1 files changed, 88 insertions, 0 deletions
diff --git a/binder.go b/binder.go
new file mode 100644
index 0000000..f618a1a
--- /dev/null
+++ b/binder.go
@@ -0,0 +1,88 @@
+package mux
+
+import (
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"net/url"
+	"reflect"
+	"strconv"
+	"strings"
+)
+
+func Bind[T any](r *http.Request, obj *T) error {
+	contentType := r.Header.Get("Content-Type")
+	switch {
+	case strings.HasPrefix(contentType, "multipart/form-data"),
+		strings.HasPrefix(contentType, "application/x-www-form-urlencoded"):
+		if err := r.ParseForm(); err != nil {
+			return err
+		}
+		return bindForm(r.Form, obj)
+	case strings.HasPrefix(contentType, "application/json"):
+		defer r.Body.Close()
+		return json.NewDecoder(r.Body).Decode(obj)
+	case r.Method == http.MethodGet:
+		return bindForm(r.URL.Query(), obj)
+	case r.Method == http.MethodPost:
+		return fmt.Errorf("invalid content-type: %s", contentType)
+	}
+
+	return nil
+}
+
+func bindForm(values url.Values, obj any) error {
+	val := reflect.ValueOf(obj)
+	if val.Kind() == reflect.Ptr {
+		val = val.Elem()
+	}
+
+	fields := val.NumField()
+
+	for i := 0; i < fields; i++ {
+		f := val.Field(i)
+		if !f.IsValid() {
+			continue
+		}
+		if !f.CanSet() {
+			continue
+		}
+		t := val.Type().Field(i)
+		k := t.Tag.Get("form")
+		if k == "" {
+			continue
+		}
+		if !values.Has(k) {
+			continue
+		}
+		v := values.Get(k)
+
+		switch f.Type().Kind() {
+		case reflect.Bool:
+			switch v {
+			case "on", "true", "1":
+				f.SetBool(true)
+			default:
+				f.SetBool(false)
+			}
+		case reflect.Int, reflect.Int64:
+			if i, e := strconv.ParseInt(v, 0, 0); e == nil {
+				f.SetInt(i)
+			} else {
+				return fmt.Errorf("could not set int value of %s: %s", k, e)
+			}
+		case reflect.Float64:
+			if fl, e := strconv.ParseFloat(v, 64); e == nil {
+				f.SetFloat(fl)
+			} else {
+				return fmt.Errorf("could not set float64 value of %s: %s", k, e)
+			}
+		case reflect.String:
+			f.SetString(v)
+		default:
+			return fmt.Errorf("unsupported format %v for field %s", f.Type().Kind(), k)
+		}
+	}
+
+	return nil
+}