Function validate_username 

pub fn validate_username(username: &str) -> Result<String>

Validate a username to prevent injection attacks.

This function validates that usernames conform to POSIX standards and don’t contain characters that could be used for command injection.

Arguments

• username - The username string to validate

Returns

Returns the validated username if validation succeeds.

Errors

Returns an error if:

• Username is empty
• Username is too long (>32 characters)
• Username contains invalid characters
• Username starts with a hyphen

Examples

use bssh::shared::validation::validate_username;

// Valid usernames
assert!(validate_username("john_doe").is_ok());
assert!(validate_username("user123").is_ok());

// Invalid usernames
assert!(validate_username("-user").is_err());
assert!(validate_username("user@domain").is_err());