Eric lippert - Amazon Web Services

while ((line = Console.ReadLine()) != null)
{
if (int.TryParse(line, out customerId))
{
var customer = await myHub.Invoke(“Get”,
customerId);
if (customer == null) Console.WriteLine(“No customer
found”);
else Console.WriteLine(“Server found a customer with
name {0}”, customer.Name);
}
}
}
the web interface, we see that the console application is notified
when a new customer is added and then prints the amount of
customers. The count is taken from the parameter that is sent to
the action while the data is passed all the way from the SignalR
hub.
Because marking void methods asynchronous is a very bad
practice, we’ve set it to return a task so that we can follow the
operation if we’d like to. The method will read a line from the
command line and try to parse it as an integer, then it will either
tell us the customer name or tell us that there are no customers
at all.
Fire up both the console application and the website and first
ask for a customer before you’ve added a customer, then add a
customer in the web interface and ask again as you can see in the
Figure below:
Figure 8
Connecting to the Hub in WinRT using HTML & JavaScript
We’ve seen how to connect to hubs using a web based
client as well as a normal .NET application running in Windows,
but what about Windows 8, more specifically WinRT
Unfortunately it’s not as simple as just including the JavaScript
on the server in a WinRT application because WinRT Applications
don’t allow loading external resources. But it’s not too difficult
either.
We’d also like the console application to subscribe to the event
where the client is notified when a customer is added. This is
easily done through the hub proxy just as we did with the
invocation of a method, but this time we use the method called
On instead. This method defines that we are listening for a certain
message. The first parameter is the message that we are
listening to and the second is the action to run when the message
is received.
This needs to be added before we start the connection and the
code looks like this:
myHub.On(“RefreshCustomers”, (customers) => {
Console.WriteLine(“New customers added, total amount
of customers {0}”, customers.Count);
});
If we run this as you see in Figure 8 and add some customers in
First off create a new blank JavaScript
Windows Store application, you can call this
MyWinRTHubClient. We can’t simply install
SignalR using NuGet this time, instead we
need to manually add some necessary files.
We need the following files for it to work,
these can be copied from the server project
we created earlier:
• jquery.signalR-1.0.1.min.js
• jquery-1.6.4.min.js
Copy these files over to the js directory in the Windows Store
project and reference them in the default HTML file created for
the project. The JavaScript that we’re adding is really not that
different from what we saw in the normal web-browser client; we
can even use the same HTML!
When the document has finished loading, we want to create a hub
connection and create a proxy for the SignalR server. This looks
similar to what we saw before, but notice that it’s not entirely the
same:
var connection = $.hubConnection(‘http://localhost:3448/’);
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