add support for getting string slice

file_layer_test.go

@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"io"
 	"os"
+	"reflect"
 	"testing"
 
 	. "github.com/smartystreets/goconvey/convey"
@@ -18,7 +19,7 @@ func TestFileLayer(t *testing.T) {
 		path := dir + "/test.json"
 		path2 := dir + "/invalid.json"
 
-		buf := bytes.NewBufferString(`{"str" : "string_data","bool" : true,"integer" : 10 ,"nested" : {"key1" : "string","key2" : 100}}`)
+		buf := bytes.NewBufferString(`{"slicestr":["a","b","c"],"str" : "string_data","bool" : true,"integer" : 10 ,"nested" : {"key1" : "string","key2" : 100}}`)
 		bufInvalid := bytes.NewBufferString(`invalid{json}[]`)
 		f, err := os.Create(path)
 		So(err, ShouldBeNil)
@@ -46,6 +47,7 @@ func TestFileLayer(t *testing.T) {
 			So(o.GetString("nested.key1", ""), ShouldEqual, "string")
 			So(o.GetInt("nested.key2", 0), ShouldEqual, 100)
 			So(o.GetBool("bool", false), ShouldBeTrue)
+			So(reflect.DeepEqual(o.GetStringSlice("slicestr"), []string{"a", "b", "c"}), ShouldBeTrue)
 
 			a := New() // Just for test load again
 			So(a.AddLayer(fl), ShouldBeNil)

onion.go

@@ -69,9 +69,10 @@ func (o Onion) Get(key string) (interface{}, bool) {
 	return nil, false
 }
 
-// The folowing two function is identical. but converting between map[string] and
-// map[interface{}] is not easy, and there is no Generic, so I decide to create
-// two almost identical function instead of writing a convertor each time
+// The folowing two function are identical. but converting between map[string] and
+// map[interface{}] is not easy, and there is no _Generic_ , so I decide to create
+// two almost identical function instead of writing a convertor each time.
+//
 // Some of the loaders like yaml, load inner keys in map[interface{}]interface{}
 // some othr like json do it in map[string]interface{} so we should suppport both
 func searchStringMap(path []string, m map[string]interface{}) (interface{}, bool) {
@@ -202,6 +203,44 @@ func (o Onion) GetBool(key string, def bool) bool {
 	}
 }
 
+func (o Onion) getSlice(key string) (interface{}, bool) {
+	v, ok := o.Get(key)
+	if !ok {
+		return nil, false
+	}
+
+	if reflect.TypeOf(v).Kind() != reflect.Slice { // Not good
+		return nil, false
+	}
+
+	return v, true
+}
+
+// GetStringSlice try to get a slice from the config
+func (o Onion) GetStringSlice(key string) []string {
+	var ok bool
+	v, ok := o.getSlice(key)
+	if !ok {
+		return nil
+	}
+
+	switch v.(type) {
+	case []string:
+		return v.([]string)
+	case []interface{}:
+		vi := v.([]interface{})
+		res := make([]string, len(vi))
+		for i := range vi {
+			if res[i], ok = vi[i].(string); !ok {
+				return nil
+			}
+		}
+		return res
+	}
+
+	return nil
+}
+
 // GetStruct fill an structure base on the config nested set
 func (o Onion) GetStruct(prefix string, s interface{}) {
 	iterateConfig(o, s, prefix)

onion_test.go

@@ -61,6 +61,10 @@ func TestOnion(t *testing.T) {
 		t1["other"] = struct{}{}
 		t1["what"] = getMap("n", "a")
 		lm.data["yes"] = t1
+		lm.data["slice1"] = []string{"a", "b", "c"}
+		lm.data["slice2"] = []interface{}{"a", "b", "c"}
+		lm.data["slice3"] = []interface{}{"a", "b", true}
+		lm.data["slice4"] = []int{1, 2, 3}
 
 		o := New()
 		So(o.AddLayer(lm), ShouldBeNil)
@@ -171,6 +175,14 @@ func TestOnion(t *testing.T) {
 			So(tmp, ShouldBeNil)
 		})
 
+		Convey("slice test", func() {
+			So(reflect.DeepEqual(o.GetStringSlice("slice1"), []string{"a", "b", "c"}), ShouldBeTrue)
+			So(reflect.DeepEqual(o.GetStringSlice("slice2"), []string{"a", "b", "c"}), ShouldBeTrue)
+			So(o.GetStringSlice("slice3"), ShouldBeNil)
+			So(o.GetStringSlice("notslice3"), ShouldBeNil)
+			So(o.GetStringSlice("yes.str1"), ShouldBeNil)
+			So(o.GetStringSlice("slice4"), ShouldBeNil)
+		})
 	})
 
 	Convey("Test layer overwrite", t, func() {