Brushing skills on SignalR for ASP.NET developers

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SignalR With ASP.NET MVC

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Introduction
• What is SignalR?
• Why do we need it?
• Where can we use it?
• How does it work?
• SignalR backplanes

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What is SignalR?
WHAT

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SignalR?
• Real-time, open-source library, persistent connection
abstraction over HTTP for .NET
• Simple and powerful API’s
• Many techniques use to keep the logical connection up,
including retry logic if transport fail.
• Scaleout back plans.

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Why do we need signalR?
WHY

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• SignalR provides a simple API for creating server-to-client
remote procedure call(RPC) that call javascript functions in
client browsers from server-side .NET code.
• SignalR also includes API for connection management(for
instance, connect and disconnect events). It handle connection
management automatically.

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• It can reach out to thousands of clients using service bus, SQL
server or Redis cache.
• Abstract away the network layer for bidirectional real-time
communications, thus helping developers focus on building the
application.

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Where can we use it?
WHERE

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Where can we use it?
• Dashboards
• Monitoring
• Job progress
• Real-time form
• Web games/ Chat rooms
• Trading

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How does it work?
HOW

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How does it work?

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How does it work?
Order of network transports:-
HTML 5 Transports:-
• WebSockets
• Server Sent Events
Comet Transports (long-held HTTP request):-
• Forever Frame
• Ajax Long Polling

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How does it work?
WebSockets
• A new HTML5 API enables bi-directional, full-duplex
communication between the browser and the server.
• It is the new standard defined as a part of HTML 5 to solve
two major problems of the current web:
- Overhead of HTTP (Network Throughput)
- Low Latency

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How does it work?
Server sent event
• A technology, where a browser receives automatic updates
from a server via an HTTP connection, the Server-Sent Events
EventSource API is standardized as part of HTML5.
• The situation was also possible before, but the web page
would seek updates. With server-sent events, the updates
come automatically.
• It supports all major browsers, except Internet Explorer.

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How does it work?
Forever Frame
● Forever Frame creates a hidden IFrame which requests to an
endpoint on the server that does not complete. The server then
continually sends a script to the client which is immediately
executed, providing a one-way realtime connection from server to
client.

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Forever Frame continued..
● The connection from the client to server uses a separate
attachment from the server to client connection, and like a
standard HTML request, creates a new link for each piece of
data sent.

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How does it work?
Ajax Long Polling
• Long polling does not create a persistent connection, but instead
polls the server with a request that stays open until the server
responds, at which point the connection closes, and a new
connection is requested immediately.
• This may introduce some latency while the connection resets.

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How does it work?
• Fallback.

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How does it work?
SignalR API & Architecture
The SignalR API contains two models for communicating between
clients and servers: Persistent Connections & Hubs Connection
Persistent Connections
• Low level access to communication.
• Direct developer access to network pipeline.
• Access to lot more communication events.
• Will be familiar to developers who have used connection-based
APIs such as WCF.

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How does it work?
Hubs
• High level abstraction
• Built on top of Persistent Connections
• Least developer work.
• Works for majority of user.
• Will be familiar to developers who have used remote invocation
APIs such as .Net Remoting.

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How does it work?

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How does it work?

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How does it work?
Demo Link
https://sahilsaini.azurewebsites.net/

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How does it work?
Selecting which clients will receive the RPC
• Clients.All.refresh(message); // All connected clients
• Clients.Caller.refresh(message); // Only the calling client
• Clients.others.refresh(message); // All clients except the calling
client
• Clients.Client(Context.ConnectionId).refresh(message); // A specific
client identified by connection ID

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How does it work?
Selecting which clients will receive the RPC
• clients.AllExcept(connectionId1,
connectionId2).refresh(message); // All connected clients except
the specified clients, identified by connection ID.
• clients.Group(groupName).refresh(message); // All connected
clients in a specified group.
• clients.Group(groupName).refresh(message); // All connected
clients in a specified group.

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SignalR Backplanes
Backplane is basically for forward messages between servers in
scaleout environments.
Why we need it?
When you application scale out, clients can get routed to different
servers. A client that is connected to one server will not receive
messages sent from another server.

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SignalR Backplanes

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SignalR Backplanes
SignalR currently provides three backplanes:
• Azure Service Bus
• Redis
• SQL Server

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SignalR Backplanes
SignalR scaleout with SQL Server:

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SignalR Backplanes
SignalR scaleout with SQL Server:
• Install Microsoft.AspNet.SignalR.SqlServer package to signalR
application.
• Write below code in startup file:-
public void Configuration(IAppBuilder app)
{
// Any connection or hub wire up and configuration should go here
string sqlConnectionString = "Connecton string to your SQL DB";
GlobalHost.DependencyResolver.UseSqlServer(sqlConnectionString);
app.MapSignalR();
}

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SignalR Backplanes
SignalR scaleout with Redis:
• Install Microsoft.AspNet.SignalR.StackExchangeRedis package to
web application
• Write below code in Startup file:-

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SignalR Backplanes
SignalR scaleout with Azure service bus:
• Install Microsoft.AspNet.SignalR.ServiceBus package to web
application

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Azure SignalR
WHAT is Azure SignalR
• Azure SignalR Service simplifies the process of adding real-time web
functionality to applications over HTTP.
• This real-time functionality allows the service to push content
updates to connected clients, such as a single page web or mobile
application.
• Fully managed service.

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Azure SignalR
Benefits using Azure SignalR Service
• Standard based
• Native ASP.NET Core support
• Broad client support
• Handle large-scale client connections
• Remove the burden to self-host SignalR

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Azure SignalR
How to use Azure signalR
• Install Microsoft.Azure.SignalR.AspNet to web application

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Azure SignalR
How to use Azure signalR

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Azure SignalR
Demo Link
https://testazuresignalr.azurewebsites.net/

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Thank You
THANK YOU

Brushing skills on SignalR for ASP.NET developers

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