subscribe

This method is to subscribe to one or more data streams. You can call unsubscribe to cancel a subscription. After you successfully subscribe to a stream, Cortex will keep sending you data sample objects.

See Data Subscription for details.

Parameters

Name	Type	Required	Description
cortexToken	string	yes	A token returned by authorize.
session	string	yes	A session id returned by createSession.
streams	array of strings	yes	The data streams you want to subscribe to.

The parameter streams must contain one or more values, chosen from this list: "eeg", "mot", "dev", "eq", "pow", "met", "com", "fac", "sys". See Data Subscription for details.

To subscribe to the "eeg" stream, you must have a paid license and activate the session.

Result

The result is an object that includes these fields:

Name	Type	Description
success	array of objects	For each stream you successfully subscribed to, this array contains an object that describe the data structure of this stream.
failure	array of objects	For each stream you failed to subscribed to, this array contains an object that describes the error.

In case of success, you get an object with these fields:

Name	Type	Description
streamName	string	The name of the stream.
cols	array of strings	The labels of the columns that are part of this stream.
sid	string	The session id.

Please note that the field cols is especially important. This field tells you which values you will get in the data stream, and in which order. See Data sample object for details.

In case of failure, you get an object with these fields:

Name	Type	Description
streamName	string	The name of the stream.
code	number	The error code.
message	string	The error message.

Examples

Subscribe successfully to motion and performance metrics.

Request

{
    "id": 1,
    "jsonrpc": "2.0",
    "method": "subscribe",
    "params": {
        "cortexToken": "xxx",
        "session": "f8cb7289-9a92-438b-8281-e5fdffe8166e",
        "streams": ["met","mot"]
    }
}

Response

{
    "id": 1,
    "jsonrpc": "2.0",
    "result": {
        "failure": [],
        "success": [
            {
                "cols": ["eng","exc","lex","str","rel","int","foc"],
                "sid": "f8cb7289-9a92-438b-8281-e5fdffe8166e",
                "streamName": "met"
            },
            {
                "cols": [
                    "COUNTER_MEMS",
                    "INTERPOLATED_MEMS",
                    "GYROX",
                    "GYROY",
                    "GYROZ",
                    "ACCX",
                    "ACCY",
                    "ACCZ",
                    "MAGX",
                    "MAGY",
                    "MAGZ"
                ],
                "sid": "f8cb7289-9a92-438b-8281-e5fdffe8166e",
                "streamName": "mot"
            }
        ]
    }
}

Subscribe successfully to performance metrics, but fail to subscribe to raw EEG.

Request

{
    "id": 1,
    "jsonrpc": "2.0",
    "method": "subscribe",
    "params": {
        "cortexToken": "xxx",
        "session": "49eb6cb0-9df6-414a-b3e8-cfa17198daa0",
        "streams": ["met","eeg"]
    }
}

Response

{
    "id": 1,
    "jsonrpc": "2.0",
    "result": {
        "failure": [
            {
                "code": -32016,
                "message": "The stream is unavailable or unsupported.",
                "streamName": "eeg"
            }
        ],
        "success": [
            {
                "cols": ["eng","exc","lex","str","rel","int","foc"],
                "sid": "49eb6cb0-9df6-414a-b3e8-cfa17198daa0",
                "streamName": "met"
            }
        ]
    }
}