refactor: [#649] use clap in HTTP tracker client

An added scaffolding for scrape command.

src/bin/http_tracker_client.rs

@@ -1,24 +1,60 @@
-use std::env;
+//! HTTP Tracker client:
+//!
+//! Examples:
+//!
+//! `Announce` request:
+//!
+//! ```text
+//! cargo run --bin http_tracker_client announce http://127.0.0.1:7070 9c38422213e30bff212b30c360d26f9a02136422 | jq
+//! ```
+//!
+//! `Scrape` request:
+//!
+//! ```text
+//! cargo run --bin http_tracker_client scrape http://127.0.0.1:7070 9c38422213e30bff212b30c360d26f9a02136422 | jq
+//! ```
 use std::str::FromStr;
 
+use clap::{Parser, Subcommand};
 use reqwest::Url;
 use torrust_tracker::shared::bit_torrent::info_hash::InfoHash;
 use torrust_tracker::shared::bit_torrent::tracker::http::client::requests::announce::QueryBuilder;
 use torrust_tracker::shared::bit_torrent::tracker::http::client::responses::announce::Announce;
 use torrust_tracker::shared::bit_torrent::tracker::http::client::Client;
 
+#[derive(Parser, Debug)]
+#[command(author, version, about, long_about = None)]
+struct Args {
+    #[command(subcommand)]
+    command: Command,
+}
+
+#[derive(Subcommand, Debug)]
+enum Command {
+    Announce { tracker_url: String, info_hash: String },
+    Scrape { tracker_url: String, info_hashes: Vec<String> },
+}
+
 #[tokio::main]
 async fn main() {
-    let args: Vec<String> = env::args().collect();
-    if args.len() != 3 {
-        eprintln!("Error: invalid number of arguments!");
-        eprintln!("Usage:   cargo run --bin http_tracker_client <HTTP_TRACKER_URL> <INFO_HASH>");
-        eprintln!("Example: cargo run --bin http_tracker_client https://tracker.torrust-demo.com 9c38422213e30bff212b30c360d26f9a02136422");
-        std::process::exit(1);
+    let args = Args::parse();
+
+    match args.command {
+        Command::Announce { tracker_url, info_hash } => {
+            announce_command(tracker_url, info_hash).await;
+        }
+        Command::Scrape {
+            tracker_url,
+            info_hashes,
+        } => {
+            scrape_command(&tracker_url, &info_hashes);
+        }
     }
+}
 
-    let base_url = Url::parse(&args[1]).expect("arg 1 should be a valid HTTP tracker base URL");
-    let info_hash = InfoHash::from_str(&args[2]).expect("arg 2 should be a valid infohash");
+async fn announce_command(tracker_url: String, info_hash: String) {
+    let base_url = Url::parse(&tracker_url).expect("Invalid HTTP tracker base URL");
+    let info_hash = InfoHash::from_str(&info_hash).expect("Invalid infohash");
 
     let response = Client::new(base_url)
         .announce(&QueryBuilder::with_default_values().with_info_hash(&info_hash).query())
@@ -31,5 +67,11 @@ async fn main() {
 
     let json = serde_json::to_string(&announce_response).expect("announce response should be a valid JSON");
 
-    print!("{json}");
+    println!("{json}");
+}
+
+fn scrape_command(tracker_url: &str, info_hashes: &[String]) {
+    println!("URL: {tracker_url}");
+    println!("Infohashes: {info_hashes:#?}");
+    todo!();
 }