Improve downloading and playing of audio

- Cache audio instead of streaming it
- Allow for searching, as well as providing full URL

Cargo.lock

@@ -5,6 +5,7 @@ dependencies = [
  "discord 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.11 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_derive 1.0.11 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_json 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "toml 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -76,6 +77,11 @@ name = "dtoa"
 version = "0.2.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "dtoa"
+version = "0.4.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "flate2"
 version = "0.2.19"
@@ -149,6 +155,11 @@ name = "itoa"
 version = "0.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "itoa"
+version = "0.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "kernel32-sys"
 version = "0.2.2"
@@ -471,6 +482,17 @@ dependencies = [
  "serde 0.8.23 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "serde_json"
+version = "1.0.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "dtoa 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "itoa 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "num-traits 0.1.40 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.11 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "siphasher"
 version = "0.2.2"
@@ -654,6 +676,7 @@ dependencies = [
 "checksum custom_derive 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)" = "ef8ae57c4978a2acd8b869ce6b9ca1dfe817bff704c220209fdef2c0b75a01b9"
 "checksum discord 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)" = "614a5375ce9ca21bf61478d51fd1eb436cbafb79229c27ce0dbe2b4eee95abf4"
 "checksum dtoa 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "0dd841b58510c9618291ffa448da2e4e0f699d984d436122372f446dae62263d"
+"checksum dtoa 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)" = "80c8b71fd71146990a9742fc06dcbbde19161a267e0ad4e572c35162f4578c90"
 "checksum flate2 0.2.19 (registry+https://github.com/rust-lang/crates.io-index)" = "36df0166e856739905cd3d7e0b210fe818592211a008862599845e012d8d304c"
 "checksum gcc 0.3.51 (registry+https://github.com/rust-lang/crates.io-index)" = "120d07f202dcc3f72859422563522b66fe6463a4c513df062874daad05f85f0a"
 "checksum gdi32-sys 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "0912515a8ff24ba900422ecda800b52f4016a56251922d397c576bf92c690518"
@@ -662,6 +685,7 @@ dependencies = [
 "checksum hyper 0.9.18 (registry+https://github.com/rust-lang/crates.io-index)" = "1b9bf64f730d6ee4b0528a5f0a316363da9d8104318731509d4ccc86248f82b3"
 "checksum idna 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)" = "014b298351066f1512874135335d62a789ffe78a9974f94b43ed5621951eaf7d"
 "checksum itoa 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "ae3088ea4baeceb0284ee9eea42f591226e6beaecf65373e41b38d95a1b8e7a1"
+"checksum itoa 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)" = "eb2f404fbc66fd9aac13e998248505e7ecb2ad8e44ab6388684c5fb11c6c251c"
 "checksum kernel32-sys 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "7507624b29483431c0ba2d82aece8ca6cdba9382bff4ddd0f7490560c056098d"
 "checksum language-tags 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "a91d884b6667cd606bb5a69aa0c99ba811a115fc68915e7056ec08a46e93199a"
 "checksum lazy_static 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)" = "3b37545ab726dd833ec6420aaba8231c5b320814b9029ad585555d2a03e94fbf"
@@ -702,6 +726,7 @@ dependencies = [
 "checksum serde_derive 1.0.11 (registry+https://github.com/rust-lang/crates.io-index)" = "cf823e706be268e73e7747b147aa31c8f633ab4ba31f115efb57e5047c3a76dd"
 "checksum serde_derive_internals 0.15.1 (registry+https://github.com/rust-lang/crates.io-index)" = "37aee4e0da52d801acfbc0cc219eb1eda7142112339726e427926a6f6ee65d3a"
 "checksum serde_json 0.8.6 (registry+https://github.com/rust-lang/crates.io-index)" = "67f7d2e9edc3523a9c8ec8cd6ec481b3a27810aafee3e625d311febd3e656b4c"
+"checksum serde_json 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)" = "48b04779552e92037212c3615370f6bd57a40ebba7f20e554ff9f55e41a69a7b"
 "checksum siphasher 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "0df90a788073e8d0235a67e50441d47db7c8ad9debd91cbf43736a2a92d36537"
 "checksum sodiumoxide 0.0.12 (registry+https://github.com/rust-lang/crates.io-index)" = "8d9da099120def269669aa349e0c3e97de4ab2c5cb9a54a765041651dd0055eb"
 "checksum solicit 0.4.4 (registry+https://github.com/rust-lang/crates.io-index)" = "172382bac9424588d7840732b250faeeef88942e37b6e35317dce98cafdd75b2"

Cargo.toml

@@ -8,3 +8,4 @@ discord = "0.8.0"
 toml = "0.4"
 serde = "1.0.11"
 serde_derive = "1.0.11"
+serde_json = "1.0"

config/example.toml

@@ -2,3 +2,4 @@ discord_token = "token goes here"
 command_prefix = "!"
 # Optionally limit the bot to only accept commands from a specific channel
 # command_channel = channel_id_here
+cache_dir = "/tmp/music-bot-rs"

src/main.rs

@@ -1,20 +1,25 @@
 extern crate discord;
 extern crate toml;
 extern crate serde;
+extern crate serde_json;
 
 #[macro_use]
 extern crate serde_derive;
 
+use std::fs;
 use std::fs::File;
 use std::io::prelude::*;
+use std::process::Command;
 use discord::{Discord, State};
 use discord::model::{Event, ChannelId};
+use serde_json::Value;
 
 #[derive(Debug, Deserialize)]
 struct Config {
     discord_token: String,
     command_prefix: String,
     command_channel: Option<u64>,
+    cache_dir: String,
 }
 
 pub fn main() {
@@ -24,6 +29,9 @@ pub fn main() {
     file.read_to_string(&mut contents).expect("failed to read config file");
     let config: Config = toml::from_str(&contents).expect("failed to parse config file");
 
+    // Ensure cache dir exists
+    fs::create_dir_all(&config.cache_dir).expect("could not create cache dir");
+
     // Log in to Discord using a bot token from the environment
     let discord = Discord::from_bot_token(&config.discord_token).expect("login failed");
 
@@ -71,7 +79,7 @@ pub fn main() {
                 // reply to a command if there was one
                 let mut split = message.content.split_whitespace();
                 let first_word = split.next().unwrap_or("");
-                let argument = split.next().unwrap_or("");
+                let arguments = split.collect::<Vec<&str>>().join(" ");
 
                 let prefix = &config.command_prefix;
 
@@ -88,15 +96,33 @@ pub fn main() {
                         },
                         "play" => {
                             let output = if let Some((server_id, channel_id)) = vchan {
-                                match discord::voice::open_ytdl_stream(argument) {
-                                    Ok(stream) => {
-                                        let voice = connection.voice(server_id);
-                                        voice.set_deaf(true);
-                                        voice.connect(channel_id);
-                                        voice.play(stream);
-                                        String::new()
-                                    },
-                                    Err(error) => format!("Error: {}", error),
+                                warn(discord.send_message(message.channel_id, &format!("Searching for \"{}\"...", arguments), "", false));
+                                let output = Command::new("youtube-dl")
+                                        .arg("-f")
+                                        .arg("webm[abr>0]/bestaudio/best")
+                                        .arg("--output")
+                                        .arg(format!("{}/%(title)s.%(ext)s", config.cache_dir))
+                                        .arg("--print-json")
+                                        .arg("--default-search")
+                                        .arg("ytsearch")
+                                        .arg(&arguments)
+                                        .output()
+                                        .expect("failed to spawn youtube-dl process");
+                                if output.status.success() {
+                                    let video_meta: Value = serde_json::from_slice(&output.stdout).expect("Failed to parse youtube-dl output");
+                                    warn(discord.send_message(message.channel_id, &format!("Playing **{}** ({})", video_meta["title"].as_str().unwrap(), video_meta["webpage_url"].as_str().unwrap()), "", false));
+                                    match discord::voice::open_ffmpeg_stream(video_meta["_filename"].as_str().unwrap()) {
+                                        Ok(stream) => {
+                                            let voice = connection.voice(server_id);
+                                            voice.set_deaf(true);
+                                            voice.connect(channel_id);
+                                            voice.play(stream);
+                                            String::new()
+                                        },
+                                        Err(error) => format!("Error: {}", error)
+                                    }
+                                } else {
+                                    format!("Error: {}", String::from_utf8_lossy(&output.stderr))
                                 }
                             } else {
                                 "You must be in a voice channel to DJ".to_owned()