I'm attempting to build a Windows Service which will execute some method when a user clicks a button in a WinForms application. I'd like to be able to pass in a few strings when the user presses the GUI button which will have the service consume them and processes a specific method. What's the best way to do this?
Thanks for help.
WCF is a handy way to handle interprocess communication. Configure it to use named pipes and it can listen for your request. Or use the MSMQ option instead if you really don't care about the response.
Check our MsgConnect (free with source), which has been created for tasks similar to yours. It's fast and has API similar to windows messages api.
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In my job we are building Web Apps that rely on a common Enterprise class. This class has a method that sends a request to our server every time the app_start or app_end event triggers so we can monitor the status remotely. But we are now requiring that at least once a day the web app reports its status, a bit like telemetry. I don't know how to accomplish this, so far I have found some options, but some have limitations:
Use hangfire. I don't like this since it requires to setup a Database or add more tables and install a new Nuget package on each project, but could be my last option.
Use a Windows Service that reads databases. This could be less work but it can't access the Web App web.config code
Use a Javascript tasks that sends an AJAX request. This requires to have an open web browser and is a big risk.
I'm looking for a server side approach that could allow to set to trigger an event or function at 1am.
I would got with Hangifire.
It is dead easy to setup and very reliable.
You don't need to setup the database, you might want to check memory storage:
https://github.com/perrich/Hangfire.MemoryStorage
Also check:
What is the equivalent to CRON jobs in ASP.NET? - C#
You can use FluentScheduler instead of Hangfire (it is more lightweight).
Instead of a Javascript task that sends an AJAX request you can use a WebJob or an Azure Function.
I have an existing complex website built using ASP.NET MVC, including a database backend, data layer, as well as the Web UI layer. Rebuilding this website in another language is not a feasible option.
There are some UI elements on some views (client side) which would benefit from live interactivity, involving both push and pull, so rather than implement some kind of custom long polling or websocket server in asp.net, I am looking to leverage node.js for Windows, and Socket.io.
My problem is that I need two way communication between both applications. Each user should only be able to receive data once they are authorised on the ASP.NET website, so I first need communication for this. Secondly, once certain events occur on the ASP.NET website I want to immediately push this data to the Node server, to be broadcast to specific users or groups of users. Thirdly, I would like any data sent to the node.js server to be pushed to the ASP.NET website for processing, as this is where all our business logic lies. The sole reason for adding Node.js is to have the possibility to push data directly to the client, I do not want to build any business logic into it (or as little as possible).
I would like to know what the fastest method of two-way push communication is between Node.Js and ASP.NET. The only good option I'm aware of so far is to create a special listener on a specific port on the node.js server and connect to that, but I was wondering if there's a more elegant or more efficient method? I also know that you could use a database inbetween but surely this would need to be polled and would be less efficient? Both servers will be running on the same server under a Visual Studio project.
Many thanks for any help you can provide.
I'm not an ASP.NET expert, but I think there are multiple ways you can achieve this:
1) As you said, you could make Node listen on a specific port for data and then react based on the data received (TCP)
2) You can make POST requests to Node.js (HTTP) and also send an auth-key in the process to be extra-secure. Like on 1) Node would react to the data you send.
3) Use something like Redis for pub-sub, send messages from ASP.NET (pub) and get them on the Node.js part (sub). This is even better if you want to scale your app across multiple machines etc.
The only good option I'm aware of so far is to create a special
listener on a specific port on the node.js server and connect to that,
but I was wondering if there's a more elegant or more efficient
method?
You can try to look at redis pub/sub model where ASP.NET MVC application and node.js would communicate through separate channels in order to achieve full-duplex communication. Or you can also try to use CouchDB change nofitications.
I also know that you could use a database inbetween but surely this
would need to be polled and would be less efficient?
Former techniques do not require you to poll for changes, but instead they will notify you when the changes happens or channel message arrives.
apologies in advance for this question being dumb, or previously covered. I have researched far and wide but have not found any resources on WCF/ Windows Services that cover this question.
I have a managed Windows Service which is working nicely. Every n (>5) seconds it checks on the status (e.g. memory consumption) of some processes and other Windows services and also does some database logging and raises events where necessary.
I intend to make an ASP.NET website that would allow users to query the status of the processes that the Windows Service is monitoring. Having researched the options it looks like the up-to-date method would be to use a WCF Service, hosted in the Windows Service, to act as intermediary between the ASP.NET website and the Windows Service. Such that, a user could request through the browser a snapshot of the current status of whatever set of processes the Windows Service was monitoring, and have this request and subsequent response relayed through the WCF service (using named pipes, I think).
So, my difficulty is that there a set of methods and events in the Windows Service for which a single root object exists (let's say MonitorObject). I don't see how the ServiceHost can be instantiated with the reference to MonitorObject so that the WCF Service can call the methods in the Windows Service. I am thinking that perhaps I need to make the Monitor object a shared (I am VB'ing) member of the Windows Service class (that contains OnStart and OnStop) and make all the events shared so that the WCF Service can just access the WindowsService.SharedMonitorObject without needing to be passed the object....
However, I am lost in the subject and am seeking any advice on how best to proceed.
Thanks in advance.
I think you're going down the right track. I wouldn't necessarily make the entire MonitorObject shared, but you might put a shared method in that object that will return the single root object to the caller.
There is a design pattern called the Singleton Pattern that will help you with this. Jon Skeet has written an excellent article on some of the things to be aware of when using this pattern in .NET. His article uses C# for the examples, but here's a SO question referencing this pattern using VB.
While it's unclear from your description, my guess is that your Windows Service is essentially single-threaded right now. Just keep in mind that once you add the WCF service, you'll need to make the methods that it references thread-safe.
I have some delphi code which, given a list of items, calculates the total price taking into account any special deals that might apply.
This code is non-trivial to rewrite in another language.
How should I set it up to communicate with a website running on the same server? The website will need to ask it for a price every time the user updates their shopping cart. It's possible that there will be multiple concurrent requests.
The delphi code needs to maintain an in-memory list of special deals, periodically refreshed from a database. So it cannot simply be executed every time or anything as simple as that.
I don't know what the website is written in, or even which http server it runs under, so I'm just looking for ideas or standard methods.
It sounds like the win32 app is already running as a Windows Service on the box. So, if you can't modify that service, you are going to have to deal with whatever way it wants to accept and respond to requests. This could be through sockets or some higher level communication protocol like web services.
You could do a couple of things. Write an assembly that knows how to communicate with the service and have your web site use that assembly. Or you could build a shim service that knows how to communicate with the legacy service, but exposes communication over higher level protocols such as web services. Either way will have the benefit of hiding the concurrency, threading and communications issue behind an easy to call interface, but the latter will make communicating with the service easier for everyone going forward.
If you can modify the delphi app to take an XML request and respond with an XML answer over a TCP socket (ideally using the HTTP protocol), you will be able to make it interoperate with most web server frameworks relatively easily. But the exact details of how to make that integration happen will depend on the language/framework it was written in.
If the web server is on windows you can compile your delphi app as a DLL that can return XML or HTML, taking parameters as part of the URL or a POST operation. Some details on making a Delphi DLL for web servers are here.
It doesn't matter what web server or OS the existing system is running under. What matters is what you want YOUR code to run under. If it is windows then the easiest solution would be to use WebBroker and write a custom ISAPI application, or use SOAP to expose web services. The first method could be used if you wanted to write a rest like API for instance, the second if your web application has the ability to consume web services.
Another option, if you are running both on the same box under IIS, is to create a COM/Automation object which you then invoke via server side scripting (ASP). If the application is an ASP.NET application, then I would use PRISM to port your code into an assembly.
I have done this with a quite complicated workers compensation calculator. I created a windows service using RemObjects Sdk. The calculations are exposed as a soap method so it can be accessed by nearly anything.
It's not necessary to use RemObjects in the service but it makes it much easier to do as it handles a lot of the underlying plumbing. The clients don't need RemObjects, they just need to be able to call soap methods. Nearly any programming langugae can do that.
You could also create an isapi dll for IIS that exposes a soap interface. This would be useful if other websites on different servers needed access to the methods. However I have handled this in my case by opening a port in the firewall to access my windows service.
There is a lot of examples on the web. A couple of places to start reading are About.Com and Dr Bob.
Torn this app into Windows Service. Write Web Service that will communicate with your windows service. You should spend some time designing your Web Service, because this Web Service is going to be your consistent interface, shielding old Delphi app. So in the future whenever you will want to write web app, mobile app, or whatever you will imagine, you will have one consistent interface – XML Web Service.
A popular way to integrate a web application with background services is a message broker.
The message flow would be:
the web application sends a "calculation request" message to a message destination on the message broker, which contains all needed parameters and also a correlation id to match the calculation request with the response from the Delphi service
one (or, in a high availability / load balanced environment more) Delphi services handle the messages: pull the next incoming message, process it by feeding the parameters to the calculation engine, and send a "calculation result message" back to the web server
the web server can either synchronously wait for the response (and discard responses which have no matching correlation ide) and build the result HTML document, or continue with other tasks and asynchronously receive the calculation result in a separate thread, for example in a Ajax based web application
See for an introduction this slideshow about the Dopplr image service:
http://de.slideshare.net/carsonified/dopplr-its-made-of-messages-matt-biddulph-presentation
If you can make it a service (but not a library), you have to do inter-process communication somehow - there are a few ways to do this on Windows:
Sockets directly which is hardest since you have to do marshalling/auth yourself
Shared Memory (yuck!)
RPC which works great but isn't trivial
DCOM which is easier but a pain to configure
WCF - but can you call it from your Windows Service written in Delphi?
I am using .Net 2.0 framework and would like to call a function in Windows service from a web service. Is this possible? And If yes, how much control I will have over the function i.e passing parameters, getting the result back etc. Any ideas would be greatly appreciated :)
Remoting is your best option if you need to pass parameter values.
If you don't need to share objects or anything too complex, ServiceController is probably easier.
You can do it through .NET remoting. If you go that route, it will appear you are calling a method and getting a result, but all your parameters will be serialized over the wire, and the result will be serialized back. Therefore, everything must be made serializable.
How about hosting a WCF service inside of the Windows Service. You can use net.tcp or named pipes to communicate between "your" web service and the one in the Windows Service. You can use the NetDataContractSerializer for serialization with type fidelity.
You could implement a basic http server that maps certain requests to functions. Query-string will be mapped to parameters. Actually not hard and I have done this in the past (as I provided some rudimentary template-based reporting). It wasn't dynamically, but it could be done dynamically. Look at HttpListener for a starting point. You could as well host the asp.net engine in it.
It has it advantages and disadvantages.
Why not package the function in its own DLL then distribute it with the Windows Service and the Web Service separately?
Create service project what export an interface COM or use PIPE to transfer data.
View this Interprocess Communication using Named Pipes in C#