I need a way to exchange data between a process and a windows service.
The process (Windows Form Application, Console Application, in the future also a Web Solution) needs to instruct and interact with the windows service.
I want to know which way is the best to accompplish this.
I'll write the solution in C#, .NET Framework version does not matter.
In the past I've used Remoting (Activator), WCF Interface with Contracts, Inter Process Exchange IPC and some named pipe implementation. What is your experience? Other ways?
I would choose WCF. It is most modern and probably best supported approach at the moment. It "replaced" older technologies in most scenarios. Nice feature of the WCF is that if you need to move your service to other protocol you can do that simply in configuration.
If you expect that windows service will always run on the same machine as other application you can use WCF with netNamedBinding. If you decide to move your service to other machine you will have to change configuration (probably to netTcpBinding) because Named pipes in WCF are limited only to IPC.
My previous experiences have always been over an IPCChannel, mainly because the only code I've had to be involved in that does any form of inter-process communication. It's never caused me any problems and the code is working away quite merrily as I type.
The only real answer to this question is, whichever you're most comfortable with.
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i'm about to decide on technology choices for an agent based application used in the transportaion systems domain.
basically there will be a central system hosting the backend, and multiple agents located across town (installed on desktops) that communicate with devices/kiosks collecting data and then transmitting them back to the central server. the central server could also be hosted on the cloud.
following are important
securing the data and communications between the device and the agent
and the agent and central server.
agents should be easily installable with little or no configuration.
near 100% uptime and availability
Does WCF fit the bill here?
if so what binding types should i go for? netTCP or wsHttp with SSL/HTTPS?
WCF is definitely a fit choice for this kind of scenario. For your bindings, the actual question is what technology you are going to use. Do you want to make the agents run in a non .NET environment like Java, then you should chose for wsHttpBinding. This binding communicates through SOAP and is very interoperable.
If you chose to use .NET agents, you might as well use netTcpBinding because they use the same WCF frameworks. It also supports binary encoding. If you really need to make a choice, take a look at the MSDN Documentation.
For your agents you could use a simple console application that runs in the background as a Windows service. WIX can help you with that (install an application as windows service), but thats all I know. WIX can also help you with basic installing and configure everything for you but it has a high learning curve so you might need to invest time in it.
I have a vb6-mysql client-server desktop application which is distributed as a setup file.
It uses DLL all logical operations as well as database operations. The EXE and the DLL are installed in the server as well as the client machines. When I say server which only means the database resides in that machine no other difference in EXE or DLLs.
As all the database operations are done in the DLL when connected from a client machine, performance would be less. It is not possible now to change all the logic into database.
Is it possible to store the DLL in the server machine only and use the same DLL by the client machine also so that database connection will always be from the server itself?
Is converting the DLL to a windows service the possible solution for this?
How can I to convert it to a service?
And finally, if it is possible to make the DLL act as a service, what would the connection issues be?
You appear to be trying to rediscover n-tier application development.
The usual way this would be done using VB6 within a LAN would be to create an ActiveX EXE instead of a DLL so you can use DCOM. However DCOM isn't something you'd want to expose over the Internet.
For such cases it is more typical to use a commonly-open-port protocol such as HTTP or HTTPS. Almost everyone has firewall settings permitting outbound HTTP and HTTPS connections and most of the major Web servers undergo regular hardening to make them safer to expose to the Internet.
The classic way to do this with VB6 was to use IIS to host the Remote Data Service, which uses a form of Web Service "under the covers" where your program doesn't deal with the gory details. However this is a deprecated approach, and today configuring IIS and the RDS components can be a chore since they are locked down hard by default.
This leaves you with such things as the deprecated SOAP Toolkit or 3rd party tools such as those in the PocketSOAP suite... or you can roll your own.
Doing this from scratch can be a bit of work but is more flexible, allowing REST instead of SOAP which can have advantages in itself. You could use whatever Web server you choose that can work with VB6 (via CGI, etc.).
The hardest approach to justify might seem the simplest on the surface: create your own protocol over TCP and write a Windows Service. This can be the most flexible of all but it can be more work than other options and you are on your own as far as making it and keeping it secure. You'll probably also face firewall issues depending on where your clients are and what the local firewall policies are there.
When we could rely on DCOM the issues were relatively small aside from security configuration headaches. With the Internet in the picture it is an entirely different story.
This really isn't something you undertake casually. Even assuming that your database is safe exposed to the Internet is naive and should be rethought.
We would like to develop WCF service for SL clients, which should support session management (PerSession) and callbacks. The WCF service would be hosted as a Windows service.
What would be best WCF binding choice (wsdual, pollingDuplex, any other)? Please also provide for/against points.
Regards,
There are no others. Silverlight does not support WSDualHttpBinding. You can choose PollingDuplexHttpBinding or PollingDuplexHttpBinding.
Have been working a little more in this area and it appears this is an area of constant and recent change. As of Silverlight 4, NetTcpTransport and HttpTransport are both supported using either text or binary encoding. It appears SL5 delivers further enhancements.
There is an interesting benchmark app here which allows you to profile relative performance of the two protocols. Though it was built for SL4, you can download, update the target framework to SL5 and see how it goes. It is a great way to make sure you've got everything setup properly.
Using NetTcpTransport should mean you can also use PerSession instancing on the server.
I'm just starting with distributed application development. I need to create (all by myself) an enterprise application for document management. That application will run on an intranet (within the firewall, no internet access is required now, BUT is probably that will be later).
The application needs to manage images that will be stored within MySQL Server (as blobs) and those images will be then recovered by the app and eventually one or more of them will be converted to PDF.
Performance is the most important non-functional requirement.
I have a couple of doubts.
What do you suggest to use, .NET Remoting or WCF over TCP-IP (I think second one is the best for the moment I need to expose the business logic over internet, changing the protocol).
Where do you suggest to make the transformation of the images to pdf files, I'm using iText. (I have thought to have the business logic stored within the IIS and exposed via WCF, and that business logic to be responsible of getting the images and transforming them to PDF, that because the IIS and the MySQL Server are the same physical machine). I ask about where to do the transformation because the app must be accessible from multiple devices, and for example, for mobile devices, the pdf maybe is not necessary.
Thank you very much in advance.
WCF, only consider remoting if WCF presents some issue such as performance in your use case. You have many many more scaling and customisation options available under WCF.
Depends. If sending the images over the net presents an issue then it may have to be done locally. However as in (1) your existing suggestion seems ok.
See .Net Remoting vs. WCF for a similar question.
Definitely remoting if this is an option
Transformation - same box that the service is; since the service is going to funnel the images anyway - this is the best place. I would not put it on DB server, to better distribute the load and to separate non-db load from db specific load.
In addition, look into .Net 4.0 RIA services. They allow you best combo of .Net Remoting and WCF
I am working on a project that involves an embedded system which runs a non-microsoft OS with a C program for the application and am developing .NET software for its end user applications. For remote configuring with the .NET software (which can go across firewalls), I am considering using WCF. I know only a little about WCF so far but I've read that it is supposed to be interoperable with environments other than .NET. The embedded environment has an HTTP stack but no built in support for web services. Does anyone have any experience with this kind of thing or know if it would be appropriate at all? If so please provide some advice or point me in the right direction.
Thanks!
WCF is interoperable because it's accessed over HTTP. Visual Studio can help you build client libraries very quickly for WCF, but client access to WCF doesn't require anything other than HTTP calls with the proper payload. If you're looking at a remote server call and your built-in support in your embedded environment is basic HTTP, look at building your server-side as REST-formatted methods. Your debugger will thank you.
What kinds of data are you planning on transferring back and forth? For something this low level and proprietary I would recommend sticking with good old fashioned Sockets.
I will be passing configuration data back and forth...basically to enable technical support staff to remotely program the device. If I were using sockets this could be binary data, but there is a requirement that customers with firewalls shouldn't need to open any ports. Because of this I was thinking of sending XML over HTTP. So, is it better to use WCF or REST on the server side? Or WCF with REST?
I'm curious about your "customers with firewalls" requirement. Sockets with binary data or XML over HTTP can use any port (not just port 80), and I'm curious if your device will be "listening" on the network, or just making an outbound connection. If your device is listening, you will need to open a port on the firewall. Making an outbound connection ("phoning home") is much easier on the firewall.
So I think you could use sockets and binary data. However, I have faced similar issues on the last two projects, and I really wanted to implement WCF using REST on the embedded device, but no one else wanted to do it - I'm hoping someone else will be first, and publish some results!
Good Luck! (and post your results!)