Homework5. Тяпуев Дмитрий. Магистратура. Политех

src/main/java/ru/vk/itmo/test/tyapuevdmitrij/Client.java

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+package ru.vk.itmo.test.tyapuevdmitrij;
+
+import one.nio.http.Request;
+import one.nio.http.Response;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.net.HttpURLConnection;
+import java.net.URI;
+import java.net.http.HttpClient;
+import java.net.http.HttpRequest;
+import java.net.http.HttpResponse;
+import java.util.Optional;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.ExecutorService;
+
+public class Client {
+    private static final Logger LOGGER = LoggerFactory.getLogger(Client.class);
+
+    public static final String PROXY_TIMESTAMP_HEADER = "proxy";
+
+    public static final String NODE_TIMESTAMP_HEADER = "node";
+
+    private static final byte[] EMPTY_BODY = new byte[0];
+    private final HttpClient httpClient;
+
+    private String url;
+
+    private long timeStamp;
+
+    private final ExecutorService proxyExecutor;
+
+    Client(ExecutorService proxyExecutor) {
+        this.httpClient = HttpClient.newBuilder().build();
+        this.proxyExecutor = proxyExecutor;
+    }
+
+    public CompletableFuture<Response> handleProxyRequest(Request request) {
+        CompletableFuture<HttpResponse<byte[]>> responseFuture = getProxyResponse(request);
+        return responseFuture.thenApplyAsync(response -> {
+            if (response == null) {
+                return new Response(Response.INTERNAL_ERROR, Response.EMPTY);
+            }
+            String statusCode = switch (response.statusCode()) {
+                case HttpURLConnection.HTTP_OK -> Response.OK;
+                case HttpURLConnection.HTTP_CREATED -> Response.CREATED;
+                case HttpURLConnection.HTTP_ACCEPTED -> Response.ACCEPTED;
+                case HttpURLConnection.HTTP_BAD_REQUEST -> Response.BAD_REQUEST;
+                case HttpURLConnection.HTTP_NOT_FOUND -> Response.NOT_FOUND;
+                case HttpURLConnection.HTTP_INTERNAL_ERROR -> Response.INTERNAL_ERROR;
+                default -> throw new IllegalStateException("Unexpected value: " + response.statusCode());
+            };
+            Optional<String> nodeHeader = response.headers().firstValue(NODE_TIMESTAMP_HEADER);
+            Response finalResponse = new Response(statusCode, response.body());
+            if (nodeHeader.isPresent()) {
+                long time = Long.parseLong(nodeHeader.get());
+                finalResponse.addHeader(Client.NODE_TIMESTAMP_HEADER + ":" + time);
+            }
+            return finalResponse;
+        }, proxyExecutor).exceptionally(throwable -> {
+            LOGGER.error("can't reach target node", throwable);
+            return new Response(Response.INTERNAL_ERROR, Response.EMPTY);
+        });
+    }
+
+    public void setUrl(String url) {
+        this.url = url;
+    }
+
+    public void setTimeStamp(long timeStamp) {
+        this.timeStamp = timeStamp;
+    }
+
+    private byte[] getRequestBody(Request request) {
+        return request.getBody() == null ? EMPTY_BODY : request.getBody();
+    }
+
+    private HttpRequest getProxyRequest(Request request) {
+        return HttpRequest.newBuilder(URI.create(url + request.getURI()))
+                .method(request.getMethodName(),
+                        HttpRequest.BodyPublishers.ofByteArray(getRequestBody(request)))
+                .header(PROXY_TIMESTAMP_HEADER, String.valueOf(timeStamp))
+                .build();
+    }
+
+    private CompletableFuture<HttpResponse<byte[]>> getProxyResponse(Request request) {
+        return httpClient.sendAsync(getProxyRequest(request),
+                HttpResponse.BodyHandlers.ofByteArray());
+    }
+}