rclone/vendor/github.com/aws/aws-sdk-go/service/dynamodb/dynamodbattribute/doc.go
2017-09-30 15:27:27 +01:00

95 lines
3.6 KiB
Go

// Package dynamodbattribute provides marshaling and unmarshaling utilities to
// convert between Go types and dynamodb.AttributeValues.
//
// These utilities allow you to marshal slices, maps, structs, and scalar values
// to and from dynamodb.AttributeValue. These are useful when marshaling
// Go value tyes to dynamodb.AttributeValue for DynamoDB requests, or
// unmarshaling the dynamodb.AttributeValue back into a Go value type.
//
// AttributeValue Marshaling
//
// To marshal a Go type to a dynamodbAttributeValue you can use the Marshal
// functions in the dynamodbattribute package. There are specialized versions
// of these functions for collections of Attributevalue, such as maps and lists.
//
// The following example uses MarshalMap to convert the Record Go type to a
// dynamodb.AttributeValue type and use the value to make a PutItem API request.
//
// type Record struct {
// ID string
// URLs []string
// }
//
// //...
//
// r := Record{
// ID: "ABC123",
// URLs: []string{
// "https://example.com/first/link",
// "https://example.com/second/url",
// },
// }
// av, err := dynamodbattribute.MarshalMap(r)
// if err != nil {
// panic(fmt.Sprintf("failed to DynamoDB marshal Record, %v", err))
// }
//
// _, err = svc.PutItem(&dynamodb.PutItemInput{
// TableName: aws.String(myTableName),
// Item: av,
// })
// if err != nil {
// panic(fmt.Sprintf("failed to put Record to DynamoDB, %v", err))
// }
//
// AttributeValue Unmarshaling
//
// To unmarshal a dynamodb.AttributeValue to a Go type you can use the Unmarshal
// functions in the dynamodbattribute package. There are specialized versions
// of these functions for collections of Attributevalue, such as maps and lists.
//
// The following example will unmarshal the DynamoDB's Scan API operation. The
// Items returned by the operation will be unmarshaled into the slice of Records
// Go type.
//
// type Record struct {
// ID string
// URLs []string
// }
//
// //...
//
// var records []Record
//
// // Use the ScanPages method to perform the scan with pagination. Use
// // just Scan method to make the API call without pagination.
// err := svc.ScanPages(&dynamodb.ScanInput{
// TableName: aws.String(myTableName),
// }, func(page *dynamodb.ScanOutput, last bool) bool {
// recs := []Record{}
//
// err := dynamodbattribute.UnmarshalListOfMaps(page.Items, &recs)
// if err != nil {
// panic(fmt.Sprintf("failed to unmarshal Dynamodb Scan Items, %v", err))
// }
//
// records = append(records, recs...)
//
// return true // keep paging
// })
//
// The ConvertTo, ConvertToList, ConvertToMap, ConvertFrom, ConvertFromMap
// and ConvertFromList methods have been deprecated. The Marshal and Unmarshal
// functions should be used instead. The ConvertTo|From marshallers do not
// support BinarySet, NumberSet, nor StringSets, and will incorrect marshal
// binary data fields in structs as base64 strings.
//
// The Marshal and Unmarshal functions correct this behavior, and removes
// the reliance on encoding.json. `json` struct tags are still supported. In
// addition support for a new struct tag `dynamodbav` was added. Support for
// the json.Marshaler and json.Unmarshaler interfaces have been removed and
// replaced with have been replaced with dynamodbattribute.Marshaler and
// dynamodbattribute.Unmarshaler interfaces.
//
// `time.Time` is marshaled as RFC3339 format.
package dynamodbattribute