From 7ca7bd94096ec85503b64b630cc3c0e486648a1c Mon Sep 17 00:00:00 2001
From: Ggicci <ggicci.t@gmail.com>
Date: Sun, 29 Oct 2023 14:31:47 -0400
Subject: [PATCH] fix: decode with default directive only works the first time

Fixed #77
---
 default.go      |  5 ++---
 default_test.go | 28 ++++++++++++++++++++++++++++
 extractor.go    |  7 +++++--
 3 files changed, 35 insertions(+), 5 deletions(-)

diff --git a/default.go b/default.go
index 4661c14..6a8bd5e 100644
--- a/default.go
+++ b/default.go
@@ -12,7 +12,7 @@ func defaultValueSetter(ctx *DirectiveRuntime) error {
 
 	// Transform:
 	// 1. ctx.Argv -> input values
-	// 2. ["default"] -> ctx.Argv
+	// 2. ["default"] -> keys
 	extractor := &extractor{
 		Form: multipart.Form{
 			Value: map[string][]string{
@@ -20,6 +20,5 @@ func defaultValueSetter(ctx *DirectiveRuntime) error {
 			},
 		},
 	}
-	ctx.Directive.Argv = []string{"default"}
-	return extractor.Execute(ctx)
+	return extractor.Execute(ctx, "default")
 }
diff --git a/default_test.go b/default_test.go
index 92e9bfb..072c04a 100644
--- a/default_test.go
+++ b/default_test.go
@@ -73,3 +73,31 @@ func TestDirectiveDefault_PatchField(t *testing.T) {
 	assert.NoError(t, err)
 	assert.Equal(t, expected, got)
 }
+
+// FIX: https://github.com/ggicci/httpin/issues/77
+// Decode parameter struct with default values only works the first time
+func TestDirectiveDeafult_Decode_twice(t *testing.T) {
+	type ThingWithDefaultValues struct {
+		Id      uint `in:"query=id;required"`
+		Page    int  `in:"query=page;default=1"`
+		PerPage int  `in:"query=page_size;default=127"`
+	}
+
+	r, _ := http.NewRequest("GET", "/?id=123", nil)
+	expected := &ThingWithDefaultValues{
+		Id:      123,
+		Page:    1,
+		PerPage: 127,
+	}
+
+	// First decode works as expected
+	xxx := ThingWithDefaultValues{}
+	err := Decode(r, &xxx)
+	assert.NoError(t, err)
+	assert.Equal(t, expected, &xxx)
+
+	// Second decode generates eror
+	err = Decode(r, &xxx)
+	assert.NoError(t, err)
+	assert.Equal(t, expected, &xxx)
+}
diff --git a/extractor.go b/extractor.go
index 6d06953..ada7e64 100644
--- a/extractor.go
+++ b/extractor.go
@@ -29,8 +29,11 @@ func newExtractor(r *http.Request) *extractor {
 	}
 }
 
-func (e *extractor) Execute(ctx *DirectiveRuntime) error {
-	for _, key := range ctx.Directive.Argv {
+func (e *extractor) Execute(ctx *DirectiveRuntime, keys ...string) error {
+	if len(keys) == 0 {
+		keys = ctx.Directive.Argv
+	}
+	for _, key := range keys {
 		if e.KeyNormalizer != nil {
 			key = e.KeyNormalizer(key)
 		}