Handling errors

Before we start coding the FTP server, let's talk about how we'll be handling the errors.

Unwrapping

In the previous projects, we used the unwrap() or expect() methods a lot. These methods are handy for fast prototyping, but when we want to write high-quality software, we should avoid them in most cases. Since we're writing an FTP server, a software that must keep running for a long time, we don't want it to crash because we called unwrap() and a client sent a bad command. So, we'll do proper error handling.

Custom error type

Since we can get different types of errors and we want to keep track of all of them, we'll create a custom error type. Let's create a new module in which we'll put this new type:

mod error;

Add it to the src/error.rs file:

use std::io;
use std::str::Utf8Error;
use std::string::FromUtf8Error;

pub enum Error {
    FromUtf8(FromUtf8Error),
    Io(io::Error),
    Msg(String),
    Utf8(Utf8Error),
}

Here, we have an enum representing the different errors that can...