Rust

Send and Receive WebSocket Messages

See more WebSocket Examples

This example how to send and receive websocket messages.

A WebSocket message can be composed of one or more frames. The simple case is where a single frame is both the first and last frame in a message. This is the case where the 1st frame in the message has the "final frame" bit set.

This example demonstrates sending and receiving multi-frame messages.

Note: The websockets.chilkat.io server imposes the following limitations:
Messages must be 16K or less, and each connection is limited to a max of 16 echoed messages.

Rust

// This example requires the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.

let ws = chilkat::WebSocket::new();

// For brevity, this example does not check for errors when etablishing the WebSocket connection.
// See Establish WebSocket Connection for more complete sample code for making the connection.

let rest = chilkat::Rest::new();
// Connect to websockets.chilkat.io
// IMPORTANT: websockets.chilkat.io accepts frames of up to 16K in size and echoes them back.
// IMPORTANT: The websockets.chilkat.io server imposes the following limitations: 
// ---------- Messages must be 16K or less, and each connection is limited to a max of 16 echoed messages.
let _ = rest.connect("websockets.chilkat.io", 80, false, false).is_ok();
let _ = ws.use_connection(&rest);
let _ = ws.add_client_headers();
let response_body_ignored = rest.full_request_no_body("GET", "/wsChilkatEcho.ashx").unwrap_or_default();
if ws.validate_server_handshake().is_err() {
    println!("{}", ws.last_error_text());
    return;
}

// This example demonstrates sending and receiving a multi-frame message.

// The websocket message will be composed of three text lines, each frame will contain a single line.

// Send the 1st frame in the message.
let mut final_frame = false;
if ws.send_frame("This is the 1st frame\r\n", final_frame).is_err() {
    println!("{}", ws.last_error_text());
    return;
}

// Send the 2nd frame in the message.
if ws.send_frame("This is the 2nd frame\r\n", final_frame).is_err() {
    println!("{}", ws.last_error_text());
    return;
}

// Send the 3rd and final frame in the message.
final_frame = true;
if ws.send_frame("This is the 3rd frame\r\n", final_frame).is_err() {
    println!("{}", ws.last_error_text());
    return;
}

// Read an incoming frames until we receive the final frame.
// Note: It may be that the echo server (websockets.chilkat.io) responds with 
// the full message in a single final frame.
let mut received_final_frame = false;
while !received_final_frame {

    if ws.read_frame().is_err() {
        println!("Failed to receive a frame");
        println!("ReadFrame fail reason = {}", ws.read_frame_fail_reason());
        println!("{}", ws.last_error_text());
        return;
    }

    received_final_frame = ws.final_frame();

    // Show the opcode and final frame bit for the frame just received:
    println!("Frame opcode: {}", ws.frame_opcode());
    println!("Final frame: {}", received_final_frame);
}

// Return the message accumulated in the above calls to ReadFrame.
let received_msg = ws.get_frame_data().unwrap_or_default();
println!("Received: {}", received_msg);

// Close the websocket connection.
if ws.send_close(true, 1000, "Closing this websocket.").is_err() {
    println!("{}", ws.last_error_text());
    return;
}

// Read the Close response.
if ws.read_frame().is_err() {
    println!("ReadFrame fail reason = {}", ws.read_frame_fail_reason());
    println!("{}", ws.last_error_text());
    return;
}

// Should receive the "Close" opcode.
println!("Received opcode: {}", ws.frame_opcode());
// Should be the same status code we sent (1000)
println!("Received close status code: {}", ws.close_status_code());
// The server may echo the close reason.  If not, this will be empty.
println!("Echoed close reason: {}", ws.close_reason());

println!("Success.");