public async Task <long> GetCountAsync(string key,
CancellationToken cancellationToken)
{
using (_tracer.StartSpan(nameof(GetCountAsync)))
{
var callSettings = CallSettings.FromCancellationToken(
cancellationToken);
var query = new Query(_options.Value.Kind)
{
Filter = Filter.GreaterThan("__key__", _keyFactory.CreateKey(key)),
Order = { { "__key__", PropertyOrder.Types.Direction.Ascending } }
};
long count = 0;
var lazyResults = _datastore.RunQueryLazilyAsync(query,
callSettings: callSettings).GetAsyncEnumerator(cancellationToken);
while (await lazyResults.MoveNextAsync())
{
Entity entity = lazyResults.Current;
if (!entity.Key.Path.First().Name.StartsWith(key))
{
break;
}
count += (long)entity[COUNT];
}
return(count);
}
}
public async Task LazyGqlQueryAsync()
{
string projectId = _fixture.ProjectId;
string namespaceId = _fixture.NamespaceId;
// Snippet: RunQueryLazilyAsync(GqlQuery,*,*)
DatastoreDb db = DatastoreDb.Create(projectId, namespaceId);
GqlQuery gqlQuery = new GqlQuery
{
QueryString = "SELECT * FROM book WHERE author = @author",
NamedBindings = { { "author", new GqlQueryParameter {
Value = "Jane Austen"
} } },
};
AsyncLazyDatastoreQuery results = db.RunQueryLazilyAsync(gqlQuery);
// AsyncLazyDatastoreQuery implements IAsyncEnumerable<Entity>, but you can
// call AsResponses() to see the raw RPC responses, or
// GetAllResultsAsync() to get all the results into memory, complete with
// the end cursor and the reason for the query finishing.
await results.ForEachAsync(entity =>
{
Console.WriteLine(entity);
});
// End snippet
// This will run the query again, admittedly...
List <Entity> entities = await results.ToList();
Assert.Equal(1, entities.Count);
Entity book = entities[0];
Assert.Equal("Jane Austen", (string)book["author"]);
Assert.Equal("Pride and Prejudice", (string)book["title"]);
}
public async Task LazyStructuredQueryAsync()
{
string projectId = _fixture.ProjectId;
string namespaceId = _fixture.NamespaceId;
// Snippet: RunQueryLazilyAsync(Query,*,*)
DatastoreDb db = DatastoreDb.Create(projectId, namespaceId);
Query query = new Query("book")
{
Filter = Filter.Equal("author", "Jane Austen")
};
AsyncLazyDatastoreQuery results = db.RunQueryLazilyAsync(query);
// AsyncLazyDatastoreQuery implements IAsyncEnumerable<Entity>, but you can
// call AsResponses() to see the raw RPC responses, or
// GetAllResultsAsync() to get all the results into memory, complete with
// the end cursor and the reason for the query finishing.
await results.ForEachAsync(entity =>
{
Console.WriteLine(entity);
});
// End snippet
// This will run the query again, admittedly...
List <Entity> entities = await results.ToListAsync();
Assert.Equal(1, entities.Count);
Entity book = entities[0];
Assert.Equal("Jane Austen", (string)book["author"]);
Assert.Equal("Pride and Prejudice", (string)book["title"]);
}