feat: BindJSON Unfriendly prompt when parsing empty body.

binding/json.go

@@ -50,6 +50,9 @@ func decodeJSON(r io.Reader, obj any) error {
 		decoder.DisallowUnknownFields()
 	}
 	if err := decoder.Decode(obj); err != nil {
+		if err == io.EOF {
+			return errors.New("empty body")
+		}
 		return err
 	}
 	return validate(obj)

binding/json_test.go

@@ -5,6 +5,7 @@
 package binding
 
 import (
+	"strings"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -28,3 +29,11 @@ func TestJSONBindingBindBodyMap(t *testing.T) {
 	assert.Equal(t, "FOO", s["foo"])
 	assert.Equal(t, "world", s["hello"])
 }
+
+func TestJSONBindingBindEmpty(t *testing.T) {
+	var s struct {
+		Foo string `binding:"required"`
+	}
+	err := jsonBinding{}.BindBody([]byte(""), &s)
+	require.True(t, strings.Contains(err.Error(), "empty body"))
+}