I have need to crate new thread for process external service call. In my module controller.
I need to insert id of created content item to thread method and use Orchard Services.
My situation:
¨
public async Task<ActionResult> CreateApplication(Apply postApply)
{
if (ModelState.IsValid)
{
var myItem = this._services.ContentManager.New("Zadosti");
dynamic dynContentItem = myItem;
dynContentItem.Zadosti.Jmeno.Value = postApply.Name;
dynContentItem.Zadosti.Prijmeni.Value = postApply.SureName;
this._services.ContentManager.Publish(myItem);
// I need to get ID of created content item and call method in new thread
CallMethodInNewThread(idOdContentItem);
}
}
CallMethodInNewThread(int id){
// External service async CALL -> wait for response
// Get content item with "id" from DB
// Update and save content item
}
Thanks for any help !
Related
services.AddHeaderPropogation(o =>
{
o.Headers.Add("Id")
o.Headers.Add("Id", context => {
return new StringValues(Guid.NewGuid().ToString())
});
});
The above code helps me to create a header called id if it doesnt exist with a new guid and if it exists, it would just use the value. This is using Microsoft Header Propogation nuget package. And it works.
But now i have a requirement to add this to Azure Application insights, but the standard way of doiing it only works when the incoming request has headers. If the new GUID is created, it doesnt trigger the ITelemetryInitializer call.
Because for adding Telmetry custom values, we have a class which inherits ITelemtryInitializer and inside that i do call to Request.Headers like below:
var requestTelemetry = telemetry as RequestTelemetry
if(context.Request.Headers.TryGetValue(id, out var value))
requestTelemtry.Properties[id] = value.ToString()
But the above line is never triggered since the Request.Headers never had this id. This id will be created only by the middleware when the api calls the next service.
So my question, is there a way to call the telemetry classes from the Startup> ConfigfureServices and inside the HeaderPropogation code, so that as soon as the new GUID is created, i can add it to telemtry. All the examples of adding to telemetry shows either from controller or DI. How to call it from the Startup itself ?
Or is there a better way to achieve the same ?
Let me post the solution I found. I didnt need to have a telemetryinitializer class to populate the guid in another class. I wanted it to be added as soon as we create it, so this is how i modified th header propogiation code in services in startup.
services.AddHeaderPropagation(options =>
{
var correlationId = "YourId";
options.Headers.Add(correlationId, context => {
var requestTelemetry = context.HttpContext.Features.Get<RequestTelemetry>();
if (context.HttpContext.Request.Headers.TryGetValue(correlationId, out var value))
{
requestTelemetry.Properties[correlationId] = value.ToString();
return value.ToString();
}
else
{
var guidId = Guid.NewGuid().ToString();
requestTelemetry.Properties[correlationId] = guidId;
return new StringValues(guidId);
}
});
});
Key for me has been the realization i can get RequestTelemetry anywhere we want in the code with this properties option.
var requestTelemetry = context.HttpContext.Features.Get<RequestTelemetry>();
So i'm testing with Blazor and gRPC and my dificulty at the moment is on how to pass the content of a variable that is on a class, specifically the gRPC GreeterService Class to the Blazor page when new information arrives. Notice that my aplication is a client and a server, and i make an initial comunication for the server and then the server starts to send to the client data(numbers) in unary mode, every time it has new data to send. I have all this working, but now i'm left it that final implementation.
This is my Blazor page
#page "/greeter"
#inject GrpcService1.GreeterService GreeterService1
#using BlazorApp1.Data
<h1>Grpc Connection</h1>
<input type="text" #bind="#myID" />
<button #onclick="#SayHello">SayHello</button>
<p>#Greetmsg</p>
<p></p>
#code {
string Name;
string Greetmsg;
async Task SayHello()
{
this.Greetmsg = await this.GreeterService1.SayHello(this.myID);
}
}
The method that later receives the communication from the server if the hello is accepted there is something like this:
public override async Task<RequestResponse> GiveNumbers(BalconyFullUpdate request, ServerCallContext context)
{
RequestResponse resp = new RequestResponse { RequestAccepted = false };
if (request.Token == publicAuthToken)
{
number = request.Number;
resp = true;
}
return await Task.FromResult(resp);
}
Every time that a new number arrives i want to show it in the UI.
Another way i could do this was, within a while condition, i could do a call to the server requesting a new number just like the SayHello request, that simply awaits for a server response, that only will come when he has a new number to send. When it comes the UI is updated. I'm just reluctant to do it this way because i'm afraid that for some reason the client request is forgotten and the client just sit's there waiting for a response that will never come. I know that i could implement a timeout on the client side to handle that, and on the server maybe i could pause the response, with a thread pause or something like that, and when the method that generates the new number has a new number, it could unpause the response to the client(no clue on how to do that). This last solution looks to me much more difficult to do than the first one.
What are your thoughts about it? And solutions..
##################### UPDATE ##########################
Now i'm trying to use a singleton, grab its instance in the Blazor page, and subcribe to a inner event of his.
This is the singleton:
public class ThreadSafeSingletonString
{
private static ThreadSafeSingletonString _instance;
private static readonly object _padlock = new object();
private ThreadSafeSingletonString()
{
}
public static ThreadSafeSingletonString Instance
{
get
{
if (_instance == null)
{
lock(_padlock)
{
if (_instance == null)
{
_instance = new ThreadSafeSingletonString();
_instance.number="";
}
}
}
return _instance;
}
set
{
_instance.number= value.number;
_instance.NotifyDataChanged();
}
}
public int number{ get; set; }
public event Action OnChange;
private void NotifyDataChanged() => OnChange?.Invoke();
And in Blazor page in code section i have:
protected override void OnInitialized()
{
threadSafeSingleton.OnChange += updateNumber();
}
public System.Action updateNumber()
{
this.fromrefresh = threadSafeSingleton.number + " que vem.";
Console.WriteLine("Passou pelo UpdateNumber");
this.StateHasChanged();
return StateHasChanged;
}
Unfortunatly the updatenumber function never gets executed...
To force a refresh of the ui you can call the StateHasChanged() method on your component:
https://learn.microsoft.com/en-us/dotnet/api/microsoft.aspnetcore.components.componentbase.statehaschanged?view=aspnetcore-3.1
Notifies the component that its state has changed. When applicable, this will cause the component to be re-rendered.
Hope this helps
Simple Request
After fully understanding that your problem is just to Update the Page not to get unsyncronous messages from the server with a bi directional connection. So jou just have to change your page like (please not there is no need to change the files generated by gRPC, I called it Number.proto so my service is named NumberService):
async Task SayHello()
{
//Request via gRPC
var channel = new Channel(Host + ":" + Port, ChannelCredentials.Insecure);
var client = new this.NumberService.NumberServiceClient(channel);
var request = new Number{
identification = "ABC"
};
var result = await client.SendNumber(request).RequestAccepted;
await channel.ShutdownAsync();
//Update page
this.Greetmsg = result;
InvokeAsync(StateHasChanged);//Required to refresh page
}
Bi Directional
For making a continious bi directional connection you need to change the proto file to use streams like:
service ChatService {
rpc chat(stream ChatMessage) returns (stream ChatMessageFromServer);
}
This Chant sample is from the https://github.com/meteatamel/grpc-samples-dotnet
The main challenge on this is do divide the task waiting for the gRPC server from the client. I found out that BackgroundService is good for this. So create a Service inherited from BackgroundService where place the while loop waiting for the server in the ExecuteAsyncmethod. Also define a Action callback to update the page (alternative you can use an event)
public class MyChatService : BackgroundService
{
Random _random = new Random();
public Action<int> Callback { get; set; }
protected override async Task ExecuteAsync(CancellationToken stoppingToken)
{
while (!stoppingToken.IsCancellationRequested)
{
// Replace next lines with the code request and wait for server...
using (_call = _chatService.chat())
{
// Read messages from the response stream
while (await _call.ResponseStream.MoveNext(CancellationToken.None))
{
var serverMessage = _call.ResponseStream.Current;
var otherClientMessage = serverMessage.Message;
var displayMessage = string.Format("{0}:{1}{2}", otherClientMessage.From, otherClientMessage.Message, Environment.NewLine);
if (Callback != null) Callback(displayMessage);
}
// Format and display the message
}
}
}
}
On the page init and the BackgroundService and set the callback:
#page "/greeter"
#using System.Threading
<p>Current Number: #currentNumber</p>
#code {
int currentNumber = 0;
MyChatService myChatService;
protected override async Task OnInitializedAsync()
{
myChatService = new MyChatService();
myChatService.Callback = i =>
{
currentNumber = i;
InvokeAsync(StateHasChanged);
};
await myChatService.StartAsync(new CancellationToken());
}
}
More information on BackgroundService in .net core can be found here: https://gunnarpeipman.com/dotnet-core-worker-service/
I'm hoping to use SignalR to provide updates to the client, the updates are going to come from a message table which is updated when things happen across the application..
My problem is that the application will have around 500-600 concurrent users and I cant have all them having a connection to the database and constantly polling against the table..
What id like to do is have a single thing{?} polling the table and then updating the hubs rather than each connection polling.. I was thinking of using a singleton for this? so maybe when the application starts something is created that will then do all the work really..
My question is - say I had a singleton that had an event which was fired every time there was an update.. what would the performance be like for say 500 controllers subscribing to this event?
Also.. if there is a better way to do this then pleases say.. this is my first and only idea sadly!
any help would be fantastic!
EDIT: the data is bring provided by a legacy application and I have no control over how the data is entered so database polling will be needed.
ste.
I'd rather not to poll the database as it would be wasteful. I would approach this problem by opening only one single point of entry for my data (an HTTP API, etc) and then broadcast the update to all connected clients through the SignalR Hub. Brad Wilson has a super cool presentation which demonstrate this approach:
Brad Wilson - Microsoft’s Modern Web Stack, Starring ASP.NET Web API
Here is a code sample for this approach which uses ASP.NET Web API technology for data entry. It uses in-memory dictionary for data store but the data storage technique is not the concern here:
// This hub has no inbound APIs, since all inbound communication is done
// via the HTTP API. It's here for clients which want to get continuous
// notification of changes to the ToDo database.
[HubName("todo")]
public class ToDoHub : Hub { }
public abstract class ApiControllerWithHub<THub> : ApiController
where THub : IHub {
Lazy<IHubContext> hub = new Lazy<IHubContext>(
() => GlobalHost.ConnectionManager.GetHubContext<THub>()
);
protected IHubContext Hub {
get { return hub.Value; }
}
}
public class ToDoController : ApiControllerWithHub<ToDoHub> {
private static List<ToDoItem> db = new List<ToDoItem> {
new ToDoItem { ID = 0, Title = "Do a silly demo on-stage at NDC" },
new ToDoItem { ID = 1, Title = "Wash the car" },
new ToDoItem { ID = 2, Title = "Get a haircut", Finished = true }
};
private static int lastId = db.Max(tdi => tdi.ID);
// Lines removed for brevity
public HttpResponseMessage PostNewToDoItem(ToDoItem item) {
lock (db) {
// Add item to the "database"
item.ID = Interlocked.Increment(ref lastId);
db.Add(item);
// Notify the connected clients
Hub.Clients.addItem(item);
// Return the new item, inside a 201 response
var response = Request.CreateResponse(HttpStatusCode.Created, item);
string link = Url.Link("apiRoute", new { controller = "todo", id = item.ID });
response.Headers.Location = new Uri(link);
return response;
}
}
// Lines removed for brevity
}
The full source code for the application which Brad demoed is also available: https://github.com/bradwilson/ndc2012.
The other option, which you don't prefer, is make your database to fire notifications as soon as data is changed. Then, you can pick that up and broadcast it through SignalR. Here is an example:
Database Change Notifications in ASP.NET using SignalR and SqlDependency
Sorry that this solution is not signalR, but maybe you can get ideas from it.
Here is the full example for download on GitHub
I am using MassTransit request and response with SignalR. The web site makes a request to a windows service that creates a file. When the file has been created the windows service will send a response message back to the web site. The web site will open the file and make it available for the users to see. I want to handle the scenario where the user closes the web page before the file is created. In that case I want the created file to be emailed to them.
Regardless of whether the user has closed the web page or not, the message handler for the response message will be run. What I want to be able to do is have some way of knowing within the response message handler that the web page has been closed. This is what I have done already. It doesnt work but it does illustrate my thinking. On the web page I have
$(window).unload(function () {
if (event.clientY < 0) {
// $.connection.hub.stop();
$.connection.exportcreate.setIsDisconnected();
}
});
exportcreate is my Hub name. In setIsDisconnected would I set a property on Caller? Lets say I successfully set a property to indicate that the web page has been closed. How do I find out that value in the response message handler. This is what it does now
protected void BasicResponseHandler(BasicResponse message)
{
string groupName = CorrelationIdGroupName(message.CorrelationId);
GetClients()[groupName].display(message.ExportGuid);
}
private static dynamic GetClients()
{
return AspNetHost.DependencyResolver.Resolve<IConnectionManager>().GetClients<ExportCreateHub>();
}
I am using the message correlation id as a group. Now for me the ExportGuid on the message is very important. That is used to identify the file. So if I am going to email the created file I have to do it within the response handler because I need the ExportGuid value. If I did store a value on Caller in my hub for the web page close, how would I access it in the response handler.
Just in case you need to know. display is defined on the web page as
exportCreate.display = function (guid) {
setTimeout(function () {
top.location.href = 'GetExport.ashx?guid=' + guid;
}, 500);
};
GetExport.ashx opens the file and returns it as a response.
Thank you,
Regards Ben
I think a better bet would be to implement proper connection handling. Specifically, have your hub implementing IDisconnect and IConnected. You would then have a mapping of connectionId to document Guid.
public Task Connect()
{
connectionManager.MapConnectionToUser(Context.ConnectionId, Context.User.Name);
}
public Task Disconnect()
{
var connectionId = Context.ConnectionId;
var docId = connectionManager.LookupDocumentId(connectionId);
if (docId != Guid.Empty)
{
var userName = connectionManager.GetUserFromConnectionId(connectionId);
var user = userRepository.GetUserByUserName(userName);
bus.Publish( new EmailDocumentToUserCommand(docId, user.Email));
}
}
// Call from client
public void GenerateDocument(ClientParameters docParameters)
{
var docId = Guid.NewGuid();
connectionManager.MapDocumentIdToConnection(Context.ConnectionId, docId);
var command = new CreateDocumentCommand(docParameters);
command.Correlationid = docId;
bus.Publish(command);
Caller.creatingDocument(docId);
}
// Acknowledge you got the doc.
// Call this from the display method on the client.
// If this is not called, the disconnect method will handle sending
// by email.
public void Ack(Guid docId)
{
connectionManager.UnmapDocumentFromConnectionId(connectionId, docId);
Caller.sendMessage("ok");
}
Of course this is from the top of my head.
I am trying to set up a mocking scenario for my payment processor on a web site. Normally, my site redirects to the processor site, where the user pays. The processor then redirects back to my site, and I wait for an immediate payment notification (IPN) from the processor. The processor then posts to my NotifyUrl, which routes to the Notify action on my payments controller (PayFastController). To mock, I redirect to a local action, which after a conformation click, spawns a thread to post the IPN, as if posted by the processor, and redirects back to my registration process.
My mock processor controller uses the following two methods to simulate the processor's response:
[HttpGet]
public RedirectResult Pay(string returnUrl, string notifyUrl, int paymentId)
{
var waitThread = new Thread(Notify);
waitThread.Start(new { paymentId, ipnDelay = 1000 });
return new RedirectResult(returnUrl);
}
public void Notify(dynamic data)
{
// Simulate a delay before PayFast
Thread.Sleep(1000);
// Delegate URL determination to the model, vs. directly to the config.
var notifyUrl = new PayFastPaymentModel().NotifyUrl;
if (_payFastConfig.UseMock)
{
// Need an absoluate URL here just for the WebClient.
notifyUrl = Url.Action("Notify", "PayFast", new {data.paymentId}, "http");
}
// Use a canned IPN message.
Dictionary<string, string> dict = _payFastIntegration.GetMockIpn(data.paymentId);
var values = dict.ToNameValueCollection();
using (var wc = new WebClient())
{
// Just a reminder we are posting to Trocrates here, from PayFast.
wc.UploadValues(notifyUrl, "POST", values);
}
}
However, I get an 'Object reference not set to an instance of an object.' exception on the following line:
notifyUrl = Url.Action("Notify", "PayFast", new {data.paymentId}, "http");
data.paymentId has a valid value, e.g. 112, so I'm not passing any null references to the Url.Action method. I suspect I have lost some sort of context somewhere by calling Notify on a new thread. However, if I use just notifyUrl = Url.Action("Notify", "PayFast");, I avoid the exception, but I get a relative action URL, where I need the overload that takes a protocol parameter, as only that overload gives me the absolute URL that WebClient.UploadValues says it needs.
When you are inside the thread you no longer have access to the HttpContext and the Request property which the Url helper relies upon. So you should never use anything that relies on HttpContext inside threads.
You should pass all the information that's needed to the thread when calling it, like this:
waitThread.Start(new {
paymentId,
ipnDelay = 1000,
notifyUrl = Url.Action("Notify", "PayFast", new { paymentId }, "http")
});
and then inside the thread callback:
var notifyUrl = new PayFastPaymentModel().NotifyUrl;
if (_payFastConfig.UseMock)
{
// Need an absoluate URL here just for the WebClient.
notifyUrl = data.notifyUrl;
}