I have a Windows service written in C# that handles processing of digital documents, and a web application written in PHP. I need to be able to notify the C# service that new documents are ready for processing.
Currently, the C# service is reading the MySQL database every 10 seconds to see if there are new tasks to be performed. This creates a 10 second lag in the responsiveness of the web application. I'd like to be able to trigger the C# service immediately when the document is ready.
I'm looking for an answer that will allow PHP to notify the C# service without any delay.
Here are some possible ideas that I've had;
Use a shared memory object between PHP and C#, and have a thread in C# wait for that object to be signaled. Is this possible with PHP?
PHP connects to C# using a socket on localhost, sends a nak and disconnects. This seems inefficient to me.
Configure MySQL to use an in-memory table, and have the C# service query the table every second.
Is it difficult to create some kind of web service in C# that uses XML or SOAP, and would there be any lag (+1 second) in calling that service via PHP?
That's all I can think of. Maybe there is some kind of standard way this should be done, and I'm just not aware of it.
It'd be pretty trivial to make a REST facade in WCF that triggers your c# service on a POST against /. Security can be layered on depending on the nature of your deployment.
http://msdn.microsoft.com/en-us/library/bb412178.aspx
I'm going to go ahead and try to answer this.
In your service, add an OnCustomCommand handler as described in this question to trigger the service work: How to send a custom command to a .NET windows Service from .NET code?
Create a separate C# application that simply sends the command to your service and call that from PHP via the exec() function.
You could self-host an ASP.NET WebAPI in your service
Related
I'm using EF (6) with ASP.net MVC (c#). My hardware architecture:
main server - include windows service.
web-server - running my web-application UI.
The users request for some answer. My web-site adds the question to the Data-Base (SQL - server) with EF.
In my main server, the service detects the changes (new task arrived) and solve it.
The detection of new task made by busy waiting, which I do not like.
How it's being done:
My EF layer includes custom function, which fire every N minutes SQL stored procedure.
If the SP retrieve information, the service solve it.
What I want:
when new task added from the web-site, the web-site will send signal to the main server. When the signal arrives to the main server, it will immediately start to solve it.
How this can be done?
Thank you!
seems like a perfect use case for singalR....
please take a look at http://www.asp.net/signalr
signalR will choose the best suited communication method. it also uses sockets if available otherwise fallback to other means of transport.
You can create one more service for Comm. between two servers .
Solution implemented with WCF is very trivial to Develop ..
Whenever new Question is posted .. your webserver can invoke this webservice ..
bottom - line : Look into WCF
We do this a lot, I think you have a few options:
A shared storage mechanism which is polled from the receiver (what you are currently doing)
Using something like a webservice call to send a command to the receiver (Normally a synchronous processing technique)
Using a messaging framework such as NServicebus to send the command to the receiver (an asynchronous fault tolerant technique)
We use all of these techniques, but the one I normally find best is the last one.
Messaging introduces fault tolerance and asynchronous processing which are both very useful when building systems spanning multiple machines.
If this sounds like something that might help check out the pubsub example for NServiceBus here: http://support.nservicebus.com/customer/portal/articles/860297-how-pub-sub-works
Or if fault tolerance doesn't really matter to you I would recommend a selfhosted webapi running inside your windows service.
I am using web services - not WCF - hosted in an iis web application written in C#/asp.net. I also have a C# winform Desktop application that had originally polled a web method to check for any messages on the server. I found the memory on the client shot up. So, instead of polling this web method I invoke it once, the web method goes into a loop checking for messages. As soon as it finds a message(s) for this client it breaks out of the loop and returns the message(s) to the client. The client in turn will process the message(s) and then re-invoke the same web method waiting for the next message(s).
I run this and the memory on the client desktop and the memory on the web server remain low. I really have 2 questions here.
1). Will the memory escalate on the server when more clients invoke the same web method?
2). Should I avoid this way of doing things?
I know there are callbacks available using WCF and I know I can create a hub using Signal R. what I would like to know is there anything wrong/different to how I am doing it and/or is there a better way of doing it?
Many Thanks.
I would like to have a client application and web application (or service, no UI) and I would like to connect to said web service from within my desktop application and to have two simultaneous network stream, one of them for uploading data and reading them on server and the other one for sending stuff to the client application.
I am not looking for a solution that uses anything more than that like WCF or anything, I just want a way to create connection between web server and my client application and exchange pure binary data. I would implement the protocol myself, I am not looking for any entities or encapsulation like WCF provides.
I don't even know what project type is the best choice here. I thought about empty ASP.NET application maybe that I'd upload on FTP but I have no idea what I should do next to make the application connectible to. I am not asking for complete solution of course, rather some articles that focus on how to make a plain and simple connection between server and client. I want server to be able to immediately update client and vice versa, that's why I am looking for a way to have stream.
Edit: I may as well say that the service is meant to be placed on ASP.NET hosting and I don't know how ports work on these, if there are any restrictions or anything.
"Web service" and "Network stream" are incompatible concepts. Web-services are (ideally) stateless and disconnected - so they work regardless of how the underlying network works. Messages are exchanged only from client-to-server and are encapsulated in HTTP request/response pairs. Hence "web service".
If you want to exchange "pure binary data" (as you put it) then you just need to work with sockets (or use .NET's TcpClient, which wraps up sockets in an easier-to-use API). ASP.NET would be inappropriate for this.
You can technically have an application that uses sockets that runs within an ASP.NET host process but this might not work depending on how security is set-up and it's also bound by the ASP.NET process lifecycle (so it is activated by IIS and can be shut-down or recycled at any time without warning).
You do not want to use ASP.NET Web Services for this (ASMX). That is a legacy technology, and should not be used for new development.
Why do you not want to use WCF? Do you believe it's too complicated? The thing about WCF is that it removes the complication of creating your own protocols.
Also, which version of .NET are you using? WCF get a lot easier to configure with .NET 4.0.
Here is simple duplex example using WCF.
Try it, check if performance you've got is enough, try to use alternative bindings ( like net.tcp). WCF is really neat tool to use. Once become more familiar with it you will love it.
Also check chapter on bindings in WCF from Learning WCF
Have a look at the MVC4 APIController. It works much like stock MVC except that methods return XML or JSON (or anything else you like).
Eg
/api/Users/Get
would could return something like
{
{"Username":"Bob", "Id":3},
{"Username":"Steve", "Id":4}
}
You can also return files and other streams by using special return types. You even get strongly typed, validated input through the use of models.
There's an example here which shows a full CRUD controller and sample AJAX calls from JS which you can replicate in your desktop app
We have a Website (hosted somewhere) and C# Application (which is installed on my PC). I need to accomplish the following:
Customers fill up the form on the website, i.e. the task is "created"
C# Application immediately receives this data from the website and process it
The result is sent back to the server, i.e. "task accomplished" message
The website updates status regarding this task
How do you build this kind of link between the website and an app?
In the past I've used TCPListener to communicate between two C# apps. I'm also familiar with the UDPlistener and such.. Will this knowledge be of some use? The website is going to be build on the PHP.
Some tips and advises are appreciated. Thanks.
Your website should not be dependant on an application running on your home or office PC, so the site should publish some kind of service or feed. You can make this a webservice, which is quite easy in PHP.
You then consume this service from your C# application. Make it request the new tasks regularly, by polling the service. When you've received new tasks you process them in your application, and when you've done what you want to do you update the tasks on your server using another webservice call.
All this can be done using some sort of queue in the database that backs your website.
Make the C# application a web service may be a windows host depending on your requirement
you can the webservice from php as shown here Using PHP to call a WCF web service with multiple bindings
If you have the control over your web host and your client, you could try setting up a WCF service with duplex contracts which allows the server to callback your client. Your PHP site can call the WCF service and it can in turn notify the client. Else you will have to go with the polling method where the Desktop client has to poll the web service to get the list of pending tasks.
I'm about to start to develop and application in C# but I realized that I haven't the enough knowledge to develop it yet :S.
The thing's that I need to find out a way to let the Web server comunicate with my application, i.e., in short, is there a way to let the web server (not the Client which is the trivial case) send a messege to a Client application?
I know that I way to solve it's to make Client applications periodically send messages to the web server but that's not what I want 'cause polling generates overhead
Sorry about my english! I'm not a native speaker.
Thanks in advance!
Generally this type of interaction is achieved with Comet or WebSockets - I'm not sure how your app will be communicating with the server, but I would bet you can do what you're trying to do using one of those.
You could implement a WCF service in your client that could listen for a connection from the server (or anything else). The server can communicate with the client as easy as calling the API.
Getting started with WCF is really easy using the wizards in VS.
Here is a link that talks about using WCF with ASP, but it can be used outside of asp as well.
It seems like you meant "push" messaging, the challenge around this is for the server to keep track of the lost of clients and manage who should recieve which message.
If you want to get it done with minimal overhead you can check out the Amazon Simple Notification Service.
SNS is a cloud-based messaging and notification service hosted and managed for you, SNS is based on a topic/subscriber model and you set it up via a few simple API calls, it is metered but quite inexpensive for the most part.
edit: For C# Libraries and frameworks to do it yourself, I am not an expert in the C# world so I think other answerers will know it better.
Disclosure: I work at amazon so I am naturally inclined to like their product