(Objective-C) WebSocket Binance Trade Stream (subscribe and receive updates)

Subscribe to a binance trade stream and receive updates.

For more information, see https://binance-docs.github.io/apidocs/spot/en/#live-subscribing-unsubscribing-to-streams

Chilkat Objective-C Library Downloads MAC OS X (Cocoa) Libs iOS Libs

#import <CkoWebSocket.h>
#import <CkoRest.h>
#import <NSString.h>
#import <CkoJsonObject.h>

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

CkoWebSocket *ws = [[CkoWebSocket alloc] init];

// 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.

CkoRest *rest = [[CkoRest alloc] init];

// Connect to wss://stream.binance.com:9443
BOOL success = [rest Connect: @"stream.binance.com" port: [NSNumber numberWithInt: 9443] tls: YES autoReconnect: NO];
if (success == NO) {
    NSLog(@"%@",rest.LastErrorText);
    return;
}

success = [ws UseConnection: rest];
if (success == NO) {
    NSLog(@"%@",ws.LastErrorText);
    return;
}

[ws AddClientHeaders];

//  Raw streams are accessed at /ws/<streamName>
NSString *responseBody = [rest FullRequestNoBody: @"GET" uriPath: @"/ws/btcusdt"];
if (rest.LastMethodSuccess == NO) {
    NSLog(@"%@",rest.LastErrorText);
    return;
}

success = [ws ValidateServerHandshake];
if (success != YES) {
    NSLog(@"%@",ws.LastErrorText);
    NSLog(@"%@",responseBody);
    NSLog(@"%@",rest.ResponseHeader);
    return;
}

NSLog(@"%@",responseBody);
NSLog(@"%@",rest.ResponseHeader);

// POST JSON to subscribe to a stream

// {
// "method": "SUBSCRIBE",
// "params":
// [
// "btcusdt@aggTrade",
// "btcusdt@depth"
// ],
// "id": 1
// }

CkoJsonObject *json = [[CkoJsonObject alloc] init];
[json UpdateString: @"method" value: @"SUBSCRIBE"];
[json UpdateString: @"params[0]" value: @"btcusdt@aggTrade"];
[json UpdateString: @"params[1]" value: @"btcusdt@depth"];
[json UpdateInt: @"id" value: [NSNumber numberWithInt: 1]];

// Send a full message in a single frame
BOOL finalFrame = YES;
success = [ws SendFrame: [json Emit] finalFrame: finalFrame];
if (success != YES) {
    NSLog(@"%@",ws.LastErrorText);
    return;
}

CkoJsonObject *jsonTradeData = [[CkoJsonObject alloc] init];
jsonTradeData.EmitCompact = NO;

// Begin reading the trade stream response.
// We'll just read the 1st 10 updates and then exit..
BOOL receivedFinalFrame = NO;
int numTradesReceived = 0;
while (numTradesReceived < 5) {

    success = [ws ReadFrame];
    if (success != YES) {
        NSLog(@"%@",@"Failed to receive a frame");
        NSLog(@"%@%d",@"ReadFrame fail reason = ",[ws.ReadFrameFailReason intValue]);
        NSLog(@"%@",ws.LastErrorText);
        return;
    }

    // The responses we desire are in Text frames, where the opcode = 1.
    if ([ws.FrameOpcodeInt intValue] == 1) {
        NSString *receivedJson = [ws GetFrameData];

        [jsonTradeData Load: receivedJson];
        NSLog(@"%@",[jsonTradeData Emit]);

        numTradesReceived = numTradesReceived + 1;
    }

}

// Close the websocket connection.
success = [ws SendClose: YES statusCode: [NSNumber numberWithInt: 1000] reason: @"Closing this websocket."];
if (success != YES) {
    NSLog(@"%@",ws.LastErrorText);
    return;
}

// Read the Close response.
success = [ws ReadFrame];
if (success != YES) {
    NSLog(@"%@%d",@"ReadFrame fail reason = ",[ws.ReadFrameFailReason intValue]);
    NSLog(@"%@",ws.LastErrorText);
    return;
}

NSLog(@"%@",@"Success.");

// The output of the above code is shown here: