tracker: add http tracker support

Cargo.toml

@@ -4,3 +4,9 @@ version = "0.1.0"
 authors = ["Simon Bernier St-Pierre <sbernierstpierre@gmail.com>"]
 
 [dependencies]
+sha1 = "0.2"
+url = "1.2"
+
+[dependencies.hyper]
+version = "0.9"
+default-features = false

docs.md

@@ -3,7 +3,7 @@
  * [x] encoding
 * Tracker
  * [ ] udp [spec](http://www.bittorrent.org/beps/bep_0015.html)
- * [ ] http [spec](http://www.bittorrent.org/beps/bep_0003.html#trackers)
+ * [x] http [spec](http://www.bittorrent.org/beps/bep_0003.html#trackers)
 * Metainfo
  * [ ] torrent files [spec](https://wiki.theory.org/BitTorrentSpecification#Metainfo_File_Structure)
  * [ ] magnet links

examples/decode-torrent.rs

@@ -7,6 +7,8 @@ use std::str;
 
 use magnolia::bencode::*;
 use magnolia::metainfo::Metainfo;
+use magnolia::torrent::Torrent;
+use magnolia::tracker::http;
 
 fn load_file(path: &str) -> io::Result<()> {
     let mut buf = Vec::new();
@@ -14,8 +16,18 @@ fn load_file(path: &str) -> io::Result<()> {
     f.read_to_end(&mut buf)?;
 
     let obj = decode(&buf).unwrap();
-    let meta = Metainfo::from_bencode(obj);
+    let meta = Metainfo::from_bencode(obj).unwrap();
-    println!("{:#?}", meta);
+
+    let t = Torrent {
+        metainfo: meta,
+        uploaded: 0,
+        downloaded: 0,
+        left: 0,
+    };
+
+    let resp = http::get_peers([1u8; 20], 55555, &t).unwrap();
+
+    print!("{:?}", resp);
 
     Ok(())
 }

src/lib.rs

@@ -1,3 +1,9 @@
+extern crate hyper;
+extern crate sha1;
+extern crate url;
+
 pub mod bencode;
 pub mod buffer;
 pub mod metainfo;
+pub mod torrent;
+pub mod tracker;

src/torrent.rs

@@ -0,0 +1,8 @@
+use metainfo::Metainfo;
+
+pub struct Torrent {
+    pub metainfo: Metainfo,
+    pub downloaded: u64,
+    pub uploaded: u64,
+    pub left: u64,
+}

src/tracker/http.rs

@@ -0,0 +1,96 @@
+use std::io::Read;
+use std::net::Ipv4Addr;
+
+use hyper::Client;
+use url::form_urlencoded::byte_serialize;
+
+use bencode::{decode, Dict};
+use torrent::Torrent;
+use tracker::{Peer, TrackerError, TrackerResponse, TrackerResult};
+
+macro_rules! ts {
+    ( $e:expr ) => {
+        match $e {
+            Some(x) => x,
+            None => return Err(TrackerError::InvalidResponse),
+        }
+    }
+}
+
+pub fn get_peers(peer_id: [u8; 20], port: u16, torrent: &Torrent) -> TrackerResult {
+    let url = format!("{}?info_hash={}&peer_id={}&port={}&uploaded={}\
+                       &downloaded={}&left={}&compact=1",
+                      torrent.metainfo.announce,
+                      urlencode(&torrent.metainfo.info_hash),
+                      urlencode(&peer_id),
+                      port,
+                      torrent.uploaded,
+                      torrent.downloaded,
+                      torrent.left);
+
+    let client = Client::new();
+    let mut resp = client.get(&url).send()?;
+    let mut buff = Vec::new();
+    resp.read_to_end(&mut buff)?;
+
+    let obj = decode(&buff)?;
+    let info = ts!(obj.as_dict());
+    parse_object(info)
+}
+
+fn parse_object(info: &Dict) -> TrackerResult {
+    if let Some(reason) = info.get_bytes("failure reason") {
+        Err(TrackerError::TrackerFailure(ts!(reason.string())))
+    } else {
+        let interval = ts!(info.get_int("interval"));
+        let peerstring = ts!(info.get_bytes("peers"));
+
+        if peerstring.len() % 6 != 0 {
+            return Err(TrackerError::InvalidResponse)
+        }
+
+        let peers = peerstring.chunks(6).map(|chunk| {
+            Peer {
+                addr: Ipv4Addr::new(chunk[0], chunk[1], chunk[2], chunk[3]),
+                port: (chunk[4] as u16) << 8 | (chunk[5] as u16) << 0,
+            }
+        }).collect();
+
+        Ok(TrackerResponse {
+            interval: interval as u64,
+            peers: peers,
+        })
+    }
+}
+
+fn urlencode(bytes: &[u8]) -> String {
+    byte_serialize(bytes).collect::<Vec<_>>().join("")
+}
+
+#[test]
+fn test_failure() {
+    let mut info = Dict::new();
+    info.insert("failure reason", "unknown hash");
+    assert!(parse_object(&info).is_err());
+}
+
+#[test]
+fn test_invalid_peer_list() {
+    let mut info = Dict::new();
+    info.insert("interval", 900);
+    info.insert("peers", vec![1u8, 1, 1, 1]);
+    assert!(parse_object(&info).is_err());
+}
+
+
+#[test]
+fn test_success() {
+    let mut info = Dict::new();
+    info.insert("interval", 900);
+    info.insert("peers", vec![1u8, 1, 1, 1, 1, 1]);
+    let resp = parse_object(&info).unwrap();
+    assert_eq!(resp.interval, 900);
+    assert_eq!(resp.peers.len(), 1);
+    assert_eq!(resp.peers[0].addr.octets(), [1, 1, 1, 1]);
+    assert_eq!(resp.peers[0].port, 257);
+}

src/tracker/mod.rs

@@ -0,0 +1,48 @@
+pub mod http;
+
+use std::io;
+use std::net::Ipv4Addr;
+
+use hyper;
+
+use bencode::DecodeError;
+
+pub type TrackerResult = Result<TrackerResponse, TrackerError>;
+
+#[derive(Debug)]
+pub struct TrackerResponse {
+    pub interval: u64,
+    pub peers: Vec<Peer>,
+}
+
+#[derive(Debug)]
+pub enum TrackerError {
+    IoError(io::Error),
+    HttpError(hyper::Error),
+    InvalidResponse,
+    TrackerFailure(String),
+}
+
+impl From<io::Error> for TrackerError {
+    fn from(from: io::Error) -> Self {
+        TrackerError::IoError(from)
+    }
+}
+
+impl From<hyper::Error> for TrackerError {
+    fn from(from: hyper::Error) -> Self {
+        TrackerError::HttpError(from)
+    }
+}
+
+impl From<DecodeError> for TrackerError {
+    fn from(_: DecodeError) -> Self {
+        TrackerError::InvalidResponse
+    }
+}
+
+#[derive(Debug)]
+pub struct Peer {
+    pub addr: Ipv4Addr,
+    pub port: u16,
+}