Merge remote-tracking branch 'origin/dev' into 529-remove-deprecated-rpc

# Conflicts:
#	src/main/java/com/limechain/Main.java
#	src/main/java/com/limechain/rpc/RpcClient.java

src/main/java/com/limechain/Main.java

@@ -9,9 +9,14 @@
 
 public class Main {
 
+    private static final String WS_RPC = "wsRpc";
+
     private static final DivLogger log = new DivLogger();
 
     public static void main(String[] args) {
+        exportHttpRpc(RpcClient::sendRpcRequest, JSString.valueOf(HTTP_RPC));
+        exportWsRpc(new WsRpcClientImpl(), JSString.valueOf(WS_RPC));
+
         log.log("Starting LimeChain node...");
 
         RpcApp rpcApp = new RpcApp();
@@ -24,4 +29,7 @@ public static void main(String[] args) {
         client.start();
         log.log(Level.INFO, "\uD83D\uDE80Started light client!");
     }
+
+    @JSBody(params = {"c", "apiName"}, script = "window[apiName] = c;")
+    private static native void exportWsRpc(WsRpcClient c, JSString apiName);
 }

src/main/java/com/limechain/rpc/WebsocketState.java

@@ -0,0 +1,16 @@
+package com.limechain.rpc;
+
+import lombok.Getter;
+import lombok.RequiredArgsConstructor;
+
+@Getter
+@RequiredArgsConstructor
+public enum WebsocketState {
+
+    CONNECTING(0),
+    OPEN(1),
+    CLOSING(2),
+    CLOSED(3);
+
+    private final int intValue;
+}

src/main/java/com/limechain/rpc/WsRpcClient.java

@@ -0,0 +1,14 @@
+package com.limechain.rpc;
+
+import org.teavm.jso.JSObject;
+import org.teavm.jso.core.JSString;
+
+/**
+ * TeaVM overlay interface for a client used to communicate with a full node's RPC server.
+ */
+public interface WsRpcClient extends JSObject {
+
+    void send(JSString rpcString);
+
+    String nextResponse();
+}

src/main/java/com/limechain/rpc/WsRpcClientImpl.java

@@ -0,0 +1,89 @@
+package com.limechain.rpc;
+
+import com.limechain.constants.RpcConstants;
+import lombok.SneakyThrows;
+import lombok.extern.java.Log;
+import org.teavm.jso.browser.Window;
+import org.teavm.jso.core.JSString;
+import org.teavm.jso.websocket.WebSocket;
+
+import java.util.ArrayDeque;
+import java.util.Queue;
+
+/**
+ * The implementation of {@link WsRpcClient}. Uses a native JS Websocket implementation.
+ */
+@Log
+public class WsRpcClientImpl implements WsRpcClient {
+
+    private static final int WS_OPEN_WAIT_MS = 50;
+
+    private WebSocket ws;
+    private final Queue<String> responseQueue;
+
+    public WsRpcClientImpl() {
+        responseQueue = new ArrayDeque<>();
+        openWebsocketConnection();
+    }
+
+    private void openWebsocketConnection() {
+        log.info("Initializing RPC websocket connection...");
+        //TODO change when configuring chain.
+        ws = new WebSocket(RpcConstants.POLKADOT_WS_RPC);
+        initHandlers();
+    }
+
+    private void initHandlers() {
+        ws.onClose(e -> {
+            log.info("RPC websocket connection was closed.");
+            log.info("Retrying connection...");
+            Window.setTimeout(this::openWebsocketConnection, 1000);
+        });
+
+        ws.onError(e -> {
+            log.warning("There was an error in the RPC websocket connection. Closing connection...");
+            ws.close();
+        });
+
+        ws.onOpen(e -> log.info("Websocket connection is open."));
+        ws.onMessage(e -> responseQueue.offer(e.getDataAsString()));
+    }
+
+    /**
+     * Waits for the current ws connection to be in an opened state then sends an RPC request to the full node.
+     */
+    @Override
+    public void send(JSString rpcString) {
+        new Thread(() -> {
+            handleSocketState();
+            ws.send(rpcString.stringValue());
+        }).start();
+    }
+
+    /**
+     * Handles the state of the websocket when sending a message. If the connection is in a closing (2) or a closed (3)
+     * state the client throws an error.
+     */
+    @SneakyThrows
+    private void handleSocketState() {
+        int startState = ws.getReadyState();
+        int openedState = WebsocketState.OPEN.getIntValue();
+
+        while (startState != openedState) {
+            if (startState > openedState) {
+                throw new Exception("Calling function of a closed websocket is prohibited.");
+            }
+
+            Thread.sleep(WS_OPEN_WAIT_MS);
+            startState = ws.getReadyState();
+        }
+    }
+
+    /**
+     * Polls the first item in the queue and returns it as a string.
+     */
+    @Override
+    public String nextResponse() {
+        return responseQueue.poll();
+    }
+}

src/main/java/com/limechain/utils/json/JsonParser.java

@@ -159,10 +159,10 @@ private Object parseNumber() {
 
     private boolean isValidNumberChar() {
         return (Character.isDigit(json.charAt(index))
-            || json.charAt(index) == '-'
-            || json.charAt(index) == '.'
-            || json.charAt(index) == 'e'
-            || json.charAt(index) == 'E');
+                || json.charAt(index) == '-'
+                || json.charAt(index) == '.'
+                || json.charAt(index) == 'e'
+                || json.charAt(index) == 'E');
     }
 
     private void skipWhitespace() {