--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/main/java/openjdk/http/tutorial/exercise1/Retrievals.java Tue Jan 16 19:14:34 2018 +0000
@@ -0,0 +1,229 @@
+/*
+ * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package openjdk.http.tutorial.exercise1;
+
+import java.io.IOException;
+import java.io.UncheckedIOException;
+import java.net.URI;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.nio.file.StandardOpenOption;
+import java.util.Arrays;
+import java.util.Map;
+import java.util.concurrent.CompletableFuture;
+import java.util.function.Function;
+
+import com.fasterxml.jackson.core.type.TypeReference;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import jdk.incubator.http.HttpClient;
+import jdk.incubator.http.HttpRequest;
+import jdk.incubator.http.HttpResponse;
+import jdk.incubator.http.HttpResponse.BodyHandler;
+
+import static java.lang.System.out;
+import static java.util.stream.Collectors.joining;
+import static jdk.incubator.http.HttpClient.Version.*;
+import static jdk.incubator.http.HttpResponse.BodyHandler.*;
+
+/**
+ * @author Chris Hegarty
+ */
+public class Retrievals {
+
+ /**
+ * Exercise 1.
+ *
+ * Retrieve the response status code from a request to the given
+ * URI. The returned response code will be a int.
+ *
+ * Hint: use the discard BodyHandler since the response body is not
+ * interesting.
+ *
+ * Hint: static imports reduce boilerplate when using BodyHandlers
+ * and BodyProcessors, e.g. import static
+ * jdk.incubator.http.HttpResponse.BodyHandler.discard
+ */
+ public static int retrieveTheStatusCode(URI uri)
+ throws IOException, InterruptedException
+ {
+ HttpClient client = HttpClient.newBuilder().version(HTTP_1_1).build();
+ HttpRequest request = HttpRequest.newBuilder(uri).GET().build();
+ HttpResponse<?> response = client.send(request, discard(null));
+
+ return response.statusCode();
+ }
+
+ /**
+ * Exercise 1.
+ *
+ * Retrieve the response body from a given URI. Return the response
+ * body as a String.
+ *
+ * Hint: use the asString BodyHandler to convert the HTTP response
+ * body to a String.
+ *
+ * Hint: static imports reduce boilerplate when using BodyHandlers
+ * and BodyProcessors, e.g. import static
+ * jdk.incubator.http.HttpResponse.BodyHandler.asString
+ */
+ public static String retrieveResourceAsString(URI uri)
+ throws IOException, InterruptedException
+ {
+ HttpClient client = HttpClient.newBuilder().version(HTTP_1_1).build();
+ HttpRequest request = HttpRequest.newBuilder(uri).GET().build();
+ HttpResponse<String> response = client.send(request, asString());
+
+ return response.body();
+ }
+
+ /**
+ * Exercise 2.
+ *
+ * Retrieve the response body from a given URI, streaming teh body
+ * out to a file. Return the file's Path.
+ *
+ * Hint: use {@linkplain BodyHandler#asFile} to stream the HTTP
+ * response body to a file.
+ */
+ public static Path retrieveResourceAsFile(URI uri)
+ throws IOException, InterruptedException
+ {
+ HttpClient client = HttpClient.newBuilder().build();
+ HttpRequest request = HttpRequest.newBuilder()
+ .uri(uri)
+ .version(HTTP_1_1)
+ .GET()
+ .build();
+ HttpResponse<Path> response = client.send(request,
+ asFile(Paths.get("retrieveResourceAsFile.txt"), StandardOpenOption.TRUNCATE_EXISTING, StandardOpenOption.WRITE));
+
+ System.out.println("CHEGAR: sc=" + response.statusCode());
+ System.out.println("CHEGAR: by=" + Files.readAllLines(response.body()).stream().collect(joining()));
+
+ return response.body();
+ }
+
+
+ /**
+ * Asserts that the response code is 200 ( OK ).
+ *
+ * Can be used in CompletableFuture pipelines when checking the
+ * response of an {@linkplain HttpClient#sendAsync} call. For
+ * example:
+ * client.sendAsync(request, bodyHandler)
+ * .thenApply(Retrievals::require200StatusCode)
+ * .thenApply(...)
+ *
+ */
+ public static <T> HttpResponse<T> require200StatusCode(HttpResponse<T> response) {
+ int sc = response.statusCode();
+ if (sc != 200) {
+ IOException e = new IOException("Expected 200, got: " + sc);
+ throw new UncheckedIOException(e);
+ }
+ return response;
+ }
+
+ /**
+ * Exercise 3.
+ *
+ * Retrieve the response body from a given URI, using the
+ * asynchronous send API, sendAsync. Return a CompletableFuture that
+ * completes with the response body as a String.
+ *
+ * Hint: The {@linkplain CompletableFuture#thenApply(Function)}
+ * method can be used to map the HttpResponse to a String.
+ */
+ public static CompletableFuture<String> retrieveResourceAsStringUsingAsyncAPI(URI uri) {
+ return HttpClient.newHttpClient()
+ .sendAsync(HttpRequest.newBuilder(uri).version(HTTP_1_1).build(), asString()) // TODO: why version needed?
+ .thenApply(Retrievals::require200StatusCode)
+ .thenApply(HttpResponse::body);
+ }
+
+
+ /**
+ * Wrapper around Jackson's ObjectMapper that provides an unchecked
+ * {@code readValue}, what can be used to help solve the next
+ * exercise, 4.
+ */
+ public static class UncheckedObjectMapper extends ObjectMapper {
+
+ /** Parses the given JSON string into a Map. */
+ Map<String,String> readValue(String content) {
+ try {
+ return this.readValue(content, new TypeReference<>(){});
+ } catch (IOException ioe) {
+ throw new UncheckedIOException(ioe);
+ }
+ }
+ }
+
+ /**
+ * Exercise 4.
+ *
+ * Retrieve the response body from a given URI. The response body
+ * will be in the JSON format. The Jackson based UncheckedObjectMapper
+ * ( above ) can be used to parse the String response body into a
+ * Map.
+ *
+ * Hint: The asynchronous send API will allow construction of a
+ * pipeline of CompletableFutures.
+ *
+ * Hint: The {@linkplain CompletableFuture#thenApply(Function)}
+ * method can be used to map the HttpResponse to a String, and then
+ * again from a Sting to a Map ( via the object mapper ).
+ */
+ public CompletableFuture<Map<String,String>> JSONBodyAsMap(URI uri) {
+ UncheckedObjectMapper objectMapper = new UncheckedObjectMapper();
+ return HttpClient.newHttpClient()
+ .sendAsync(HttpRequest.newBuilder(uri).version(HTTP_1_1).build(), asString())
+ .thenApply(HttpResponse::body)
+ .thenApply(objectMapper::readValue);
+ }
+
+
+
+ /**
+ * Post the given {@code data}, and receive the same data in
+ * response. Return the response body data as a String.
+ */
+ public static String postData(URI uri, String data)
+ throws IOException, InterruptedException
+ {
+ HttpClient client = HttpClient.newBuilder().build();
+ HttpRequest request = HttpRequest.newBuilder()
+ .uri(uri)
+ .version(HTTP_1_1)
+ .POST(HttpRequest.BodyProcessor.fromString(data))
+ .build();
+ HttpResponse<String> response = client.send(request, asString());
+
+ return response.body();
+ }
+
+
+ // JSON processor
+}