// Get a value from a DynamoDB table containing entries like:
// {"id": "my primary key", "value": "valuable value"}
func (ig *ItemGetter) Get(id string) (value string) {
var input = &dynamodb.GetItemInput{
Key: map[string]*dynamodb.AttributeValue{
"id": {
S: aws.String(id),
},
},
TableName: aws.String("my_table"),
AttributesToGet: []*string{
aws.String("value"),
},
}
if output, err := ig.DynamoDB.GetItem(input); err == nil {
if _, ok := output.Item["value"]; ok {
dynamodbattribute.Unmarshal(output.Item["value"], &value)
}
}
return
}
func ExampleUnmarshal() {
type Record struct {
Bytes []byte
MyField string
Letters []string
A2Num map[string]int
}
expect := Record{
Bytes: []byte{48, 49},
MyField: "MyFieldValue",
Letters: []string{"a", "b", "c", "d"},
A2Num: map[string]int{"a": 1, "b": 2, "c": 3},
}
av := &dynamodb.AttributeValue{
M: map[string]*dynamodb.AttributeValue{
"Bytes": {B: []byte{48, 49}},
"MyField": {S: aws.String("MyFieldValue")},
"Letters": {L: []*dynamodb.AttributeValue{
{S: aws.String("a")}, {S: aws.String("b")}, {S: aws.String("c")}, {S: aws.String("d")},
}},
"A2Num": {M: map[string]*dynamodb.AttributeValue{
"a": {N: aws.String("1")},
"b": {N: aws.String("2")},
"c": {N: aws.String("3")},
}},
},
}
actual := Record{}
err := dynamodbattribute.Unmarshal(av, &actual)
fmt.Println(err, reflect.DeepEqual(expect, actual))
// Output:
// <nil> true
}