w.Header(), httpheader.EntityTag{Opaque: m.ETag})
+
+	enc := json.NewEncoder(w)
+
+	err := enc.Encode(obj)
+	if err != nil {
+		return Errorf(ErrInternalServerError, "encode JSON response failed (%w)", err)
+	}
+
+	return nil
+}
+
+func WriteList(w http.ResponseWriter, list []any, etag string) error {
+	w.Header().Set("Content-Type", "application/json")
+	httpheader.SetETag(w.Header(), httpheader.EntityTag{Opaque: etag})
+
+	enc := json.NewEncoder(w)
+
+	err := enc.Encode(list)
+	if err != nil {
+		return Errorf(ErrInternalServerError, "encode JSON response failed (%w)", err)
+	}
+
+	return nil
+}