Open a connection to a server specified by a URL:

Write a basic HTTP request to the socket:

Read the entire response as a string:

Display the result, without extra newlines:

Close the socket connection:

Open a ZMQ socket:

Connect to the socket:

Send a string to the server socket:

Read the string from the client socket:

Convert the ByteArray to a string:

Close the sockets:

Open a web socket to a server that echoes incoming data:

Read the server's first message:

Send a message and receive the server's echo:

Open a ZMQ socket on an available port:

Connect to the socket, manually specifying the port:

Send any expression to the server socket:

Read the expression from the client socket:

Send a list of expressions to the server socket:

Read the expressions from the client socket:

Close the sockets:

This example demonstrates the use of a ZMQ publish-subscribe model where a single server broadcasts messages and multiple clients receive these messages. For simplicity, this example runs both the publisher and the multiple subscribers in the same Wolfram Engine process. Typically, the publisher and the subscribers are running in different processes and/or on different machines.

Open a socket for the publisher:

Connect multiple subscribers to the publisher:

Ensure that all subscribers are listening to all messages:

No messages have been sent yet, so the subscribers are not ready to read anything:

Send a message from the publisher:

Now the subscribers are ready to read the message:

Read the message with all the subscribers:

Convert the resulting byte arrays into strings:

Close the publisher and the subscriber sockets:

ReadString only works on TCP sockets, as ReadString will wait until the socket is closed by the server before returning the data. ZMQ sockets are never closed by the server and so thus block indefinitely.

Open a ZMQ socket and connect a client:

Write a message to the server and close it:

ReadString now will block indefinitely:

Close the client socket:

When using TCP server sockets opened with SocketOpen, the connection must be closed before ReadString will return.

Open a TCP socket and connect a client:

Write a message to the remote client and close the server:

ReadString now will block indefinitely as the socket hasn't been closed yet:

Closing the remote socket will force ReadString to return:

Close the sockets:

When using an HTTPRequest, it must be well formed and appropriate for establishing web socket connections:

Non–web socket service names cannot be used with web socket connections:

Web socket connection attempts can fail: