I am starting on a fairly basic Server/Client application (logic wise), but I am a bit confused as to what I should use for my needs. It looks like there a few options, but basically I am going to have a Master Server, and X amount of client applications (one per dedicated machine). The main purpose of this setup is so that I can basically do the following...
-Issue command to server (console app) via an ASP front end to install software on one of the remote clients.
- Server tells client to download zip package (from a various FTP site) to location and extract it to specific path.
I am not positive, but it looks like C# has Sockets and then some sort of WebClient type of deal. I am assuming Sockets would be the best route to take, and to use asynchronous (each remote client is connected in its own thread, dealing with the server individually of others).
Any information on this would be great!
Without going into too much detail for your specific requirements, I would definitely look at WCF.
It encompasses a lot of the existing remoting, client / server, web services scenarios in a very complete and secure framework.
Client Server Programming with WCF
WebClient allows you to make HTTP requests, so I don't think it's very relevant here.
There are many approaches you can take for this app.
One is of course going with WCF, which provides about a million time more options than you will need. However, WCF does have a learning curve and in particular it's hard to understand what exactly is hidden behind all the abstractions without prior experience. Furthermore, this solution is not available if you are targeting .NET 2.0.
You can also implement a simple TCP client/server model using sockets. While you can program against raw sockets, .NET also offers the convenience classes System.Net.Sockets.TcpListener for the server and System.Net.Sockets.TcpClient for the clients. This approach is much closer to the metal, but this is a tradeoff: it's much easier to understand what exactly you are doing, but you will have to implement a fair bit of functionality yourself.
Related
I am currently involved in a simple to medium complex IOT project. The main purpose of our application is gathering data from our devices and analyzing that data as well as calculating statistics.
On the server side we run a MVC application. Up until now we used Hangfire to schedule the calculations. Hangfire is an amazing tool for scheduling emails and other simple stuff, for more advanced things it's too slow. The calculations can take up a lot of time and are processor-intensive (we are trying to optimize them though), so we need to call them in a background task, a simple API call won't be enough.
I thought about splitting the application into multiple parts, the website, the core and a windows service.
The problem is, I never tried that before and I have no idea what the best practice is to achieve that kind of thing. I searched for examples and articles, but all I found were suggestions to use Hangfire and/or Quartz.NET.
Does anyone have any resources on what the best practice is to build a MVC application, a Windows service and how they could communicate (probably through a queue)? What is the best practice in such a situation?
Although there may be many different possible ways to connect a site with a windows service, I'd probably chose one of the following two, based on your statements:
Direct communication
One way of letting your site send data to your backend windows service would be to use WCF. The service would expose an endpoint. For simplicity's sake this could be a basicHttpBinding or a netTcpBinding. The choice should be made based on your specific requirements; if the data is small then basicHttp may be "sufficient".
The advantage of this approach is that there's relatively little overhead needed: You'll just have to setup the windows service (which you'll have to do anyway) and open a port for the WCF binding. The site acts as client, the service as server. There's nothing special with it, just because the client being a MVC site. You can take almost any WCF tutorial as a starting point.
Note that instead of WCF you could use another technology like .NET Remoting or even sockets just as well. Personally, I often use WCF because I'm quite used to it, but this choice is pretty opinion based.
Queued communication
If reliability and integrity is crucial for your project, then using a queue might be a good idea. Again: depending on your needs, there may come diffeent products into consideration. If you don't need much monitoring and out-of-the-box management goodies, then even a very simplistic technology like MSMQ may be sufficient.
If your demands to the aforementioned points are more relevant, then maybe you should look for something else. Just recently I got in touch with Service Bus for Windows Server (SBWS). It's the Azure Service Bus's little brother which can be used on premises locally on your windows server. The nice thing about it is, that it comes at no extra charge as it's already licensed with your windows server licence.
As with the first point: MSMQ and SBWS are just two examples. There may be a lot of other products like NServiceBus, ZeroMQ or others usable, you name it.
I am creating a windows application in dotnet framework 4.5. The architecture involves a connection between Application and Central Server where it communicates to central server and sends data in case of a crash (a crash report is submitted). Also it downloads data from the server.
It's basically a two tier application. I am not sure which method will be best for the communication between these two as per the industry standards as well as acceptable to anti-virus applications.
So far, I have known about Socket communication as well as WCF but not sure if there are other methods or which one is better as per the requirements.
Please help.
Thanks!
Depends on the needs that you have, a web-service is always a good option, since it is very friendly for the network because it usually works in port 80 or 8080 and it has fail-safe mechanisms like exception handling which could make your job allot easier. If you use sockets, you might have problems, since the "network guys" will need to create rules for your application to work, and you still need to handle "manually" all of the connection problems.
I guess it depends on your needs, maybe give some more information so that you can get a more specific answer. In my opinion, I would say to go with the web-service since it is able to send binary data through the network in a safe way and it's more "scallable" (not sure if I translated this word correctly).
You can use both option with the WCF, but maybe you are looking for some other option? Is there any specific needs?
I want to study network programming, there’s a chapter named “networking” in “C# in a nutshell”, this chapter contains ‘WebClient’, ‘HttpClient’, ‘FTP’, ‘TCP’ and so on. But some body tell me to study WCF, I want to know what’s the relationship between WCF and c# networking programming, I remembered I have seen somewhere that WCF encapsulates network programming, it’s more flexible and convenient, but not efficiency. Does this mean the relationship between them like ado.net technology with orm? Which I should to study, network programming or WCF? Does c# network programming an obsolete technology?
Thanks
"network programming" usually refers to sockets, this is the lowest level of network communication and deals with pushing bytes on the network - all the other communication systems are built on top of sockets.
Most projects don't use sockets directly because there are simple higher level systems you can use but I think it's still worthwhile to learn the basics because it's not so complicated and it will help you deal with problems in those higher level systems.
The next level is WebClient and friends, those are relatively straightforward classes that implement a communication protocol on top of sockets (for example HTTP).
It's definitely worth your time to learn how to use those because they are simple and extremely useful (for example if you want to pull a file from the internet or communicate with a 3rd party service).
At the highest level you have WCF, this is an extensive (and in my personal opinion over-complicated and over-engineered) framework that gives you a class interface for an external network based service while trying (unsuccessfully) to hide all the communication details.
WCF is very popular in big organizations and "enterprise systems", so, if you want to get a job developing enterprise systems for big organizations learning WCF is a very smart career move.
So, my advice, start with sockets, learn just the basics - this will help you understand how things work under the covers (this will become very useful when you have to debug network problems).
Than move on to the higher level classes, write a simple program that uses WebClient to read a page from the internet so you are comfortable with the concept, don't bother
with all the advanced options, they are there and you can look them up later when you need them.
Learning just the basics of sockets and WebClient should take just a few hours, after that (if you want to work on big systems) learn how to use WCF.
Then you will have the WCF knowledge for your resume and you will know how to just get something over the internet with a few lines of code without using a gigantic framework when you don't need it.
If you want to study network programming you'll want to read about sockets and TCP/IP (and later on UDP if you want to stream or smaller packets). Sockets are the API that most OS:es uses to handle protocols like TCP/IP.
Your comparison is correct. WCF is a framework on top of the networking layer in .NET. Just as ORMs are frameworks on top of ADO.NET.
WCF is not the so called network programming. They are two concepts with some relationship.
Usually network programming means socket programming and TCP/IP. You are supposed to be familiar with protocols, such as HTTP, FTP, SNMP and so on. Then you can write programs that serve as protocol servers and clients. Network programming is still hot, though it is no longer that popular.
WCF is a framework for web services, which is HTTP only (mainly SOAP).
If possible, you should learn both or at least know of both.
How to create a NATIVE chat app for the iPhone? So far we have been exploring a few options:
Creating a web service using php or other web based language and have the app connect to that. Only problem is we can't figure out how to create "push" messaging with this, where the user will not have to refresh the conversation constantly.
Hosting an application on a server such as Windows Azure which will communicate to the iPhone app using TCP/IP. This way it seems like "push" messaging could be achieved by simply sending a packet to the iPhone. However, we have never done this before and don't know if we would run into any unforeseen potholes.
Have any of you made such an app before? If so how did you go about doing it? If not, what method would you recommend?
Thank you in advance!
EDIT:
To tell you exactly what we're trying to do: we need to make an app where a user can join a chat room and send/ receive messages from that chat room. There will also be custom features like that users will have their own profiles, etc. We would also like to make this as flexible as possible, so that we can integrate it on other platforms like android and blackberry later on.
So essentially the part that I'm stuck on is the send/ receive messages from a chat room. What technology should we use server side?
Something with an open socket, like Socket.IO could work. Node.js is a good server-side framework to explore. Here's an related SO question: iPhone Objective-C socket communication with Socket.IO
EDIT:
Question has changed since posting this answer -- originally question asked about web apps. ALso, originally the question was not clear that you wanted answers about the server side more than the client side.
On the server side, I would still recommend Node.js -- sounds like you want to use C# though, which makes me wonder why you're asking again about what server side tech to use. Most languages will provide you with ways to connect a socket to a client and access a database, which are the two main requirements of the app that it sounds like you want to make. Use whatever language you're comfortable with. However, some are going to come with libraries that may come in handy for this type of communication -- Node.js and Ruby on Rails (more useful if you want to do a polling-based solution)
Look at http://code.google.com/p/cocoaasyncsocket/ for a good library for doing socket communication from the iPhone without having to delve too deep into the low-level functions.
I've done this several times. Scaling to 100K concurrent users is non-trivial. If you want an off-the-shelf system I suspect ejabberd may do what you want. although the protocol IMHO is too verbose and uses far more bandwidth than necessary.
If you want to write your own solution and have the flexibility to write your own protocol and have the maximum possible scalability in the future then use a language that allows you to distribute the application across several servers. It is easier to allow that from the get go rather than writing a single server solution then have to retroactively make it distributable.
Having written servers like this in c++, Java and Erlang I would say the easiest and most relevant tool was Erlang. It makes good use of multi core processors and with a good design it facilitates distributing across several servers. C++ was the hardest!
I have also used Java with tools like JETTY and RabbitMQ to write a highly scalable system that required using HTTP as the protocol.
Personally I prefer a custom binary protocol as it allows you to reduce bandwidth to a minimum, and avoids DOS attacks and such as the protocol is well defined and lengths are sent before the packet, where as non binary protocols need to be parsed as they come in, with no idea of how big the packets may be.
Why not try XMPP protocol first? XMPP is based on TCP/IP.
There are several OpenSource server solution, clients, and application libraries. XMPP already supports chat room like service. You can define extension easily.
I'm writing a simple little game for my kids - it doesn't really matter what it does, though I couldn't tell you anyway, since I/they haven't quite decided yet! However, I think it will have a server component and a number of client components, and I'm looking at ways that the clients can communicate with the server.
ALL my previous experience... my entire career in fact... has involved the server element either being a database, a web server, or the two in tandem. Neither are appropriate in this case, so I'm curious as to what means I could & should use to communicate between the two.
Obviously, it would be preferable to adopt a technology or technique that I can re-use in my work, where I'm increasingly working with Windows Forms. I imagine there are 1001 different approaches I could adopt; it's a question of sorting the wheat from the chaff.
I've literally just started reading about WCF, but its unclear as yet, if this service-oriented approach is what I'm looking for.
I'm being deliberately vague about what the applications will do; I expect the client will announce their presence to the server, will feed user choices up to the server, and in return, the server will periodically update the client with what is going on in the wider game. The game will be turn-based rather than real-time... and quite low-tech really!
Suggestions? Ideally, with links to good learning resources if any are known.
Conclusion:
I actually thought there might be more viable alternatives; there is Remoting (now depracated), but the consensus says that WCF is the way to go - in my case, self-hosting looks appealing.
Thanks for the responses.
It looks like you're interested in WCF and that is a reasonable technology to use in this case.
When writing a network game the easiest approach is to use the client server approach here too. With WCF you have some different hosting possibilities, hosting in IIS or self hosting. I would go for self hosting to avoid the need for IIS on your home computers.
The service could be hosted in either a windows service or actually in one of the clients. I recommend running as a windows service. The service could very well run on one the same machine as one of the clients.
Edit:
If you want to host the server in one of the clients you could provide a menu option "start service" that starts a self hosted service on that computer (and automatically connect the client part to localhost). After the service has started you can present the computer name that you enter on the "other" computers to connect.
I would suggest to separate the service part into a separate project, then you can easily break out the service to a windows service later on if you like.
Edit2:
By the way, since WCF is driven by calls from the client you need to poll the server for changes. You can google wcf long polling or just long polling for methods to "push" messages from the server to the client.
Check out this article on creating a chat application using WCF -- http://www.codeproject.com/KB/IP/WCFWPFChatRoot.aspx
I've played around with this code in the past and the project was pretty simple to launch locally.
Here is a good book on WCF, which can help get you started. It has quite a bit of a learning curve (I still have barely scratched the surface myself), but I get the sense that it's a very powerful way to set up a service-based application. On the page I linked, check out the Examples link, which includes a bunch of code from the book, including Juval's ServiceModelEx, which has a wide variety of useful classes for working with WCF.
I'm going to go against the crowd here and suggestion NOT using WCF. WCF is a great technology for service oriented architecture, however it is largely written on the idea that clients will not stay connected to the server, but rather connect, send a message, perhaps receive a result, and disconnect.
There is a mechanism that can be used for long connected clients, but frankly, it doesn't work very well, has all kinds of issues and quirks, and is not very reliable in terms of knowing when clients have disconnected or not, or whether the clients know if they are still connected to the server. It's more of a bolted on solution that tries to shoehorn itself into the WCF model.
The other issue is one of firewalls. There can't be a firewall between the initiator and the receiver (or there must be an open port). That means you can't easily have two clients behind firewalls that want to talk to each other. You need some kind of exposed intermediate server that is open. While this problem applies to all solutions, it's easier to manage with straight TCP connections than WCF.
I'm not a huge proponent of rolling your own solution, but WCF really is overkill for simple two way communication between client apps.
I have not yet found a good open source network library for .NET. I know lots of people will chime in with various libraries, but every one i've seen is old and has various flaws. Most seem to be someone that ripped out their library from an app and tried to package it as a generic one, but leaving in all the assumptions of their app.
The problem is that recent versions of .NET have added lots of new network functionality, particularly in terms of asynchronous support. As of yet, i've not seen any libraries which implement these functions.
Anyone want to help me build a good, from scratch, network library based on .net 3.5+?
I would look at Remoting if I was you. It is fairly easy to impliment and you can definatly use it at work.
There is a tutorial on it here:
http://generally.wordpress.com/2007/05/31/a-simple-remoting-example-in-c/