feat: initial public version

server/io.go

@@ -0,0 +1,49 @@
+// Reading requests and writing responses.
+package server
+
+import (
+	"encoding/json"
+	"errors"
+	"io"
+	"net/http"
+)
+
+// readJson decodes the request body from JSON.
+func readJson[T any](r *http.Request) (T, error) {
+	var obj T
+	if r.Header.Get("content-type") != "application/json" {
+		return obj, errors.New(http.StatusText(http.StatusUnsupportedMediaType))
+	}
+	data, err := io.ReadAll(r.Body)
+	if err != nil {
+		return obj, err
+	}
+	err = json.Unmarshal(data, &obj)
+	if err != nil {
+		return obj, err
+	}
+	return obj, err
+}
+
+// writeJson encodes an object into JSON and writes it to the response.
+func writeJson(w http.ResponseWriter, obj any) error {
+	data, err := json.Marshal(obj)
+	if err != nil {
+		return err
+	}
+
+	w.Header().Set("content-type", "application/json")
+	_, err = w.Write(data)
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+// writeError encodes an error object into JSON and writes it to the response.
+func writeError(w http.ResponseWriter, code int, obj any) {
+	data, _ := json.Marshal(obj)
+	w.Header().Set("content-type", "application/json")
+	w.WriteHeader(code)
+	w.Write(data) //nolint:errcheck
+}