Error Handling

AdonisJS-inspired typed error system with HTTP status semantics.

RokError Enum

#![allow(unused)]
fn main() {
use rok_utils::RokError;

let err = RokError::NotFound("User #42".into());
assert_eq!(err.code(), "E_NOT_FOUND");
assert_eq!(err.status(), 404);
assert!(err.is_self_handled());
}

Error Codes

Result Extensions

context

Add context to any error:

#![allow(unused)]
fn main() {
use rok_utils::{RokResultExt, RokError};

fn find_user(id: u64) -> Result<String, RokError> {
    if id == 42 {
        Ok("Alice".to_string())
    } else {
        Err(RokError::NotFound(format!("User #{id}")))
    }
}

let result = find_user(42).context("Database query failed");
assert!(result.is_ok());
}

or_not_found

Convert None to NotFound error:

#![allow(unused)]
fn main() {
use rok_utils::{RokResultExt, RokError};

let users = vec!["Alice", "Bob"];
let user = users.get(0).or_not_found("User at index 0");
assert_eq!(user.unwrap(), "Alice");
}

Validation Errors

#![allow(unused)]
fn main() {
use rok_utils::RokError;

fn validate_email(email: &str) -> Result<(), RokError> {
    if email.contains('@') {
        Ok(())
    } else {
        Err(RokError::ValidationFailure {
            field: "email".to_string(),
            reason: "Must contain @".to_string(),
        })
    }
}

let result = validate_email("invalid");
assert!(matches!(result, Err(RokError::ValidationFailure { .. })));
}

Handling Different Errors

#![allow(unused)]
fn main() {
use rok_utils::RokError;

fn handle_error(err: &RokError) -> String {
    match err {
        RokError::NotFound(msg) => format!("404: {}", msg),
        RokError::ValidationFailure { field, reason } => {
            format!("Validation error on {}: {}", field, reason)
        }
        RokError::Unauthorized(msg) => format!("401: {}", msg),
        _ => format!("Error: {}", err.code()),
    }
}
}

See Also

• Recipes: Error Handling
• Migration Guide