Enum CortexError 

pub enum CortexError {
    ConnectionFailed {
        url: String,
        reason: String,
    },
    ConnectionLost {
        reason: String,
    },
    NotConnected,
    AuthenticationFailed {
        reason: String,
    },
    TokenExpired,
    AccessDenied {
        reason: String,
    },
    UserNotLoggedIn,
    NotApproved,
    LicenseError {
        reason: String,
    },
    NoHeadsetFound,
    HeadsetInUse,
    HeadsetError {
        reason: String,
    },
    SessionError {
        reason: String,
    },
    StreamError {
        reason: String,
    },
    ApiError {
        code: i32,
        message: String,
    },
    CortexStarting,
    MethodNotFound {
        method: String,
    },
    Timeout {
        seconds: u64,
    },
    RetriesExhausted {
        attempts: u32,
        last_error: Box<CortexError>,
    },
    ProtocolError {
        reason: String,
    },
    ConfigError {
        reason: String,
    },
    WebSocket(String),
    Tls(String),
    Io(Error),
    Json(Error),
}

All errors that can occur when interacting with the Emotiv Cortex API.

Variants

ConnectionFailed

Failed to establish a WebSocket connection to the Cortex service.

Fields

url: String

reason: String

ConnectionLost

WebSocket connection was lost after being established.

Fields

reason: String

NotConnected

The client is not connected to the Cortex service.

AuthenticationFailed

Authentication failed (invalid client_id/client_secret or expired token).

Fields

reason: String

TokenExpired

The Cortex token has expired and needs to be refreshed.

AccessDenied

Access denied — the user hasn’t approved the app in the Emotiv Launcher.

Fields

reason: String

UserNotLoggedIn

User is not logged in to EmotivID in the Launcher.

NotApproved

The application has not been approved in the EMOTIV Launcher.

LicenseError

License expired, invalid, or missing for the requested operation.

Fields

reason: String

NoHeadsetFound

No headset found (either not paired or not powered on).

HeadsetInUse

The headset is being used by another session or application.

HeadsetError

Headset connection failed or the headset disconnected unexpectedly.

Fields

reason: String

SessionError

Session-related error (create, update, close failed).

Fields

reason: String

StreamError

Subscribe/unsubscribe failed for the requested streams.

Fields

reason: String

ApiError

Raw Cortex API error that doesn’t map to a more specific variant.

Fields

code: i32

message: String

CortexStarting

The Cortex service is still starting up — try again shortly.

MethodNotFound

The requested API method was not found (likely a version mismatch).

Fields

method: String

Timeout

An operation timed out waiting for a response.

Fields

seconds: u64

RetriesExhausted

All retry attempts have been exhausted.

Fields

attempts: u32

last_error: Box<CortexError>

ProtocolError

Received an unexpected or malformed message from the Cortex service.

Fields

reason: String

ConfigError

Configuration file error (missing, malformed, or invalid values).

Fields

reason: String

WebSocket(String)

Low-level WebSocket transport error.

Tls(String)

TLS/SSL error during connection.

Io(Error)

Filesystem or I/O error (config file reading, etc.).

Json(Error)

JSON serialization/deserialization error.

Implementations

impl CortexError

pub fn from_api_error(code: i32, message: impl Into<String>) -> Self

Map a Cortex API error code + message to the most specific error variant.

Known error codes from the Cortex v2 API docs (2026-02-12):

• -32601: Method not found
• -32001: No headset connected
• -32002: Invalid license ID
• -32004: Headset unavailable
• -32005: Session already exists
• -32012: Session must be activated
• -32014: Invalid cortex token
• -32015: Cortex token expired
• -32016: Invalid stream
• -32021: Invalid client credentials
• -32024: License expired
• -32033: User not logged in
• -32142: Unpublished/unapproved application
• -32152: Headset not ready

Legacy Cortex deployments may also return older codes such as -32102 and -32122.

Examples

use emotiv_cortex_v2::CortexError;

let err = CortexError::from_api_error(-32015, "token expired");
assert!(matches!(err, CortexError::TokenExpired));

let err = CortexError::from_api_error(-32001, "no headset");
assert!(matches!(err, CortexError::NoHeadsetFound));

pub fn is_retryable(&self) -> bool

Returns true if this error is transient and the operation can be retried.

Examples

use emotiv_cortex_v2::CortexError;

assert!(CortexError::Timeout { seconds: 10 }.is_retryable());
assert!(CortexError::CortexStarting.is_retryable());
assert!(!CortexError::NoHeadsetFound.is_retryable());

pub fn is_connection_error(&self) -> bool

Returns true if this error indicates the connection is dead and a reconnect is needed.

Examples

use emotiv_cortex_v2::CortexError;

assert!(CortexError::NotConnected.is_connection_error());
assert!(!CortexError::TokenExpired.is_connection_error());

Trait Implementations

impl Debug for CortexError

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Display for CortexError

fn fmt(&self, __formatter: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Error for CortexError

fn source(&self) -> Option<&(dyn Error + 'static)>

Returns the lower-level source of this error, if any.

fn description(&self) -> &str

👎Deprecated since 1.42.0: use the Display impl or to_string()

fn cause(&self) -> Option<&dyn Error>

👎Deprecated since 1.33.0: replaced by Error::source, which can support downcasting

fn provide<'a>(&'a self, request: &mut Request<'a>)

🔬This is a nightly-only experimental API. (error_generic_member_access)

Provides type-based access to context intended for error reports.

impl From<Error> for CortexError

fn from(source: Error) -> Self

Converts to this type from the input type.

impl From<Error> for CortexError

fn from(source: Error) -> Self

Converts to this type from the input type.

impl From<Error> for CortexError

fn from(err: Error) -> Self

Converts to this type from the input type.

impl From<Error> for CortexError

Available on crate feature config-toml only.

fn from(err: Error) -> Self

Converts to this type from the input type.