Added device_id and exposed it through /api/0/info

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "aw_server"
-version = "0.1.0"
+version = "0.8.0"
 authors = ["Johan Bjäreholt <johan@bjareho.lt>", "Erik Bjäreholt <erik@bjareho.lt>"]
 edition = "2018"
 default-run = "aw-server-rust"
@@ -37,6 +37,7 @@ fern = { version = "0.5", features = ["colored"] }
 toml = "0.5"
 gethostname = "0.2"
 regex = "1.0"
+uuid = { version = "0.8", features = ["serde", "v4"] }
 
 [target.'cfg(target_os="android")'.dependencies]
 jni = { version = "0.5", default-features = false }

src/endpoints/mod.rs

@@ -1,3 +1,4 @@
+use std::fs;
 use std::path::PathBuf;
 use std::sync::Mutex;
 
@@ -6,7 +7,9 @@ use rocket::response::{NamedFile};
 use rocket::State;
 use rocket_contrib::json::JsonValue;
 use gethostname::gethostname;
+use uuid::Uuid;
 
+use crate::dirs;
 use crate::config::AWConfig;
 
 #[macro_export]
@@ -60,6 +63,23 @@ fn root_favicon(state: State<ServerState>) -> Option<NamedFile> {
     NamedFile::open(state.asset_path.join("favicon.ico")).ok()
 }
 
+/// Retrieves the device ID, if none exists it generates one (using UUID v4)
+fn get_device_id() -> String {
+    // TODO: Cache to avoid retrieving on every /info call
+    // TODO: How should these unwraps be removed?
+    //       Should this be propagated into a 500 Internal Server Error? How?
+    // I chose get_data_dir over get_config_dir since the latter isn't yet supported on Android.
+    let mut path = dirs::get_data_dir().unwrap();
+    path.push("device_id");
+    if path.exists() {
+        fs::read_to_string(path).unwrap()
+    } else {
+        let uuid = Uuid::new_v4().to_hyphenated().to_string();
+        fs::write(path, &uuid).unwrap();
+        uuid
+    }
+}
+
 #[get("/")]
 fn server_info() -> JsonValue {
     let testing : bool;
@@ -78,7 +98,8 @@ fn server_info() -> JsonValue {
     json!({
         "hostname": hostname,
         "version": format!("aw-server-rust v{}", VERSION.unwrap_or("(unknown)")),
-        "testing": testing
+        "testing": testing,
+        "device_id": get_device_id(),
     })
 }