Zig

Read Bitfinex WebSocket Ticker Channel

See more WebSocket Examples

Subscribes to the public Bitfinex websocket ticker channel and receives ticker updates. Zig

const std = @import("std");
const chilkat = @import("chilkat");

pub fn main(init: std.process.Init) !void {
    const alloc = init.arena.allocator();

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

    const ws = try chilkat.WebSocket.init();
    defer ws.deinit();

    // 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.

    const rest = try chilkat.Rest.init();
    defer rest.deinit();

    // Connect to api.bitfinex.com
    try rest.connect("api.bitfinex.com", 443, true, false);
    ws.useConnection(rest) catch {};
    ws.addClientHeaders() catch {};

    const response_body = try rest.fullRequestNoBody(alloc, "GET", "/ws");
    ws.validateServerHandshake() catch {
        std.debug.print("{s}\n", .{try ws.getLastErrorText(alloc)});
        std.debug.print("{s}\n", .{response_body});
        std.debug.print("{s}\n", .{try rest.getResponseHeader(alloc)});
        return;
    };

    // After connecting, the bitfinex websocket server will send
    // an info message that contains the actual version of the websocket stream.
    // Receive that message..
    ws.readFrame() catch {
        std.debug.print("Failed to receive a frame\n", .{});
        std.debug.print("ReadFrame fail reason = {d}\n", .{ws.getReadFrameFailReason()});
        std.debug.print("{s}\n", .{try ws.getLastErrorText(alloc)});
        return;
    };

    // We should get this:
    // {"event":"info","version":1.1,"platform":{"status":1}}
    std.debug.print("{s}\n", .{try ws.getFrameData(alloc)});

    // Subscribe to the public ticker feed.
    // See https://docs.bitfinex.com/docs for more information.
    const json = try chilkat.JsonObject.init();
    defer json.deinit();
    json.appendString("event", "subscribe") catch {};
    json.appendString("channel", "ticker") catch {};
    json.appendString("pair", "BTCUSD") catch {};

    const final_frame = true;
    try ws.sendFrame(try json.emit(alloc), final_frame);

    // Read the response.
    ws.readFrame() catch {
        std.debug.print("Failed to receive a frame\n", .{});
        std.debug.print("ReadFrame fail reason = {d}\n", .{ws.getReadFrameFailReason()});
        std.debug.print("{s}\n", .{try ws.getLastErrorText(alloc)});
        return;
    };

    // Examine the response
    // We should get this:
    // {"event":"subscribed","channel":"ticker","chanId":2751,"pair":"BTCUSD"}
    std.debug.print("{s}\n", .{try ws.getFrameData(alloc)});

    // Begin reading the ticker feed.
    // We'll just read the 1st 5 updates and then exit..
    var num_updates_received: i32 = 0;
    while (num_updates_received < 5) {
        ws.readFrame() catch {
            std.debug.print("Failed to receive a frame\n", .{});
            std.debug.print("ReadFrame fail reason = {d}\n", .{ws.getReadFrameFailReason()});
            std.debug.print("{s}\n", .{try ws.getLastErrorText(alloc)});
            return;
        };

        // The responses we desire are in Text frames, where the opcode = 1.
        if (ws.getFrameOpcodeInt() == 1) {
            const received_text = try ws.getFrameData(alloc);
            std.debug.print("{s}\n", .{received_text});
            // Should receive a line of text such as this:
            // [2751,7349,36.34269559,7349.1,41.01777063,-116.2,-0.0156,7349.1,22188.26055319,7560,7270.5]
            num_updates_received = num_updates_received + 1;
        }
    }

    // Close the websocket connection.
    ws.sendClose(true, 1000, "Closing this websocket.") catch {
        std.debug.print("{s}\n", .{try ws.getLastErrorText(alloc)});
        return;
    };

    // Read the Close response.
    ws.readFrame() catch {
        std.debug.print("ReadFrame fail reason = {d}\n", .{ws.getReadFrameFailReason()});
        std.debug.print("{s}\n", .{try ws.getLastErrorText(alloc)});
        return;
    };

    std.debug.print("Success.\n", .{});
}