Add initial proof of concept for http server

src/main/java/org/asamk/signal/http/HttpServerHandler.java

@@ -0,0 +1,111 @@
+package org.asamk.signal.http;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.node.ContainerNode;
+import com.fasterxml.jackson.databind.node.ObjectNode;
+import com.sun.net.httpserver.HttpExchange;
+import com.sun.net.httpserver.HttpServer;
+
+import org.asamk.signal.commands.Commands;
+import org.asamk.signal.commands.JsonRpcNamespace;
+import org.asamk.signal.commands.LocalCommand;
+import org.asamk.signal.jsonrpc.JsonRpcException;
+import org.asamk.signal.jsonrpc.JsonRpcRequest;
+import org.asamk.signal.jsonrpc.JsonRpcResponse;
+import org.asamk.signal.manager.Manager;
+import org.asamk.signal.manager.MultiAccountManager;
+import org.asamk.signal.output.JsonWriterImpl;
+import org.asamk.signal.util.Util;
+
+import java.io.IOException;
+import java.io.StringWriter;
+import java.net.InetSocketAddress;
+import java.nio.charset.StandardCharsets;
+import java.util.Map;
+import java.util.concurrent.Executors;
+
+public class HttpServerHandler {
+
+    private final ObjectMapper objectMapper = Util.createJsonObjectMapper();
+
+    public void init(int port, MultiAccountManager m) {
+
+        try {
+
+            System.out.println("Starting server on port " + port);
+
+            final var server = HttpServer.create(new InetSocketAddress(port), 0);
+            server.setExecutor(Executors.newFixedThreadPool(10));
+
+            server.createContext("/api/v1", httpExchange -> {
+                try {
+                    if (!"POST".equals(httpExchange.getRequestMethod())) {
+                        sendResponse(405, "NOT SUPPORTED", httpExchange);
+                    }
+
+                    final var request = objectMapper.readValue(httpExchange.getRequestBody(), JsonRpcRequest.class);
+                    final Map params = objectMapper.treeToValue(request.getParams(), Map.class);
+
+                    System.out.println("Command called " + request.getMethod());
+
+                    final var command = Commands.getCommand(request.getMethod());
+                    final var manager = getManagerFromParams(request.getParams(), m);
+
+                    if (command instanceof LocalCommand) {
+                        final var writer = new StringWriter();
+                        final var ns = new JsonRpcNamespace(params);
+
+                        ((LocalCommand) command).handleCommand(ns, manager, new JsonWriterImpl(writer));
+
+                        sendResponse(200, writer.toString(), httpExchange);
+                    }
+                    else {
+                        sendResponse(404, "COMMAND NOT FOUND", httpExchange);
+                    }
+
+                }
+                catch (Throwable aEx) {
+                    aEx.printStackTrace();
+                    sendResponse(500, "ERROR", httpExchange);
+                }
+            });
+
+            server.start();
+
+            // TODO there may be a better way to keep the main thread running.
+            try {
+                while (true) {
+                    Thread.sleep(1000);
+                }
+            } catch (InterruptedException ex) { }
+
+            System.out.println("Server shut down");
+
+        } catch (Throwable ex) {
+            ex.printStackTrace();
+        }
+
+    }
+
+    private void sendResponse(int status, String body, HttpExchange httpExchange) throws IOException {
+        final var byteResponse = body.getBytes(StandardCharsets.UTF_8);
+        httpExchange.sendResponseHeaders(status, byteResponse.length);
+        httpExchange.getResponseBody().write(byteResponse);
+        httpExchange.getResponseBody().close();
+    }
+
+    private Manager getManagerFromParams(final ContainerNode<?> params, MultiAccountManager c) throws JsonRpcException {
+        if (params != null && params.hasNonNull("account")) {
+            final var manager = c.getManager(params.get("account").asText());
+            ((ObjectNode) params).remove("account");
+            if (manager == null) {
+                throw new JsonRpcException(new JsonRpcResponse.Error(JsonRpcResponse.Error.INVALID_PARAMS,
+                        "Specified account does not exist",
+                        null));
+            }
+            return manager;
+        }
+        return null;
+    }
+
+}