Why am I getting no data from my Azure SignalR Service back to my KendoUI Grid? - asp.net-core

Question

I'm using a KendoUI Grid in my ASP.NET Core 5 application. The grid is SignalR enabled and my application is hosted in Azure. I also use the Azure SignalR Service to handle the hubs which is what is recommended by the documentation.
I have 4 hubs powering my 4 different grids and yet, none of them are receiving data back from the SignalR Service in Azure it seems and I have no idea what is wrong. The grids seem to load, missing data, I can see the negotiations in the console with signalR and they return 200 OK. However, there is just no data being returned.
I'm not sure if it's a problem with the way I've set up my application or my Azure SignalR Service.
Here is how I have implemented the Azure SignalR Service in my application.
Startup.cs (ConfigureServices)
public IConfiguration Configuration { get; }
// This method gets called by the runtime. Use this method to add services to the container.
public void ConfigureServices(IServiceCollection services)
{
var mvcBuilder = services.AddControllersWithViews(options => {
var policy = new AuthorizationPolicyBuilder()
.RequireAuthenticatedUser()
.Build();
options.Filters.Add(new AuthorizeFilter(policy));
});
mvcBuilder.AddMicrosoftIdentityUI().AddJsonOptions(options =>
{
//Use the default property (Pascal) casing.
options.JsonSerializerOptions.PropertyNamingPolicy = null;
});
services.AddRazorPages();
services.AddSignalR(options => {
//Debug only
options.EnableDetailedErrors = true;
}).AddAzureSignalR()
.AddJsonProtocol(options =>
{
//Prevents signalr converting all text to lower case.
options.PayloadSerializerOptions.PropertyNamingPolicy = null;
});
//Kendo
services.AddKendo();
services.AddHealthChecks();
}
Startup.cs (Configure)
public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
//Localization needed for date formats on datepickers
var supportedCultures = new[] {
new CultureInfo("en-GB")
};
//Localization set to En GB for datetime using the above supported cultures
app.UseRequestLocalization(new RequestLocalizationOptions
{
DefaultRequestCulture = new RequestCulture("en-GB"),
SupportedCultures = supportedCultures,
SupportedUICultures = supportedCultures
});
app.UseHttpsRedirection();
app.UseStaticFiles();
app.UseRouting();
app.UseAuthentication();
app.UseAuthorization();
app.UseEndpoints(endpoints =>
{
endpoints.MapHealthChecks("/healthcheck");
endpoints.MapControllerRoute("default", "{controller=Home}/{action=Index}/{id?}");
});
app.UseAzureSignalR(endpoints =>
{
endpoints.MapHub<RequirementHub>("/requirementHub");
endpoints.MapHub<PositionHub>("/positionHub");
endpoints.MapHub<FixtureHub>("/fixtureHub");
endpoints.MapHub<NewswireHub>("/newswireHub");
});
}
I am using SignalR installed in my client library in it's latest version.
libman.js
{
"provider": "unpkg",
"library": "#microsoft/signalr#latest",
"destination": "wwwroot/vendor/signalr/",
"files": [
"dist/browser/signalr.js",
"dist/browser/signalr.min.js"
]
},
I have hub controllers for each of my grids that uses SignalR. I have shown the code for one of the hub controllers but they are all structured exactly the same, the only thing that changes is the name of the repository they are getting data from.
RequirementHub
using MyCompany.Data;
using MyCompany.Repo;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.SignalR;
using System;
using System.Collections.Generic;
using System.Threading.Tasks;
namespace MyCompany.UI.Hubs
{
public class RequirementHub : Hub
{
private readonly IRepository<Requirement> _requirement;
public RequirementHub(IRepository<Requirement> requirement)
{
_requirement = requirement;
}
public override Task OnConnectedAsync()
{
Groups.AddToGroupAsync(Context.ConnectionId, GetGroupName());
return base.OnConnectedAsync();
}
public override Task OnDisconnectedAsync(Exception e)
{
Groups.RemoveFromGroupAsync(Context.ConnectionId, GetGroupName());
return base.OnDisconnectedAsync(e);
}
public IEnumerable<Requirement> Read()
{
var data = _requirement.GetAll();
return data;
}
public async Task Update(Requirement model)
{
await _requirement.UpdateAsync(model);
await Clients.OthersInGroup(GetGroupName()).SendAsync("update", model);
}
public string GetGroupName()
{
return GetRemoteIpAddress();
}
public string GetRemoteIpAddress()
{
return Context.GetHttpContext()?.Connection.RemoteIpAddress.ToString();
}
}
}
This now brings us to the grid itself. Here is the code for the requirement grid, again, there are 4 grids and they are all structured the same but with different names and referencing their respective hubs.
Home.cshtml
<div id="requirement-grid"></div>
<script>
$('#requirement_grid').kendoGrid({
dataSource: {
type: "signalr",
autoSync: true,
pageSize: 20,
sort: [
{
field: "Id",
dir: "desc"
}
],
schema: {
model: {
id: "Id",
fields: {
"Id": {
editable: false,
nullable: true
}
}
}
},
transport: {
signalr: {
promise: requirement_hub_start,
hub: requirement_hub,
server: {
read: "read",
update: "update",
create: "create",
destroy: "destroy"
},
client: {
read: "read",
update: "update",
create: "create",
destroy: "destroy"
}
}
},
autoBind: true,
reorderable: true,
sortable: true,
pageable: {
pageSize: 30,
refresh: true
},
columns: [
{
field: "Id"
}
]
});
</script>
You'll notice that the promise and hub are defined as requirement_hub_start and requirement_hub the code for those lives in its own JavaScript file as:
hubs.js
//Hub URL
var requirement_url = "/requirementHub";
var fixture_url = "/fixtureHub";
var position_url = "/positionHub";
var newswire_url = "/newswireHub";
//Connection Builder
var requirement_hub = new signalR.HubConnectionBuilder().withUrl(
requirement_url, {
transport: signalR.HttpTransportType.LongPolling
}).build();
var position_hub = new signalR.HubConnectionBuilder().withUrl(
position_url, {
transport: signalR.HttpTransportType.LongPolling
}).build();
var fixture_hub = new signalR.HubConnectionBuilder().withUrl(
fixture_url, {
transport: signalR.HttpTransportType.LongPolling
}).build();
var newswire_hub = new signalR.HubConnectionBuilder().withUrl(
newswire_url, {
transport: signalR.HttpTransportType.LongPolling
}).build();
//Hub Start
var position_hub_start = position_hub.start({
json: true
});
var requirement_hub_start = requirement_hub.start({
json: true
});
var fixture_hub_start = fixture_hub.start({
json: true
});
var newswire_hub_start = newswire_hub.start({
json: true
});
I looked at the documentation and have placed my SignalR Service connection string in my appsettings.json (until I can get this working):
appsettings.json
"Azure": {
"SignalR": {
"ConnectionString": "Endpoint=https://mycompanysignalr.service.signalr.net;AccessKey=xxx=;Version=1.0;",
"Enabled": "true"
}
}
Additionally, I have ensured that web sockets are switched ON in my Azure web app which was another recommendation of the documentation. I'm a little confused at this point, I've been over my setup 100 times and I can't see anything obvious that could be preventing data coming back.
Is there another step I need to follow or have I done something wrong? Has anyone had this problem before?

Answer 1

Please check the Signalr ConnectionStrings in your appsettings.json. You can copy it from azure portal and replace it, then try.
The above suggestion is to consider whether you have used different Signalr ConnectionStrings from the Dev environment to the production environment, which caused this problem.
In addition, what pricing tier are you using? If you use Free tier, azure signalr service will limit your use.
That will happen, you have no problem at the beginning, the program is normal, and when the limit is exceeded, the program will be abnormal. At the beginning of the next day, it can be used for a while. This is a restriction given by the Free pricing tier.