feat(form): add array collection format in form binding (#3986)

* feat(form): add array collection format in form binding

* feat(form): add array collection format in form binding

* test(form): fix test code for array collection format in form binding

binding/form_mapping.go

@@ -182,6 +182,38 @@ func trySetCustom(val string, value reflect.Value) (isSet bool, err error) {
 	return false, nil
 }
 
+func trySplit(vs []string, field reflect.StructField) (newVs []string, err error) {
+	cfTag := field.Tag.Get("collection_format")
+	if cfTag == "" || cfTag == "multi" {
+		return vs, nil
+	}
+
+	var sep string
+	switch cfTag {
+	case "csv":
+		sep = ","
+	case "ssv":
+		sep = " "
+	case "tsv":
+		sep = "\t"
+	case "pipes":
+		sep = "|"
+	default:
+		return vs, fmt.Errorf("%s is not supported in the collection_format. (csv, ssv, pipes)", cfTag)
+	}
+
+	totalLength := 0
+	for _, v := range vs {
+		totalLength += strings.Count(v, sep) + 1
+	}
+	newVs = make([]string, 0, totalLength)
+	for _, v := range vs {
+		newVs = append(newVs, strings.Split(v, sep)...)
+	}
+
+	return newVs, nil
+}
+
 func setByForm(value reflect.Value, field reflect.StructField, form map[string][]string, tagValue string, opt setOptions) (isSet bool, err error) {
 	vs, ok := form[tagValue]
 	if !ok && !opt.isDefaultExists {
@@ -198,6 +230,10 @@ func setByForm(value reflect.Value, field reflect.StructField, form map[string][
 			return ok, err
 		}
 
+		if vs, err = trySplit(vs, field); err != nil {
+			return false, err
+		}
+
 		return true, setSlice(vs, value, field)
 	case reflect.Array:
 		if !ok {
@@ -208,6 +244,10 @@ func setByForm(value reflect.Value, field reflect.StructField, form map[string][
 			return ok, err
 		}
 
+		if vs, err = trySplit(vs, field); err != nil {
+			return false, err
+		}
+
 		if len(vs) != value.Len() {
 			return false, fmt.Errorf("%q is not valid value for %s", vs, value.Type().String())
 		}

binding/form_mapping_test.go

@@ -264,6 +264,45 @@ func TestMappingArray(t *testing.T) {
 	require.Error(t, err)
 }
 
+func TestMappingCollectionFormat(t *testing.T) {
+	var s struct {
+		SliceMulti []int  `form:"slice_multi" collection_format:"multi"`
+		SliceCsv   []int  `form:"slice_csv" collection_format:"csv"`
+		SliceSsv   []int  `form:"slice_ssv" collection_format:"ssv"`
+		SliceTsv   []int  `form:"slice_tsv" collection_format:"tsv"`
+		SlicePipes []int  `form:"slice_pipes" collection_format:"pipes"`
+		ArrayMulti [2]int `form:"array_multi" collection_format:"multi"`
+		ArrayCsv   [2]int `form:"array_csv" collection_format:"csv"`
+		ArraySsv   [2]int `form:"array_ssv" collection_format:"ssv"`
+		ArrayTsv   [2]int `form:"array_tsv" collection_format:"tsv"`
+		ArrayPipes [2]int `form:"array_pipes" collection_format:"pipes"`
+	}
+	err := mappingByPtr(&s, formSource{
+		"slice_multi": {"1", "2"},
+		"slice_csv":   {"1,2"},
+		"slice_ssv":   {"1 2"},
+		"slice_tsv":   {"1	2"},
+		"slice_pipes": {"1|2"},
+		"array_multi": {"1", "2"},
+		"array_csv":   {"1,2"},
+		"array_ssv":   {"1 2"},
+		"array_tsv":   {"1	2"},
+		"array_pipes": {"1|2"},
+	}, "form")
+	require.NoError(t, err)
+
+	assert.Equal(t, []int{1, 2}, s.SliceMulti)
+	assert.Equal(t, []int{1, 2}, s.SliceCsv)
+	assert.Equal(t, []int{1, 2}, s.SliceSsv)
+	assert.Equal(t, []int{1, 2}, s.SliceTsv)
+	assert.Equal(t, []int{1, 2}, 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)
+}
+
 func TestMappingStructField(t *testing.T) {
 	var s struct {
 		J struct {