dynamodb: Do not omit empty value in some types

See http://docs.aws.amazon.com/amazondynamodb/latest/APIReference/API_PutItem.html for what empty values we should omit.
crowdmob · Jan 6, 2014 · 14fa9b4 · 14fa9b4
1 parent 49c7886
commit 14fa9b4
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Showing 2 changed files with 41 additions and 1 deletion.
diff --git a/dynamodb/marshaller.go b/dynamodb/marshaller.go
@@ -20,7 +20,7 @@ func MarshalAttributes(m interface{}) ([]Attribute, error) {
 	builder.buffer = []Attribute{}
 	for _, f := range cachedTypeFields(v.Type()) { // loop on each field
 		fv := fieldByIndex(v, f.index)
-		if !fv.IsValid() || isEmptyValue(fv) {
+		if !fv.IsValid() || isEmptyValueToOmit(fv) {
 			continue
 		}
 
@@ -293,6 +293,18 @@ func numericReflectedValueString(v reflect.Value) (string, error) {
 	return "", fmt.Errorf("UnsupportedNumericValueError %#v", v.Type())
 }
 
+// In DynamoDB we should omit empty value in some type
+// See http://docs.aws.amazon.com/amazondynamodb/latest/APIReference/API_PutItem.html
+func isEmptyValueToOmit(v reflect.Value) bool {
+	switch v.Kind() {
+	case reflect.Array, reflect.Map, reflect.Slice, reflect.String, reflect.Interface, reflect.Ptr:
+		// should omit if empty value
+		return isEmptyValue(v)
+	}
+	// otherwise should not omit
+	return false
+}
+
 // ---------------- Below are copied handy functions from http://golang.org/src/pkg/encoding/json/encode.go --------------------------------
 func isEmptyValue(v reflect.Value) bool {
 	switch v.Kind() {

diff --git a/dynamodb/marshaller_test.go b/dynamodb/marshaller_test.go
@@ -65,6 +65,10 @@ func testObjectTime() *TestStructTime {
 	}
 }
 
+func testObjectWithZeroValues() *TestStruct {
+	return &TestStruct{}
+}
+
 func testObjectWithNilSets() *TestStruct {
 	return &TestStruct{
 		TestBool:        true,
@@ -135,6 +139,19 @@ func testAttrsTime() []dynamodb.Attribute {
 	}
 }
 
+func testAttrsWithZeroValues() []dynamodb.Attribute {
+	return []dynamodb.Attribute{
+		dynamodb.Attribute{Type: "N", Name: "TestBool", Value: "0", SetValues: []string(nil)},
+		dynamodb.Attribute{Type: "N", Name: "TestInt", Value: "0", SetValues: []string(nil)},
+		dynamodb.Attribute{Type: "N", Name: "TestInt32", Value: "0", SetValues: []string(nil)},
+		dynamodb.Attribute{Type: "N", Name: "TestInt64", Value: "0", SetValues: []string(nil)},
+		dynamodb.Attribute{Type: "N", Name: "TestUint", Value: "0", SetValues: []string(nil)},
+		dynamodb.Attribute{Type: "N", Name: "TestFloat32", Value: "0", SetValues: []string(nil)},
+		dynamodb.Attribute{Type: "N", Name: "TestFloat64", Value: "0", SetValues: []string(nil)},
+		dynamodb.Attribute{Type: "S", Name: "TestSub", Value: `{"SubBool":false,"SubInt":0,"SubString":"","SubStringArray":null}`, SetValues: []string(nil)},
+	}
+}
+
 func testAttrsWithNilSets() []dynamodb.Attribute {
 	return []dynamodb.Attribute{
 		dynamodb.Attribute{Type: "N", Name: "TestBool", Value: "1", SetValues: []string(nil)},
@@ -224,6 +241,17 @@ func (s *MarshallerSuite) TestMarshalNilSets(c *gocheck.C) {
 	c.Check(attrs, gocheck.DeepEquals, expected)
 }
 
+func (s *MarshallerSuite) TestMarshalZeroValues(c *gocheck.C) {
+	testObj := testObjectWithZeroValues()
+	attrs, err := dynamodb.MarshalAttributes(testObj)
+	if err != nil {
+		c.Errorf("Error from dynamodb.MarshalAttributes: %#v", err)
+	}
+
+	expected := testAttrsWithZeroValues()
+	c.Check(attrs, gocheck.DeepEquals, expected)
+}
+
 func (s *MarshallerSuite) TestMarshalEmptySets(c *gocheck.C) {
 	testObj := testObjectWithEmptySets()
 	attrs, err := dynamodb.MarshalAttributes(testObj)