ClientServerCompressionExample.java
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package org.apache.hc.client5.http.examples;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.charset.StandardCharsets;
import org.apache.commons.compress.compressors.CompressorException;
import org.apache.commons.compress.compressors.CompressorStreamFactory;
import org.apache.hc.client5.http.entity.EntityBuilder;
import org.apache.hc.client5.http.entity.compress.ContentCoding;
import org.apache.hc.client5.http.impl.classic.CloseableHttpClient;
import org.apache.hc.client5.http.impl.classic.HttpClients;
import org.apache.hc.core5.http.ClassicHttpRequest;
import org.apache.hc.core5.http.ClassicHttpResponse;
import org.apache.hc.core5.http.ContentType;
import org.apache.hc.core5.http.HttpStatus;
import org.apache.hc.core5.http.impl.bootstrap.HttpServer;
import org.apache.hc.core5.http.impl.bootstrap.ServerBootstrap;
import org.apache.hc.core5.http.io.HttpRequestHandler;
import org.apache.hc.core5.http.io.entity.ByteArrayEntity;
import org.apache.hc.core5.http.io.entity.EntityUtils;
import org.apache.hc.core5.http.io.entity.StringEntity;
import org.apache.hc.core5.http.io.support.ClassicRequestBuilder;
import org.apache.hc.core5.http.protocol.HttpContext;
import org.apache.hc.core5.io.CloseMode;
/**
* A minimal end-to-end example that shows how the new
* {@code EntityBuilder.compressed(ContentCoding)} method (added in 5.6)
* can be used to send a request body compressed with Zstandard and to receive
* a transparently decompressed response.
* <p>
* The code spins up an in-process {@link HttpServer} on a random port. The
* client builds a simple {@code POST /echo} request whose entity is
* compressed by calling
* {@code .compressed(ContentCoding.ZSTD)}. The server handler decodes the
* incoming body with Apache Commons Compress, echoes the text, re-encodes it
* with Zstandard, sets {@code Content-Encoding: zstd} and returns it. On the
* way back, HttpClient detects the header, selects the matching decoder that
* was registered automatically through {@code ContentDecoderRegistry} and
* hands application code a plain {@code String}.
* <p>
* To run the example you need HttpClient 5.6-SNAPSHOT, Commons Compress
* 1.21 or newer and its transitive dependency {@code zstd-jni}. On JDK 17+
* the first invocation of the Zstandard codec prints a warning about loading
* native code; add {@code --enable-native-access=ALL-UNNAMED} if you prefer a
* clean console.
*
* @since 5.6
*/
public final class ClientServerCompressionExample {
private ClientServerCompressionExample() {
}
public static void main(final String[] args) throws Exception {
int port = 8080;
if (args.length >= 1) {
port = Integer.parseInt(args[0]);
}
final HttpServer server = ServerBootstrap.bootstrap()
.setListenerPort(port)
.setCanonicalHostName("localhost")
.register("/echo", new EchoHandler())
.create();
server.start();
final int actualPort = server.getLocalPort();
try (CloseableHttpClient client = HttpClients.createDefault()) {
final String requestBody = "Hello Zstandard world!";
System.out.println("Request : " + requestBody);
final ClassicHttpRequest post = ClassicRequestBuilder
.post("http://localhost:" + actualPort + "/echo")
.setEntity(EntityBuilder.create()
.setText(requestBody)
.compressed(ContentCoding.ZSTD)
.build())
.build();
final String reply = client.execute(
post,
rsp -> EntityUtils.toString(rsp.getEntity(), StandardCharsets.UTF_8));
System.out.println("Response: " + reply);
} finally {
server.close(CloseMode.GRACEFUL);
}
}
/**
* Simple echo handler that decodes and re-encodes Zstandard bodies.
*/
private static final class EchoHandler implements HttpRequestHandler {
@Override
public void handle(
final ClassicHttpRequest request,
final ClassicHttpResponse response,
final HttpContext context) throws IOException {
try (InputStream in = new CompressorStreamFactory()
.createCompressorInputStream(ContentCoding.ZSTD.token(), request.getEntity().getContent())) {
final byte[] data = readAll(in);
final String text = new String(data, StandardCharsets.UTF_8);
response.setCode(HttpStatus.SC_OK);
response.addHeader("Content-Encoding", ContentCoding.ZSTD.token());
final ByteArrayOutputStream baos = new ByteArrayOutputStream();
try (final OutputStream zstdOut = new CompressorStreamFactory()
.createCompressorOutputStream("zstd", baos)) {
zstdOut.write(text.getBytes(StandardCharsets.UTF_8));
}
response.setEntity(new ByteArrayEntity(baos.toByteArray(), ContentType.TEXT_PLAIN));
} catch (final CompressorException ex) {
response.setCode(HttpStatus.SC_BAD_REQUEST);
response.setEntity(new StringEntity("Unable to process compressed payload", StandardCharsets.UTF_8));
}
}
private static byte[] readAll(final InputStream in) throws IOException {
final ByteArrayOutputStream buf = new ByteArrayOutputStream();
final byte[] tmp = new byte[8 * 1024];
int n;
while ((n = in.read(tmp)) != -1) {
buf.write(tmp, 0, n);
}
return buf.toByteArray();
}
}
}