Book Image

Rust Programming By Example

By : Guillaume Gomez, Antoni Boucher
Book Image

Rust Programming By Example

By: Guillaume Gomez, Antoni Boucher

Overview of this book

Rust is an open source, safe, concurrent, practical language created by Mozilla. It runs blazingly fast, prevents segfaults, and guarantees safety. This book gets you started with essential software development by guiding you through the different aspects of Rust programming. With this approach, you can bridge the gap between learning and implementing immediately. Beginning with an introduction to Rust, you’ll learn the basic aspects such as its syntax, data types, functions, generics, control flows, and more. After this, you’ll jump straight into building your first project, a Tetris game. Next you’ll build a graphical music player and work with fast, reliable networking software using Tokio, the scalable and productive asynchronous IO Rust library. Over the course of this book, you’ll explore various features of Rust Programming including its SDL features, event loop, File I/O, and the famous GTK+ widget toolkit. Through these projects, you’ll see how well Rust performs in terms of concurrency—including parallelism, reliability, improved performance, generics, macros, and thread safety. We’ll also cover some asynchronous and reactive programming aspects of Rust. By the end of the book, you’ll be comfortable building various real-world applications in Rust.
Table of Contents (18 chapters)
Title Page
Copyright and Credits
Packt Upsell
Events and Basic Game Mechanisms

Downloading a file

A very useful feature of an FTP server is the ability to download files. So, it's time to add the command to do so.

First of all, we add the case in the handle_cmd() method:

fn handle_cmd(mut self, cmd: Command) -> Result<Self> {
    match cmd {
        Command::Retr(file) => self = await!(self.retr(file))?,
        // …

Here is the start of the retr() function:

use std::fs::File;
use std::io::Read;

use error::Error;

fn retr(mut self, path: PathBuf) -> Result<Self> {
    if self.data_writer.is_some() {
        let path = self.cwd.join(path);
        let (new_self, res) = self.complete_path(path.clone());
        self = new_self;
        if let Ok(path) = res {
            if path.is_file() {
                self = await!(self.send(Answer::new(ResultCode::DataConnectionAlreadyOpen, "Starting to send file...")))?;
                let mut file = File::open(path)?;
                let mut out = vec![];