Building Real-Time Applications With SignalR & .NET 7

[@MilanJovanovicTech]

Get the source code for this video for FREE → the-dotnet-weekly.ck.page/signalr-intro Want to master Clean Architecture? Go here: bit.ly/3PupkOJ Want to unlock Modular Monoliths? Go here: bit.ly/3SXlzSt

[@ugochukwuumerie6378]

Thanks. Did you just type it out manually at the end of the message?

[@the_unico]

@@ugochukwuumerie6378 I also dont know if that is a closed square bracket.

[@lasindunuwanga5292]

Very nice 😂😂 Thanks

[@majormartintibor]

Nicely narrated. I do like the strongly typed hub section a lot, you stand out with that one from the rest of the field. The postman part is also a nice touch.

[@MilanJovanovicTech]

Much appreciated! And glad you enjoyed it it

[@brunohenrigarcia9966]

For those who want to know, the final character in message is the 30 of ASCII table

[@MilanJovanovicTech]

There are a few blog posts in the description to check it out

[@jithin.johnson]

Helpful, thank you.

[@unka1723]

1E, hex.

[@marna_li]

There is also the experimental "Microsoft.AspNetCore.SignalR.Client.SourceGenerator" package that allows you to generate clients based on the interface for a typed client and a interface describing the methods on the hub. Comes in handy with Blazor since it can just register a component which implements the typed client interface - automatically setting up the handlers. And then you can use the proxy to call the hub methods.

[@MilanJovanovicTech]

That's new for me

[@superjosefer21]

I installed it, but i dont know how to use it? there is a tutorial of this package??

[@marna_li]

@@superjosefer21 Search for the package name on Google, and you will find blog articles. Basically, you need to add some attributes used by the generator. I have a project but I can’t share links here.

[@Yetemedim]

Thank you Milan for this introductory video. I'm just learning the SignalR and this video helped me a lot. Also, It's great to see the best trilogy of WoW displayed background :D

[@MilanJovanovicTech]

I wish I could go back in time and replay that trilogy 😁

[@flobuilds]

Signalr is great. But i always wondered how notifications are done. Like for mobile apps also when they aren't running (maybe a background task with the app). With Emails you probably have an Email notification service somewhere in the backend for handling all the emails from the different services. But how could i handle push notifications?

[@codeme8016]

Not sure just guessing, that relates to the mobile side development. Once the mobile app receives the message it should populate it as a notification using the Android/iOS notification service.

[@MilanJovanovicTech]

It wouldn't work - the client will need to be connected. For a proper notification you need a service that supports it, whole 'nother story...

[@jeremiahgavin9687]

Push notifications on the client side are handled by an android background service or an IOS background service. Your server has to send the notification to APNS(for IOS) and or FCMS(for Android). You could use something like the GoRush server as a service in your backend infra and have your application server send notifications via HTTP to the GoRush server for push notis. SignalR is for in-app realtime behavior and data, not push notifications.

[@flobuilds]

@@jeremiahgavin9687 ohh never heard of that thank you so much.

[@AbuBakrSadiqi-b7t]

A very nice touch, I like the strongly typed hub section. More videos on SignalR particularly on authorization will be nice.

[@MilanJovanovicTech]

Check this one also: kzbin.info/www/bejne/hWjSkqt8nLOoj9E

[@chizuru1999]

How did you set up your visual studio to display all those options when you press ctrl + space or after typing . (dot)? Like you get all the possible function overrides in a list.

[@MilanJovanovicTech]

ReSharper

[@chizuru1999]

@@MilanJovanovicTech Thanks

[@class1c156]

I think that if we using endpoint to send message, we can use [Authorize] attribute on it instead of putting attribute on Hub method, yes? Sorry for sometimes bad english, I am not native speaker

[@MilanJovanovicTech]

The [Authorize] on the Hub is for clients connecting to the Hub

[@shabtaiben-david8173]

in my Postman shows that hub is connected successfully, but OnConnectedAsync is NOT invoked, accordingly no messages can be sent

[@MilanJovanovicTech]

Probably the special character and/or message format

[@foundev]

Yes, Even I am facing the same issue. Did you figure it out the fix?

[@hipekk]

​@@foundev @shabtaiben-david8173 you must use the appropriate character at the end of the message. It must be: 0x1E.

[@shatrughan2010]

i am also facing the same issue i verified their is no special character , do you know what could be the other reason in postman it shows connected but neither i see sent message from server nor the heartbeat

[@dinhhuy9714]

hi here, i got the same issue and ive tried everything even having downloaded this source code but still doesnt work

[@omarbousbia6916]

Thank you very much for this tutorial Milan. I did the same except for installing the SignalR client package. When I connect from postman I only receive one message saying that it's connected, but the ChatHub class breakpoint does not hit in VS !!!

[@MilanJovanovicTech]

Did you get it working eventually?

[@omarbousbia6916]

@@MilanJovanovicTech no

[@Spud9]

Same

[@StephenKorow]

Was this issue ever resolved?

[@omarbousbia6916]

@@StephenKorow did not try again

[@InuyashaITB]

What extension is it that lets your autocomplete show all the possible overloads of the function you are calling?

[@nucasspro1]

just type "override"

[@MilanJovanovicTech]

Maybe ReSharper

[@МаксимВеснин-и6э]

You're the best! Links to another video in the end are very useful! Thank you for these videos.

[@MilanJovanovicTech]

Glad you like them!

[@igorkalezic4739]

I ran into an issue where postman says it's connected and shows the message sent but there is no message received and my breakpoint in OnConnectedAsync doesn't get hit.

[@MilanJovanovicTech]

Checked the pinned comment? And the examples in description?

[@dantheflipman]

The examples show the NULL ASCII char being used for the end of the postman request, the one you need to use is the "ASCII code 30 = RS ( Record separator )" character. This fixed it for me.

[@igorkalezic4739]

Got it, thanks.

[@בןסלומון-ז4כ]

hey, can you help me with this one ? i tried both "rs" and "?" from the blog and still have the same issue

[@MilanJovanovicTech]

@@בןסלומון-ז4כ Check pinned comment

[@amayweather]

thanks for explaining the main points, I would like to hear about error handling in the hub methods.

[@MilanJovanovicTech]

Noted!

[@amayweather]

​@@MilanJovanovicTechnice. Realy enjoy your videos, keep it on!

[@priya30081]

Where is the Hub class? My builder is not declared correctly, the program is messy. Do you have the complete solution available to download?

[@MilanJovanovicTech]

Hub comes from SignalR

[@matthewrossee]

Hi Milan. How would you use SignalR with clean architecture and DDD? The way I see it: some domain entity raises a domain event, the event is saved to the database OnSavingChangesAsync using the outbox pattern. Then some background worker like Quartz picks up that event, and uses correct handler in application layer. Now, how should I reference the Hub in the application layer? Because I feel like using IHubContext is a leaky abstraction. Maybe a better approach would be to use an interface like IMessageSender, that would be implemented in infrastructure layer, and then IHubContext could be injected without polluting the application layer?

[@MilanJovanovicTech]

You can hide it behind a service interface, liek INotificationService. In the NotificationService implementation you can use IHubContext

[@omkarmanjare4936]

Infrastructure layer. In the clean architecture , the external tools and coponents reside in the Infrastructure layer so that tomrrow if you decide to replace SignalR with some different tool that will serve the purpose of sending realtime notification, can be easily adjusted without impacting the core business logic

[@mishkamishka7468]

OnConnectedAsync method is not being called when I am connecting to hub successfully

[@MilanJovanovicTech]

You ain't doing it right 😅

[@mishkamishka7468]

@@MilanJovanovicTech I have exact same code :D

[@akg_akgoud]

@@MilanJovanovicTechplease tell how to do it I am facing the same issue

[@gangstacoder4234]

hey I had a minor question that how should i add token auth in the signalr hub

[@MilanJovanovicTech]

learn.microsoft.com/en-us/aspnet/core/signalr/authn-and-authz?view=aspnetcore-7.0

[@ThuanTran-lm9pi]

Great video , i did followed you but i go struck instep 4.04 , i only see sen't messages , i don't see received messages

[@MilanJovanovicTech]

Did you manage to hit the OnConnectedAsync method?

[@ThuanTran-lm9pi]

​@@MilanJovanovicTech i found my error and i fixed it, thank you, your next videoi hope you will connect reactjs with this api

[@brenodev]

Thanks for the great video. I got a question. When you mapped the broadcast endpoint, couldn't you have used the SendMessage method on your hub?

[@MilanJovanovicTech]

I used a typed hub context, so no

[@DiogoLScarmagnani]

Very simple and helpful explanation. Thank you.

[@MilanJovanovicTech]

Glad it was helpful!

[@teckyify]

Thank you for the overview, was well and quickly explained. For the example I whished you'd had shown a short example which makes more sense, like sending a continous heartbeat to the clients which communicate server health. Doing always A->B action mapping is not an enlightening example in my opinion (posting to the endpoint to trigger the WS push).

[@MilanJovanovicTech]

Check out the next video: kzbin.info/www/bejne/hWjSkqt8nLOoj9E

[@goharali1825]

we can do this without installing the library as well. so why installlibrary explicitly?

[@MilanJovanovicTech]

To make a point

[@laolaoal4784]

this is a great tutorial, thank u. how would u recommend to use signalr in clean architecture project (that uses services not mediator) ?

[@MilanJovanovicTech]

Hide the Hub behind an interface, and create it in the Infrastructure projdct

[@wadeaashraf2761]

How can I use signalr to video calls or voice calls?

[@MilanJovanovicTech]

No idea, you'll have to do some research

[@regestea]

what is the shortcut of null termination character ?

[@MilanJovanovicTech]

Helpful in general

[@saulomarcosdev3849]

Thank you and stay awesome too!

[@MilanJovanovicTech]

Stay awesome 🏆

[@hunainzubair4371]

Hi Milan just a quick question that it is sending request every 10 sec is it bad for performance??

[@MilanJovanovicTech]

No, not really

[@pilotboba]

I belive you can configure the keep alive ping time. I don't recall if it's a hub setting or a connection setting.

[@InshuMussu]

Hi Milan, I don't know why my debugger is not being triggered when i use postman, while the postman shows the connected status :(

[@MilanJovanovicTech]

Probably not using the correct wildcard character

[@InshuMussu]

@MilanJovanovicTech wildcard? 🤔

[@anupampatel6890]

Very nice explanation to beginner

[@MilanJovanovicTech]

Thank you so much!

[@sardoraskarov8054]

when i run it in visual studio it works on localhost but when i publish to iis server it doesn't work

[@MilanJovanovicTech]

Could be a CORS issue

[@sardoraskarov8054]

@@MilanJovanovicTech yes it is a CORS issue app.UseCors(options => options.AllowAnyOrigin()) gives an error CORS error Why is it working when I enter the domain in WithOrigins?

[@motorfinger]

Planning on doing a demo on how to use SignalR when the server has more than one instance (load balancing)? SignalR is quite friendly when the enviroment only have one instance, but when two... the trouble emerge :/

[@MilanJovanovicTech]

Good suggestion!

[@vittoriomorellini1939]

Great video and Great share!!! Perfect explanation of signalR. Thank you for sharing

[@MilanJovanovicTech]

Glad you liked it!

[@vittoriomorellini1939]

@@MilanJovanovicTech yes. It is a great library. I look at some examples and I needed this lesson

[@rodrigoboanergesoliveira1682]

Strict to the point, thank you very much for sharing this knowleadge.

[@MilanJovanovicTech]

Glad it was helpful!

[@KolawoleBayoAdesina]

Hi Milan. I currently want to build a chat module api to be integrated into a mobile App. Is SignalR the best option for one-to-one real time chatting.

[@MilanJovanovicTech]

It's good, but not that offline clients won't receive messages

[@gotsane]

Great video, I am curious if you planned on discussing the grouping functions of signalr at any point? I would love to see some follow up videos on the topic.

[@MilanJovanovicTech]

I'll definitely do a follow-up, with building out some UI

[@andythebritton]

SignalR seems very cool. Just waiting for the right project to come my way. Would be interested to see your take on implementing the client side.

[@MilanJovanovicTech]

I'm planning some Blazor content, so this will be ideal

[@arborinfelix]

I have a .net web api on my iis server with windows authentication. I have an angular frontend wich consumes the .net web api. It runs without problems. After I implemented the signalr it gives me cors errors even though I never had cors issues before signalr. all the headers, methods and origins are already defined. Is there something in signalr that alters the cors settings?

[@MilanJovanovicTech]

Credentials most likely

[@aussieraver7182]

Smart man, the only World of Warcraft trilogy that needs to be on display.

[@MilanJovanovicTech]

Everything after that is just... 🥲

[@jeganathperialwar7788]

Could you please test this app with docker? i am facing issues while running signalr inside the docker

[@MilanJovanovicTech]

Will do

[@alisteinn]

Great Tutorial!!

[@MilanJovanovicTech]

Glad it was helpful!

[@benp7328]

Really nice demo. However (like every other demo) you send to all users. What app needs to do this in the real world!? We send to specific users....and that doesn't seem to work

[@MilanJovanovicTech]

Just need to pass in an Auth header, and get the user with Clients(userId): www.milanjovanovic.tech/blog/adding-real-time-functionality-to-dotnet-applications-with-signalr#sending-messages-to-a-specific-user

[@ranjanpandey2225]

Which laptop do u use for .NET development?

[@MilanJovanovicTech]

I use a desktop PC

[@ranjanpandey2225]

@@MilanJovanovicTech any laptop u suggest?

[@jeremiahgavin9687]

@@ranjanpandey2225 Newer generation(Last 3 years, newer is better) Intel i5 or i7, last 2 years of AMD mobile chips(6000 series and up). Gaming laptops are usually the best bang for buck performance wise although the majority of them have terrible battery life.

[@camilleb1754]

I don't understand, how to create a Record Separator at the end

[@MilanJovanovicTech]

Check the articles in the video description

[@mylesdavies9476]

Interesting topic, not something I have delved into yet but definitely on the list as I can see the potential usecases. What's a typical approach for identifying users (assuming JWT auth in use with userid/nameidentifier) and directing a message to a specific user?

[@MilanJovanovicTech]

Just pass the JWT in Auth header and should work fine

[@mylesdavies9476]

@@MilanJovanovicTech does the hub somehow hold the user claim data for each connected client so you can then say issue message to user with username x based on a username value coming from elsewhere in the app?

[@MilanJovanovicTech]

@@mylesdavies9476 Check out my blog post, this section specifically: www.milanjovanovic.tech/blog/adding-real-time-functionality-to-dotnet-applications-with-signalr#sending-messages-to-a-specific-user TLDR; Yes - it does hold user info, and I explained how it extracts the User ID.

[@mylesdavies9476]

@@MilanJovanovicTech ah that looks perfect! Nice and simple then, thanks 🙂

[@abhinavsrivastava2128]

Can you please make a video on event streaming also where we can leverage the h2 instead of h1.1 on signalR, since net7 already supports upto h3

[@MilanJovanovicTech]

What are h1/h3?

[@abhinavsrivastava2128]

Sorry i should've been verbose... h1 => HTTP 1.1 h2 => HTTP 2 h3 => HTTP3 over QUIC

[@Priyanshu-f2s]

Can I create a real time order status just like zomato using signalR?

[@MilanJovanovicTech]

Yes, you could use SignalR for that

[@fikolec]

Worth to mention: methods with optional parameters (I mean those with default value eg. int i = 0) may be ignored by your hub with strongly-typed client interface. This is what I was struggling with for long hours..

[@MilanJovanovicTech]

That's quite interesting. As in - the Hub won't send the default values?

[@vivekkaushik9508]

A better example would be to create two frontend applications(React/Blazor) and have them talk to each other or sending events from frontend to backend or vice-versa.

[@MilanJovanovicTech]

Maybe, but I didn't want to introduce UI apps

[@KpakpatoTv-ks6hd]

😅you could as well make those videos since you got the idea😂

[@kodindoyannick5328]

Thank you Milan for this great video.

[@MilanJovanovicTech]

My pleasure!

[@jodainemoore8300]

In postman its saying connected but its not hitting my break point in: public override async Task OnConnectedAsync()

[@MilanJovanovicTech]

Check the blog post for the message format

[@АртурМирзаев-й7в]

If you solved the problem, please tell me how. Same situation.

[@jodainemoore8300]

@@АртурМирзаев-й7в Read the entire blog carefully, I missed the key information when I skimmed read it. In addition, I found IAmTimCorey signalR video more useful for my level. it goes in depth and shows the other side of signalR using HubConnectionBuilder etc. instead of using Postman.

[@davittonoyan6537]

I have the same problem, if you solved can you help me?

[@RioTheHitman]

Nice can you also do a video on handling messages after a message has already been broadcasted but the user was disconnected at the time of the broadcast.

[@MilanJovanovicTech]

It's lost in that case

[@اسيرالعلم-ك9ظ]

I Got error message after I connected to the hub {"error":"Handshake was canceled"}

[@MilanJovanovicTech]

Probably the incorrect token

[@古-r4p]

I just met: {"error":"Handshake was canceled."} when I firstly connected to the WebSocket after 10 or 20 seconds. Do any one have idea on working with that?

[@MilanJovanovicTech]

It's 99% the wildcard character

[@davidmorrison9641]

Hmm.. I can't get this to work. I downloaded the code, thank you very much for that, and when I run it, the message never hits the breakpoints. I tried both the project you supplied, as well as recreating it from scratch. Not sure what I'm doing wrong.

[@MilanJovanovicTech]

Could be the wildcard character? (that's what most folks have trouble with)

[@omidkianifar5144]

Does Signalr compatible with DDD? HOW

[@MilanJovanovicTech]

It's infrastructure, so what does it matter?

[@doheavyWeight]

I hit postman but not goes to end point hub

[@MilanJovanovicTech]

Wellp, something is wrong

[@doheavyWeight]

@@MilanJovanovicTech I thing this ASCII code not running

[@naveenkumar-hx1cx]

I have applicationA and applicatioB, from applicationB send message to applicationA is this is possible

[@MilanJovanovicTech]

Yes

[@WaleedAslam-i9q]

tried with postman as you did but only got connected message also debugger didn't hit. No receiveing message at all. Many other comments are also related to this issue. If possible kindly take a look :)

[@MilanJovanovicTech]

I updated the pinned comment to include the ASCII character ''

[@dantheflipman]

The examples show the NULL ASCII char being used for the end of the postman request, the one you need to use is the "ASCII code 30 = RS ( Record separator )" character. This fixed it for me.

[@ahmedgaber3714]

Thank you for this great video i understand vary good .but in postman he gave me that he connected to my url and send argument but gave me error: handshake was cancelled

[@MilanJovanovicTech]

Try something different? 🤔

[@ahmedgaber3714]

@@MilanJovanovicTech i change api project to razor like example in microsoft document then open two window it work ! so where is the problem in api project 😂😂

[@shahidnoor1984]

Sir please make video on how send it to specific user using end point of API

[@MilanJovanovicTech]

Covered that in the new video

[@alekseigwynbleidd9413]

Maybe someone could help me finding that ASCII character? i copied one from Milan's pinned comment, but it still doesnt work, im connected , but my breakpoint is not activated

[@MilanJovanovicTech]

Should be this:  If not, check here: trailheadtechnology.com/using-postman-with-signalr-websockets-development/

[@js.1337]

Thank you very much for this short tutorial. I have practically no idea about C# and signalr. This video helped a lot.

[@MilanJovanovicTech]

Glad it was helpful!

[@CrieveATT]

Make sure you've properly installed the role for Web Server (IIS) -> Web Server -> Application Development -> WebSocket Protocol before attempting to follow this tutorial if your remote server hasn't be fully configured yet.

[@MilanJovanovicTech]

🤔

[@lasindunuwanga5292]

You haven't explain how to get record separate character

[@MilanJovanovicTech]

Check the pinned comment

[@lasindunuwanga5292]

@@MilanJovanovicTech hey, there is no pinned comment

[@MilanJovanovicTech]

@@lasindunuwanga5292 Should be now!

[@lasindunuwanga5292]

@@MilanJovanovicTech thank you

[@pilotboba]

I see you started by referencing the client package. I don't think that was needed for this demo, since you were only using the server components. The client package adds the ability for a C# client like Blazor or Maui or whatever client.

[@MilanJovanovicTech]

What's the correct one to use then?

[@davidjackson148]

Something missing here. Just followed this exactly and it doesn't work :(

[@MilanJovanovicTech]

Probably the wildcard character?

[@davidjackson148]

what wildcard char ?@@MilanJovanovicTech

[@akg_akgoud]

Not hitting break point to chat-hub

[@MilanJovanovicTech]

Wrong delimiter character, most likely

[@dcal1736]

OMG. Every example of SignalR is a damn chat app example. Is that all SignalR is good for. It's like showing a code example with how to write a line of code to print Hello World. Geeezzz. How about SignalR with data from a database. Anything other than just a damn chat example.

[@MilanJovanovicTech]

Make a better one

[@diamond8467]

Why does that matter lol. It shows basics of sinalR framework, if you want to learning db connection go elsewhere, it is not database tutorial, mate

[@juancarlosquirino830]

@@MilanJovanovicTechgoat

[@iceneno2491]

Excellent !

[@MilanJovanovicTech]

Many thanks!

[@princeowusu9854]

It took to a whole 4hours to solve this issue: I don't know what the last character might but please make sure you include it or else you won't be able to connect: {"protocol":"json","version":1}

[@MilanJovanovicTech]

All messages need to end with a null termination character, which is just the ASCII character 0x1E. www.milanjovanovic.tech/blog/adding-real-time-functionality-to-dotnet-applications-with-signalr

[@princeowusu9854]

@@MilanJovanovicTech oh okay. Thanks

[@camilleb1754]

doesn't work :(

[@MilanJovanovicTech]

It does 😁

[@umollerstrom]

Great! 👍

[@MilanJovanovicTech]

Thank you! Cheers!

[@baranacikgoz]

Somebody has to make a video about how to send a message to a specific user😂

[@MilanJovanovicTech]

In the meantime: www.milanjovanovic.tech/blog/adding-real-time-functionality-to-dotnet-applications-with-signalr#sending-messages-to-a-specific-user

[@hexoter]

its very simple , you just need his connectionid , wich u can store in ur dbo. or you cand send to a group wich the user has registered

[@iamowaais]

First Viewer 😅

[@MilanJovanovicTech]

🥳

[@multhiermr2107]

ı WANNA SEE YOUR BOOKS

[@MilanJovanovicTech]

Not writing any

[@melekmuxtarli1675]

I'm not getting a response in Postman🥲I launch the application from the controller, but I don't see it in Postman. I downloaded your source code and ran it, but it didn't work in Postman. Help

[@MilanJovanovicTech]

It's the format of the message being sent from Postman... Check this article www.rafaagahbichelab.dev/articles/signalr-dotnet-postman for the wildcard character

[@THE_NE0]

Thanks for the video, in my personal opinion the video didn't add value compared to the thousands of blog posts covering the same example, i would suggest something more advanced like one to one communication with identity, i mean in real world, if you gonna receive a notification or message, it's probably gonna be for you and not a broadcast, just saying 🤷

[@jeancarlosreyesencarnacion]

Yes, you're right.

[@MilanJovanovicTech]

I still have to make something beginner friendly from to time

[@THE_NE0]

@@MilanJovanovicTech there's enough beginner friendly tutorials out there, that's my opinion 🤷

[@antwanwimberly1729]

🇺🇸

[@MilanJovanovicTech]

🇷🇸

[@pbooth88]

Very rushed tutorial.

[@MilanJovanovicTech]

You're among the few to say so

[@fooballers7883]

This could be really good to use with arduino...any tutorials on that ? Thanks for this video.

[@MilanJovanovicTech]

Nope

[@fernandocristan8339]

I have a scenario where the front application needs to communicate with the API and the API communicates with a desktop application on the client machine, the same using the front. The API sends data from a document that needs to be issued by hardware, government stuff. The API when sending needs to receive the response from the hardware, is it possible? What do you suggest for this scenario?

[@MilanJovanovicTech]

If you can run SignalR on that hardware, it should be possible

[@fernandocristan8339]

@@MilanJovanovicTech we have a desktop app that omunicate with that hardware, this app will receive the server notificatio, process comunication with hardware than send the response