I have an application which I 've used signalr. Application is working fine. But the problem is it is increasing the number of IIS requests when I pushed data using Signalr.
Is there any way to automatically end the request once the pushed the data. ( Is there any mechanism in Signalr to do that?)
Related
I have ASP.NET Core Web API deployed as App Service on Azure. App Service is set up to require Client Certificate. Also AlwaysOn for App Service is set to True.
Issue is that first request with small payload sent to Web API takes approximately 2-3 seconds, and with large payload timed out. But after first small successful request, next one with large payload executes in less than a second. After some period of inactivity the issue occurs again, and first request to Web API again either takes time or timed out.
When Require Incoming Certificate is disabled, no issues with first request execution time, it executes quite fast always.
Web apps are unloaded if they are idle for a set period of time.
Quoted from official docs:
The downside is that the response to the first request after the web app is unloaded is longer, to allow the web app to load and start serving responses.
If you're using a Basic and Standard service plan, you can turn on the Always On setting to keep the app always loaded:
In the Azure portal, go to your web app.
Select Application settings.
For Always On, select On.
I'm reading the very limited information about Azure SignalR service as well as the quick start guide and want to make sure I'm understanding this correctly.
We still seem to have a hub and if I understand this correctly, the function of Azure SignalR service is to simply push the messages to connected clients.
In my case, I store the history of chat so by hitting the hub first, I'm able to still use my backend logic to persist chat history or do any other processing that I may want. Then simply allow Azure SignalR service to push the data to connected clients.
The main benefit seems to be handling the scaling of the service.
Am I getting this right?
Yes, you are totally right.
You will use exactly the same API of ASP.NET Core SignalR to write your business logics, which means you can persist whatever you want when the messages from clients hit your hubs.
Azure SignalR Service will be the underlying transport between your app server and connected clients. For example, when you want to broadcast messages to all your clients, you actually only send one message to Azure SignalR Service and the service will broadcast the message to all clients for you. So that you don't have to worry about the scale-out. Azure SignalR Service will handle the scaling-out for you.
You understand correctly.
SignalR is not yet ready for production (when speaking about ASP.NET Core), SignalR for ASP.NET MVC has been around for a while (stable).
SignalR consists of 2 pieces: server and client. The server is as you describe: a "hub" that you can use to push information to clients.
On a webpage you load a piece of generated javascript (generated automatically from your hub definitions). Basically you let your website visitors (clients) connect to the hub through signalR's mechanism (signalR will choose the proper way to connect depending on the browser), and then 'subscribe' to the different methods you have active in your hub.
The workings are simple: whenever you call code in your hub (can be from clients, or from backend code) communication is automatically handled for you to all subscribed clients.
Note: If you are running this on an azure web app: enable the "always on" setting, and set the "websockets" toggle to "enabled", otherwise you'll see strange behaviour.
Note2: The RC version for signalR core 1.0 has just been released (7th of may 2018) so it might be a while before this software starts becoming stable and available through the public nuget/npm channels.
how to refresh local data automatically when server data changes in azure mobile app(android).Right now i m using a timer that refresh my server request but this approach is not satisfactory as my app keep on sending requests to azure.What is the best approach for doing this?I also tried to understand one of the answer in stack overflow based on Exponential Back Off Delay Based but failed to understand.Kindly just guide me on this
For communicating server-side updates to client apps, use SignalR.
Here's some guidance on using it with Azure Mobile Apps: Real-time with ASP.NET SignalR and Azure Mobile .NET Backend
We just released an update for Azure Mobile Services .NET backend which enables you to use ASP.NET SignalR for real-time, bi-directional communications with your mobile applications. SignalR will use WebSockets under the covers when it's available, and fallback to other “techniques” (i.e. HTTP hacks 😉) when it isn't. Regardless of the mode, your application code stays the same.
I have a Web site deployed on Azure Web App. My web site gets very slow at times. This behavior is random.
On checking IIS Logs during the period of slowness, I found few requests coming in where the Client IP Address is blank (It shows "-").
The response time of these requests runs into minutes and finally they result into HTTP 500 error. This happens only for the requests where c-ip is blank.
All other requests that have a Client-IP address are processed successfully. But because of the bad requests my application becomes very slow. I have to restart my Web App to resolve this issue.
What could be the possible reason behind these requests having a blank Client IP Address ? Could this be a malicious attack on the web site ?
Difficult to say. Could you add Application Insights service to your project? It allows you to see what is going on before and after 5 minutes of "this" request. The second reason can be the mode of your Azure Web App - is it free or shared or standard?
After AI added, you could share some more insights, because it is important to know what is that request about, not just the fact that it was processed.
https://azure.microsoft.com/en-us/documentation/articles/app-insights-start-monitoring-app-health-usage/
I am working on a node.js based Web application that needs to be able to push data down to the browser. The Web app will be sitting behind a load balancer.
Assuming the Web app has a POST REST API as:
/update_client
and assuming there is a third-party application calls this API to push some data to the Web app, and then the Web app pushes the data down to the browser.
Now assuming I have two servers behind the load balancer, with the Web app running. A browser client connects to server 1 to listen on the event. Then the other applications hits the /update_client API at the server 2. Now since the two activities happen on two different servers, how can server 2 notify server 1 to send the data to the connected clients?
And what if I am using auto scaling, with dynamic number of servers behind the load balancer?
You need to have some kind of shared resource behind the servers so they all know about updates. I show how to use Redis Pub / Sub for this in a blog post I wrote recently.
Server Sent Events with Node JS