feat(form): Support default values for collections in form binding (#4048)

binding/form_mapping.go

@@ -159,6 +159,14 @@ func tryToSetValue(value reflect.Value, field reflect.StructField, setter setter
 		if k, v := head(opt, "="); k == "default" {
 			setOpt.isDefaultExists = true
 			setOpt.defaultValue = v
+
+			// convert semicolon-separated default values to csv-separated values for processing in setByForm
+			if field.Type.Kind() == reflect.Slice || field.Type.Kind() == reflect.Array {
+				cfTag := field.Tag.Get("collection_format")
+				if cfTag == "" || cfTag == "multi" || cfTag == "csv" {
+					setOpt.defaultValue = strings.ReplaceAll(v, ";", ",")
+				}
+			}
 		}
 	}
 
@@ -224,6 +232,12 @@ func setByForm(value reflect.Value, field reflect.StructField, form map[string][
 	case reflect.Slice:
 		if !ok {
 			vs = []string{opt.defaultValue}
+
+			// pre-process the default value for multi if present
+			cfTag := field.Tag.Get("collection_format")
+			if cfTag == "" || cfTag == "multi" {
+				vs = strings.Split(opt.defaultValue, ",")
+			}
 		}
 
 		if ok, err = trySetCustom(vs[0], value); ok {
@@ -238,6 +252,12 @@ func setByForm(value reflect.Value, field reflect.StructField, form map[string][
 	case reflect.Array:
 		if !ok {
 			vs = []string{opt.defaultValue}
+
+			// pre-process the default value for multi if present
+			cfTag := field.Tag.Get("collection_format")
+			if cfTag == "" || cfTag == "multi" {
+				vs = strings.Split(opt.defaultValue, ",")
+			}
 		}
 
 		if ok, err = trySetCustom(vs[0], value); ok {

binding/form_mapping_test.go

@@ -323,6 +323,72 @@ func TestMappingCollectionFormat(t *testing.T) {
 	assert.Equal(t, [2]int{1, 2}, s.ArrayPipes)
 }
 
+func TestMappingCollectionFormatInvalid(t *testing.T) {
+	var s struct {
+		SliceCsv []int `form:"slice_csv" collection_format:"xxx"`
+	}
+	err := mappingByPtr(&s, formSource{
+		"slice_csv": {"1,2"},
+	}, "form")
+	require.Error(t, err)
+
+	var s2 struct {
+		ArrayCsv [2]int `form:"array_csv" collection_format:"xxx"`
+	}
+	err = mappingByPtr(&s2, formSource{
+		"array_csv": {"1,2"},
+	}, "form")
+	require.Error(t, err)
+}
+
+func TestMappingMultipleDefaultWithCollectionFormat(t *testing.T) {
+	var s struct {
+		SliceMulti       []int     `form:",default=1;2;3" collection_format:"multi"`
+		SliceCsv         []int     `form:",default=1;2;3" collection_format:"csv"`
+		SliceSsv         []int     `form:",default=1 2 3" collection_format:"ssv"`
+		SliceTsv         []int     `form:",default=1\t2\t3" collection_format:"tsv"`
+		SlicePipes       []int     `form:",default=1|2|3" collection_format:"pipes"`
+		ArrayMulti       [2]int    `form:",default=1;2" collection_format:"multi"`
+		ArrayCsv         [2]int    `form:",default=1;2" collection_format:"csv"`
+		ArraySsv         [2]int    `form:",default=1 2" collection_format:"ssv"`
+		ArrayTsv         [2]int    `form:",default=1\t2" collection_format:"tsv"`
+		ArrayPipes       [2]int    `form:",default=1|2" collection_format:"pipes"`
+		SliceStringMulti []string  `form:",default=1;2;3" collection_format:"multi"`
+		SliceStringCsv   []string  `form:",default=1;2;3" collection_format:"csv"`
+		SliceStringSsv   []string  `form:",default=1 2 3" collection_format:"ssv"`
+		SliceStringTsv   []string  `form:",default=1\t2\t3" collection_format:"tsv"`
+		SliceStringPipes []string  `form:",default=1|2|3" collection_format:"pipes"`
+		ArrayStringMulti [2]string `form:",default=1;2" collection_format:"multi"`
+		ArrayStringCsv   [2]string `form:",default=1;2" collection_format:"csv"`
+		ArrayStringSsv   [2]string `form:",default=1 2" collection_format:"ssv"`
+		ArrayStringTsv   [2]string `form:",default=1\t2" collection_format:"tsv"`
+		ArrayStringPipes [2]string `form:",default=1|2" collection_format:"pipes"`
+	}
+	err := mappingByPtr(&s, formSource{}, "form")
+	require.NoError(t, err)
+
+	assert.Equal(t, []int{1, 2, 3}, s.SliceMulti)
+	assert.Equal(t, []int{1, 2, 3}, s.SliceCsv)
+	assert.Equal(t, []int{1, 2, 3}, s.SliceSsv)
+	assert.Equal(t, []int{1, 2, 3}, s.SliceTsv)
+	assert.Equal(t, []int{1, 2, 3}, s.SlicePipes)
+	assert.Equal(t, [2]int{1, 2}, s.ArrayMulti)
+	assert.Equal(t, [2]int{1, 2}, s.ArrayCsv)
+	assert.Equal(t, [2]int{1, 2}, s.ArraySsv)
+	assert.Equal(t, [2]int{1, 2}, s.ArrayTsv)
+	assert.Equal(t, [2]int{1, 2}, s.ArrayPipes)
+	assert.Equal(t, []string{"1", "2", "3"}, s.SliceStringMulti)
+	assert.Equal(t, []string{"1", "2", "3"}, s.SliceStringCsv)
+	assert.Equal(t, []string{"1", "2", "3"}, s.SliceStringSsv)
+	assert.Equal(t, []string{"1", "2", "3"}, s.SliceStringTsv)
+	assert.Equal(t, []string{"1", "2", "3"}, s.SliceStringPipes)
+	assert.Equal(t, [2]string{"1", "2"}, s.ArrayStringMulti)
+	assert.Equal(t, [2]string{"1", "2"}, s.ArrayStringCsv)
+	assert.Equal(t, [2]string{"1", "2"}, s.ArrayStringSsv)
+	assert.Equal(t, [2]string{"1", "2"}, s.ArrayStringTsv)
+	assert.Equal(t, [2]string{"1", "2"}, s.ArrayStringPipes)
+}
+
 func TestMappingStructField(t *testing.T) {
 	var s struct {
 		J struct {