feat: support query array in httpx.Parse (#4440)

core/mapping/unmarshaler.go

@@ -50,6 +50,7 @@ type (
 
 	unmarshalOptions struct {
 		fillDefault  bool
+		fromArray    bool
 		fromString   bool
 		opaqueKeys   bool
 		canonicalKey func(key string) string
@@ -811,6 +812,19 @@ func (u *Unmarshaler) processNamedField(field reflect.StructField, value reflect
 		return u.processNamedFieldWithoutValue(field.Type, value, opts, fullName)
 	}
 
+	if u.opts.fromArray {
+		fieldKind := field.Type.Kind()
+		if fieldKind != reflect.Slice && fieldKind != reflect.Array {
+			valueKind := reflect.TypeOf(mapValue).Kind()
+			if valueKind == reflect.Slice || valueKind == reflect.Array {
+				val := reflect.ValueOf(mapValue)
+				if val.Len() > 0 {
+					mapValue = val.Index(0).Interface()
+				}
+			}
+		}
+	}
+
 	return u.processNamedFieldWithValue(field.Type, value, valueWithParent{
 		value:  mapValue,
 		parent: valuer,
@@ -990,6 +1004,16 @@ func WithDefault() UnmarshalOption {
 	}
 }
 
+// WithFromArray customizes an Unmarshaler with converting array values to non-array types.
+// For example, if the field type is []string, and the value is [hello],
+// the field type can be `string`, instead of `[]string`.
+// Typically, this option is used for unmarshaling from form values.
+func WithFromArray() UnmarshalOption {
+	return func(opt *unmarshalOptions) {
+		opt.fromArray = true
+	}
+}
+
 // WithOpaqueKeys customizes an Unmarshaler with opaque keys.
 // Opaque keys are keys that are not processed by the unmarshaler.
 func WithOpaqueKeys() UnmarshalOption {

core/mapping/unmarshaler_test.go

@@ -5639,6 +5639,62 @@ func TestUnmarshalFromStringSliceForTypeMismatch(t *testing.T) {
 	}, &v))
 }
 
+func TestUnmarshalWithFromArray(t *testing.T) {
+	t.Run("array", func(t *testing.T) {
+		var v struct {
+			Value []string `key:"value"`
+		}
+		unmarshaler := NewUnmarshaler("key", WithFromArray())
+		if assert.NoError(t, unmarshaler.Unmarshal(map[string]any{
+			"value": []string{"foo", "bar"},
+		}, &v)) {
+			assert.ElementsMatch(t, []string{"foo", "bar"}, v.Value)
+		}
+	})
+
+	t.Run("not array", func(t *testing.T) {
+		var v struct {
+			Value string `key:"value"`
+		}
+		unmarshaler := NewUnmarshaler("key", WithFromArray())
+		if assert.NoError(t, unmarshaler.Unmarshal(map[string]any{
+			"value": []string{"foo"},
+		}, &v)) {
+			assert.Equal(t, "foo", v.Value)
+		}
+	})
+
+	t.Run("not array and empty", func(t *testing.T) {
+		var v struct {
+			Value string `key:"value"`
+		}
+		unmarshaler := NewUnmarshaler("key", WithFromArray())
+		if assert.NoError(t, unmarshaler.Unmarshal(map[string]any{
+			"value": []string{""},
+		}, &v)) {
+			assert.Empty(t, v.Value)
+		}
+	})
+
+	t.Run("not array and no value", func(t *testing.T) {
+		var v struct {
+			Value string `key:"value"`
+		}
+		unmarshaler := NewUnmarshaler("key", WithFromArray())
+		assert.Error(t, unmarshaler.Unmarshal(map[string]any{}, &v))
+	})
+
+	t.Run("not array and no value and optional", func(t *testing.T) {
+		var v struct {
+			Value string `key:"value,optional"`
+		}
+		unmarshaler := NewUnmarshaler("key", WithFromArray())
+		if assert.NoError(t, unmarshaler.Unmarshal(map[string]any{}, &v)) {
+			assert.Empty(t, v.Value)
+		}
+	})
+}
+
 func TestUnmarshalWithOpaqueKeys(t *testing.T) {
 	var v struct {
 		Opaque string `key:"opaque.key"`

rest/httpx/requests.go

@@ -23,9 +23,16 @@ const (
 )
 
 var (
-	formUnmarshaler = mapping.NewUnmarshaler(formKey, mapping.WithStringValues(), mapping.WithOpaqueKeys())
+	formUnmarshaler = mapping.NewUnmarshaler(
-	pathUnmarshaler = mapping.NewUnmarshaler(pathKey, mapping.WithStringValues(), mapping.WithOpaqueKeys())
+		formKey,
-	validator       atomic.Value
+		mapping.WithStringValues(),
+		mapping.WithOpaqueKeys(),
+		mapping.WithFromArray())
+	pathUnmarshaler = mapping.NewUnmarshaler(
+		pathKey,
+		mapping.WithStringValues(),
+		mapping.WithOpaqueKeys())
+	validator atomic.Value
 )
 
 // Validator defines the interface for validating the request.

rest/httpx/requests_test.go

@@ -49,6 +49,61 @@ func TestParseForm(t *testing.T) {
 	})
 }
 
+func TestParseFormArray(t *testing.T) {
+	t.Run("slice", func(t *testing.T) {
+		var v struct {
+			Name    []string  `form:"name"`
+			Age     []int     `form:"age"`
+			Percent []float64 `form:"percent,optional"`
+		}
+
+		r, err := http.NewRequest(
+			http.MethodGet,
+			"/a?name=hello&name=world&age=18&age=19&percent=3.4&percent=4.5",
+			http.NoBody)
+		assert.NoError(t, err)
+		if assert.NoError(t, Parse(r, &v)) {
+			assert.ElementsMatch(t, []string{"hello", "world"}, v.Name)
+			assert.ElementsMatch(t, []int{18, 19}, v.Age)
+			assert.ElementsMatch(t, []float64{3.4, 4.5}, v.Percent)
+		}
+	})
+
+	t.Run("slice with single value", func(t *testing.T) {
+		var v struct {
+			Name    []string  `form:"name"`
+			Age     []int     `form:"age"`
+			Percent []float64 `form:"percent,optional"`
+		}
+
+		r, err := http.NewRequest(
+			http.MethodGet,
+			"/a?name=hello&age=18&percent=3.4",
+			http.NoBody)
+		assert.NoError(t, err)
+		if assert.NoError(t, Parse(r, &v)) {
+			assert.ElementsMatch(t, []string{"hello"}, v.Name)
+			assert.ElementsMatch(t, []int{18}, v.Age)
+			assert.ElementsMatch(t, []float64{3.4}, v.Percent)
+		}
+	})
+
+	t.Run("slice with empty and non-empty", func(t *testing.T) {
+		var v struct {
+			Name []string `form:"name"`
+		}
+
+		r, err := http.NewRequest(
+			http.MethodGet,
+			"/a?name=&name=1",
+			http.NoBody)
+		assert.NoError(t, err)
+		if assert.NoError(t, Parse(r, &v)) {
+			assert.ElementsMatch(t, []string{"1"}, v.Name)
+		}
+	})
+}
+
 func TestParseForm_Error(t *testing.T) {
 	var v struct {
 		Name string `form:"name"`

rest/httpx/util.go

@@ -20,10 +20,16 @@ func GetFormValues(r *http.Request) (map[string]any, error) {
 	}
 
 	params := make(map[string]any, len(r.Form))
-	for name := range r.Form {
+	for name, values := range r.Form {
-		formValue := r.Form.Get(name)
+		filtered := make([]string, 0, len(values))
-		if len(formValue) > 0 {
+		for _, v := range values {
-			params[name] = formValue
+			if len(v) > 0 {
+				filtered = append(filtered, v)
+			}
+		}
+
+		if len(filtered) > 0 {
+			params[name] = filtered
 		}
 	}
 

rest/router/patrouter_test.go

@@ -137,7 +137,7 @@ func TestPatRouter(t *testing.T) {
 }
 
 func TestParseSlice(t *testing.T) {
-	body := `names=%5B%22first%22%2C%22second%22%5D`
+	body := `names=first&names=second`
 	reader := strings.NewReader(body)
 	r, err := http.NewRequest(http.MethodPost, "http://hello.com/", reader)
 	assert.Nil(t, err)
@@ -388,7 +388,7 @@ func TestParseQueryRequired(t *testing.T) {
 }
 
 func TestParseOptional(t *testing.T) {
-	r, err := http.NewRequest(http.MethodGet, "http://hello.com/kevin/2017?nickname=whatever&zipcode=", nil)
+	r, err := http.NewRequest(http.MethodGet, "http://hello.com/kevin/2017?nickname=whatever", nil)
 	assert.Nil(t, err)
 
 	router := NewRouter()