/// <summary>
/// Create new node in the Graph for
/// </summary>
public async Task UpdatGraphForNewVideo(YouTubeVideoAdded video)
{
String videoId = video.VideoId.ToGuid().ToString();
String userId = video.UserId.ToGuid().ToString();
Logger.Information("{user} Inserting video {video} to graph", userId, videoId);
// Create Traversal to add a Vertex Video, Edge 'upload from user to Vide, and Tags
var traversal = DseGraph.Traversal(_session)
// Creating Video Vertex based on ID
.CreateOrUpdateVideoVertex(
videoId,
video.Name,
video.Description,
video.PreviewImageLocation
)
// Edge User -- Uploaded --> Video
.CreateEdgeUploadedForUserAndVideo(userId);
// Add Tags Vertices and edges to video
foreach (string tag in video.Tags)
{
traversal.CreateTagVertexAndEdgeToVideo(tag);
}
await _session.ExecuteGraphAsync(traversal);
}
/// <summary>
/// Gets the personalized video suggestions for a specific user.
/// Based on DSL tutorial provided here, we changed the recommendation from pre-aggration
/// tables to real-time graph recommendation.
/// https://academy.datastax.com/content/gremlin-dsls-net-dse-graph
/// </summary>
public override async Task <GetSuggestedForUserResponse> GetSuggestedForUser(GetSuggestedForUserRequest request,
ServerCallContext context)
{
Logger.Information("Request suggested video(s) for user {user}", request.UserId.Value);
GraphTraversalSource g = DseGraph.Traversal(_session);
// DSL Baby !
var traversal = g.RecommendVideos(request.UserId.ToGuid().ToString(), 5, 4, 1000, 5);
GraphResultSet result = await _session.ExecuteGraphAsync(traversal);
// Building GRPC response from list of results vertices (hopefully 'numberOfVideosExpected')
var grpcResponse = new GetSuggestedForUserResponse
{
UserId = request.UserId,
PagingState = ""
};
foreach (IVertex vertex in result.To <IVertex>())
{
Logger.Information("Result " + vertex);
grpcResponse.Videos.Add(MapVertexToVideoPreview(vertex));
}
return(grpcResponse);
}
public async Task RateVideoInGraph(String videoId, String userId, int rating)
{
var traversal = DseGraph.Traversal(_session).V(); //Added V() here so it doesn't fail
//TODO Not sure what is expected here
// .UserRateVideo(userId, videoId, rating);
await _session.ExecuteGraphAsync(traversal);
}
public async Task With_GraphSON2_It_Should_Retrieve_Vertex_Instances()
{
var statement = new SimpleGraphStatement("{\"@type\": \"g:Bytecode\", \"@value\": {" +
" \"step\": [[\"V\"], [\"hasLabel\", \"person\"]]}}");
statement.SetGraphLanguage(GraphSON2Language);
var rs = await _session.ExecuteGraphAsync(statement).ConfigureAwait(false);
var results = rs.ToArray();
Assert.Greater(results.Length, 0);
foreach (var graphNode in results)
{
var vertex = graphNode.ToVertex();
Assert.AreEqual("person", vertex.Label);
}
}
/// <summary>
/// Create new node in the Graph for
/// </summary>
public async Task AddUserVertexToGraph(UserCreated user)
{
String userId = user.UserId.ToGuid().ToString();
Logger.Information("Inserting to graph Vertext user {user} ", userId);
// Create Traversal
var traversal = DseGraph.Traversal(_session)
.CreateUserVertex(userId, user.Email);
// Add Vertex 'user' with expected properties asynchronously
await _session.ExecuteGraphAsync(traversal);
}
public async Task RateVideoInGraph(String videoId, String userId, int rating)
{
var traversal = DseGraph.Traversal(_session)
.UserRateVideo(userId, videoId, rating);
await _session.ExecuteGraphAsync(traversal);
}