Develop Reference

Xamarin Android WiFi Direct routing

I have been working on some wifi direct communication. It currently works but I am having to rethink how routing will happen. I need to route upload streams (two different file inputs and a string input) to specific paths. The ideas I have had to sort the input streams are
add a header (can't find any docs on how to accomplish that and this would be by far the easiest way to handle this situation)
create a distinct socket for each input stream
I feel like the different distinct sockets could lead to multiple simultaneous connections. I am not sure if that could cause an issue but it seems like it potentially could.
There must be a cleaner way to handle this. I have not been able to track down any documentation on this and I would really like to hear if someone has a better idea.

Ended up setting my own system. sent everything as a byte[] in the format
[Header length][Header][Body]. This made the data easy to parse into it own areas.

Custom WMS Service

I'm doing an program, which is running on an local system, with no internet access. Is it possible to create my own custom Web Map Service (WMS) server, using C#. I no that there are free open source system's. But i like to have full control.
Thanks Morten Starck

That is very possible, but you might be in for a headache or two before you are done. The implementation specification and more is available from the Open Geospatial Consortium at the url below.
http://www.opengeospatial.org/standards/wms
It's quite a large specification but you might be able to get away with implementing only the parts you really need and leaving some of the more specific stuff out. You will of course also need to parse and render the map data from some source which might be your largest problem (for which I really would suggest you have a look at SharpMap, http://sharpmap.codeplex.com/ instead of rolling your own).

Server - client project (messanging protocols)

I want to do a project, that will include server and clients sides, using TcpSocket network communication (I use TcpListener for server and TcpClient for client side) and threading. But threading is not giving me any problems so far any longer.
But what it does, is something else... because the project will not include only chat, (but also creating new game, joining game, making moves, leaving game), I need to define somehow the message format.
I have read about messaging protocols and about using first few bytes of each message to tell the server what they are trying to do. The problem is that I do NOT know how to do it. So can someone show me an example of creating formated message?
Maybe its good to mention I use StreamReader and StreamWriter classes to pass data between server and clients. Is this a good way?
To add:
My problem now, is how to seperate this data, so that the server will know what to do with it. I have read about using 1nd few bytes to "be reserved" for the type of the message. But the problem is I don't know how to solve this issue. So far I was only using StreamReader and StreamWriter classes to pass only strings. If I use these kind of coding, it will all become too messy (not recognizable), if you know what I mean.
So I need to do something like it:
To send bytes:
1st few bytes the type of the data (but I don't know which class to use, maybe a BinaryWriter, and BinaryReader on the other side??)
the rest of the message
on server I have to have some code that will recognize these "1st few bytes" so the code will know what to do with the test of the message.
and based on these "1st few bytes" the code has to send data back to clients
Do you have any ideas on what this might look like, I mean as a skeleton (something basic, so I can work on with it).
Every bit of help would be very much appreciated.
I have found one example here on stackOverflow.com. It seems to be a code into a right direction. What do you think guys?

One option that might be much easier than defining your own protocol would be to use some existing library, like WCF or JSON-RPC.
Libraries like this have their disadvantages (they often produce output that is relatively big). If if you build your applications in a modular way, you can easily switch the communication backend later, when you find your first solution wasn't good enough.

You have a few options:
Make the message format textual - including its header. So, the header contains the message size, written out as text string, and ends with some terminator (\r\n for example.) HTTP takes this approach - the headers are text. When receiving the message, you process it with ReadLine, and parse header lines with stuff like int.TryParse(str).
Send message:
output.WriteLine(message.Length);
output.Write(message);
Receive message:
int len = int.Parse(input.ReadLine());
//message is the next 'len' characters
A second option: entire message is in a binary format - the message header is binary, and specifies amongst other things the message length. Message content is written as a stream of bytes, encoded using for example Encoding.UTF8.GetBytes(str).
Or, perhaps use the HTTP protocol? I believe there is basic support for HTTP server in the form of HttpListener. Here is a simple intro to HttpListener
Whatever you do, avoid using WCF :)

Transferring binary data using sockets?

I am thinking of making a server/client application that does this: the client(s) will connect to the server and the server will send back a list of folders (probably music or videos) that the client will be able to stream or download. I am going to make a GUI for this so that it won't be a text-only interface. I want it so that when the client connects to the server and gets the information about the media files that can be streamed/downloaded, the client will show the folders/files in an explorer-like interface (folders will show up with a folder icon, videos will show up with a video icon, etc.)
This seems really big to me but I really want to learn more about socket programming with C# and feel that getting my hands really dirty is the best way. As you can imagine, I have a lot of confusion about how to start this and what it is that I need to do to make this work.
The first part of my question is: If I want to let a client receive a list of files/folders and also have the ability to download/stream them, do I need to do something with transferring binary data using sockets or am I completely wrong on that? If I'm wrong, do I need to use something else like file readers and somehow use them over sockets?
The second part to my question is: when I transfer this information over to a client, how can I make the client show the appropriate icons for videos, folders, mp3s, etc.? I'm thinking that if I have to transfer binary data I will have to use that data to somehow populate the client GUI with the correct icons/data. I am stuck on exactly how to handle that. Are there certain methods/classes that I can use to parse that data and do what I want to do with it? Again, I don't know if I'm wrong about needing to transfer binary data but either way I am confused on what it is that's necessary to handle this.
I apologize if any of my terminology is wrong. I am obviously not an expert in C# yet ;)

Any time you are sending data between machines (or between processes), you are already talking binary data (you could argue that everything is binary data, but when working with it as an OO model it doesn't feel like it). The point here is that all you need to do is serialize your messages. There are a myriad of serialization frameworks - some aimed at convenience, some aimed to range-of-features, and som can use aimed at performance (minimum bandwidth etc).
Even the inbuilt ones would work - for example, you can use XmlSerializer etc to write to a Stream (such as the NetworkStream you typically use with a socket). But please - not BinaryFormatter (it will hurt you, honest). Personally I'd use something a bit less verbose such as protobuf-net, but I'm somewhat biased since I wrote it ;p
However, note that when working with sockets, you are typically sending multiple (separate) messages as part of the conversation. In order for each end to correctly and conveniently read the right data per-message from the stream, it is common to prefix each message with the length (number of bytes) - for example, as a little-endian int taking a fixed 4 bytes. So the reading process is:
read 4 bytes
interpret that as an int, let's say n
read n bytes
run that data through your deserializer, perhaps via MemoryStream
process the message
and the sending process might be:
serialize the message, perhaps to a MemoryStream
query the length and form the 4 byte prefix
write the prefix
write the data

You don't have to go to as low level as Socket, unless you just want to learn of course.
I suggest using WCF. It will completely meet your requirements, will be flexible and you will not have to deal with sockets directly.
WCF is a big framework, but you can quickly learn how to use it.
Introduction to WCF
Here you can find how to retrieve and show file icon in Windows.
If you client is hosted by Windows, you don't need to transfer icons, you can just retrieve image on the client by filename/extension.

Creating multi-part messages from single-part messages in custom pipeline (BizTalk)

I have read somewhere that I better use multi-part types on receive and send ports, but can't understand one thing. If I receive some XML data through say HTTP port how do I put it in right path in the message. Should I create custom pipeline for this or there is something else (I'm new to BizTalk)?

Sergej,
You must have picked up this concept half baked from the article 8 Tips and Tricks for BizTalk Programming (http://msdn.microsoft.com/en-us/magazine/cc163423.aspx)
As explained in the article, it makes more sense to create Multi-Part messages inside the orchestrations, so when you want to change something in the schema its easy to do so without deleting all the links between the ports and send/receive shapes.
Assigning a message to a specific part (normally the first part) should not be a big issue within the orchestration, you should be able to do it via maps or within the message assignment shape.
HTH

There's really no hard and fast rule about using multi-part message types for something like this; it really depends a lot on your scenario.
However, I'd like to point out that, underneath, all messages in BizTalk are, at the lowest level, multi-part messages. The question is whether accessing those extra parts (if they are present) is easy in an orchestration or not ;)
That said, let me point out that, in many cases, there's little reason to use multi-part message types in orchestrations. For example, the HTTP or FILE adapters will never generate a message with multiple parts on their own, unless perhaps you've got something like the SMIME decoding component on your receive pipeline.
Some other adapters do definitely take advantage of multi-part message types, like perhaps the POP adapter (attachments) or the SOAP adapter. But unless you've got an scenario like this, that really requires multi-part message types, I see little reason why you'd start with those.