Objective-C

Subscribe to Multiple Bitfinex Tickers on One Connection

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Subscribes to multiple ticker symbols on the public Bitfinex websocket ticker channel and receives ticker updates. Objective-C

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

BOOL success = NO;

// 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 api.bitfinex.com
success = [rest Connect: @"api.bitfinex.com" port: [NSNumber numberWithInt: 443] tls: YES autoReconnect: NO];
[ws UseConnection: rest];
[ws AddClientHeaders];

NSString *responseBody = [rest FullRequestNoBody: @"GET" uriPath: @"/ws"];
success = [ws ValidateServerHandshake];
if (success != YES) {
    NSLog(@"%@",ws.LastErrorText);
    NSLog(@"%@",responseBody);
    NSLog(@"%@",rest.ResponseHeader);
    return;
}

// After connecting, the bitfinex websocket server will send
// an info message that contains the actual version of the websocket stream.
// Receive that message..
success = [ws ReadFrame];
if (success != YES) {
    NSLog(@"%@",@"Failed to receive a frame");
    NSLog(@"%@%d",@"ReadFrame fail reason = ",[ws.ReadFrameFailReason intValue]);
    NSLog(@"%@",ws.LastErrorText);
    return;
}

// We should get this:
// {"event":"info","version":1.1,"platform":{"status":1}}
NSLog(@"%@",[ws GetFrameData]);

// Subscribe to the BTCUSD ticker feed.
// See https://docs.bitfinex.com/docs for more information.
CkoJsonObject *json1 = [[CkoJsonObject alloc] init];
[json1 AppendString: @"event" value: @"subscribe"];
[json1 AppendString: @"channel" value: @"ticker"];
[json1 AppendString: @"pair" value: @"BTCUSD"];

BOOL finalFrame = YES;
success = [ws SendFrame: [json1 Emit] finalFrame: finalFrame];

// Subscribe to the ETHUSD ticker feed.
CkoJsonObject *json2 = [[CkoJsonObject alloc] init];
[json2 AppendString: @"event" value: @"subscribe"];
[json2 AppendString: @"channel" value: @"ticker"];
[json2 AppendString: @"pair" value: @"ETHUSD"];

success = [ws SendFrame: [json2 Emit] finalFrame: finalFrame];

// Begin reading the ticker feed.
// / This will include a single confirmation response for each subscription.

// We'll just read the 1st 5 updates and then exit..
BOOL receivedFinalFrame = NO;
int numUpdatesReceived = 0;
while (numUpdatesReceived < 7) {

    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 *receivedText = [ws GetFrameData];
        NSLog(@"%@",receivedText);
        // 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]
        // Initially, a single confirmation response for each subscription would be received, such as this:
        // {"event":"subscribed","channel":"ticker","chanId":810,"pair":"BTCUSD"}
        numUpdatesReceived = numUpdatesReceived + 1;
    }

}

// This is sample output:
// You can see that the 1st message received is the subscription confirmation for the BTCUSD subscribe request.
// The next message is a BTCUSD ticker update.
// The next message is the confirmation for the ETHUSD subscription.
// The next message is an ETHUSD update.
// The BTCUSD channel ID is "537", and the ETHUSD channel ID is "700".  The channel IDs are provided in the 
// subscription confirmation messages.  Each ticker update begins with the channel ID..

// {"event":"subscribed","channel":"ticker","chanId":537,"pair":"BTCUSD"}
// [537,6457.9,79.59102302,6458,22.49395741,-24.1,-0.0037,6457.9,13644.52820029,6540,6370.76958739]
// {"event":"subscribed","channel":"ticker","chanId":700,"pair":"ETHUSD"}
// [700,496.9,247.24493326,496.92,284.09636979,-2.47,-0.0049,496.9,74154.05945261,502.85,486.96]
// [537,"hb"]
// [700,"hb"]
// [700,496.92,233.34338276,496.93,431.78867277,-2.45,-0.0049,496.92,74167.99173586,502.85,486.96]

// 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.");