I have been reading articles about asynchronous messaging between clients using MVC3 and the SignalR library (http://sergiotapia.com/2011/09/signalr-with-mvc3-chat-app-build-asynchronous-real-time-persistant-connection-websites/)
We currently use activemq for some of our fat client apps and use topics to broadcast data to everyone. Does anyone know if this sort of thing could be used in MVC3 as well?
I'd like to create an application that doesn't require a user to install anything (and could even be used on a phone), but it would be monitoring continuously-changing data. We're talking refreshing data every 2-3 seconds.
If you want to have asynchronous messaging with client (browser) use SignalR. ActiveMQ and MSMQ are technologies for thick clients and server-to-server communication. They require installation (MSMQ requires windows installation) and they are not accessible from browser (well I can imagine accessing MSMQ through ActiveX or ActiveMQ from Java applet but that is not what you are looking for).
One of the possible ways to go is to build a web service which will implement communication with AMQ/MSMQ via their APIs and do poll this web service from your webpage (via ajax call for example) to refresh the data as it's needed.
Related
I am working on a project which is basically a Customer Feedback Analysis Dashboard. There are few graphs on the dashboard and data for each graph is fetched from the server through API requests.
Right now the dashboard is updated every time the page is refreshed. I want it to be updated immediately when there is a new feedback in the system. I am confused, whether I use websockets to send data for each graph or just a flag and use that flag to fetch data through API requests.
Like, facebook/twitter does. They tell you about new posts/tweets and when you click that button your feed/wall gets updated.
If you want to "push" data from server to client and you want that data to show up in a timely fashion (e.g. within 10-20 seconds of when it was available on the server), then you will want to implement some sort of "push" solution where the server can efficiently push data to the client whenever there is new data to send.
There are several possible approaches:
webSockets
socket.io
Server-sent events
Mobile platform-specific push (Android and iOS)
For a general purpose solution that works within a browser, you will want to use one of the first three. socket.io is built on top of webSockets (it just adds more features) so architecturally, they are similar.
Server-sent events are fairly new (modern browsers only) and are only for one way communication (from server to client). webSockets can be used for communication either way.
I'd personally recommend socket.io because of the features it offers (such as automatic client reconnection) and a simplified messaging layer. You can see the feature difference between socket.io and webSockets here. With socket.io, the client makes a connection to the server when the web page is loaded and that connection is persistent. After the connection is established, then either client or server can send messages to the other at any time in a very efficient manner.
Other useful references:
Push notification | is websocket mandatory?
websocket vs rest API for real time data?
Why to use websocket and what is the advantage of using it?
What are the pitfalls of using Websockets in place of RESTful HTTP?
Ajax vs Socket.io
I want to automate REST API using Jmeter. My requirement is trigger and validate the signals generated from the field.Messages from the field like "communication lost" need to check whether this message reached API or not.These messages are developed using "signalr".Can anyone tell me how can i get the messages from signalr in Jmeter.
As per SignalR main page:
ASP.NET SignalR is a new library for ASP.NET developers that makes developing real-time web functionality easy. SignalR allows bi-directional communication between server and client. Servers can now push content to connected clients instantly as it becomes available. SignalR supports Web Sockets, and falls back to other compatible techniques for older browsers.
So my expectation is that you can use WebSocket Sampler plugin in order to test this functionality. The plugin can be installed using JMeter Plugins Manager, check out WebSocket Testing With Apache JMeter article for comprehensive information on installation, configuration and usage of the plugin for WebSockets load testing.
Firstly, here is state of my application:
I have a request coming in from a client (angularjs app) into my API (web api 2). This request is processed and a record is stored in a database. A response is then sent back to the client.
Currently, I have a windows service polling and processing this record(s).
Processing this record can be long running. As a side effect to processing this record, there might be notifications generated to be sent back to one or more clients.
My question is how do I architect this, such that I can utilise SignalR to be able to push the notifications back to the client.
My stumbling block:
I can register and store (in-memory backed by a db) the client's SignalR connectionid along with the application's own user identifier. This way I can match a generated notification with a signalr client.
At the moment, I'm hosting the SignalR hubs within the IIS process. So how do I get back from the Windows Service to IIS to notify the client when a notification is generated?
Furthermore, I should say I am already using SignalR elsewhere in the application and am using a SQL Server backplane.
The issue's with the current architecture:
Any processing is done in the same web request, and notifications are sent out via SignalR before a response to the client is returned. Luckily, the processing is minimal and very quick.
I think this is not very good in terms of performance or maintenance in the long run.
Potential solutions:
Remove SignalR hubs from IIS and host them somewhere else - windows service?
Expose an endpoint on the API to for the windows service to call to push the notification once a notification is generated?
Finally, to add more ingredients to the mix: Use a service bus to remove the polling component of the windows service, and move to a pub/sub architecture. Although this is more work than I want to chew off right now.
Any ideas/recommendations/constructive criticisms are welcome.
Thanks.
Take a look at this sample for starters
Another more advanced solution can be using a backplane to manage the communications between the front end and the backend...
HTH
I'm new to ServiceStack and want some validation on a pattern we're thinking about using.
We want to use ServiceStack with Xamarin and Message Queues. While I understand how REST works under the covers, I'm not sure how the Message Queues on ServiceStack work and if its appropriate for mobile devices.
Specifically we know that all mobile devices are essentially behind a NAT firewall setup by the Telco. Meaning Clients can talk to servers, but servers cant talk directly to clients, without the client talking first.
While the concept of a ServiceBus is designed specifically to handle this case, i'm not sure if its "mobile network friendly".
I would assume that the client side implementation, would need to work in one of two ways: polling, blocking get.
Polling would have the client side frequently runing a Http GET to ask the server if anything is available on a queue. A Blocking Get would, perform a Http GET but have the server return nothing until data is ready. Or is there another technique that i'm missing?
If it is a poll, is there any way to control the Poll frequencies in service stack. If its a blocking get how is this configured..
What happens when the app goes to the background, do we need to cancel the connections manually. etc.etc.
We tool an old version of the ServiceStack client library and ported them to xamarin. We now see that the latest ServiceStack client side library is Xamarin compatible.
So, basically my question is: Had anyone used Message Queues from a Xamarin Mobile to ServiceStack with RedisMQ or other server side message queue.
First of, I read the information here http://signalr.net/
You may have heard of WebSockets, a new HTML5 API that enables bi-directional communication between the browser and server. SignalR will use WebSockets under the covers when it's available, and gracefully fallback to other techniques and technologies when it isn't, while your application code stays the same.
SignalR also provides a very simple, high-level API for doing server to client RPC (call JavaScript functions in your clients' browsers from server-side .NET code) in your ASP.NET application, as well as adding useful hooks for connection management, e.g. connect/disconnect events, grouping connections, authorization.
And from answer here: How SignalR works internally?
SignalR has a few built in transports:
WebSockets
Server Sent Events
Forever Frame
Long polling
I have a little problem with understanding the article (theoretically).
So how does SignalR work briefly for each build in transports? (easy English may help, since I'm complete new to SignalR and web socket)
WebSockets
Server Sent Events
Forever Frame
Long polling