to-socket-addrs

A small replacement for std::net::ToSocketAddrs for specifying addresses without a port.

Usage

To use this crate, add to-socket-addrs as a dependency to your project's Cargo.toml:

[dependencies]
to-socket-addrs = "0.2"

After that, just use ToSocketAddrsWithDefaultPort instead of std::net::ToSocketAddrs and specify the default port number using .with_default_port(...) when creating a stream or listener.

Asynchronous analogs are also supported (if the corresponding features are enabled):

• use ToSocketAddrsWithDefaultPortAsync instead of async_std::net::ToSocketAddrs,
• use ToSocketAddrsWithDefaultPortTokio instead of tokio::net::ToSocketAddrs.

Features

• sync (enabled by default)

  Enables ToSocketAddrsWithDefaultPort.

• async

  Enables ToSocketAddrsWithDefaultPortAsync.

• tokio

  Enables ToSocketAddrsWithDefaultPortTokio.

Explanation

The standard library assumes explicit indication of the port number when creating a stream or listener:

use std::net::{TcpStream, ToSocketAddrs};

fn connect_http<A: ToSocketAddrs>(addr: A) -> TcpStream {
    TcpStream::connect(addr).unwrap()
}

let stream = connect_http("www.google.com:80");

Most often there is a certain standard port number (80 for HTTP, 21 for FTP, etc), which should be used by default if the user specifies only the server address without explicitly specifying the port number.

An ordinary user does not know what the port number is and which one should be specified in each case. The user usually just wants to specify the address (DNS name) of the server.

But the naive call connect_http("www.google.com") will fail. You should force the user to enter addresses along with the port number. Or you have to process its input and add the port number if there is none (for example, from "www.google.com" to "www.google.com:80").

It's inconvenient.

Therefore you can use this crate and write simply:

use std::net::TcpStream;
use to_socket_addrs::ToSocketAddrsWithDefaultPort as ToSocketAddrs;

fn connect_http<A: ToSocketAddrs>(addr: A) -> TcpStream {
    TcpStream::connect(addr.with_default_port(80)).unwrap()
}

let stream = connect_http("www.google.com");

The .with_default_port(...) function will check if the port number is specified and add it if necessary.