/// <summary>
/// Fetches document snapshots from the server, based on an optional transaction ID.
/// </summary>
/// <param name="documents">The document references to fetch. Must not be null, or contain null references.</param>
/// <param name="transactionId">A transaction ID, or null to not include any transaction ID.</param>
/// <param name="fieldMask">The field mask to use to restrict which fields are retrieved. May be null, in which
/// case no field mask is applied, and the complete documents are retrieved.</param>
/// <param name="cancellationToken">A cancellation token for the operation.</param>
/// <returns>The document snapshots, in the order they are provided in the response. (This may not be the order of <paramref name="documents"/>.)</returns>
internal async Task <IList <DocumentSnapshot> > GetDocumentSnapshotsAsync(IEnumerable <DocumentReference> documents, ByteString transactionId, FieldMask fieldMask, CancellationToken cancellationToken)
{
GaxPreconditions.CheckNotNull(documents, nameof(documents));
var request = new BatchGetDocumentsRequest
{
Database = RootPath,
Documents = { documents.Select(ExtractPath) },
Mask = fieldMask?.ToProto()
};
if (transactionId != null)
{
request.Transaction = transactionId;
}
var stream = Client.BatchGetDocuments(request, CallSettings.FromCancellationToken(cancellationToken));
using (var responseStream = stream.ResponseStream)
{
List <DocumentSnapshot> snapshots = new List <DocumentSnapshot>();
// Note: no need to worry about passing the cancellation token in here, as we've passed it into the overall call.
// If the token is cancelled, the call will be aborted.
while (await responseStream.MoveNext().ConfigureAwait(false))
{
var response = responseStream.Current;
var readTime = Timestamp.FromProto(response.ReadTime);
switch (response.ResultCase)
{
case BatchGetDocumentsResponse.ResultOneofCase.Found:
snapshots.Add(DocumentSnapshot.ForDocument(this, response.Found, readTime));
break;
case BatchGetDocumentsResponse.ResultOneofCase.Missing:
snapshots.Add(DocumentSnapshot.ForMissingDocument(this, response.Missing, readTime));
break;
default:
throw new InvalidOperationException($"Unknown response type: {response.ResultCase}");
}
}
return(snapshots);
}
string ExtractPath(DocumentReference documentReference)
{
GaxPreconditions.CheckArgument(documentReference != null, nameof(documents), "DocumentReference sequence must not contain null elements.");
return(documentReference.Path);
}
}
internal async Task <QuerySnapshot> GetSnapshotAsync(ByteString transactionId, CancellationToken cancellationToken)
{
var responses = StreamResponsesAsync(transactionId, cancellationToken);
Timestamp?readTime = null;
List <DocumentSnapshot> snapshots = new List <DocumentSnapshot>();
await responses.ForEachAsync(response =>
{
if (response.Document != null)
{
snapshots.Add(DocumentSnapshot.ForDocument(Database, response.Document, Timestamp.FromProto(response.ReadTime)));
}
if (readTime == null && response.ReadTime != null)
{
readTime = Timestamp.FromProto(response.ReadTime);
}
}, cancellationToken).ConfigureAwait(false);
GaxPreconditions.CheckState(readTime != null, "The stream returned from RunQuery did not provide a read timestamp.");
return(new QuerySnapshot(this, snapshots.AsReadOnly(), readTime.Value));
}
private ChangeSet ExtractChanges(Timestamp readTime)
{
ChangeSet changeSet = new ChangeSet();
foreach (var entry in _changeMap)
{
if (entry.Value == null)
{
if (_documentSet.TryGetDocument(entry.Key, out var document))
{
changeSet.Deletes.Add(document);
}
}
else
{
DocumentSnapshot snapshot = DocumentSnapshot.ForDocument(_query.Database, entry.Value, readTime);
var list = _documentSet.Contains(entry.Key) ? changeSet.Updates : changeSet.Adds;
list.Add(snapshot);
}
}
return(changeSet);
}
/// <summary>
/// Fetches document snapshots from the server, based on an optional transaction ID.
/// </summary>
/// <param name="documents">The document references to fetch. Must not be null, or contain null references.</param>
/// <param name="transactionId">A transaction ID, or null to not include any transaction ID.</param>
/// <param name="fieldMask">The field mask to use to restrict which fields are retrieved. May be null, in which
/// case no field mask is applied, and the complete documents are retrieved.</param>
/// <param name="cancellationToken">A cancellation token for the operation.</param>
/// <returns>The document snapshots, in the order they are provided in the response. (This may not be the order of <paramref name="documents"/>.)</returns>
internal async Task <IList <DocumentSnapshot> > GetDocumentSnapshotsAsync(IEnumerable <DocumentReference> documents, ByteString transactionId, FieldMask fieldMask, CancellationToken cancellationToken)
{
GaxPreconditions.CheckNotNull(documents, nameof(documents));
var request = new BatchGetDocumentsRequest
{
Database = RootPath,
Documents = { documents.Select(ExtractPath) },
Mask = fieldMask?.ToProto()
};
if (transactionId != null)
{
request.Transaction = transactionId;
}
var clock = Client.Settings.Clock ?? SystemClock.Instance;
var scheduler = Client.Settings.Scheduler ?? SystemScheduler.Instance;
var callSettings = _batchGetCallSettings.WithCancellationToken(cancellationToken);
// This is the function that we'll retry. We can't use the built-in retry functionality, because it's not a unary gRPC call.
// (We could potentially simulate a unary call, but it would be a little odd to do so.)
// Note that we perform a "whole request" retry. In theory we could collect some documents, then see an error, and only
// request the remaining documents. Given how rarely we retry anyway in practice, that's probably not worth doing.
Func <BatchGetDocumentsRequest, CallSettings, Task <List <DocumentSnapshot> > > function = async(req, settings) =>
{
var stream = Client.BatchGetDocuments(req, settings);
using (var responseStream = stream.ResponseStream)
{
List <DocumentSnapshot> snapshots = new List <DocumentSnapshot>();
// Note: no need to worry about passing the cancellation token in here, as we've passed it into the overall call.
// If the token is cancelled, the call will be aborted.
while (await responseStream.MoveNext().ConfigureAwait(false))
{
var response = responseStream.Current;
var readTime = Timestamp.FromProto(response.ReadTime);
switch (response.ResultCase)
{
case BatchGetDocumentsResponse.ResultOneofCase.Found:
snapshots.Add(DocumentSnapshot.ForDocument(this, response.Found, readTime));
break;
case BatchGetDocumentsResponse.ResultOneofCase.Missing:
snapshots.Add(DocumentSnapshot.ForMissingDocument(this, response.Missing, readTime));
break;
default:
throw new InvalidOperationException($"Unknown response type: {response.ResultCase}");
}
}
return(snapshots);
}
};
var retryingTask = RetryHelper.Retry(function, request, callSettings, clock, scheduler);
return(await retryingTask.ConfigureAwait(false));
string ExtractPath(DocumentReference documentReference)
{
GaxPreconditions.CheckArgument(documentReference != null, nameof(documents), "DocumentReference sequence must not contain null elements.");
return(documentReference.Path);
}
}
internal IAsyncEnumerable <DocumentSnapshot> StreamAsync(ByteString transactionId, CancellationToken cancellationToken) => StreamResponsesAsync(transactionId, cancellationToken) .Where(resp => resp.Document != null) .Select(resp => DocumentSnapshot.ForDocument(Database, resp.Document, Timestamp.FromProto(resp.ReadTime)));
