feat: Add GET /instance endpoint, which returns some basic information about the current session

api/README.md

@@ -42,6 +42,7 @@ All the endpoints will respond with `200` if successful or:
 - `GET /profile/{user_id}/following` Retrieve a list of profiles that the specified user is following
 
 ### Instance
+- `GET /instance` Returns a json model that contains basic information about the current session; `device_id`, `device_name`,`device_type`, `country_code`, and `preferred_locale`
 - `POST /instance/terminate` Terminates the API server.
 - `POST /instance/close` Closes the current session (and player).
 

api/src/main/java/xyz/gianlu/librespot/api/ApiServer.java

@@ -35,6 +35,8 @@ public class ApiServer {
     private Undertow undertow = null;
 
     public ApiServer(int port, @NotNull String host, @NotNull SessionWrapper wrapper) {
+        AbsSessionHandler instanceHandler = InstanceHandler.forSession(this, wrapper);
+
         this.port = port;
         this.host = host;
         this.wrapper = wrapper;
@@ -45,7 +47,8 @@ public ApiServer(int port, @NotNull String host, @NotNull SessionWrapper wrapper
                 .post("/token/{scope}", new TokensHandler(wrapper))
                 .post("/profile/{user_id}/{action}", new ProfileHandler(wrapper))
                 .post("/web-api/{endpoint}", new WebApiHandler(wrapper))
-                .post("/instance/{action}", InstanceHandler.forSession(this, wrapper))
+                .get("/instance", instanceHandler)
+                .post("/instance/{action}", instanceHandler)
                 .post("/discovery/{action}", new DiscoveryHandler())
                 .get("/events", events)
                 .setFallbackHandler(new PathHandler(ResponseCodeHandler.HANDLE_404)

api/src/main/java/xyz/gianlu/librespot/api/Utils.java

@@ -83,4 +83,9 @@ public static void internalError(@NotNull HttpServerExchange exchange, @NotNull
         exchange.setStatusCode(StatusCodes.INTERNAL_SERVER_ERROR);
         exchange.getResponseSender().send(String.format(INTERNAL_ERROR_BODY, reason));
     }
+
+    public static void methodNotAllowed(@NotNull HttpServerExchange exchange) {
+        exchange.setStatusCode(StatusCodes.METHOD_NOT_ALLOWED);
+        exchange.getResponseSender().send(StatusCodes.METHOD_NOT_ALLOWED_STRING);
+    }
 }

api/src/main/java/xyz/gianlu/librespot/api/handlers/InstanceHandler.java

@@ -16,7 +16,10 @@
 
 package xyz.gianlu.librespot.api.handlers;
 
+import com.google.gson.JsonObject;
+import com.google.gson.JsonSyntaxException;
 import io.undertow.server.HttpServerExchange;
+import io.undertow.util.Headers;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 import xyz.gianlu.librespot.api.ApiServer;
@@ -55,6 +58,16 @@ private static String getAction(@NotNull HttpServerExchange exchange) throws IOE
         return action;
     }
 
+    private static String getInstanceInfo(@NotNull Session session) throws JsonSyntaxException {
+        JsonObject infoObj = new JsonObject();
+        infoObj.addProperty("device_id", session.deviceId());
+        infoObj.addProperty("device_name", session.deviceName());
+        infoObj.addProperty("device_type", session.deviceType().toString());
+        infoObj.addProperty("country_code", session.countryCode());
+        infoObj.addProperty("preferred_locale", session.preferredLocale());
+        return infoObj.toString();
+    }
+
     private static class SessionHandler extends AbsSessionHandler {
         private final ApiServer server;
 
@@ -71,19 +84,31 @@ protected void handleRequest(@NotNull HttpServerExchange exchange, @NotNull Sess
                 return;
             }
 
-            String action = getAction(exchange);
-            if (action == null) return;
-
-            switch (action) {
-                case "terminate":
-                    exchange.endExchange();
-                    new Thread(server::stop).start();
-                    break;
-                case "close":
-                    session.close();
+            String requestMethod = exchange.getRequestMethod().toString();
+            switch(requestMethod) {
+                case "GET":
+                    String info = getInstanceInfo(session);
+                    exchange.getResponseHeaders().put(Headers.CONTENT_TYPE, "application/json");
+                    exchange.getResponseSender().send(info);
+                    return;
+                case "POST":
+                    String action = getAction(exchange);
+                    if (action == null) return;
+
+                    switch (action) {
+                        case "terminate":
+                            exchange.endExchange();
+                            new Thread(server::stop).start();
+                            break;
+                        case "close":
+                            session.close();
+                            break;
+                        default:
+                            Utils.methodNotAllowed(exchange);
+                            break;
+                    }
                     break;
                 default:
-                    Utils.invalidParameter(exchange, "action");
                     break;
             }
         }
@@ -105,20 +130,31 @@ protected void handleRequest(@NotNull HttpServerExchange exchange, @NotNull Sess
                 return;
             }
 
-            String action = getAction(exchange);
-            if (action == null) return;
-
-            switch (action) {
-                case "terminate":
-                    exchange.endExchange();
-                    new Thread(server::stop).start();
-                    break;
-                case "close":
-                    player.close();
-                    session.close();
+            String requestMethod = exchange.getRequestMethod().toString();
+            switch(requestMethod) {
+                case "GET":
+                    String info = getInstanceInfo(session);
+                    exchange.getResponseHeaders().put(Headers.CONTENT_TYPE, "application/json");
+                    exchange.getResponseSender().send(info);
+                    return;
+                case "POST":
+                    String action = getAction(exchange);
+                    if (action == null) return;
+
+                    switch (action) {
+                        case "terminate":
+                            exchange.endExchange();
+                            new Thread(server::stop).start();
+                            break;
+                        case "close":
+                            session.close();
+                            break;
+                        default:
+                            Utils.methodNotAllowed(exchange);
+                            break;
+                    }
                     break;
                 default:
-                    Utils.invalidParameter(exchange, "action");
                     break;
             }
         }