refactor: pass request token as a flag instead of an argument

Cargo.toml

@@ -4,6 +4,7 @@ version = "0.1.0"
 authors = ["0xazure <stuart.crust@gmail.com>"]
 
 [dependencies]
+clap = "~2.32.0"
 reqwest = "0.8.7"
 serde = "1.0"
 serde_json = "1.0"

src/lib.rs

@@ -1,12 +1,13 @@
 extern crate chrono;
+extern crate clap;
 extern crate reqwest;
 extern crate serde_derive;
 extern crate serde_json;
 
 use chrono::{DateTime, Utc};
 use reqwest::header::{qitem, Accept, Authorization, Bearer, Link, RelationType, UserAgent};
 use serde_derive::Deserialize;
-use std::{env, error, fmt, mem};
+use std::{error, fmt, mem};
 
 #[derive(Debug)]
 pub struct Config {
@@ -15,19 +16,6 @@ pub struct Config {
 }
 
 impl Config {
-    pub fn new(mut args: env::Args) -> Result<Config, &'static str> {
-        args.next();
-
-        let username = match args.next() {
-            None => return Err("No username provided"),
-            Some(arg) => arg,
-        };
-
-        let token = args.next();
-
-        Ok(Config { username, token })
-    }
-
     fn url(self) -> Option<String> {
         Some(format!(
             "https://api.github.com/users/{}/starred",
@@ -36,6 +24,15 @@ impl Config {
     }
 }
 
+impl<'a> From<clap::ArgMatches<'a>> for Config {
+    fn from(matches: clap::ArgMatches) -> Self {
+        Config {
+            username: matches.value_of("USERNAME").unwrap().to_owned(),
+            token: matches.value_of("TOKEN").map(String::from),
+        }
+    }
+}
+
 #[derive(Debug)]
 struct ClientBuilder {
     inner: reqwest::ClientBuilder,

src/main.rs

@@ -1,13 +1,25 @@
+extern crate clap;
 extern crate supernova;
 
-use std::{env, process};
+use clap::{App, Arg, crate_name, crate_version};
+use std::process;
 use supernova::Config;
 
 fn main() {
-    let config = Config::new(env::args()).unwrap_or_else(|err| {
-        println!("Problem parsing arguments: {}", err);
-        process::exit(1);
-    });
+    let config: Config = App::new(crate_name!())
+        .version(crate_version!())
+        .arg(
+            Arg::with_name("USERNAME")
+                .help("The user whose stars to collect")
+                .required(true),
+        ).arg(
+            Arg::with_name("TOKEN")
+                .short("t")
+                .long("token")
+                .help("Sets the authentication token for requests to GitHub")
+                .takes_value(true),
+        ).get_matches()
+        .into();
 
     if let Err(e) = supernova::collect_stars(config) {
         println!("Application error: {}", e);