Good morning,
I'm new to network programming but have been doing research and got the basics of setting up a server/client application. I would like to send binary data via TCP from the server to the client to parse and print out integers based on certain field lengths.
I'm basically creating a dummy server to send network data and would like for my client to parse it.
My idea is to create a byte array: byte[] data = {1,0,0,0,1,0,0,1) to represent 8 bytes being set. For example, the client would read the first 2 bytes and print a 2 followed by the next 6 bytes and print a 9.
This is a simple example. The byte array I would like to send would be 864 bytes. I would parse the first 96,48,48 etc.
Would this be a good way of doing this? If not, how should I send 1s and 0s? I found many example sending strings but I would like to send binary data.
Thanks.
You seem to be confusing bits and bytes.
A byte is composed of 8 bits, which can represent integer values from 0 to 255.
So, Instead of sending {1,0,0,0,1,0,0,1}, splitting the byte array and parsing the bytes as bits to get 2 and 9, you could simply create your array as:
byte[] data={2,9};
To send other primitive data types(int,long,float,double...), you can convert them to a byte array.
int x=96;
byte[] data=BitConverter.GetBytes(x);
The byte array can then be written into stream as
stream.Write(data,0,data.Length);
On the client side, parse the byte arrays as:
int x=BitConverter.ToInt32(data,startIndex);
MSDN has great references on TCP clients and listeners.
https://msdn.microsoft.com/en-us/library/system.net.sockets.tcplistener(v=vs.110).aspx
https://msdn.microsoft.com/en-us/library/system.net.sockets.tcpclient(v=vs.110).aspx
Related
I am very new to C# and using VS, but need a little help.
I have a textbox where a user can put in a value, for example "658". I want to convert this into bytes first (max 3 bytes) before sending it to the serialport. So the first byte sent is 0x02 and the second byte sent is0x92.
The second thing I am having issues with is the same but in reverse. I receive data in bytes, for example "0x0B, 0xC7, 0x14" and then I need to convert them into a decimal value and display them in a different Textbox.
I have tried a number of conversions that did not seem to work (parse, Tobyte and even using binary converter) so I am in need of help.
Thanks
This should get you started:
Convert From Numeric to Bytes:
var textInput = "658";
// validate...
var numericInput = Convert.ToInt32(textInput);
var convertedToBytes = BitConverter.GetBytes(numericInput);
// if your system is little endian (see below), reverse array output.
Convert From Bytes to Numeric:
// fourth octet is required to convert to an int32, which requires 4 bytes.
var bytesInput = new byte[] { 0x0, 0x0B, 0xC7, 0x14 };
// if your system is little endian (see below), reverse array.
var convertedFromBytes = BitConverter.ToInt32(bytesInput, 0);
Note, you want to pay attention to endian-ness. See this: https://msdn.microsoft.com/en-us/library/bb384066.aspx
You can use Encoding.GetBytes and Encoding.GetString to convert string to byte[] and back.
https://msdn.microsoft.com/ru-ru/library/ds4kkd55(v=vs.110).aspx
https://msdn.microsoft.com/ru-ru/library/744y86tc(v=vs.110).aspx
That should no be a problem as both the sending and the receiving serial port will accept/return a byte array. So the question comes down to how you create a by array from a string.
byte[] bytes = Encoding.ASCII.GetBytes(textBox1.Text);
The way back is:
string s = Encoding.ASCII.GetString(bytes);
I have a c# library which practically starts listening on a tcpip server an accepts a buffer of a certain size.
I need to send this packet as Byte array from php over the socket in a form of byte array or equivalent.
The packet is constructed for example byte[1] (a flag) is a number from 0 to 255 and byte[6] to byte[11] contains a float number in a string fromat for example:
005.70 which takes 6 bytes representing every character.
I managed to send the flag but when i try to send the float number it does not convert on the other side (C#).
So my question how can i send a byte array to c# using php?
From the C# part the conversion is being handled as follows:
float.Parse(System.Text.Encoding.Default.GetString(Data, 6, 6));
Just after i have posted the question i have dictated my answer. I am not 100% sure if this is the right way but it managed to convert correctly.
Here is the answer:
I created an array of characters and escaped the flag (4) to be the actual byte value being (4) but i didn't escape the money value
$string = array (0=>"\0", 1=>"\4", 2=>"\0", 3=>"\0", 4=>"\0", 5=>"\0", 6=>"5", 7=>".", 8=>"7", 9=>"\0", 10=>"\0");
Imploded all together with nothing as glue:
$arrByte = implode("", $string);
and sent over the opened socket:
$success = #fwrite($this->socket, $arrByte);
I'm working on a protocol which will transfer block of xml data via tcp socket. Now say I need to read all the bytes from a xml file and build a memory buffer. Then before sending the actual data bytes I need to send one header to other peer end. Say my protocol using below header type.
MessageID=100,Size=232,CRC=190
string strHeader = "100,232,190"
Now I would like to know how can I make this header length fixed (fixed header length is required for other peer to identify it as a header) for any amount of xml data. Currently say I'm having a xml file sized 283637bytes, so the message header will look like.
string strHeader = "100,283637,190"
How can I make it generic for any size of data? The code is being written both in c++ and c#.
There are a number of ways to do it.
Fixed Length
You can pad the numbers numbers with leading zeroes so you know exactly what length of the text you need to work with. 000100,000232,000190
Use Bytes instead of strings
If you are using integers, you can read the bytes as integers instead of manipulating the string. Look into the BinaryReader class. If needing to do this on the C++ side, the concept is still the same. I am sure there many ways to convert 4 bytes into an int.
Specify the length at the beginning
Usually when working with dynamic length strings. There is an indicator of how many bytes need to be read in order to get the entire string. You could specify the first 4 bytes of your message as the length of your string and then read up to that point.
The best approach for you is to implement this as a struct like
struct typedef _msg_hdr {
int messageID;
int size;
int crc;
}msg_hdr;
This will always have 12 bytes length. Now when sending your message, first send header to the receiver. The receiver should receive it in the same structure. This is the best and easiest way
I have an application that expects 5 bytes that is derived of a number. Right now I am using Uint32 which is 4 bytes. I been told to make a class that uses a byte and a Uint32. However, im not sure how to combine them since they are numbers.
I figured the best way may be to use a Uint64 and convert it down to 5 bytes. However, I am not sure how that can be done. I need to be able to convert it to 5 bytes and a separate function in the class to convert it back to a Uint64.
Does anyone have any ideas on the best way to do this?
Thank you
Use BitConverter.GetBytes and then just remove the three bytes you don't need.
To convert it back use BitConverter.ToUInt64 remembering that you'll have to first pad your byte array with three extra (zero) bytes.
Just watch out for endianness. You may need to reverse your array if the application you are sending these bytes to expects the opposite endianess. Also the endianess will dictate whether you need to add/remove bytes from the start or end of the array. (check BitConverter.IsLittleEndian)
I have a byte array and I want to read this array byte by byte and displayed each byte as integer.
how to do this using C#?
Given that the array is called bytes:
foreach(var b in bytes)
{
Console.WriteLine((int)b);
}
Though, in all fairness, the cast to int is probably unnecessary for display purposes.
Some of the C# code I have been writing communicates via TCP/IP with legacy C++ applications. Some codes use a raw packet format where C/C++ structures are passed back and forward.
Example of what the legacy code could look like:
Best Practice Mapping a byte array to a structure in C#