So now that Angular 2 is in beta I have been using observables on the client side and I have been using ASP.NET Core Web API on the server side. My question is if I want to display a value on my website as that value changes I understand how to do it on the client side with Observables, but how do I use Observables with a Web API service on the server?
Thanks for your time....
If I understand your question correcly, you can use Refit , to generate the implementation of an interface that returns an IObservable from a REST API.
For the example below, an interface is declared for the /users/{user} REST API. The return type is an IObservable and when you compile this, Refit generates the implementation.
public interface IRestAPI
{
// Returns the raw response, as an IObservable that can be used with the
// Reactive Extensions
[Get("/users/{user}")]
IObservable<HttpResponseMessage> GetUser(string user);
}
To initialize it, you do something like this:
var api = RestService.For<IRestAPI>("http://api.example.com/users");
Related
I'm working on a service fabric project with multiple stateless services. When i try to add versioning as in the code below
[Authorize]
[ApiVersion("2.0")]
[Route("api/v{version:apiVersion}/[controller]")]
public class SessionController : Controller
{
...
}
it's not working when calling the service later using Postman or using some client winforms app i made just to call this service. And when i say it's not working i mean it's not looking for a specific version i placed in the controller.
e.g.
I'm calling http://localhost:1234/api/v1.0/session/set-session and as you can see in my controller i only have version 2.0. Now my API gets hit this way or another no matter what version number i put in.
I added code to the Startup.cs
services.AddApiVersioning(options => {
options.DefaultApiVersion = new ApiVersion(2, 0);
options.AssumeDefaultVersionWhenUnspecified = true;
options.ReportApiVersions = true;
options.ApiVersionReader = new HeaderApiVersionReader("x-api-version");
});
Specific API call looks like this:
[HttpPost]
[Route("set-session")]
public async Task<IActionResult> SetSession([FromBody] SessionModel model)
{ ... }
Can anyone tell me what am i missing or maybe api versioning is not supported in service fabric at all?
Thanks.
Does your solution work locally? Based on what I see, I would suspect - no. This should have nothing to do with Service Fabric at all.
Issue 1
I see that your base class inherits from Controller, which is allowed, but is usually ControllerBase. No concern there, just FYI. The crux of the problem is likely that your controller has not applied the [ApiController] attribute. API Versioning defines IApiControllerSpecification and IApiControllerFilter, which is used to filter which controllers should be considered an API. This is important for developers building applications that have the UI and API parts mixed. A controller is a controller in ASP.NET Core and it was difficult to distinguish these two in the early days. There is now a built-in IApiControllerSpecification that considers any controller with [ApiController] applied to be an API. This can be changed, replaced, or completely disabled using ApiVersioningOptions.UseApiBehavior = false.
If your library/application is only APIs, you can decorate all controllers at once using:
[assembly: ApiController]
Since your controller is not currently being considered an API, all requests matching the route are being directed there. The value 1.0 is being considered an arbitrary string rather than an API version. This is why it matches at all instead of HTTP 400. I suspect you must only have one API and it is defined as 2.0; otherwise, I would expect an AmbiguousActionException.
Issue 2
Your example shows that you are trying to version by URL segment, but you've configured the options to only consider the header x-api-version. This option should be configured with one of the following:
URL Segment (only)
options.ApiVersionReader = new UrlSegmentApiVersionReader();
URL Segment and Header
// registration order is irrelevant
options.ApiVersionReader = ApiVersionReader.Combine(
new UrlSegmentApiVersionReader(),
new HeaderApiVersionReader("x-api-version"));
Default (Query String and URL Segment)
// NOTE: this is the configuration
// options.ApiVersionReader = ApiVersionReader.Combine(
// new QueryStringApiVersionReader(),
// new UrlSegmentApiVersionReader());
Side Note
As defined, using the URL segment and header versioning methodologies don't make sense. You have a single route which requires an API version. A client will always have to include the API version in every request so there is no point to also supporting a header.
If you define 2 routes, then it makes sense:
[Route("api/[controller]")] // match by header
[Route("api/v{version:apiVersion}/[controller]")] // match by url segment
Versioning by URL segment, while common, is the least RESTful. It violates the Uniform Interface constraint. This issue demonstrates yet another problem with that approach. Query string, header, media type, or any combination thereof will all work with the single route template of: [Route("api/[controller]")]
Observation 1
You have configured options.AssumeDefaultVersionWhenUnspecified = true. This will have no effect when versioning by URL segment. It is impossible to provide a default value of route parameter in the middle of a template. The same would be true for api/value/{id}/subvalues if {id} is not specified.
This option will have an effect if you:
Add a second route template that doesn't have the API version parameter
You update your versioning strategy to not use a URL segment
It should be noted that is a highly abused feature. It is meant to grandfather in existing services that didn't previously have explicit versioning because adding it will break existing clients. You should be cognizant of that if that isn't your use case.
As you know Visual Studio provides scaffolding for MVC and Web API controllers. In my case I'm using Entity Framework along with Web API 2.
When I add a new web api 2 controller with actions using Entity Framework, Visual Studio pretty much creates a controller with 5 endpoints.
One of these endpoints is to retrieve a single record from the database.
Here is an example for that:
// GET: api/Courses/5
[ResponseType(typeof(Course))]
public async Task<IHttpActionResult> GetCourse(int id)
{
Course course = await _db.Courses.FindAsync(id);
if (course == null)
{
return NotFound();
}
return Ok(course);
}
The above controller works fine if I call it as api/Courses/5, but it also works fine if I call it as api/Courses?id=5.
My question is, if I add an empty Web API 2 controller, define these methods manually along with some other endpoints, I can either call the endpoint like the first call or the second call, but not both.
Is there a way to set up routing of an endpoint which would accept both options?
PS: I know how to separately set up routing for each of above options. My question is whether it is possible to set up for both.
I want to convert our existing WCF REST web services to ASP.NET Web APIso I started to look into it.
Getting one of my function (i.e. login) up and running in ASP.NET Web API was quite straight forward but there is one thing I'm confused about and I hope one of you can clarify this for me.
In our WCF REST web service, our login (POST) function was called as follows:
http://localhost/mywebsite/mywebservice.svc/Authentication/Login
We'd pass a LoginRequest to it and we'd get a LoginResponse back.
Now in ASP.NET Web API, I've our Login (POST) function is being called as follows:
http://localhost/api/authentication and I'm passing the same LoginRequest and I get the same LoginResponse.
My confusion is, how does ASP.NET Web API know to use the Login function which is defined in the AuthenticationController?
I assume it has something to do with the parameter type being passed but what if I have another function that has the same parameter type, how would it differentiate between the 2?
For example, what if I had a LocalLogin and CloudLogin (not the case btw) and both require the LoginRequest as an input parameter and both return the LoginResponse, how would it know which one to call since it's not part of the URI?
Thanks.
I have a web application which has few charts on dashboard. The data for charts is fetched on document.ready function at client side invoking a WCF service method.
What i want is now to use SignalR in my application. I am really new to SignalR. How can i call WCF methods from SignalR Hub or what you can say is that instead of pulling data from server i want the WCF service to push data to client every one minute.
Is there a way of communication between signalR and WCF service.
Also another approach can be to force client to ask for data from WCF Service every minute.
Any help will be really appreciated.
I have done following as of yet.
Client Side Function on my Dashboard page
<script src="Scripts/jquery.signalR-2.0.3.min.js"></script>
<!--Reference the autogenerated SignalR hub script. -->
<script src="/signalr/hubs"></script>
<a id="refresh">Refresh</a>
$(function() {
var dashboardHubProxy = $.connection.dashboardHub;
$.connection.hub.start().done(function() {
// dashboardHubProxy.server.refreshClient(parameters);
$("#refresh").click(function() {
dashboardHubProxy.server.refreshClient(parameters);
});
});
dashboardHubProxy.client.refreshChart = function (chartData) {
debugger;
DrawChart(chartData, 'Hourly Call Count For Last ' + Duration + ' Days', '#chartHourly', 'StackedAreaChart');
};
});
and my Dashboard Hub class is as follows
public class DashboardHub : Hub
{
private readonly ReportService ReportService = new ReportService();
public void RefreshClient(string parameters)
{
var chartData = ReportService.GenerateHourlyCallsTrendGraphicalReport(parameters);
Clients.All.refreshChart(chartData);
}
}
My SignalR startup class is as follows
[assembly: OwinStartup(typeof(CallsPortalWeb.Startup), "Configuration")]
namespace CallsPortalWeb
{
public static class Startup
{
public static void Configuration(IAppBuilder app)
{
ConfigureSignalR(app);
}
public static void ConfigureSignalR(IAppBuilder app)
{
app.MapSignalR();
}
}
}
When i click on refresh button and a debugger on RefreshClient method on hub the debugger doesn't get to the method which means i am unable to call server side method of SignalR.
Is there anything needs to be done in web.config?
I agree with AD.Net's comment. To elaborate slightly more though, the SignalR hubs can be hosted directly in your web project kinda the same way controllers are used. There is also a package out there so you can host the SignalR library on its own so it can act as a service all on its own. Either way you will need to hit the SignalR hub first as that is how it communicates then you would call your WCF service methods from within the hubs.
Brief explanation
Your HUB will have methods used by both your USER Client and your WCF Client. You may use something like UserConnected() for the user to call in and setup your logging of the connection. Then the WCF service may call your HUB with an UpdateUserStats(Guid connnectionId, UserStats stats) which would in turn call the USER client directly and provide the stats passed in like so Clients.Client(connectionId).updateStats(stats) which in turn would have a method on the USERS client named updateStats() that would handle the received information.
Initial page landing
What AD.Net provided is basic code that will be called when the user lands on the page. At this point you would want to log the ConnectionId related to that user so you can directly contact them back.
First contact with your hub touching WCF
From your Hub, you could call your WCF service as you normally would inside any normal C# code to fetch your data or perform action and return it to your user.
Method of updating the user periodically
SignalR removes the need for your client code to have to continually poll the server for updates. It is meant to allow you to push data out to the client with out them asking for it directly. This is where the persistence of the connections come into play.
You will probably want to create a wrapper to easily send messages to the hub from your application, since you are using WCF I would assume you have your business logic behind this layer so you will want the WCF service reaching out to your Hub whenever action X happens. You can do that by utilizing the Client side C# code as in this case your client is actually the user and the WCF service. With a chat application the other user is basically doing what you want your WCF service to do, which is send a message to the other client.
Usage example
You are running an online store. The dashboard displays how many orders there have been for the day. So you would wire up a call to the hub to send a message out to update the products ordered when a user places a new order. You can do this by sending it to the admin group you have configured and any admins on the dashboard would get the message. Though if these stats are very user specific, you will more then likely instead reach into the database, find the ConnectionId that the user has connected with and send the update message directly to that connectionid.
WCF Client Code Example
Just incase you want some code, this is directly from MS site on connecting with a .net client. You would use this in your WCF service, or wherever in your code you plan on connecting and then sending an update to your user.
var hubConnection = new HubConnection("http://www.contoso.com/");
IHubProxy stockTickerHubProxy = hubConnection.CreateHubProxy("StockTickerHub");
stockTickerHubProxy.On<Stock>("UpdateStockPrice", stock => Console.WriteLine("Stock update for {0} new price {1}", stock.Symbol, stock.Price));
await hubConnection.Start();
Here is a link directly to the .Net Client section: http://www.asp.net/signalr/overview/signalr-20/hubs-api/hubs-api-guide-net-client
I am sure you have seen this link but it really holds all the good information you need to get started. http://www.asp.net/signalr
Here is a more direct link that goes into usages with code for you. http://www.asp.net/signalr/overview/signalr-20/hubs-api/hubs-api-guide-server
ADDED: Here is a blog specific to Dashboards with SignalR and their polling.
http://solomon-t.blogspot.com/2012/12/signalr-and-interval-polling-for.html
ADDED: Here is a page on managing users signalR connections.
http://www.asp.net/signalr/overview/signalr-20/hubs-api/mapping-users-to-connections
Update for your code update
The .Net Client library (in NuGet) gives your .net code access to the hub. Since you are a client you will need to connect to the hub just like the User who is also a client. Your hub would act as the server for this. So with the .Net Client I am assuming you would setup a windows service that would internally poll, or something event based that would call the .Net Client code portion of it which would reach out to your hub. Your hub would take the information provided, more than likely a ConnectionId or GroupId and broad cast the User (which is perhaps on a website so it would be the JS client) a method that would update the front end for the user client. Basically what I mention under "Brief Explanation".
Now, to directly respond to the code you posted. That is Javascript, I would expect a connect like you have done. Updating the chart on initial connection is fine as well. If this is all the code signalR wise though you are missing a client side method to handle the refresh. Technically, instead of calling Clients.Caller.RefreshChart() you could just return that data and use it, which is what your javascript is doing right now. You are returning void but it is expecting a your date.
Now, I would actually say correct your javascript instead of correcting the hub code. Why? Because having a method in JS on your client that is called "refreshChart()" can be reused for when you are having your server reach out and update the client.
So I would recommend, dropping anything that is related to updating the dashboard in your JS done statement. If you want to do a notification or something to the user that is fine but dont update the grid.
Now create a JS client function called "refreshChart", note the lower case R, you can call it with a big R in c# but the js library will lowercase it so when you make the function have it will receive your dashboard information.
Now, on the server polling, or executing on some action, your WCF would call a method on the hub that would be say "UpdateDashboar(connectionId,dashInfo)" and that method would then inside of it call the "refreshChart" just like you are doing in your RefreshClient method, accept instead of doing Clients.Caller you would use Clients.Client(connectionId).refreshChart(chartInfo).
Directly the reason your code is not working is because you need to turn that Void into the type you expect to be returned. If the rest is coded right you will have it update once. You will need to implement the other logic I mentioned if you want it constantly updating. Which is again why I asked about how you are persisting your connections. I added a link to help you with that if you are not sure what I am talking about.
You should use the SignalR Hub to push data to the client. Your hub can consume a WCF service (the same way your client can) to get the data.
from client:
hub.VisitingDashBoard();
on the hub in the VisitingDashBoard method:
var data = wcfClient.GetDashboardData()//may be pass the user id from the context
Clients.Caller.UpdateDashboard(data)
Of course your client will have a handler for UpdateDashboard call
if I send a request, and I expect the response to come trough SignalR, is it possible to test this using a LoadTest or PerformanceTest in Visual Studio?
Short answer: Yes
I've done this several times in CodedWebTests but it would also be possible to do in a declarative WebTest. You can use a custom PreWebTest Event Handler to create your signalR client and connect to your SignalR hub. What you choose to do with the signalR notification is up to you but I like to save it to the WebTestContext as well as display it on the test results screen using the AddCommentToResult method.
The method below creates a hubConnection invokes the "addToGroup" function on the hub and then tells the client what to do when it receives a message.
using Microsoft.AspNet.SignalR.Client;
public class SignalRPlugin : WebtTestPlugin
{
public override void PreWebTest(object sender, PreWebTestEventArgs e)
{
var hubConnection = new HubConnection("yourSignalRUrl");
var hubProxy = hubConnection.CreateHubProxy("notifications");
hubConnection.Start().Wait();
hubProxy.Invoke("addToGroup", "me");
hubProxy.On<string>("message", s =>
{
e.Webtest.AddCommentToResult(s);
e.Webtest.Context.Add("signalRMessages", s);
});
}
}
Use it by attaching the event handler in your test constructor.
public MyWebTest()
{
PreWebTest += new SignalRPlugin().PreWebTest;
}
Then once you have the signalR messages you can use a custom validation rule to validate that the response was received. Just have a while loop checking the WebTestContext for the "signalRMessages" key. I strongly suggest making sure you add a timeout feature so you are not waiting forever if the messages never come in.
The other option if you are writing CodedWebTests is to create a WaitForNotifications method that basically does the same thing as the validation rule. The advantage with this is that you can use an extraction rule to get data out of the last response and then use that data in validating your signalR messages. If you still need to fail a test in your WaitForNotification method use WebTest.InternalSetOutcome(Outcome.Fail);
The best way to load test a SignalR application is by building on the crank project included in the source.
This is a simple ramp up solution built with the .Net client but it is relatively easy to modify to call whatever hub methods you require and to analyse the responses.
You can always attach the Visual Studio profiler to your iis express instance to get detailed profiling data if required.