Develop Reference

How to make use of IFormFile and attach it to the DTO to be sent to client in ASP.NET Core

I am writing a web app using .NET for the backend and React as client. I want to implement the authorization to a login form and thus made two model (DTOs) to send back to the client. One for the login and register respectively. I have an AccountController class where I am handling the Post and Get requests for the current user (user after logged in).
As mentioned above I have a model class named User and its UserDTO. Inside of that model class, I made some props (eg. username, password, profilePictureURL, email) etc. I want the user to upload an image which in turn will get appended to the profilePictureURL into the request back to the server.
This is my User model:
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Identity;
namespace API.Entities
{
public class User : IdentityUser
{
public IFormFile profilePhotoURL {get; set; }
public string Name { get; set; }
}
}
userName, email and phone numbers are being derived from IdentityUser class from .NET.
registerDTO
using Microsoft.AspNetCore.Http;
namespace API.DTOs
{
public class RegisterDTO : LoginDTO
{
public string Email { get; set; }
public string Name { get; set; }
public FormFile profilePhotoURL { get; set; }
public string PhoneNumber { get; set; }
}
}
Inside of AccountController, my POST method for registering is:
[HttpPost("register"), DisableRequestSizeLimit]
public async Task<IActionResult> RegisterUser(RegisterDTO registerDTO)
{
//getting the file from request
var postedProfile = Request.Form.Files[0];
// setting the Uploads folder
var Uploads = Path.Combine(Directory.GetCurrentDirectory(), "Uploads");
if (postedProfile.Length > 0)
{
var fileName = ContentDispositionHeaderValue.Parse(postedProfile.ContentDisposition).FileName.Trim();
var pathToSave = Path.Combine(Uploads, fileName.ToString());
using (var fileStream = new FileStream(pathToSave, FileMode.Create))
{
await postedProfile.CopyToAsync(fileStream);
}
Ok($"File Uploaded successfully");
}
else
{
return BadRequest(new ProblemDetails
{
Title = "400 - Bad Request",
Status = 400,
Detail = "File not uploaded"
});
}
var registeredUser = new User
{
UserName = registerDTO.userName,
Email = registerDTO.Email,
Name = registerDTO.Name,
profilePhotoURL = postedProfile,
PhoneNumber = registerDTO.PhoneNumber
};
var result = await _userManager.CreateAsync(registeredUser, registerDTO.Password);
if (!result.Succeeded)
{
foreach (var Error in result.Errors)
{
ModelState.AddModelError(Error.Code, Error.Description);
}
return ValidationProblem();
}
await _userManager.AddToRoleAsync(registeredUser, "Member");
return StatusCode(201);
}
I want to set the uploaded image into the profilePhotoURL property of my registerDTO class, but when on checking this in swagger, I get the following error:
The JSON value could not be converted to Microsoft.AspNetCore.Http.FormFile. Path: $.profilePhotoURL | LineNumber: 5 | BytePositionInLine: 36.
The above error is in the ModelState errors.
How could I make a method (inside of AccountController's POST request for registering a new user) to upload a file of type IFormFile and then set it inside of the User object?
All suggestions are welcome :)

Your backend was a webapi project, model binding get data from the request body(Json value) by default,but formfile get values from posted form fields.
If you could post a form in your react app,just create a model for the form and add the [FromForm]Attribute
[HttpPost("register"), DisableRequestSizeLimit]
public IActionResult RegisterUser([FromForm] RegisterModel registermodel)
{
return StatusCode(200);
}

Posting form file to ASP .NET Core API using AWS SDK Test Lambda Context and APIGatewayProxyRequest

I have an ASP .NET Core API endpoint which accepts the below model:
public class FileUploadModel
{
public IFormFile? File { get; set; }
public DateTime? Time { get; set; }
public string Comment { get; set; }
}
The project has been created via aws lambda template. I am trying to write a test scenario, which asserts the endpoint behavior when I am sending a request to it. For this purpose, I am using APIGatewayProxyFunction.
Below is the test function:
[Fact]
public async Task TestPost()
{
var lambdaFunction = new LambdaEntryPoint();
var requestStr = File.ReadAllText("./SampleRequests/Files-Post.json");
var request = JsonSerializer.Deserialize<APIGatewayProxyRequest>(requestStr, new JsonSerializerOptions
{
PropertyNameCaseInsensitive = true
});
request.Body = #"{""time"":""2022-04-27T20:00:00.000Z"",""comment"":""dummy comment""}";
// How to put file in request?
var context = new TestLambdaContext();
var response = await lambdaFunction.FunctionHandlerAsync(request, context);
Assert.Equal(200, response.StatusCode);
Assert.Equal(#"{""fileId"":""xxxxxxxxxx""}", response.Body);
}
My problem is that the APIGatewayProxyRequest accepts string as the request body, and I want to add a file to the request. How could I put a file alongside other inputs in the same request? Thanks

Save conversation history from MS bot to cosmos db

The bot I'm developing is a replacement for a contact form for potential clients that want to be contacted by a company, so the user inputs have to be saved in a database. I have successfully connected a Cosmos DB to my bot which collect the state data when the bot is used. I have a dialog stack with one dialog per user input (Name, email and the message the user want to leave).
I can't find any helpful documentation on how to save conversation history for bots written in C#. Can anyone help me out? I'm still a beginner in Bot Framework and C#.
Here is my global.asax file:
public class WebApiApplication : System.Web.HttpApplication
{
protected void Application_Start()
{
GlobalConfiguration.Configure(WebApiConfig.Register);
var uri = new Uri(ConfigurationManager.AppSettings["DocumentDbUrl"]);
var key = ConfigurationManager.AppSettings["DocumentDbKey"];
var store = new DocumentDbBotDataStore(uri, key);
Conversation.UpdateContainer(
builder =>
{
builder.Register(c => store)
.Keyed<IBotDataStore<BotData>>(AzureModule.Key_DataStore)
.AsSelf()
.SingleInstance();
builder.Register(c => new CachingBotDataStore(store, CachingBotDataStoreConsistencyPolicy.ETagBasedConsistency))
.As<IBotDataStore<BotData>>()
.AsSelf()
.InstancePerLifetimeScope();
});
}
}
Here is my NameDialog to collect the user's name: (the other dialogs are almost identical to this)
[Serializable]
public class NameDialog : IDialog<string>
{
private int attempts = 3;
public async Task StartAsync(IDialogContext context)
{
await context.PostAsync("What's your name?");
context.Wait(this.MessageReceivedAsync);
}
private async Task MessageReceivedAsync(IDialogContext context, IAwaitable<IMessageActivity> result)
{
var message = await result;
if ((message.Text != null) && (message.Text.Trim().Length > 0))
{
context.Done(message.Text);
}
else
{
--attempts;
if (attempts > 0)
{
await context.PostAsync("I couldn't understand, can you try again?");
context.Wait(this.MessageReceivedAsync);
}
else
{
context.Fail(new TooManyAttemptsException("This is not a valid input"));
}
}
}
}

I submitted a couple of comments asking for clarification in what you're looking for, but figured I may as well just provide an all-encompassing answer.
Use V4
If your bot is new, just use V4 of BotBuilder/BotFramework. It's easier, there's more features, and better support. I'll provide answers for both, anyway.
Saving Custom Data in V4
References:
Write directly to Storage-Cosmos
For custom storage where you specify the User Id:
// Create Cosmos Storage
private static readonly CosmosDbStorage _myStorage = new CosmosDbStorage(new CosmosDbStorageOptions
{
AuthKey = CosmosDBKey,
CollectionId = CosmosDBCollectionName,
CosmosDBEndpoint = new Uri(CosmosServiceEndpoint),
DatabaseId = CosmosDBDatabaseName,
});
// Write
var userData = new { Name = "xyz", Email = "xyz#email.com", Message = "my message" };
var changes = Dictionary<string, object>();
{
changes.Add("UserId", userData);
};
await _myStorage.WriteAsync(changes, cancellationToken);
// Read
var userDataFromStorage = await _myStorage.read(["UserId"]);
For User Data where the bot handles the Id:
See Basic Bot Sample.
Key parts:
Define the Greeting State
public class GreetingState
{
public string Name { get; set; }
public string City { get; set; }
}
Instantiate a State Accessor
private readonly IStatePropertyAccessor<GreetingState> _greetingStateAccessor;
[...]
_greetingStateAccessor = _userState.CreateProperty<GreetingState>(nameof(GreetingState));
[...]
Dialogs.Add(new GreetingDialog(_greetingStateAccessor));
Save UserState at the end of OnTurnAsync:
await _userState.SaveChangesAsync(turnContext);
Greeting Dialog to Get and Set User Data
var greetingState = await UserProfileAccessor.GetAsync(stepContext.Context, () => null);
[...]
greetingState.Name = char.ToUpper(lowerCaseName[0]) + lowerCaseName.Substring(1);
await UserProfileAccessor.SetAsync(stepContext.Context, greetingState);
Saving Full Conversation History in V4
References:
Conversation History Sample
Transcript Storage Docs
Just read the docs and look at the sample for this one. Too much code to copy/paste.
Saving Custom Data in V3
References:
Manage custom data storage
BotState Class Reference
Using Azure Table Storage with Cosmos
Sample showing how to store UserData
I'll copy/paste the code from this good answer to a similar question on StackOverflow, for posterity:
public class WebChatController : Controller
{
public ActionResult Index()
{
var connectionString = ConfigurationManager.ConnectionStrings["StorageConnectionString"].ConnectionString;
CloudStorageAccount storageAccount = CloudStorageAccount.Parse(connectionString);
CloudTableClient tableClient = storageAccount.CreateCloudTableClient();
CloudTable table = tableClient.GetTableReference("BotStore");
string userId = Guid.NewGuid().ToString();
TableQuery<BotDataRow> query = new TableQuery<BotDataRow>().Where(TableQuery.GenerateFilterCondition("PartitionKey", QueryComparisons.Equal, userId));
var dataRow = table.ExecuteQuery(query).FirstOrDefault();
if(dataRow != null)
{
dataRow.Data = Newtonsoft.Json.JsonConvert.SerializeObject(new
{
UserName = "This user's name",
Email = "whatever#email.com",
GraphAccessToken = "token",
TokenExpiryTime = DateTime.Now.AddHours(1)
});
dataRow.Timestamp = DateTimeOffset.UtcNow;
table.Execute(TableOperation.Replace(dataRow));
}
else
{
var row = new BotDataRow(userId, "userData");
row.Data = Newtonsoft.Json.JsonConvert.SerializeObject(new
{
UserName = "This user's name",
Email = "whatever#email.com",
GraphAccessToken = "token",
TokenExpiryTime = DateTime.Now.AddHours(1)
});
row.Timestamp = DateTimeOffset.UtcNow;
table.Execute(TableOperation.Insert(row));
}
var vm = new WebChatModel();
vm.UserId = userId;
return View(vm);
}
public class BotDataRow : TableEntity
{
public BotDataRow(string partitionKey, string rowKey)
{
this.PartitionKey = partitionKey;
this.RowKey = rowKey;
}
public BotDataRow() { }
public bool IsCompressed { get; set; }
public string Data { get; set; }
}
}
Saving User Data:
See State API Bot Sample
Saving Full Conversation History in V3
References:
Blog post for saving conversation history to a SQL Server
Sample that uses Middleware to log all activity
Intercept messages docs
Basically, you want to first capture all activity using IActivityLogger, like in the sample just above:
Create DebugActivityLogger
public class DebugActivityLogger : IActivityLogger
{
public async Task LogAsync(IActivity activity)
{
Debug.WriteLine($"From:{activity.From.Id} - To:{activity.Recipient.Id} - Message:{activity.AsMessageActivity()?.Text}");
// Add code to save in whatever format you'd like using "Saving Custom Data in V3" section
}
}
Add the following to Global.asax.cs:
public class WebApiApplication : System.Web.HttpApplication
{
protected void Application_Start()
{
var builder = new ContainerBuilder();
builder.RegisterType<DebugActivityLogger>().AsImplementedInterfaces().InstancePerDependency();
builder.Update(Conversation.Container);
GlobalConfiguration.Configure(WebApiConfig.Register);
}
}

C# Cast FormData to an Object

I'm posting a file and a json object to my API using angularjs. I'm able to get all the data from the server (file and model object):
public async Task<IHttpActionResult> send()
{
var path = HttpContext.Current.Server.MapPath("~/uploads");
var provider = new MultipartFormDataStreamProvider(root);
var result = await Request.Content.ReadAsMultipartAsync(provider);
var modelFromClient = result.FormData["model"];
}
The modelFromClient i receive has this format : "model":"{\"name\":\"James\",\"comments\":\"test\"}
But i want to cast the modelFromClient json to my user model which is :
public User {
public string name{ get; set; }
public string comments{ get; set; }
}
So at the end, i want to be able to get my attributes like i used to do when i send the object explicitly trought the url :
public async Task<IHttpActionResult> add(User user) {
// here, my user object will have all the values that i set in my client side and i get them like this :
user.name;
user.comments;
...// other attributes
// Save the object in dataBase
user.Save();
}
I hope you understand my need

If you are in control of the client json, then perhaps you could omit the model field and just send the content like so:
{
"name": "james",
"comments": "test"
}
This would allow you to use your existing controller implementation "as-is".
If however, the client json is out of your control, then you need to deserialize it into a model that is representative of the json. Changing your model to the following would likely work:
public Model
{
public User model { get; set; }
}
Because you are reading out the raw json from the request, you can deserialize it manually before calling add() directly
And then your controller would change to this (Assumes Json.Net is referenced):
public async Task<IHttpActionResult> send()
{
var path = HttpContext.Current.Server.MapPath("~/uploads");
var provider = new MultipartFormDataStreamProvider(root);
var result = await Request.Content.ReadAsMultipartAsync(provider);
var modelFromClient = result.FormData["model"];
var clientModel = JsonConvert.Deserialize<Model>(modelFromClient);
return await add(clientModel.user);
}
public async Task<IHttpActionResult> add(User user)
{
//Do whatever you need with user
//Save the object in database
user.Save();
}

How to implement "user interactive" dependency injection in ASP MVC

I have a full engine that relies on abstractions based on user interactions. This works great with WPF/Xamarin app, cause I can implements this abstractions with window/form.
I have a little problem for porting this engine into ASP MVC.
A simple example can be show as this.
Abstraction interface (simplified)
public interface IQuestionBox
{
Task<bool> ShowYesNoQuestionBox(string message);
}
For WPF, it's really simple, I implement this interface as return the result of a window by calling ShowDialog().
In a simple business class, I can have this kind of calls (simplified) :
public async Task<string> GetValue(IQuestionBox qbox)
{
if(await qbox.ShowYesNoQuestionBox("Question ?"))
{
return "Ok";
}
return "NOk";
}
I really don't see how can I implement this kind of behavior in ASP, due to stateless of HTTP, knowing that this kind of call can be as various as domain/business need. The way I think it should be done is by returning a PartialView to inject into popup, but I don't see how to do this without breaking all the process ...
Anyone has ever done this ?

as I've said, I strongly doesn't recommend this pratice, but its possible, bellow the code that allows to do it, let's go:
To become it's possible I abused the use from TaskCompletionSource, this class allow us to set manually result in a task.
First we need to create a structure to encapsulate the process:
public class Process
{
// this dictionary store the current process running status, you will use it to define the future answer from the user interaction
private static Dictionary<string, Answare> StatusReport = new Dictionary<string, Answare>();
// this property is the secret to allow us wait for the ShowYesNoQuestion call, because til this happen the server doesn't send a response for the client.
TaskCompletionSource<bool> AwaitableResult { get; } = new TaskCompletionSource<bool>(true);
// here we have the question to interact with the user
IQuestionBox QuestionBox { get; set; }
// this method, receive your bussiness logical the receive your question as a parameter
public IQuestionBox Run(Action<IQuestionBox> action)
{
QuestionBox = new QuestionBox(this);
// here we create a task to execute your bussiness logical processment
Task.Factory.StartNew(() =>
{
action(QuestionBox);
});
// and as I said we wait the result from the processment
Task.WaitAll(AwaitableResult.Task);
// and return the question box to show the messages for the users
return QuestionBox;
}
// this method is responsable to register a question to receive future answers, as you can see, we are using our static dictionary to register them
public void RegisterForAnsware(string id)
{
if (StatusReport.ContainsKey(id))
return;
StatusReport.Add(id, new Answare()
{
});
}
// this method will deliver an answer for this correct context based on the id
public Answare GetAnsware(string id)
{
if (!StatusReport.ContainsKey(id))
return Answare.Empty;
return StatusReport[id];
}
// this method Releases the processment
public void Release()
{
AwaitableResult.SetResult(true);
}
// this method end the process delivering the response for the user
public void End(object userResponse)
{
if (!StatusReport.ContainsKey(QuestionBox.Id))
return;
StatusReport[QuestionBox.Id].UserResponse(userResponse);
}
// this method define the answer based on the user interaction, that allows the process continuing from where it left off
public static Task<object> DefineAnsware(string id, bool result)
{
if (!StatusReport.ContainsKey(id))
return Task.FromResult((object)"Success on the operation");
// here I create a taskcompletaionsource to allow get the result of the process, and send for the user, without it would be impossible to do it
TaskCompletionSource<object> completedTask = new TaskCompletionSource<object>();
StatusReport[id] = new Answare(completedTask)
{
HasAnswared = true,
Value = result
};
return completedTask.Task;
}
}
After that the question implementation
public interface IQuestionBox
{
string Id { get; }
Task<bool> ShowYesNoQuestionBox(string question);
HtmlString ShowMessage();
}
class QuestionBox : IQuestionBox
{
Process CurrentProcess { get; set; }
public string Id { get; } = Guid.NewGuid().ToString();
private string Question { get; set; }
public QuestionBox(Process currentProcess)
{
CurrentProcess = currentProcess;
CurrentProcess.RegisterForAnswer(this.Id);
}
public Task<bool> ShowYesNoQuestionBox(string question)
{
Question = question;
CurrentProcess.Release();
return AwaitForAnswer();
}
public HtmlString ShowMessage()
{
HtmlString htm = new HtmlString(
$"<script>showMessage('{Question}', '{Id}');</script>"
);
return htm;
}
private Task<bool> AwaitForAnswer()
{
TaskCompletionSource<bool> awaitableResult = new TaskCompletionSource<bool>(true);
Task.Factory.StartNew(() =>
{
while (true)
{
Thread.Sleep(2000);
var answare = CurrentProcess.GetAnswer(this.Id);
if (!answare.HasAnswered)
continue;
awaitableResult.SetResult(answare.Value);
break;
}
});
return awaitableResult.Task;
}
}
The differences for yours implementaion are:
1 - I create an Identifier to know for who I have to send the aswer, or just to stop the process.
2 - I receive a Process as parameter, because this allows us to call the method
CurrentProcess.Release(); in ShowYesNoQuestion, here in specific, releases the process to send the response responsable to interact with the user.
3 - I create the method AwaitForAnswer, here one more time we use from the TaskCompletionSource class. As you can see in this method we have a loop, this loop is responsable to wait for the user interaction, and til receive a response it doesn't release the process.
4 - I create the method ShowMessage that create a simple html script alert to simulate the user interaction.
Then a simple process class as you should be in your bussiness logical:
public class SaleService
{
public async Task<string> GetValue(IQuestionBox qbox)
{
if (await qbox.ShowYesNoQuestionBox("Do you think Edney is the big guy ?"))
{
return "I knew, Edney is the big guy";
}
return "No I disagree";
}
}
And then the class to represent the user answer
public class Answer
{
// just a sugar to represent empty responses
public static Answer Empty { get; } = new Answer { Value = true, HasAnswered = true };
public Answer()
{
}
// one more time abusing from TaskCompletionSource<object>, because with this guy we are abble to send the result from the process to the user
public Answer(TaskCompletionSource<object> completedTask)
{
CompletedTask = completedTask;
}
private TaskCompletionSource<object> CompletedTask { get; set; }
public bool Value { get; set; }
public bool HasAnswered { get; set; }
// this method as you can see, will set the result and release the task for the user
public void UserResponse(object response)
{
CompletedTask.SetResult(response);
}
}
Now we use all the entire structure create for this:
[HttpPost]
public IActionResult Index(string parametro)
{
// create your process an run it, passing what you want to do
Process process = new Process();
var question = process.Run(async (questionBox) =>
{
// we start the service
SaleService service = new SaleService();
// wait for the result
var result = await service.GetValue(questionBox);
// and close the process with the result from the process
process.End(result);
});
return View(question);
}
// here we have the method that deliver us the user response interaction
[HttpPost]
public async Task<JsonResult> Answer(bool result, string id)
{
// we define the result for an Id on the process
var response = await Process.DefineAnswer(id, result);
// get the response from process.End used bellow
// and return to the user
return Json(response);
}
and in your view
<!-- Use the question as the model page -->
#model InjetandoInteracaoComUsuario.Controllers.IQuestionBox
<form asp-controller="Home" asp-action="Index">
<!-- create a simple form with a simple button to submit the home -->
<input type="submit" name="btnDoSomething" value="All about Edney" />
</form>
<!-- in the scripts section we create the function that we call on the method ShowMessage, remember?-->
<!-- this method request the action answer passing the questionbox id, and the result from a simple confirm -->
<!-- And to finalize, it just show an alert with the process result -->
#section scripts{
<script>
function showMessage(message, id) {
var confirm = window.confirm(message);
$.post("/Home/Answer", { result: confirm, id: id }, function (e) {
alert(e);
})
}
</script>
#Model?.ShowMessage()
}
As I've said, I realy disagree with this pratices, the correct should to write a new dll, to support the web enviroment, but I hope it help you.
I put the project on github to you can download an understand all the solution
I realy hope it can help you

You can create a web socket connection from client side to server side. And work with front-end content with web socket request. It could be implemented as following:
Client side:
$app = {
uiEventsSocket : null,
initUIEventsConnection : function(url) {
//create a web socket connection
if (typeof (WebSocket) !== 'undefined') {
this.uiEventsSocket = new WebSocket(url);
} else if (typeof (MozWebSocket) !== 'undefined') {
this.uiEventsSocket = new MozWebSocket(url);
} else {
console.error('WebSockets unavailable.');
}
//notify if there is an web socket error
this.uiEventsSocket.onerror = function () {
console.error('WebSocket raised error.');
}
this.uiEventsSocket.onopen = function () {
console.log("Connection to " + url + " established");
}
//handling message from server side
this.uiEventsSocket.onmessage = function (msg) {
this._handleMessage(msg.data);
};
},
_handleMessage : function(data){
//the message should be in json format
//the next line fails if it is not
var command = JSON.parse(data);
//here is handling the request to show prompt
if (command.CommandType == 'yesNo') {
var message = command.Message;
var result = confirm(message);
//not sure that bool value will be successfully converted
this.uiEventsSocket.send(result ? "true" : "false");
}
}
}
And init it from ready or load event:
window.onload = function() { $app.initUIEventsConnection(yourUrl); }
Note that you url should begin with ws:// instead of http:// and wss:// instead of https:// (Web Sockets and Web Sockets Secure).
Server side.
Here is a good article for how to setup web sockets at asp.net core application or you could find another one. Note that you should group web socket connections from single user and if you want to send a message to the concrete user, you should send message for every connection from this user.
Every web socket you should accept with AcceptWebSocketAsync() method call and then add instance of this web socket to singleton, which contains a set of web sockets connection groupped by user.
The following class will be used to operate commands:
public class UICommand
{
public string CommandType { get; set; }
public string Message { get; set; }
public Type ReturnType { get; set; }
}
And a full code of singleton for handling sockets
public class WebSocketsSingleton
{
private static WebSocketsSingleton _instance = null;
//here stored web sockets groupped by user
//you could use user Id or another marker to exactly determine the user
private Dictionary<string, List<WebSocket>> _connectedSockets;
//for a thread-safety usage
private static readonly ReaderWriterLockSlim Locker = new ReaderWriterLockSlim();
public static WebSocketsSingleton Instance {
get {
if (this._instance == null)
{
this._instance = new WebSocketsSingleton();
}
return this._instance;
}
}
private WebSocketsSingleton()
{
this._connectedSockets = new Dictionary<string, List<WebSocket>>();
}
/// <summary>
/// Adds a socket into the required collection
/// </summary>
public void AddSocket(string userName, WebSocket ws)
{
if (!this._connectedSockets.ContainsKey(userName))
{
Locker.EnterWriteLock();
try
{
this._connectedSockets.Add(userName, new List<WebSocket>());
}
finally
{
Locker.ExitWriteLock();
}
}
Locker.EnterWriteLock();
try
{
this._connectedSockets[userName].Add(ws);
}
finally
{
Locker.ExitWriteLock();
}
}
/// <summary>
/// Sends a UI command to required user
/// </summary>
public async Task<string> SendAsync(string userName, UICommand command)
{
if (this._connectedSockets.ContainsKey(userName))
{
var sendData = Encoding.UTF8.GetBytes(JsonConvert.SerializeObject(command));
foreach(var item in this._connectedSockets[userName])
{
try
{
await item.SendAsync(new ArraySegment<byte>(sendData), WebSocketMessageType.Text, true, CancellationToken.None);
}
catch (ObjectDisposedException)
{
//socket removed from front end side
}
}
var buffer = new ArraySegment<byte>(new byte[1024]);
var token = CancellationToken.None;
foreach(var item in this._connectedSockets[userName])
{
await Task.Run(async () => {
var tempResult = await item.ReceiveAsync(buffer, token);
//result received
token = new CancellationToken(true);
});
}
var resultStr = Encoding.Utf8.GetString(buffer.Array);
if (command.ReturnType == typeof(bool))
{
return resultStr.ToLower() == "true";
}
//other methods to convert result into required type
return resultStr;
}
return null;
}
}
Explanation:
on establishing connection from web socket it will be added with
AddSocket method
on sending request to show a message, the required command will be passed into SendAsync method
the command will be serialized to JSON (using Json.Net, however you could serialize in your way) and send to all sockets, related to the required user
after the command sent, application will wait for respond from front end side
the result will be converted to required type and sent back to your IQuestionBox
In the web socket handling your should add some kind of the following code:
app.Use(async (http, next) =>
{
if (http.WebSockets.IsWebSocketRequest)
{
var webSocket = await http.WebSockets.AcceptWebSocketAsync();
var userName = HttpContext.Current.User.Identity.Name;
WebSocketsSingleton.Instance.AddSocket(userName, webSocket);
while(webSocket.State == WebSocketState.Open)
{
//waiting till it is not closed
}
//removing this web socket from the collection
}
});
And your method implementation of ShowYesNoQuestionBox should be kind of following:
public async Task<bool> ShowYesNoQuestionBox(string userName, string text)
{
var command = new UICommand
{
CommandType = "yesNo",
Message = text,
ReturnType = typeof(bool)
};
return await WebSocketsSingleton.Instance.SendAsync(string userName, command);
}
Note that there should be added userName to prevent sending the same message to all of the connected users.
WebSocket should create the persistent connection between server and client sides, so you could simply send commands in two ways.
I am kindly new to Asp.Net Core, so the final implementation could be a bit different from this.

It's actually much the same, except your UI is sort of disconnected and proxied with the HTTP protocol for the most part.
you essentially need to build the same code as your WPF code but then in the browser construct ajax calls in to the controller actions to apply your logic.
To clarify ...
so lets say you are building up a process over a series of questions that based on the users answer you put different steps in to the process.
You can either ...
build the process in the database
build it in session on the server
build it on the client as a js object
then do a post for execution ofthe constructed process.
think of the "statelessness" as a series of short interactions, but the state you keep between them can be done either on the client, in a db or in the users logged in session on the web server.

In your controller you can add an ActionResult that will give you the html response to your jquery modal popup request. Here is an example
public class MController : Controller {
public ActionResult doWork(requirement IQuestionBox)
{
// model is already modelBound/IOC resolved
return PartialView("_doWork", requirement );
}
}
//scripts
$(function(){
$.ajax({
url:"/m/doWork",
type:"get",
success:function(data){
$modal.html(data); // bind to modal
}
});
});
Apologies for not fully understanding the question.
hope this helps!