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package request
import (
"reflect"
"github.com/aws/aws-sdk-go/aws"
"github.com/aws/aws-sdk-go/aws/awsutil"
)
//type Paginater interface {
// HasNextPage() bool
// NextPage() *Request
// EachPage(fn func(data interface{}, isLastPage bool) (shouldContinue bool)) error
//}
// HasNextPage returns true if this request has more pages of data available.
func (r *Request) HasNextPage() bool {
return len(r.nextPageTokens()) > 0
}
// nextPageTokens returns the tokens to use when asking for the next page of
// data.
func (r *Request) nextPageTokens() []interface{} {
if r.Operation.Paginator == nil {
return nil
}
if r.Operation.TruncationToken != "" {
tr, _ := awsutil.ValuesAtPath(r.Data, r.Operation.TruncationToken)
if len(tr) == 0 {
return nil
}
switch v := tr[0].(type) {
case *bool:
if !aws.BoolValue(v) {
return nil
}
case bool:
if v == false {
return nil
}
}
}
tokens := []interface{}{}
tokenAdded := false
for _, outToken := range r.Operation.OutputTokens {
v, _ := awsutil.ValuesAtPath(r.Data, outToken)
if len(v) > 0 {
tokens = append(tokens, v[0])
tokenAdded = true
} else {
tokens = append(tokens, nil)
}
}
if !tokenAdded {
return nil
}
return tokens
}
// NextPage returns a new Request that can be executed to return the next
// page of result data. Call .Send() on this request to execute it.
func (r *Request) NextPage() *Request {
tokens := r.nextPageTokens()
if len(tokens) == 0 {
return nil
}
data := reflect.New(reflect.TypeOf(r.Data).Elem()).Interface()
nr := New(r.Config, r.ClientInfo, r.Handlers, r.Retryer, r.Operation, awsutil.CopyOf(r.Params), data)
for i, intok := range nr.Operation.InputTokens {
awsutil.SetValueAtPath(nr.Params, intok, tokens[i])
}
return nr
}
// EachPage iterates over each page of a paginated request object. The fn
// parameter should be a function with the following sample signature:
//
// func(page *T, lastPage bool) bool {
// return true // return false to stop iterating
// }
//
// Where "T" is the structure type matching the output structure of the given
// operation. For example, a request object generated by
// DynamoDB.ListTablesRequest() would expect to see dynamodb.ListTablesOutput
// as the structure "T". The lastPage value represents whether the page is
// the last page of data or not. The return value of this function should
// return true to keep iterating or false to stop.
func (r *Request) EachPage(fn func(data interface{}, isLastPage bool) (shouldContinue bool)) error {
for page := r; page != nil; page = page.NextPage() {
if err := page.Send(); err != nil {
return err
}
if getNextPage := fn(page.Data, !page.HasNextPage()); !getNextPage {
return page.Error
}
}
return nil
}
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