C# socket send

C# socket send DEFAULT

Writing a WebSocket server in C#

Introduction

If you would like to use the WebSocket API, it is useful if you have a server. In this article I will show you how to write one in C#. You can do it in any server-side language, but to keep things simple and more understandable, I chose Microsoft's language.

This server conforms to RFC 6455 so it will only handle connections from Chrome version 16, Firefox 11, IE 10 and over.

First steps

WebSockets communicate over a TCP (Transmission Control Protocol) connection. Luckily, C# has a TcpListener class which does as the name suggests. It is in the System.Net.Sockets namespace.

Note: It is a good idea to include the namespace with the  keyword in order to write less. It allows usage of a namespace's classes without typing the full namespace every time.

TcpListener

Constructor:

specifies the IP of the listener, and specifies the port.

Note: To create an object from a , use the  static method of .

Methods:

  • Waits for a Tcp connection, accepts it and returns it as a TcpClient object.

Here's a barebones server implementation:

TcpClient

Methods:

  • Gets the stream which is the communication channel. Both sides of the channel have reading and writing capability.

Properties:

  • This Property indicates how many bytes of data have been sent. The value is zero until is true.

NetworkStream

Methods:

  • Writes bytes from buffer, offset and size determine length of message.
  • Reads bytes to . and determine the length of the message.

Let us extend our example.

Handshaking

When a client connects to a server, it sends a GET request to upgrade the connection to a WebSocket from a simple HTTP request. This is known as handshaking.

This sample code can detect a GET from the client. Note that this will block until the first 3 bytes of a message are available. Alternative solutions should be investigated for production environments.

The response is easy to build, but might be a little bit difficult to understand. The full explanation of the Server handshake can be found in RFC 6455, section 4.2.2. For our purposes, we'll just build a simple response.

You must:

  1. Obtain the value of the "Sec-WebSocket-Key" request header without any leading or trailing whitespace
  2. Concatenate it with "258EAFA5-E914-47DA-95CA-C5AB0DC85B11" (a special GUID specified by RFC 6455)
  3. Compute SHA-1 and Base64 hash of the new value
  4. Write the hash back as the value of "Sec-WebSocket-Accept" response header in an HTTP response

Decoding messages

After a successful handshake, the client will send encoded messages to the server.

If we send "MDN", we get these bytes:

129 131 61 84 35 6 112 16 109

Let's take a look at what these bytes mean.

The first byte, which currently has a value of 129, is a bitfield that breaks down as such:

FIN (Bit 0)RSV1 (Bit 1)RSV2 (Bit 2)RSV3 (Bit 3)Opcode (Bit 4:7)
10000x1=0001
  • FIN bit: This bit indicates whether the full message has been sent from the client. Messages may be sent in frames, but for now we will keep things simple.
  • RSV1, RSV2, RSV3: These bits must be 0 unless an extension is negotiated which supplies a nonzero value to them.
  • Opcode: These bits describe the type of message received. Opcode 0x1 means this is a text message. Full list of Opcodes

The second byte, which currently has a value of 131, is another bitfield that breaks down as such:

MASK (Bit 0)Payload Length (Bit 1:7)
10x83=0000011
  • MASK bit: Defines whether the "Payload data" is masked.  If set to 1, a masking key is present in Masking-Key, and this is used to unmask the "Payload data". All messages from the client to the server have this bit set.
  • Payload Length: If this value is between 0 and 125, then it is the length of message. If it is 126, the following 2 bytes (16-bit unsigned integer) are the length. If it is 127, the following 8 bytes (64-bit unsigned integer) are the length.

Note: Because the first bit is always 1 for client-to-server messages, you can subtract 128 from this byte to get rid of the MASK bit.

Note that the MASK bit is set in our message. This means that the next four bytes (61, 84, 35, and 6) are the mask bytes used to decode the message. These bytes change with every message.

The remaining bytes are the encoded message payload.

Decoding algorithm

D_i = E_i XOR M_(i mod 4)

where D is the decoded message array, E is the encoded message array, M is the mask byte array, and i is the index of the message byte to decode.

Example in C#:

Put together

wsserver.cs

client.html

Related

Sours: https://developer.mozilla.org/en-US/docs/Web/API/WebSockets_API/Writing_WebSocket_server

This tutorial will explain how to connect to a host machine, and then send data via TCP Socket.

First, we need to add the namespaces:

using System.Net; using System.Net.Sockets;

And the function:

public static void SendData(string data, Int32 port, string ips) { IPAddress host = IPAddress.Parse(ips);// IPEndPoint ipendpoint = new IPEndPoint(host, port); // assign host and port Socket socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp); try { socket.Connect(ipendpoint); } catch (SocketException e) { MessageBox.Show(e.Message); socket.Close(); return; } try { socket.Send(Encoding.ASCII.GetBytes(data)); } catch (SocketException e) { MessageBox.Show(e.Message); socket.Close(); return; } socket.Close(); }

Then call the function:

SendData("Hello World!", 1212,"127.0.0.1");

Note: The port should be listening. To check that, open the Command Prompt, then type netstat –an and hit enter.

Possible Errors:

Error 1:
No connection could be made because the target machine actively refused it 127.0.0.1:1212.

Cause: A nonexisting port or the part is not listening.

Error 2:
A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond 122.4.0.3:1212

Cause: Host name doesn’t exist.

 

Sours: http://www.tutorialspanel.com/socket-connect-data-send-using-csharp/index.htm
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Socket Programming in C#

Socket programming is a way of connecting two nodes on a network to communicate with each other. Basically, it is a one-way Client and Server setup where a Client connects, sends messages to the server and the server shows them using socket connection. One socket (node) listens on a particular port at an IP, while other socket reaches out to the other to form a connection. Server forms the listener socket while the client reaches out to the server. Before going deeper into Server and Client code, it is strongly recommended to go through TCP/IP Model.
 

  Before creating client’s socket a user must decide what ‘IP Address‘ that he want to connect to, in this case, it is the localhost. At the same time, we also need the ‘Family‘ method that will belong to the socket itself. Then, through the ‘connect‘ method, we will connect the socket to the server. Before sending any message, it must be converted into a byte array. Then and only then, it can be sent to the server through the ‘send‘ method. Later, thanks to the ‘receive‘ method we are going to get a byte array as answer by the server. It is notable that just like in the C language, the ‘send’ and ‘receive’ methods still return the number of bytes sent or received.

C#

 
 
 
 
 
 
 
 
 

In the same way, we need an ‘IP address’ that identifies the server in order to let the clients to connect. After creating the socket, we call the ‘bind‘ method which binds the IP to the socket. Then, call the ‘listen‘ method. This operation is responsible for creating the waiting queue which will be related to every opened ‘socket‘. The ‘listen‘ method takes as input the maximum number of clients that can stay in the waiting queue. As stated above, there is communication with the client through ‘send‘ and ‘receive‘ methods. 

Note: Don’t forget the conversion into a byte array. 

C#

 
 
 
 
 

To run on Terminal or Command Prompt: 



  • First save the files with .cs extension. Suppose we saved the files as client.cs and server.cs.
  • Then compile both the files by executing the following commands:
$ csc client.cs$ csc server.cs
  • After successful compilation opens the two cmd one for Server and another for Client and first try to execute the server as follows

  • After that on another cmd execute the client code and see the following output on the server side cmd.

  • Now you can see the changes on the server as soon as the client program executes.




My Personal Notesarrow_drop_up
Sours: https://www.geeksforgeeks.org/socket-programming-in-c-sharp/

Socket Send and Receive [C#]

This example shows how to send and receive data via TCP/IP using Socket in .NET Framework. There are methods Socket.Send and Socket.Receive.

Socket.Send method

Send method sends data from your buffer to a connected Socket. When you call the Send method it returns number of bytes which were „sent“. But it doesn't mean that the bytes were already received by the other side, it only means that the data were stored in a socket buffer and the socket will be trying to send them. If the socket buffer is full a WouldBlock error occurs. You should wait for a while a try to send the data again.

Following method sends size bytes stored in the buffer from the offset position. If the operation lasts more than timeout milliseconds it throws an exception.

[C#]
public static voidSend(Socket socket, byte[] buffer, int offset, int size, int timeout) { int startTickCount = Environment.TickCount; int sent = 0; do { if (Environment.TickCount > startTickCount + timeout) throw newException("Timeout."); try { sent += socket.Send(buffer, offset + sent, size - sent, SocketFlags.None); } catch (SocketException ex) { if (ex.SocketErrorCode == SocketError.WouldBlock || ex.SocketErrorCode == SocketError.IOPending || ex.SocketErrorCode == SocketError.NoBufferSpaceAvailable) { Thread.Sleep(30); } elsethrow ex; } } while (sent < size); }

To call the Send method use following code snippet (suppose the static Send method is defined in MyClass class). TCP/IP socket can be obtained using TcpClient class. Use TcpClient.Client property to get the underlying Socket (this property is public since .NET Framework 2.0).

[C#]
Socket socket = tcpClient.Client; string str = "Hello world!"; try { MyClass.Send(socket, Encoding.UTF8.GetBytes(str), 0, str.Length, 10000); } catch (Exception ex) { }

Socket.Receive method

Receive method receives data from a bound Socket to your buffer. The method returns number of received bytes. If the socket buffer is empty a WouldBlock error occurs. You should try to receive the data later.

Following method tries to receive size bytes into the buffer to the offset position. If the operation lasts more than timeout milliseconds it throws an exception.

[C#]
public static voidReceive(Socket socket, byte[] buffer, int offset, int size, int timeout) { int startTickCount = Environment.TickCount; int received = 0; do { if (Environment.TickCount > startTickCount + timeout) throw newException("Timeout."); try { received += socket.Receive(buffer, offset + received, size - received, SocketFlags.None); } catch (SocketException ex) { if (ex.SocketErrorCode == SocketError.WouldBlock || ex.SocketErrorCode == SocketError.IOPending || ex.SocketErrorCode == SocketError.NoBufferSpaceAvailable) { Thread.Sleep(30); } elsethrow ex; } } while (received < size); }

Call the Receive method using code such this:

[C#]
Socket socket = tcpClient.Client; byte[] buffer = new byte[12]; try { MyClass.Receive(socket, buffer, 0, buffer.Length, 10000); string str = Encoding.UTF8.GetString(buffer, 0, buffer.Length); } catch (Exception ex) { }

See also

  • Socket – MSDN – provides many methods for network communications
  • Socket.Send – MSDN – sends data to a socket
  • Socket.Receive – MSDN – receives data from a socket
  • SocketError – MSDN – enumeration with error codes for the Socket (WouldBlock)
  • TcpClient – MSDN – provides client connections for TCP
  • TcpClient.Client – MSDN – gets the underlying Socket

By Jan Slama, 2007

Sours: https://www.csharp-examples.net/socket-send-receive/

Send c# socket

Socket.Send Method

Definition

Important

Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.

Sends data to a connected Socket.

Overloads

Send(IList<ArraySegment<Byte>>, SocketFlags, SocketError)

Sends the set of buffers in the list to a connected Socket, using the specified SocketFlags.

Send(Byte[], Int32, Int32, SocketFlags, SocketError)

Sends the specified number of bytes of data to a connected Socket, starting at the specified offset, and using the specified SocketFlags.

Send(Byte[], Int32, Int32, SocketFlags)

Sends the specified number of bytes of data to a connected Socket, starting at the specified offset, and using the specified SocketFlags.

Send(ReadOnlySpan<Byte>, SocketFlags, SocketError)

Sends data to a connected Socket using the specified SocketFlags.

Send(Byte[], Int32, SocketFlags)

Sends the specified number of bytes of data to a connected Socket, using the specified SocketFlags.

Send(IList<ArraySegment<Byte>>)

Sends the set of buffers in the list to a connected Socket.

Send(IList<ArraySegment<Byte>>, SocketFlags)

Sends the set of buffers in the list to a connected Socket, using the specified SocketFlags.

Send(Byte[])

Sends data to a connected Socket.

Send(ReadOnlySpan<Byte>, SocketFlags)

Sends data to a connected Socket using the specified SocketFlags.

Send(Byte[], SocketFlags)

Sends data to a connected Socket using the specified SocketFlags.

Send(ReadOnlySpan<Byte>)

Sends data to a connected Socket.

Send(IList<ArraySegment<Byte>>, SocketFlags, SocketError)

Sends the set of buffers in the list to a connected Socket, using the specified SocketFlags.

Parameters

Returns

Int32

The number of bytes sent to the Socket.

Attributes

CLSCompliantAttribute

Exceptions

Remarks

This overload requires at least one buffer that contains the data you want to send. The SocketFlags value defaults to 0. If you specify the DontRoute flag as the parameter, the data you are sending will not be routed.

If you are using a connectionless protocol, you must call Connect before calling this method, or Send will throw a SocketException. If you are using a connection-oriented protocol, you must either use Connect to establish a remote host connection, or use Accept to accept an incoming connection.

If you are using a connectionless protocol and plan to send data to several different hosts, you should use the SendTo method. If you do not use the SendTo method, you will have to call Connect before each call to Send. You can use SendTo even after you have established a default remote host with Connect. You can also change the default remote host prior to calling Send by making another call to Connect.

If you are using a connection-oriented protocol, Send will block until all of the bytes in the buffer are sent, unless a time-out was set by using Socket.SendTimeout. If the time-out value was exceeded, the Send call will throw a SocketException. In non-blocking mode, Send may complete successfully even if it sends less than the number of bytes in the buffer. It is your application's responsibility to keep track of the number of bytes sent and to retry the operation until the application sends the bytes in the buffer. There is also no guarantee that the data you send will appear on the network immediately. To increase network efficiency, the underlying system may delay transmission until a significant amount of outgoing data is collected. A successful completion of the Send method means that the underlying system has had room to buffer your data for a network send.

Note

The successful completion of a send does not indicate that the data was successfully delivered. If no buffer space is available within the transport system to hold the data to be transmitted, send will block unless the socket has been placed in nonblocking mode.

Send(Byte[], Int32, Int32, SocketFlags, SocketError)

Sends the specified number of bytes of data to a connected Socket, starting at the specified offset, and using the specified SocketFlags.

Parameters

buffer
Byte[]

An array of type Byte that contains the data to be sent.

offset
Int32

The position in the data buffer at which to begin sending data.

size
Int32

The number of bytes to send.

Returns

Int32

The number of bytes sent to the Socket.

Exceptions

ArgumentOutOfRangeException

is less than 0.

-or-

is greater than the length of .

-or-

is less than 0.

-or-

is greater than the length of minus the value of the parameter.

SocketException

is not a valid combination of values.

-or-

An operating system error occurs while accessing the Socket.

Examples

The following code example specifies the data buffer, an offset, a size, and SocketFlags for sending data to a connected Socket.

Remarks

Send synchronously sends data to the remote host specified in the Connect or Accept method and returns the number of bytes successfully sent. Send can be used for both connection-oriented and connectionless protocols.

In this overload, if you specify the DontRoute flag as the parameter, the data you are sending will not be routed.

If you are using a connectionless protocol, you must call Connect before calling this method or Send will throw a SocketException. If you are using a connection-oriented protocol, you must either use Connect to establish a remote host connection, or use Accept to accept an incoming connection.

If you are using a connectionless protocol and plan to send data to several different hosts, you should use SendTo. If you do not use SendTo, you will have to call Connect before each call to Send. It is okay to use SendTo even after you have established a default remote host with Connect. You can also change the default remote host prior to calling Send by making another call to Connect.

You must also be sure that the size does not exceed the maximum packet size of the underlying service provider. If it does, the datagram will not be sent and Send will throw a SocketException.

If you are using a connection-oriented protocol, Send will block until the requested number of bytes are sent, unless a time-out was set by using Socket.SendTimeout. If the time-out value was exceeded, the Send call will throw a SocketException. In nonblocking mode, Send may complete successfully even if it sends less than the number of bytes you request. It is your application's responsibility to keep track of the number of bytes sent and to retry the operation until the application sends the requested number of bytes. There is also no guarantee that the data you send will appear on the network immediately. To increase network efficiency, the underlying system may delay transmission until a significant amount of outgoing data is collected. A successful completion of the Send method means that the underlying system has had room to buffer your data for a network send.

Note

The successful completion of a send does not indicate that the data was successfully delivered. If no buffer space is available within the transport system to hold the data to be transmitted, send will block unless the socket has been placed in nonblocking mode.

See also

Send(Byte[], Int32, Int32, SocketFlags)

Sends the specified number of bytes of data to a connected Socket, starting at the specified offset, and using the specified SocketFlags.

Parameters

buffer
Byte[]

An array of type Byte that contains the data to be sent.

offset
Int32

The position in the data buffer at which to begin sending data.

size
Int32

The number of bytes to send.

Returns

Int32

The number of bytes sent to the Socket.

Exceptions

ArgumentOutOfRangeException

is less than 0.

-or-

is greater than the length of .

-or-

is less than 0.

-or-

is greater than the length of minus the value of the parameter.

SocketException

is not a valid combination of values.

-or-

An operating system error occurs while accessing the Socket.

Examples

The following code example specifies the data buffer, an offset, a size, and SocketFlags for sending data to a connected Socket.

Remarks

Send synchronously sends data to the remote host specified in the Connect or Accept method and returns the number of bytes successfully sent. Send can be used for both connection-oriented and connectionless protocols.

In this overload, if you specify the DontRoute flag as the parameter, the data you are sending will not be routed.

If you are using a connectionless protocol, you must call Connect before calling this method or Send will throw a SocketException. If you are using a connection-oriented protocol, you must either use Connect to establish a remote host connection, or use Accept to accept an incoming connection.

If you are using a connectionless protocol and plan to send data to several different hosts, you should use SendTo. If you do not use SendTo, you will have to call Connect before each call to Send. It is okay to use SendTo even after you have established a default remote host with Connect. You can also change the default remote host prior to calling Send by making another call to Connect.

You must also be sure that the size does not exceed the maximum packet size of the underlying service provider. If it does, the datagram will not be sent and Send will throw a SocketException.

If you are using a connection-oriented protocol, Send will block until the requested number of bytes are sent, unless a time-out was set by using Socket.SendTimeout. If the time-out value was exceeded, the Send call will throw a SocketException. In nonblocking mode, Send may complete successfully even if it sends less than the number of bytes you request. It is your application's responsibility to keep track of the number of bytes sent and to retry the operation until the application sends the requested number of bytes. There is also no guarantee that the data you send will appear on the network immediately. To increase network efficiency, the underlying system may delay transmission until a significant amount of outgoing data is collected. A successful completion of the Send method means that the underlying system has had room to buffer your data for a network send.

Note

The successful completion of a send does not indicate that the data was successfully delivered. If no buffer space is available within the transport system to hold the data to be transmitted, send will block unless the socket has been placed in nonblocking mode.

See also

Send(ReadOnlySpan<Byte>, SocketFlags, SocketError)

Parameters

buffer
ReadOnlySpan<Byte>

A span of bytes that contains the data to be sent.

socketFlags
SocketFlags

A bitwise combination of the enumeration values that specifies send and receive behaviors.

errorCode
SocketError

When this method returns, contains one of the enumeration values that defines error codes for the socket.

Returns

Int32

The number of bytes sent to the Socket.

Exceptions

Remarks

Send synchronously sends data to the remote host specified in the Connect or Accept method and returns the number of bytes successfully sent. Send can be used for both connection-oriented and connectionless protocols.

This overload requires a buffer that contains the data you want to send. The SocketFlags value defaults to 0, the buffer offset defaults to 0, and the number of bytes to send defaults to the size of the buffer.

If you're using a connectionless protocol, you must call Connect before calling this method, or Send will throw a SocketException. If you're using a connection-oriented protocol, you must either use Connect to establish a remote host connection, or use Accept to accept an incoming connection.

If you're using a connectionless protocol and plan to send data to several different hosts, you should use the SendTo method. If you don't use the SendTo method, you'll have to call Connect before each call to Send. You can use SendTo even after you've established a default remote host with Connect. You can also change the default remote host before calling Send by making another call to Connect.

If you're using a connection-oriented protocol, Send will block until all of the bytes in the buffer are sent, unless a time-out was set by using Socket.SendTimeout. If the time-out value was exceeded, the Send call will throw a SocketException. In nonblocking mode, Send may complete successfully even if it sends less than the number of bytes in the buffer. It is your application's responsibility to keep track of the number of bytes sent and to retry the operation until the application sends the bytes in the buffer. There's also no guarantee that the data you send will appear on the network immediately. To increase network efficiency, the underlying system may delay transmission until a significant amount of outgoing data is collected. A successful completion of the Send method means that the underlying system has had room to buffer your data for a network send.

This member outputs trace information when you enable network tracing in your application. For more information, see Network Tracing in the .NET Framework.

Important

The successful completion of a send does not indicate that the data was successfully delivered. If no buffer space is available within the transport system to hold the data to be transmitted, send will block unless the socket has been placed in nonblocking mode.

See also

Send(Byte[], Int32, SocketFlags)

Sends the specified number of bytes of data to a connected Socket, using the specified SocketFlags.

Parameters

buffer
Byte[]

An array of type Byte that contains the data to be sent.

size
Int32

The number of bytes to send.

Returns

Int32

The number of bytes sent to the Socket.

Exceptions

SocketException

is not a valid combination of values.

-or-

An operating system error occurs while accessing the socket.

Examples

The following code example sends the data found in buffer, and specifies None for SocketFlags.

Remarks

Send synchronously sends data to the remote host established in the Connect or Accept method and returns the number of bytes successfully sent. Send can be used for both connection-oriented and connectionless protocols.

This overload requires a buffer that contains the data you want to send, the number of bytes you want to send, and a bitwise combination of any SocketFlags. If you specify the DontRoute flag as the parameter, the data you're sending won't be routed.

If you're using a connectionless protocol, you must call Connect before calling this method, or Send will throw a SocketException. If you're using a connection-oriented protocol, you must either use Connect to establish a remote host connection, or use Accept to accept an incoming connection.

If you're using a connectionless protocol and plan to send data to several different hosts, you should use the SendTo method. If you don'tuse the SendTo method, you'll have to call the Connect method before each call to the Send method. You can use SendTo even after you've established a default remote host with Connect. You can also change the default remote host before calling Send by making another call to Connect.

With a connection-oriented protocol, Send will block until the requested number of bytes are sent, unless a time-out was set by using Socket.SendTimeout. If the time-out value was exceeded, the Send call will throw a SocketException. In nonblocking mode, Send may complete successfully even if it sends less than the number of bytes you request. It is your application's responsibility to keep track of the number of bytes sent and to retry the operation until the application sends the requested number of bytes. There is also no guarantee that the data you send will appear on the network immediately. To increase network efficiency, the underlying system may delay transmission until a significant amount of outgoing data is collected. A successful completion of the Send method means that the underlying system has had room to buffer your data for a network send.

This member outputs trace information when you enable network tracing in your application. For more information, see Network Tracing in the .NET Framework.

Important

The successful completion of a send does not indicate that the data was successfully delivered. If no buffer space is available within the transport system to hold the data to be transmitted, send will block unless the socket has been placed in nonblocking mode.

See also

Send(IList<ArraySegment<Byte>>)

Sends the set of buffers in the list to a connected Socket.

Parameters

Returns

Int32

The number of bytes sent to the Socket.

Exceptions

SocketException

An error occurred when attempting to access the socket. See remarks section below.

Remarks

Send can be used for both connection-oriented and connectionless protocols.

This overload requires at least one buffer that contains the data you want to send.

If you are using a connectionless protocol, you must call Connect before calling this method, or Send will throw a SocketException. If you are using a connection-oriented protocol, you must either use Connect to establish a remote host connection, or use Accept to accept an incoming connection.

If you are using a connectionless protocol and plan to send data to several different hosts, you should use the SendTo method. If you do not use the SendTo method, you will have to call Connect before each call to Send. You can use SendTo even after you have established a default remote host with Connect. You can also change the default remote host prior to calling Send by making another call to Connect.

If you are using a connection-oriented protocol, Send will block until all of the bytes in the buffer are sent, unless a time-out was set by using Socket.SendTimeout. If the time-out value was exceeded, the Send call will throw a SocketException. In nonblocking mode, Send may complete successfully even if it sends less than the number of bytes in the buffer. It is your application's responsibility to keep track of the number of bytes sent and to retry the operation until the application sends the bytes in the buffer. There is also no guarantee that the data you send will appear on the network immediately. To increase network efficiency, the underlying system may delay transmission until a significant amount of outgoing data is collected. A successful completion of the Send method means that the underlying system has had room to buffer your data for a network send.

Note

The successful completion of a send does not indicate that the data was successfully delivered. If no buffer space is available within the transport system to hold the data to be transmitted, send will block unless the socket has been placed in nonblocking mode.

Send(IList<ArraySegment<Byte>>, SocketFlags)

Sends the set of buffers in the list to a connected Socket, using the specified SocketFlags.

Parameters

Returns

Int32

The number of bytes sent to the Socket.

Exceptions

Remarks

This overload requires at least one buffer that contains the data you want to send. The SocketFlags value defaults to 0. If you specify the DontRoute flag as the parameter, the data you are sending will not be routed.

If you are using a connectionless protocol, you must call Connect before calling this method, or Send will throw a SocketException. If you are using a connection-oriented protocol, you must either use Connect to establish a remote host connection, or use Accept to accept an incoming connection.

If you are using a connectionless protocol and plan to send data to several different hosts, you should use the SendTo method. If you do not use the SendTo method, you will have to call Connect before each call to Send. You can use SendTo even after you have established a default remote host with Connect. You can also change the default remote host prior to calling Send by making another call to Connect.

If you are using a connection-oriented protocol, Send will block until all of the bytes in the buffer are sent, unless a time-out was set by using Socket.SendTimeout. If the time-out value was exceeded, the Send call will throw a SocketException. In non-blocking mode, Send may complete successfully even if it sends less than the number of bytes in the buffer. It is your application's responsibility to keep track of the number of bytes sent and to retry the operation until the application sends the bytes in the buffer. There is also no guarantee that the data you send will appear on the network immediately. To increase network efficiency, the underlying system may delay transmission until a significant amount of outgoing data is collected. A successful completion of the Send method means that the underlying system has had room to buffer your data for a network send.

Note

The successful completion of a send does not indicate that the data was successfully delivered. If no buffer space is available within the transport system to hold the data to be transmitted, send will block unless the socket has been placed in nonblocking mode.

Send(Byte[])

Sends data to a connected Socket.

Parameters

buffer
Byte[]

An array of type Byte that contains the data to be sent.

Returns

Int32

The number of bytes sent to the Socket.

Exceptions

Examples

The following code example demonstrates sending data on a connected Socket.

Remarks

Send synchronously sends data to the remote host specified in the Connect or Accept method and returns the number of bytes successfully sent. Send can be used for both connection-oriented and connectionless protocols.

This overload requires a buffer that contains the data you want to send. The SocketFlags value defaults to 0, the buffer offset defaults to 0, and the number of bytes to send defaults to the size of the buffer.

If you are using a connectionless protocol, you must call Connect before calling this method, or Send will throw a SocketException. If you are using a connection-oriented protocol, you must either use Connect to establish a remote host connection, or use Accept to accept an incoming connection.

If you are using a connectionless protocol and plan to send data to several different hosts, you should use the SendTo method. If you do not use the SendTo method, you will have to call Connect before each call to Send. You can use SendTo even after you have established a default remote host with Connect. You can also change the default remote host prior to calling Send by making another call to Connect.

If you are using a connection-oriented protocol, Send will block until all of the bytes in the buffer are sent, unless a time-out was set by using Socket.SendTimeout. If the time-out value was exceeded, the Send call will throw a SocketException. In nonblocking mode, Send may complete successfully even if it sends less than the number of bytes in the buffer. It is your application's responsibility to keep track of the number of bytes sent and to retry the operation until the application sends the bytes in the buffer. There is also no guarantee that the data you send will appear on the network immediately. To increase network efficiency, the underlying system may delay transmission until a significant amount of outgoing data is collected. A successful completion of the Send method means that the underlying system has had room to buffer your data for a network send.

Note

The successful completion of a send does not indicate that the data was successfully delivered. If no buffer space is available within the transport system to hold the data to be transmitted, send will block unless the socket has been placed in nonblocking mode.

See also

Send(ReadOnlySpan<Byte>, SocketFlags)

Parameters

buffer
ReadOnlySpan<Byte>

A span of bytes that contains the data to be sent.

socketFlags
SocketFlags

A bitwise combination of the enumeration values that specifies send and receive behaviors.

Returns

Int32

The number of bytes sent to the Socket.

Exceptions

See also

Send(Byte[], SocketFlags)

Parameters

buffer
Byte[]

An array of type Byte that contains the data to be sent.

Returns

Int32

The number of bytes sent to the Socket.

Exceptions

Examples

The following code example demonstrates sending data on a connected Socket.

Remarks

Send synchronously sends data to the remote host established in the Connect or Accept method and returns the number of bytes successfully sent. The Send method can be used for both connection-oriented and connectionless protocols.

This overload requires a buffer that contains the data you want to send and a bitwise combination of SocketFlags. The buffer offset defaults to 0, and the number of bytes to send defaults to the size of the buffer. If you specify the DontRoute flag as the parameter value, the data you are sending will not be routed.

If you are using a connectionless protocol, you must call Connect before calling this method, or Send will throw a SocketException. If you are using a connection-oriented protocol, you must either use Connect to establish a remote host connection, or use Accept to accept an incoming connection.

If you are using a connectionless protocol and plan to send data to several different hosts, you should use the SendTo method. If you do not use the SendTo method, you will have to call the Connect method before each call to Send. You can use SendTo even after you have established a default remote host with Connect. You can also change the default remote host prior to calling Send by making another call to Connect.

If you are using a connection-oriented protocol, Send will block until all of the bytes in the buffer are sent, unless a time-out was set by using Socket.SendTimeout. If the time-out value was exceeded, the Send call will throw a SocketException. In nonblocking mode, Send may complete successfully even if it sends less than the number of bytes in the buffer. It is your application's responsibility to keep track of the number of bytes sent and to retry the operation until the application sends the requested number of bytes. There is also no guarantee that the data you send will appear on the network immediately. To increase network efficiency, the underlying system may delay transmission until a significant amount of outgoing data is collected. A successful completion of the Send method means that the underlying system has had room to buffer your data for a network send.

Note

The successful completion of a send does not indicate that the data was successfully delivered. If no buffer space is available within the transport system to hold the data to be transmitted, send will block unless the socket has been placed in nonblocking mode.

See also

Send(ReadOnlySpan<Byte>)

Sends data to a connected Socket.

Parameters

buffer
ReadOnlySpan<Byte>

A span of bytes that contains the data to be sent.

Returns

Int32

The number of bytes sent to the Socket.

Exceptions

Remarks

Send synchronously sends data to the remote host specified in the Connect or Accept method and returns the number of bytes successfully sent. Send can be used for both connection-oriented and connectionless protocols.

This overload requires a buffer that contains the data you want to send. The SocketFlags value defaults to 0, the buffer offset defaults to 0, and the number of bytes to send defaults to the size of the buffer.

If you're using a connectionless protocol, you must call Connect before calling this method, or Send will throw a SocketException. If you're using a connection-oriented protocol, you must either use Connect to establish a remote host connection, or use Accept to accept an incoming connection.

If you're using a connectionless protocol and plan to send data to several different hosts, you should use the SendTo method. If you don't use the SendTo method, you'll have to call Connect before each call to Send. You can use SendTo even after you have established a default remote host with Connect. You can also change the default remote host before calling Send by making another call to Connect.

If you're using a connection-oriented protocol, Send will block until all of the bytes in the buffer are sent, unless a time-out was set by using Socket.SendTimeout. If the time-out value was exceeded, the Send call will throw a SocketException. In nonblocking mode, Send may complete successfully even if it sends less than the number of bytes in the buffer. It is your application's responsibility to keep track of the number of bytes sent and to retry the operation until the application sends the bytes in the buffer. There's also no guarantee that the data you send will appear on the network immediately. To increase network efficiency, the underlying system may delay transmission until a significant amount of outgoing data is collected. A successful completion of the Send method means that the underlying system has had room to buffer your data for a network send.

This member outputs trace information when you enable network tracing in your application. For more information, see Network Tracing in the .NET Framework.

Important

The successful completion of a send does not indicate that the data was successfully delivered. If no buffer space is available within the transport system to hold the data to be transmitted, send will block unless the socket has been placed in nonblocking mode.

See also

Sours: https://docs.microsoft.com/en-us/dotnet/api/system.net.sockets.socket.send
C# Socket Programming - Multiple Clients

C# (CSharp) System.Net.Sockets Socket.SendTo Examples

static void Main(string[] args) { byte[] data = new byte[1024]; string input, stringData; IPEndPoint ipep = new IPEndPoint(IPAddress.Parse("38.98.173.2"), 58642); //IPEndPoint ipep = new IPEndPoint(IPAddress.Parse("127.0.0.1"), 58642); Socket server = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp); string welcome = "Hello, are you there?"; data = Encoding.ASCII.GetBytes(welcome); server.SendTo(data, data.Length, SocketFlags.None, ipep); IPEndPoint sender = new IPEndPoint(IPAddress.Any, 0); EndPoint Remote = (EndPoint)sender; data = new byte[1024]; int recv = server.ReceiveFrom(data, ref Remote); Console.WriteLine("Message received from {0}:", Remote.ToString()); Console.WriteLine(Encoding.ASCII.GetString(data, 0, recv)); while (true) { input = Console.ReadLine(); if (input == "exit") break; server.SendTo(Encoding.ASCII.GetBytes(input), Remote); data = new byte[1024]; recv = server.ReceiveFrom(data, ref Remote); stringData = Encoding.ASCII.GetString(data, 0, recv); Console.WriteLine(stringData); } Console.WriteLine("Stopping client"); server.Close(); }
Sours: https://csharp.hotexamples.com/examples/System.Net.Sockets/Socket/SendTo/php-socket-sendto-method-examples.html

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