Making gzip compression work

It's a little too much work to have the necessary server support on our
own to do mime/multipart decoding, so instead, just compress one part,
on our own.

src/main/java/io/jenkins/plugins/launchable/GzipFileMimePart.java

@@ -0,0 +1,51 @@
+package io.jenkins.plugins.launchable;
+
+import org.apache.commons.io.output.CloseShieldOutputStream;
+import org.apache.http.entity.ContentType;
+import org.apache.http.entity.mime.MIME;
+import org.apache.http.entity.mime.content.AbstractContentBody;
+
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.util.zip.GZIPOutputStream;
+
+final class GzipFileMimePart extends AbstractContentBody {
+    private final File file;
+    private final String filename;
+
+    public GzipFileMimePart(File file, ContentType contentType, String filename) {
+        super(contentType);
+        this.file = file;
+        this.filename = filename == null ? file.getName() : filename;
+    }
+
+    @Override
+    public void writeTo(OutputStream out) throws IOException {
+        try (OutputStream o = new GZIPOutputStream(new CloseShieldOutputStream(out));
+             InputStream in = new FileInputStream(this.file)) {
+            final byte[] tmp = new byte[4096];
+            int l;
+            while ((l = in.read(tmp)) != -1) {
+                o.write(tmp, 0, l);
+            }
+        }
+    }
+
+    @Override
+    public String getTransferEncoding() {
+        return MIME.ENC_BINARY;
+    }
+
+    @Override
+    public long getContentLength() {
+        return this.file.length();
+    }
+
+    @Override
+    public String getFilename() {
+        return filename;
+    }
+}

src/main/java/io/jenkins/plugins/launchable/Ingester.java

@@ -5,11 +5,8 @@
 import hudson.util.Secret;
 import jenkins.model.GlobalConfiguration;
 import net.sf.json.JSONObject;
-import org.apache.http.HttpHeaders;
-import org.apache.http.client.entity.GzipCompressingEntity;
 import org.apache.http.client.methods.CloseableHttpResponse;
 import org.apache.http.client.methods.HttpPost;
-import org.apache.http.entity.ContentType;
 import org.apache.http.entity.mime.MultipartEntityBuilder;
 import org.apache.http.impl.client.CloseableHttpClient;
 import org.apache.http.impl.client.HttpClients;
@@ -20,6 +17,9 @@
 import java.util.logging.Level;
 import java.util.logging.Logger;
 
+import static org.apache.http.entity.ContentType.APPLICATION_JSON;
+import static org.apache.http.entity.ContentType.APPLICATION_OCTET_STREAM;
+
 @Extension
 public class Ingester extends GlobalConfiguration {
     private Secret apiKey;
@@ -66,10 +66,10 @@ public boolean configure(StaplerRequest req, JSONObject json) throws FormExcepti
                 HttpPost hc = new HttpPost(String.format("%s/intake/organizations/%s/workspaces/%s/events/jenkins", endpoint, orgWs.getOrganization(), orgWs.getWorkspace()));
 
                 MultipartEntityBuilder builder = MultipartEntityBuilder.create();
-                builder.addTextBody("metadata", properties.build().toString(), ContentType.APPLICATION_JSON);
-                builder.addBinaryBody("file", report, ContentType.APPLICATION_XML, "junitResult.xml");
+                builder.addTextBody("metadata", properties.build().toString(), APPLICATION_JSON);
+                builder.addPart("file", new GzipFileMimePart(report, APPLICATION_OCTET_STREAM, "junitResult.xml.gz"));
 
-                hc.setEntity(new GzipCompressingEntity(builder.build()));
+                hc.setEntity(builder.build());
                 hc.addHeader("Authorization", "Bearer " + apiKey.getPlainText());
 
                 try (CloseableHttpResponse response = httpClient.execute(hc)) {