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std.net — WebSocket

WebSocket client for ws:// URLs; wss:// also works on OpenSSL builds (see Overview). Event-driven like TCP/HTTP: install on_message/on_close, then send.

Connect and echo​

var ws = std.net.websocket("ws://echo.example/socket")

ws.on_message(fn(data, is_binary) {
  if (is_binary) { print("binary frame:", data) }
  else { print("text:", data) }
})
ws.on_close(fn() { print("socket closed") })

ws.send("hi")                                  // text frame
ws.send({data: "raw bytes", binary: true})     // binary frame

print(ws.is_open())                            // true while connected

std.async.sleep(5000)                          // stay alive to receive
ws.close()

Reference​

MethodDescription
websocket(url)Constructor — connect to ws:///wss://host:port/path
send(text)Send a text frame
send({data, binary: true})Send a binary frame
on_message(fn(data, is_binary))Per incoming frame
on_close(fn())When the peer closes
last_error()Most recent background error (connection/send failure or callback exception)
is_open()true while the connection is live
close()Close the connection

Frame types​

  • Text frames: ws.send("hello") → peer receives text; is_binary == false on arrival.
  • Binary frames: ws.send({data: "bytes", binary: true}) → is_binary == true. Use when sending non-UTF8 payloads or when the server expects binary.

data is always a string (binary payloads are binary strings). Combine with std.crypto/std.hash if you need to encode/decode them.

Lifecycle​

  • The constructor connects immediately; is_open() reflects the live state.
  • Like all network objects, callbacks run on background fibers — std.async.sleep keeps the script alive to receive.
  • No reconnection is automatic — on close, create a new websocket(url) if you want to reconnect.

See also​