Hi, this is possible ways and in
this video, I'm going to teach you how to write a simple, very
lean web socket server in C sharp using the console
application. And I'm also going to show you how to connect that
to all the previous clients and all the previous applications
that we have done in the previous videos on this playlist
fun with WebSockets. So, as usual, we're going to start by
simply starting a new Visual Studio project. And in I'm going
to create a new project. And it's going to be a console
application on the dotnet framework. So it's going to be
this one dotnet framework, I'm going to put it on my desktop,
and I'm going to call it C sharp, C sharp server, okay. And
it's going to be on the dotnet framework 4.5 bla bla bla. And
as I create this project, you can see that now I have this
folder on my server that is the on my on my desktop, which is
the server, and I can start writing code here. As we saw on
the previous video, I'm going to import the web socket library.
So that's I'm going to browse here and I'm going to type web
socket sharp. And I'm going to select this one, which I believe
is the one that the original one by the author of the of the
project. So I'm going to install this dependency. And then now in
my code, I can just import that dependency by typing using web
socket sharp. Okay. All right. The next thing that I'm going to
do is that because I'm writing a server, I actually need to
import another namespace, which contains code specifically for
WebSocket server stuff. So that's going to be within the
same library, web sockets sharp dot, you can see that I have a
server namespace that I'm going to need to import here. Okay. Wonderful. All right. So what is
next, the next thing that we're going to do is, we're going to
initialize this server. So the way we're going to do this is by
creating a web socket server instance. So I'm going to do new
webs website. So I'm going to do web socket server. And web
socket server is going to create a new variable. And I'm going to
initialize this web net, this WebSocket server with with the
URL where this is going to be leaving. Because this server is
going to be leaving on my machine, I don't need to give it
a name or domain, what I need to do is I need to specify that the
server is going to be the machine that this code is going
to be leaving on the way I do that is by typing localhost,
which is the nickname typically that we typically use for
referring to the machine where we live in. Or alternatively, I
could just type the zero there. 127 001, which is the IP that is
reserved, always for local host for the same machine where
you're living on. Alright. And now the second thing that we
want to do is I would like to assign a port, because it's going to live in
our machine, machines have different ports, which point to
different processes leaving on that machine. So I can just technically, what I should do is
I should use a port manager to check which ports on my local
machine are open or closed and are busy with other processes.
But I know that if I basically if I type a random number,
there's a very high chance that I'm not going to hit a port that
is being used. And if I do, I will get an error. So it's not
it's not a big deal. So I'm just going to choose 789 and zero.
Okay. And then what I'm going to do is I'm going to start this
server, and I'm going to type some message here, console
writeline. Server started on this address here. All right, just just for the
sake of having some feedback. And then to make sure that this
program stays alive because it's a console application. So we're
going to do as we typically do the trick of just requesting a
key before we stop the server.
Alright. So stop up. What am I doing?
Yes. So whenever the user presses any
key, then we will stop the server and we will shut down the
console application. So let's start this. If I start
this, and I'm going to make sure that this window shows up.
Always on the screen, you can see that the WebSocket server
has started at Nissan this address, blah, blah, blah. So I
wonder if I can use my previous code now to connect to this
server already. So what I'm going to do is I'm going to copy
this address right? I'm going to, I'm going to replace, what am I doing. So I'm going to
replace that with my address here, which was in my client. And it was this one here.
Alright. So I'm going to try to connect to the server. And turns
out that and the WebSocket server that I specified is not
really working. It's not really working, because I have not
really created any service, all my WebSocket server do to handle incoming connections.
What does that mean? What it means is that when you have a
server, you have to create some kind of Route, or you have to
create some kind of place where clients can go. And then where
different functionality have different behavior is served for
those clients. So remember, in previous examples, we were doing
an echo server that took information and then just send
the same information back to the server to the client. So in C
sharp, and with the web socket, sharp library, we have to do
something like that. And the way we do that is by extending and
subclassing, a very particular class that lives in WebSocket
charcoaled, the WebSocket server behavior, okay, that is little
confusing, perhaps maybe at the beginning. So let me show you
how that is done. What I'm going to do is I'm going to write a
new public class, that is going to be called, for example, Echo.
And what I'm going to do is, I'm going to make sure that I am
extending, I'm using as the template, I'm extending a web
socket, behavior class that comes with this library. So when
someone, whoever the author of this library was, what they did,
was they created this template that you can use to create your
own implementations of a behavior for the WebSocket
server. What does that mean? What it
means is now that we have the WebSocket behavior, what I can
do is I can override, override. And you can see, I can
override certain functions that come with the class. So for
example, on close on error on message on open, and this may
ring a bell. Because when we saw the client, we saw that we had
the event handlers that look very similar on close on error
message. So these are basically a way of doing event handling,
which is whenever I receive a message from the client, what I
want to do is whatever I want to do here, and what I want to do
probably is that I want to send, I'm going to write to the
console, for example, console writeline received message from
client on gram. And then I'm going to print which which I'm
going to print e dot data. And then what I want to do is I want
to send back to the client, the same message. So that's going to
be send that open parentheses d dot data. Okay. Are we all here? Does that make
sense? All right. So I think this behavior should work
already. But now what we need to do is we need to make sure that
these WebSocket server has that behavior somewhere attached to
it. The way we're going to do that is we're going to say,
we're going to use a slightly esoteric or strange syntax that
can't be the library, which is for to the WebSocket server,
we're going to add a web socket service. Alright. And you can
see that as I was autocompleting, you see that I
have the angle bracket notations. What that means is
that he needs a type to know what kind of service to attach
to this server. What I'm going to do is I'm going to attach the
echo class, which is the one that has the code that knows how
to run an how to handle the behavior of that server. And
then I'm going to open and close parentheses. And inside the
parentheses, I'm going to add a an extension to the route or to
the host of the WebSocket server, so that that particular
route is the one that has the particular Aiko behavior.
Alright, so let me show how that works. I'm going to open and
close double quotes, and I'm going to add a route with a
forward slash that I'm going to call a call. What that means is that any
client that goes to this URL, plus this route afterwards will
hit a website. conserver that has an Aiko
behavior. Okay? Does that make sense? So
I'm going to actually copy this here just for clarity. And then
I'm going to run this server, okay WebSocket server started on
this route. So I'm going to copy this route, actually, oops,
sorry, I close the I close the server, I'm going to copy this
route. And I'm going to bring it back to my client. So I'm going to here in my
client, remember when we will switch from the cloud server
with this to the local one. So now what I'm going to do here is
I'm going to add another an equal, this is going to be the
route. And I'm going to start this code. And what I'm good,
you can see that as I do, if I minimize here, the server did
receive a message from the client. Hello, from bootcamp.
And then the client received the echo
message from the server back. So hello from P Comm. And then he
didn't know what to do, because we were doing JSON parsing and
geometry, etc, etc. Does this does this make sense? So the way so the pattern, this
is what I will leave typically is technically referred to the
pattern that the web sockets sharp library offers for
creating servers is customizing behavior by extending a web
socket behavior class, and then attaching those behaviors to the
server under a particular route. Which is very interesting,
because it also means that we can add several behaviors to the
same WebSocket server, just the way in, which only differ in how
do we access them. So for example, code, that the code
that I've written here is great, but it doesn't really do what
we've done in the other examples, which is echoing one
message to all the clients that are connected to the server,
this, this server would only echo to the one client that is
connected to the server. And we can see that behavior. If, for
example, I go, we have here, the server. Now this is the clients,
I'm going to stop the client, we have the server, right. And then
what I'm going to do is, I'm going to go to my client folder,
and in the client folder, because I have executed I have
compiled in the the code in in debug, you can see that I
actually have an application that I can double click, which
is the C sharp client. So you see I double click on this, it
is open a client, I get the server back and forth. But if I
open a second one, you see, this one also gets the echo from the
server, but the other client did not receive that message from
the second client. And if I open a third one, none of the first
or the second ones, get the message broadcasted from the
server. So right now it's working on a one to one basis.
And what we want to do is we want to work on a one to many
basis. So how are we going to do that? Well, we're going to
create another, we're going to create another behavior, that is
going to be called a call to all. So I'm going to public
class a call all and I'm going to extend WebSocket behavior.
Alright. And then what I'm going to do is
I'm going to copy this here. And then I'm going to blah, blah,
blah, received message from, from a co client received
message from a co all client, right? And what I'm going to do here now,
instead of sending the data, the way we do this with this library
with a web socket sharp library is just by accessing the
sessions property of the library. And then just saying
send to sorry, not using broadcast to have broadcast Yes,
broadcast, which is send a message to everyone that is
connected to the server. And that's going to be dot data. So let's see if this works. I'm
going to execute this code. And this is the server. And now in
my client, I need to change from echo to into a COBOL. So I'm
going to connect now. Oops, and the current state of the
connection is not open. Whoo, what is going on here? Let me take a look at what's
going on. Oh, yeah, silly mistake.
Remember, on the server, we did create the behavior. But we
forgot to attach that behavior to the server. So I'm going to
copy this, I'm going to attach another service. This is going
to be a call for all right and on this route here. And then I'm
also just for the sake of clarity, I'm going to write line
to the console that we have two servers, two services and Running on the same server. So
now I'm going to execute this code, we have the server that
has both behaviors, I'm going to minimize that. And then I have
here Echo, which have already executed one. So it is compiled.
So we can now go to my C sharp client, the application that
gets compiled in the background. And then I can execute this one.
And then you can see that I receive a message from the echo
client. And I'm going to click for a second time. And you can
see that this one received, but this the second client also
received the message. And if I do it a third time, you can see
that as I connect, the other two clients also receive
notifications of this echo. Okay. So, all right, so that was
it. And then now if we extended this more, we could just connect
them and, and we could exchange JSON information, coordinate and
draw the ASCII box, etc, etc. But I'm actually going to leave
that up as an exercise for you, the viewer for give you an
opportunity to have your own phone as well with this, okay. All right, great. So I hope this
was helpful for you. And thank you very much for watching these
videos, please consider liking them subscribing to the channel,
etc, etc. And let's move on to the next videos in the series
and keep finding new ways of connecting different things
together and having some fun with WebSockets I
