func ExampleIterator_Cursor() {
ctx := context.Background()
client, _ := datastore.NewClient(ctx, "my-proj")
cursorStr := ""
// [START cursor_paging]
const pageSize = 5
query := datastore.NewQuery("Tasks").Limit(pageSize)
if cursorStr != "" {
cursor, err := datastore.DecodeCursor(cursorStr)
if err != nil {
log.Fatalf("Bad cursor %q: %v", cursorStr, err)
}
query = query.Start(cursor)
}
// Read the tasks.
var tasks []Task
var task Task
it := client.Run(ctx, query)
_, err := it.Next(&task)
for err == nil {
tasks = append(tasks, task)
_, err = it.Next(&task)
}
if err != datastore.Done {
log.Fatalf("Failed fetching results: %v", err)
}
// Get the cursor for the next page of results.
nextCursor, err := it.Cursor()
// [END cursor_paging]
_ = err // Check the error.
_ = nextCursor // Use nextCursor.String as the next page's token.
}
func ExampleDecodeCursor() {
// See Query.Start for a fuller example of DecodeCursor.
// getCursor represents a function that returns a cursor from a previous
// iteration in string form.
cursorString := getCursor()
cursor, err := datastore.DecodeCursor(cursorString)
if err != nil {
// TODO: Handle error.
}
_ = cursor // TODO: Use the cursor with Query.Start or Query.End.
}
func ExampleQuery_Start() {
// This example demonstrates how to use cursors and Query.Start
// to resume an iteration.
ctx := context.Background()
client, err := datastore.NewClient(ctx, "project-id")
if err != nil {
// TODO: Handle error.
}
// getCursor represents a function that returns a cursor from a previous
// iteration in string form.
cursorString := getCursor()
cursor, err := datastore.DecodeCursor(cursorString)
if err != nil {
// TODO: Handle error.
}
it := client.Run(ctx, datastore.NewQuery("Post").Start(cursor))
_ = it // TODO: Use iterator.
}