I'm working on project that will work real time: I have to write a video streaming client-server app, this server will to send the AVI/MPEG etc to an web application. I have some questions:
What is the protocol recommend to do this, http? rtp? or other?
In the web application, how do I to show it to user? using an flash player,java applet(I don't ensure if it's possible with it) or HTML5, what is the best way to do this currently?
I hope this is clean for you. Any help is very appreciadted. Thanks in advance. :)
There are several different ways to implement this (some that require programming and others that don't). Which one you choose depends on your requirements.
Red5 is an obvious solution which will allow you to only have to focus on the web side as long as your player of choice is flash.
FlourineFx provides a similar environment for .NET with a little more effort.
I've also done this with IIS and a custom server using HttpListener with much success if you're set on a pure Windows/C# solution. The caveat I'd add here is that it isn't always simple. In an environment with limited throughput, you will have problems since HTTP doesn't have the time corrections that RTP/RTMP/RTSP have but in a decent network it works 3 9's of the time (I've only tested with a single player though).
UPDATE
If you're talking about live streaming with .NET I'd suggest looking into the DirectShow (or related DirectX) API's. There is a wrapper for it for .NET available called DirectShow.NET.
Related
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 have a quite advanced application, where I need to add some client/server functionality. Some examples of functionalities is:
Chat
One vs. one fight in a browser game
Draw people on a map
I am creating this application in ASP.NET and AJAX. I do not use Silverlight/Java Applet/Flash or anything else. If possible, I do not want to change this for other reasons.
I thought about creating some kind of game server, and then communicating either web services or TCP protocol: But I have NO idea if this is a good idea. Also, I don't know how to do this.
So my question is:
What's the best way to implement this? And is it even possible? And if it is, could you give a reference or two?
Thanks a lot,
Lars
For doing chat & multiplayer games, the crux of the problem is in getting the server to asynchronously send messages to the client. This can be accomplished by a method called reverse-Ajax (or commet). Here is a simple example for how to do reverse-Ajax with ASP.NET. This is a very involved concept (at least until we can use HTML5 WebSockets) with a lot of thought going into security concerns, et al. I assume that by asking this question you are already quite familiar with Ajax & browser scripting (if not, you have a lot of reading to do).
Tutorial on writing a basic chat server: (in c# no less)
http://www.dreamincode.net/forums/topic/33396-basic-clientserver-chat-application-in-c%23/
Sgive you a good foundation on server development.
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/
Hi I'm a PHP developer and I have some experience with Java. I'm trying to learn C# and my first project would be a program that starts the timer on a PC by clicking a button on another PC in the network. The problem is, I don't know where to start? What do I need to read up on? The OS for both PCs is Windows XP so they're desktop apps. I'd appreciate any help from you C# gurus. I hope my start as a C# programmer would be successful. Thank you!
For the communication channel you should use WCF - here is an article showing how a simple client/server is written.
In terms of a UI for these - you may want to use winforms or WPF. WPF is the future, but winforms are easier to get to grips with. There is a Microsoft website dedicated to both of them.
There are several timer classes in the framework - see this article for comparisons.
If you are using .NET 3+, then WCF is generally the recommended technology. It is basically a merge of .NET remoting, web services, etc. into one library.
Edit: Sorry, my answer was based on Midhat's answer. Oded gave the best guidance since he actually read the question! WCF is only what you would use to communicate from one application to another. In your scenario, you can set up WCF as a TCP/IP server/client.
You need .Net remoting http://www.beansoftware.com/net-tutorials/net-remoting-tutorial.aspx
I've started with Flex recently, I've noticed that some plugin for Visual Studio exist, instead of buying a licence for another program (Flex Builder).
I was wondering how I could manage to remotely connect to my database with a Flash/Flex application with the help of C#/Asp.Net.
If I've correctly understood what I've read in the last few days, there is basically no way to 'query' to a database with Flex 3. So I suppose there is another way by using a webservice in C# on the database server that would respond to the Http query from Flex.
Am I right or totally of the track? If you have any other thoughts about this, please share.
I prefer (and recommend) using Webservices for the communication between Flex and C#. It's easy to use, and they both support serialization, so you can easily transfer Strong-Typed Objects. More on Flex and .NET can be found at http://www.adobe.com/devnet/flex/flex_net.html
Alternatively, you could consider using WebORB. This program functions as a gateway between and Flex, and enables you to use the Flash RemoteObject API for the communication to C#. More on this can be found at http://www.adobe.com/devnet/flex/articles/flextodotnet_remoteobject.html.
You really should consider using FluorineFx.
It takes about 5 minutes to set up an will allow Flex to call your methods like a service. You can then pass classes back and forth from .NET to Flex and back.
It's also the standard form of communication by Adobe, it's free and it's super fast.
Your understanding is correct. Flex is intended for developing client-side applications, and communication with a database is done through a server-side application.
Pretty much the same as building a JavaScript application. Though, Flex has several additional options for communicating with the backend. Webservices are great in a lot of cases, but the other options are worth looking into.
Here's a pretty happening article on the topic, if you haven't already seen it.
http://www.dehats.com/drupal/?q=node/33