feat: Support usePost for FDv2 polling and streaming requests

Makefile

@@ -21,8 +21,8 @@ run-contract-tests:
       | VERSION=v2 PARAMS="-url http://localhost:8001 -host 10.0.2.2 -debug -skip-from $(SUPPRESSION_FILE) $(TEST_HARNESS_PARAMS_V2)" sh
 	@echo "Running SDK contract test v3..."
 	@curl $${GITHUB_TOKEN:+ -H "Authorization: Token $${GITHUB_TOKEN}"} \
-      -s https://raw.githubusercontent.com/launchdarkly/sdk-test-harness/v3.1.0-alpha.6/downloader/run.sh \
-      | VERSION=v3.1.0-alpha.6 PARAMS="-url http://localhost:8001 -host 10.0.2.2 -debug -stop-service-at-end -skip-from $(SUPPRESSION_FILE_FDV2) $(TEST_HARNESS_PARAMS_V3)" sh
+      -s https://raw.githubusercontent.com/launchdarkly/sdk-test-harness/v3.2.0-alpha.10/downloader/run.sh \
+      | VERSION=v3.2.0-alpha.10 PARAMS="-url http://localhost:8001 -host 10.0.2.2 -debug -stop-service-at-end -skip-from $(SUPPRESSION_FILE_FDV2) $(TEST_HARNESS_PARAMS_V3)" sh
 
 contract-tests: build-contract-tests start-emulator start-contract-test-service run-contract-tests
 

contract-tests/src/main/java/com/launchdarkly/sdktest/Representations.java

@@ -78,6 +78,7 @@ public static class SdkConfigClientSideParams {
         LDContext initialContext;
         boolean evaluationReasons;
         boolean useReport;
+        boolean usePost;
         boolean includeEnvironmentAttributes;
     }
 

contract-tests/src/main/java/com/launchdarkly/sdktest/SdkClientEntity.java

@@ -284,7 +284,7 @@ private LDConfig buildSdkConfig(SdkConfigParams params, LDLogAdapter logAdapter,
     ConfigHelper.configureIsolatedInMemoryPersistence(builder);
 
     if (params.dataSystem != null) {
-      configureDataSystem(builder, params.dataSystem);
+      configureDataSystem(builder, params.dataSystem, params.clientSide.usePost);
     } else {
       if (params.polling != null && params.polling.baseUri != null) {
         endpoints.polling(params.polling.baseUri);
@@ -391,15 +391,16 @@ private LDConfig buildSdkConfig(SdkConfigParams params, LDLogAdapter logAdapter,
     return builder.build();
   }
 
-  private void configureDataSystem(LDConfig.Builder builder, SdkConfigDataSystemParams dataSystem) {
+  private void configureDataSystem(LDConfig.Builder builder, SdkConfigDataSystemParams dataSystem,
+                                   boolean usePost) {
     if (Boolean.TRUE.equals(dataSystem.useDefaultDataSystem)) {
-      builder.dataSystem(Components.dataSystem());
+      builder.dataSystem(Components.dataSystem().usePost(usePost));
       return;
     }
 
     SdkConfigConnectionModeConfig connModeConfig = dataSystem.connectionModeConfig;
 
-    DataSystemBuilder dsBuilder = Components.dataSystem();
+    DataSystemBuilder dsBuilder = Components.dataSystem().usePost(usePost);
 
     // at the time of writing this, we did not have contract tests that could test platform state changes,
     // disabling automatic mode simplifies the behavior being tested

contract-tests/src/main/java/com/launchdarkly/sdktest/TestService.java

@@ -43,7 +43,8 @@ public class TestService extends NanoHTTPD {
             "evaluation-hooks",
             "track-hooks",
             "client-per-context-summaries",
-            "client-event-source-http-errors"
+            "client-event-source-http-errors",
+            "client-use-post"
     };
     private static final String MIME_JSON = "application/json";
     static final Gson gson = new GsonBuilder()

launchdarkly-android-client-sdk/src/main/java/com/launchdarkly/sdk/android/DataSourceBuildInputsInternal.java

@@ -35,13 +35,14 @@ final class DataSourceBuildInputsInternal extends DataSourceBuildInputs {
             ServiceEndpoints serviceEndpoints,
             HttpConfiguration http,
             boolean evaluationReasons,
+            boolean usePost,
             SelectorSource selectorSource,
             ScheduledExecutorService sharedExecutor,
             @NonNull File cacheDir,
             LDLogger baseLogger,
             @Nullable PersistentDataStoreWrapper.ReadOnlyPerEnvironmentData perEnvironmentData
     ) {
-        super(evaluationContext, serviceEndpoints, http, evaluationReasons,
+        super(evaluationContext, serviceEndpoints, http, evaluationReasons, usePost,
                 selectorSource, sharedExecutor, cacheDir, baseLogger);
         this.perEnvironmentData = perEnvironmentData;
     }
@@ -60,6 +61,7 @@ static DataSourceBuildInputsInternal get(DataSourceBuildInputs inputs) {
                 inputs.getServiceEndpoints(),
                 inputs.getHttp(),
                 inputs.isEvaluationReasons(),
+                inputs.isUsePost(),
                 inputs.getSelectorSource(),
                 inputs.getSharedExecutor(),
                 inputs.getCacheDir(),

launchdarkly-android-client-sdk/src/main/java/com/launchdarkly/sdk/android/DataSystemComponents.java

@@ -141,7 +141,7 @@ public Synchronizer build(DataSourceBuildInputs inputs) {
                     StandardEndpoints.FDV2_STREAMING_REQUEST_BASE_PATH,
                     requestor,
                     initialReconnectDelayMillis,
-                    inputs.isEvaluationReasons(), inputs.getHttp().isUseReport(),
+                    inputs.isEvaluationReasons(), inputs.isUsePost(),
                     httpProps, inputs.getSharedExecutor(),
                     inputs.getBaseLogger(), null);
         }
@@ -159,10 +159,12 @@ public FDv1PollingSynchronizerBuilderImpl pollIntervalMillis(int pollIntervalMil
 
         @Override
         public Synchronizer build(DataSourceBuildInputs inputs) {
+            // The FDv1 endpoints do not accept POST. REPORT is their method that carries the
+            // context in the request body, so usePost selects REPORT here.
             FeatureFetcher fetcher = new HttpFeatureFlagFetcher(
                 inputs.getServiceEndpoints().getPollingBaseUri(),
                 inputs.isEvaluationReasons(),
-                inputs.getHttp().isUseReport(),
+                inputs.isUsePost(),
                 LDUtil.makeHttpProperties(inputs.getHttp()),
                 inputs.getCacheDir(),
                 inputs.getBaseLogger()
@@ -360,9 +362,8 @@ private static FDv2Requestor makePollingRequestor(DataSourceBuildInputs inputs,
                 "polling", inputs.getBaseLogger());
         return new DefaultFDv2Requestor(
                 inputs.getEvaluationContext(), pollingBase,
-                StandardEndpoints.FDV2_POLLING_REQUEST_GET_BASE_PATH,
-                StandardEndpoints.FDV2_POLLING_REQUEST_REPORT_BASE_PATH,
-                httpProps, inputs.getHttp().isUseReport(),
+                StandardEndpoints.FDV2_POLLING_REQUEST_BASE_PATH,
+                httpProps, inputs.isUsePost(),
                 inputs.isEvaluationReasons(), null, inputs.getBaseLogger());
     }
 }

launchdarkly-android-client-sdk/src/main/java/com/launchdarkly/sdk/android/DefaultFDv2Requestor.java

@@ -31,7 +31,7 @@
 /**
  * Default OkHttp-based implementation of {@link FDv2Requestor}.
  * <p>
- * Builds GET or REPORT requests to the FDv2 polling endpoint. If the current selector is
+ * Builds GET or POST requests to the FDv2 polling endpoint. If the current selector is
  * non-empty, its state is sent as the {@code basis} query parameter. ETag tracking is used
  * to detect 304 Not Modified responses; when the server returns 304 the application layer
  * treats it as {@code ChangeSetType.None} (no flags changed), so no OkHttp disk cache is
@@ -40,7 +40,6 @@
  * The OkHttpClient is closed by {@link #close()}.
  */
 final class DefaultFDv2Requestor implements FDv2Requestor {
-    private static final String METHOD_REPORT = "REPORT";
     private static final String BASIS_PARAM = "basis";
     private static final String FILTER_PARAM = "filter";
     private static final String WITH_REASONS_PARAM = "withReasons";
@@ -50,10 +49,10 @@ final class DefaultFDv2Requestor implements FDv2Requestor {
     private final OkHttpClient httpClient;
     private final URI pollingUri;
     private final okhttp3.Headers headers;
-    private final boolean useReport;
+    private final boolean usePost;
     private final boolean evaluationReasons;
     @Nullable
-    private final RequestBody reportBody;
+    private final RequestBody postBody;
     @Nullable
     private final String payloadFilter;
     private final LDLogger logger;
@@ -67,10 +66,10 @@ final class DefaultFDv2Requestor implements FDv2Requestor {
     /**
      * @param evaluationContext  the context to evaluate flags for
      * @param baseUri            polling base URI from service endpoints
-     * @param getRequestPath     path for GET requests (context appended as a path segment)
-     * @param reportRequestPath  path for REPORT requests (context sent in the request body)
+     * @param requestPath        polling request path; GET appends the base64-encoded context as a
+     *                           path segment, POST uses the path as is
      * @param httpProperties     SDK HTTP configuration (timeouts, proxy, TLS, user-agent, etc.)
-     * @param useReport          if true, send context in the request body via REPORT; otherwise
+     * @param usePost            if true, send the context in the request body via POST; otherwise
      *                           append the base64-encoded context to the GET path
      * @param evaluationReasons  if true, append {@code withReasons=true} to the query string
      * @param payloadFilter      optional payload filter key; sent as {@code filter} query param
@@ -79,29 +78,27 @@ final class DefaultFDv2Requestor implements FDv2Requestor {
     DefaultFDv2Requestor(
             @NonNull LDContext evaluationContext,
             @NonNull URI baseUri,
-            @NonNull String getRequestPath,
-            @NonNull String reportRequestPath,
+            @NonNull String requestPath,
             @NonNull HttpProperties httpProperties,
-            boolean useReport,
+            boolean usePost,
             boolean evaluationReasons,
             @Nullable String payloadFilter,
             @NonNull LDLogger logger) {
-        this.useReport = useReport;
+        this.usePost = usePost;
         this.evaluationReasons = evaluationReasons;
         this.payloadFilter = payloadFilter;
         this.logger = logger;
         this.headers = httpProperties.toHeadersBuilder().build();
 
         // Precompute the base polling URI for the chosen request method. For GET, the
         // base64-encoded context is a fixed path segment (context never changes after
-        // construction). For REPORT, the context goes in the request body so no path
+        // construction). For POST, the context goes in the request body so no path
         // segment is needed.
-        URI basePollingUri = HttpHelpers.concatenateUriPath(baseUri,
-                useReport ? reportRequestPath : getRequestPath);
-        this.pollingUri = useReport
+        URI basePollingUri = HttpHelpers.concatenateUriPath(baseUri, requestPath);
+        this.pollingUri = usePost
                 ? basePollingUri
                 : HttpHelpers.concatenateUriPath(basePollingUri, LDUtil.urlSafeBase64(evaluationContext));
-        this.reportBody = useReport
+        this.postBody = usePost
                 ? RequestBody.create(JsonSerialization.serialize(evaluationContext), JSON)
                 : null;
 
@@ -139,8 +136,8 @@ public Future<FDv2PayloadResponse> poll(@NonNull Selector selector) {
                     .url(requestUri.toURL())
                     .headers(headers);
 
-            if (useReport) {
-                reqBuilder.method(METHOD_REPORT, reportBody);
+            if (usePost) {
+                reqBuilder.post(postBody);
             } else {
                 synchronized (etagLock) {
                     if (!requestUri.equals(lastRequestUri)) {
@@ -207,7 +204,7 @@ private void handleResponse(
                 return;
             }
 
-            if (!useReport) {
+            if (!usePost) {
                 synchronized (etagLock) {
                     cachedEtag = response.header(ETAG_HEADER);
                 }

launchdarkly-android-client-sdk/src/main/java/com/launchdarkly/sdk/android/FDv2DataSourceBuilder.java

@@ -34,10 +34,13 @@ class FDv2DataSourceBuilder implements ComponentConfigurer<DataSource>, Closeabl
     private final Map<ConnectionMode, ModeDefinition> modeTable;
     private final ConnectionMode startingMode;
     private final ModeResolutionTable resolutionTable;
+    private final boolean usePost;
 
     private ConnectionMode activeMode;
     private boolean includeInitializers = true; // start with initializers
     private ScheduledExecutorService sharedExecutor;
+    // The useReport warning is logged on the first build only. Builds run on one thread.
+    private boolean useReportWarningLogged = false;
 
     FDv2DataSourceBuilder() {
         this(DataSystemComponents.makeDefaultModeTable(), ConnectionMode.STREAMING, ModeResolutionTable.MOBILE);
@@ -54,10 +57,24 @@ class FDv2DataSourceBuilder implements ComponentConfigurer<DataSource>, Closeabl
             @NonNull Map<ConnectionMode, ModeDefinition> modeTable,
             @NonNull ConnectionMode startingMode,
             @NonNull ModeResolutionTable resolutionTable
+    ) {
+        this(modeTable, startingMode, resolutionTable, false);
+    }
+
+    /**
+     * @param usePost true if FDv2 polling and streaming requests send the context in the request
+     *                body with POST instead of encoding it into the GET path
+     */
+    FDv2DataSourceBuilder(
+            @NonNull Map<ConnectionMode, ModeDefinition> modeTable,
+            @NonNull ConnectionMode startingMode,
+            @NonNull ModeResolutionTable resolutionTable,
+            boolean usePost
     ) {
         this.modeTable = modeTable;
         this.startingMode = startingMode;
         this.resolutionTable = resolutionTable;
+        this.usePost = usePost;
     }
 
     /**
@@ -75,6 +92,15 @@ ConnectionMode getStartingMode() {
         return startingMode;
     }
 
+    /**
+     * Returns whether FDv2 flag requests send the context in the request body with POST.
+     *
+     * @return true if flag requests use POST
+     */
+    boolean isUsePost() {
+        return usePost;
+    }
+
     /**
      * Configures the mode to build for and whether to include initializers.
      * Called by {@link ConnectivityManager} before each {@link #build} call.
@@ -108,6 +134,15 @@ public DataSource build(ClientContext clientContext) {
 
         ConnectionMode mode = activeMode != null ? activeMode : startingMode;
 
+        // The FDv2 endpoints take POST, not REPORT. The data system has its own usePost option,
+        // so the FDv1 useReport option does not apply here.
+        if (clientContext.getHttp().isUseReport() && !useReportWarningLogged) {
+            useReportWarningLogged = true;
+            clientContext.getBaseLogger().warn(
+                    "useReport has no effect with the FDv2 data system and is ignored. " +
+                    "Use DataSystemBuilder.usePost to send the evaluation context in the request body.");
+        }
+
         ModeDefinition modeDef = modeTable.get(mode);
         if (modeDef == null) {
             throw new IllegalStateException(
@@ -159,6 +194,7 @@ private DataSourceBuildInputsInternal makeInputs(ClientContext clientContext) {
                 clientContext.getServiceEndpoints(),
                 clientContext.getHttp(),
                 clientContext.isEvaluationReasons(),
+                usePost,
                 selectorSource,
                 sharedExecutor,
                 impl.getPlatformState().getCacheDir(),

launchdarkly-android-client-sdk/src/main/java/com/launchdarkly/sdk/android/FDv2StreamingSynchronizer.java

@@ -53,15 +53,15 @@
  * <p>
  */
 final class FDv2StreamingSynchronizer implements Synchronizer {
-    private static final String METHOD_REPORT = "REPORT";
+    private static final String METHOD_POST = "POST";
     private static final String PING = "ping";
     private static final long READ_TIMEOUT_MS = 300_000; // 5 minutes
     private static final long MAX_RECONNECT_TIME_MS = 300_000; // 5 minutes
 
     private final HttpProperties httpProperties;
     private final URI streamBaseUri;
     private final String streamRequestPath;
-    private final boolean useReport;
+    private final boolean usePost;
     private final LDContext evaluationContext;
     private final SelectorSource selectorSource;
     @Nullable
@@ -92,7 +92,7 @@ final class FDv2StreamingSynchronizer implements Synchronizer {
      * @param requestor                    optional requestor for handling ping events via poll; may be null
      * @param initialReconnectDelayMillis  delay before reconnecting after an error, in milliseconds
      * @param evaluationReasons           true to request evaluation reasons in the stream
-     * @param useReport                    true to use HTTP REPORT for the request body
+     * @param usePost                      true to send the context in the request body with POST
      * @param httpProperties               HTTP configuration for the stream request
      * @param executor                     executor used to run the streaming loop on a background
      *                                     thread; should use background-priority threads
@@ -107,7 +107,7 @@ final class FDv2StreamingSynchronizer implements Synchronizer {
             @Nullable FDv2Requestor requestor,
             int initialReconnectDelayMillis,
             boolean evaluationReasons,
-            boolean useReport,
+            boolean usePost,
             @NonNull HttpProperties httpProperties,
             @NonNull Executor executor,
             @NonNull LDLogger logger,
@@ -120,7 +120,7 @@ final class FDv2StreamingSynchronizer implements Synchronizer {
         this.requestor = requestor;
         this.initialReconnectDelayMillis = initialReconnectDelayMillis;
         this.evaluationReasons = evaluationReasons;
-        this.useReport = useReport;
+        this.usePost = usePost;
         this.httpProperties = httpProperties;
         this.executor = executor;
         this.logger = logger;
@@ -188,9 +188,9 @@ private void startStream() {
                     return reqBuilder.build();
                 });
 
-        if (useReport) {
+        if (usePost) {
             connectStrategy = connectStrategy.methodAndBody(
-                    METHOD_REPORT,
+                    METHOD_POST,
                     RequestBody.create(JsonSerialization.serialize(evaluationContext), JSON));
         }
 
@@ -244,7 +244,7 @@ private void startStream() {
 
     private URI getStreamUri() {
         URI uri = HttpHelpers.concatenateUriPath(streamBaseUri, streamRequestPath);
-        if (!useReport) {
+        if (!usePost) {
             uri = HttpHelpers.concatenateUriPath(uri, LDUtil.urlSafeBase64(evaluationContext));
         }
         if (evaluationReasons) {

launchdarkly-android-client-sdk/src/main/java/com/launchdarkly/sdk/android/LDConfig.java

@@ -814,7 +814,7 @@ public LDConfig build() {
                 ModeResolutionTable resolutionTable = ModeResolutionTable.createMobile(
                         startingMode, backgroundMode);
                 effectiveDataSource = new FDv2DataSourceBuilder(
-                        modeTable, startingMode, resolutionTable);
+                        modeTable, startingMode, resolutionTable, this.dataSystemBuilder.isUsePost());
                 effectiveAutoModeSwitching = this.dataSystemBuilder.getAutomaticModeSwitchingConfig();
             } else {
                 effectiveDataSource = this.dataSource == null

launchdarkly-android-client-sdk/src/main/java/com/launchdarkly/sdk/android/StandardEndpoints.java

@@ -17,8 +17,8 @@ private StandardEndpoints() {}
     static final String ANALYTICS_EVENTS_REQUEST_PATH = "/mobile/events/bulk";
     static final String DIAGNOSTIC_EVENTS_REQUEST_PATH = "/mobile/events/diagnostic";
 
-    static final String FDV2_POLLING_REQUEST_GET_BASE_PATH = "/sdk/poll/eval";
-    static final String FDV2_POLLING_REQUEST_REPORT_BASE_PATH = "/sdk/poll/eval";
+    // GET appends the base64url context as a path segment; POST sends it in the body.
+    static final String FDV2_POLLING_REQUEST_BASE_PATH = "/sdk/poll/eval";
     static final String FDV2_STREAMING_REQUEST_BASE_PATH = "/sdk/stream/eval";
 
     /**