Report the upload settings to the server

Uploads now carry the client's upload configuration as X-UDC-* headers,
built by the new UploadSettings default method getReportedPreferences().
Nothing about the user or their work is reported.

Author: vogella

org.eclipse.epp.usagedata.recording/src/org/eclipse/epp/usagedata/internal/recording/settings/UploadSettings.java

@@ -10,6 +10,9 @@
  *******************************************************************************/
 package org.eclipse.epp.usagedata.internal.recording.settings;
 
+import java.util.Collections;
+import java.util.Map;
+
 import org.eclipse.epp.usagedata.internal.recording.filtering.NullFilter;
 import org.eclipse.epp.usagedata.internal.recording.filtering.UsageDataEventFilter;
 
@@ -49,4 +52,15 @@ public interface UploadSettings {
 
 	public abstract String getUserAgent();
 
+	/**
+	 * This method answers the settings that should travel with an upload, so
+	 * that a server can tell how the client that sent it was configured. Keys
+	 * become {@code X-UDC-<key>} headers. The default is to send nothing.
+	 *
+	 * @return the settings to report, never <code>null</code>.
+	 */
+	public default Map<String, String> getReportedPreferences() {
+		return Collections.emptyMap();
+	}
+
 }

org.eclipse.epp.usagedata.recording/src/org/eclipse/epp/usagedata/internal/recording/settings/UsageDataRecordingSettings.java

@@ -19,7 +19,9 @@
 import java.io.Writer;
 import java.util.ArrayList;
 import java.util.Comparator;
+import java.util.LinkedHashMap;
 import java.util.List;
+import java.util.Map;
 import java.util.UUID;
 import java.util.concurrent.TimeUnit;
 
@@ -509,6 +511,29 @@ private boolean hasExplicitValue(IPreferenceStore store, String key) {
 		return store.contains(key) && !store.isDefault(key);
 	}
 
+	/**
+	 * This method answers the settings that travel with an upload. It reports
+	 * how uploading is configured, never anything about the user or what they
+	 * were doing.
+	 */
+	public Map<String, String> getReportedPreferences() {
+		Map<String, String> reported = new LinkedHashMap<String, String>();
+		reported.put("upload-mode", uploadModeName(getUploadMode())); //$NON-NLS-1$
+		reported.put("upload-period-days", String.valueOf(getPeriodBetweenUploads() / (24 * 60 * 60 * 1000))); //$NON-NLS-1$
+		reported.put("filter-eclipse-only", String.valueOf(getPreferencesStore().getBoolean(FILTER_ECLIPSE_BUNDLES_ONLY_KEY))); //$NON-NLS-1$
+		reported.put("filter-bundle-events", String.valueOf(getPreferencesStore().getBoolean(FILTER_BUNDLE_EVENTS_KEY))); //$NON-NLS-1$
+		reported.put("retention-days", String.valueOf(UPLOAD_FILE_RETENTION_DAYS)); //$NON-NLS-1$
+		return reported;
+	}
+
+	private String uploadModeName(int mode) {
+		switch (mode) {
+			case UPLOAD_MODE_AUTOMATIC: return "automatic"; //$NON-NLS-1$
+			case UPLOAD_MODE_MANUAL: return "manual"; //$NON-NLS-1$
+			default: return "ask"; //$NON-NLS-1$
+		}
+	}
+
 	public void setUploadMode(int mode) {
 		getPreferencesStore().setValue(UPLOAD_MODE_KEY, mode);
 		UsageDataRecordingActivator.getDefault().savePluginPreferences();

org.eclipse.epp.usagedata.recording/src/org/eclipse/epp/usagedata/internal/recording/uploading/BasicUploader.java

@@ -34,6 +34,7 @@
 import java.time.Duration;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Map;
 import java.util.UUID;
 
 import org.eclipse.core.runtime.IProgressMonitor;
@@ -82,6 +83,12 @@ public class BasicUploader extends AbstractUploader {
 
 	private static final String USER_AGENT = "User-Agent"; //$NON-NLS-1$
 
+	/**
+	 * The prefix for the headers that report how the client is configured, one
+	 * header per entry of {@link UploadSettings#getReportedPreferences()}.
+	 */
+	private static final String PREFERENCE_HEADER_PREFIX = "X-UDC-"; //$NON-NLS-1$
+
 	private boolean uploadInProgress = false;
 
 	private ListenerList responseListeners = new ListenerList();
@@ -203,6 +210,10 @@ UploadResult doUpload(IProgressMonitor monitor) throws Exception {
 			.timeout(Duration.ofMillis(getSocketTimeout()))
 			.POST(BodyPublishers.ofByteArray(multipartBody));
 
+		for (Map.Entry<String, String> preference : getSettings().getReportedPreferences().entrySet()) {
+			requestBuilder.header(PREFERENCE_HEADER_PREFIX + preference.getKey(), preference.getValue());
+		}
+
 		boolean loggingServerActivity = getSettings().isLoggingServerActivity();
 		if (loggingServerActivity) {
 			requestBuilder.header("LOGGING", "true"); //$NON-NLS-1$ //$NON-NLS-2$