Added support for an optional fee in arbitrary transactions, to give the option for data to be published instantly (i.e. no proof of work / mempow required when fee is sufficient).

Takes effect at a future undecided timestamp.

src/main/java/org/qortal/api/resource/ArbitraryResource.java

@@ -773,6 +773,7 @@ public class ArbitraryResource {
 					   @QueryParam("description") String description,
 					   @QueryParam("tags") List<String> tags,
 					   @QueryParam("category") Category category,
+					   @QueryParam("fee") Long fee,
 					   String path) {
 		Security.checkApiCallAllowed(request);
 
@@ -781,7 +782,7 @@ public class ArbitraryResource {
 		}
 
 		return this.upload(Service.valueOf(serviceString), name, null, path, null, null, false,
-				title, description, tags, category);
+				fee, title, description, tags, category);
 	}
 
 	@POST
@@ -818,6 +819,7 @@ public class ArbitraryResource {
 					   @QueryParam("description") String description,
 					   @QueryParam("tags") List<String> tags,
 					   @QueryParam("category") Category category,
+					   @QueryParam("fee") Long fee,
 					   String path) {
 		Security.checkApiCallAllowed(request);
 
@@ -826,7 +828,7 @@ public class ArbitraryResource {
 		}
 
 		return this.upload(Service.valueOf(serviceString), name, identifier, path, null, null, false,
-				title, description, tags, category);
+				fee, title, description, tags, category);
 	}
 
 
@@ -864,6 +866,7 @@ public class ArbitraryResource {
 										@QueryParam("description") String description,
 										@QueryParam("tags") List<String> tags,
 										@QueryParam("category") Category category,
+										@QueryParam("fee") Long fee,
 										String base64) {
 		Security.checkApiCallAllowed(request);
 
@@ -872,7 +875,7 @@ public class ArbitraryResource {
 		}
 
 		return this.upload(Service.valueOf(serviceString), name, null, null, null, base64, false,
-				title, description, tags, category);
+				fee, title, description, tags, category);
 	}
 
 	@POST
@@ -907,6 +910,7 @@ public class ArbitraryResource {
 										@QueryParam("description") String description,
 										@QueryParam("tags") List<String> tags,
 										@QueryParam("category") Category category,
+										@QueryParam("fee") Long fee,
 										String base64) {
 		Security.checkApiCallAllowed(request);
 
@@ -915,7 +919,7 @@ public class ArbitraryResource {
 		}
 
 		return this.upload(Service.valueOf(serviceString), name, identifier, null, null, base64, false,
-				title, description, tags, category);
+				fee, title, description, tags, category);
 	}
 
 
@@ -952,6 +956,7 @@ public class ArbitraryResource {
 								 @QueryParam("description") String description,
 								 @QueryParam("tags") List<String> tags,
 								 @QueryParam("category") Category category,
+								 @QueryParam("fee") Long fee,
 								 String base64Zip) {
 		Security.checkApiCallAllowed(request);
 
@@ -960,7 +965,7 @@ public class ArbitraryResource {
 		}
 
 		return this.upload(Service.valueOf(serviceString), name, null, null, null, base64Zip, true,
-				title, description, tags, category);
+				fee, title, description, tags, category);
 	}
 
 	@POST
@@ -995,6 +1000,7 @@ public class ArbitraryResource {
 								 @QueryParam("description") String description,
 								 @QueryParam("tags") List<String> tags,
 								 @QueryParam("category") Category category,
+								 @QueryParam("fee") Long fee,
 								 String base64Zip) {
 		Security.checkApiCallAllowed(request);
 
@@ -1003,7 +1009,7 @@ public class ArbitraryResource {
 		}
 
 		return this.upload(Service.valueOf(serviceString), name, identifier, null, null, base64Zip, true,
-				title, description, tags, category);
+				fee, title, description, tags, category);
 	}
 
 
@@ -1043,6 +1049,7 @@ public class ArbitraryResource {
 							 @QueryParam("description") String description,
 							 @QueryParam("tags") List<String> tags,
 							 @QueryParam("category") Category category,
+							 @QueryParam("fee") Long fee,
 							 String string) {
 		Security.checkApiCallAllowed(request);
 
@@ -1051,7 +1058,7 @@ public class ArbitraryResource {
 		}
 
 		return this.upload(Service.valueOf(serviceString), name, null, null, string, null, false,
-				title, description, tags, category);
+				fee, title, description, tags, category);
 	}
 
 	@POST
@@ -1088,6 +1095,7 @@ public class ArbitraryResource {
 							 @QueryParam("description") String description,
 							 @QueryParam("tags") List<String> tags,
 							 @QueryParam("category") Category category,
+							 @QueryParam("fee") Long fee,
 							 String string) {
 		Security.checkApiCallAllowed(request);
 
@@ -1096,14 +1104,14 @@ public class ArbitraryResource {
 		}
 
 		return this.upload(Service.valueOf(serviceString), name, identifier, null, string, null, false,
-				title, description, tags, category);
+				fee, title, description, tags, category);
 	}
 
 
 	// Shared methods
 
-	private String upload(Service service, String name, String identifier,
-						  String path, String string, String base64, boolean zipped,
+	private String upload(Service service, String name, String identifier, String path,
+						  String string, String base64, boolean zipped, Long fee,
 						  String title, String description, List<String> tags, Category category) {
 		// Fetch public key from registered name
 		try (final Repository repository = RepositoryManager.getRepository()) {
@@ -1167,9 +1175,14 @@ public class ArbitraryResource {
 				}
 			}
 
+			// Default to zero fee if not specified
+			if (fee == null) {
+				fee = 0L;
+			}
+
 			try {
 				ArbitraryDataTransactionBuilder transactionBuilder = new ArbitraryDataTransactionBuilder(
-						repository, publicKey58, Paths.get(path), name, null, service, identifier,
+						repository, publicKey58, fee, Paths.get(path), name, null, service, identifier,
 						title, description, tags, category
 				);
 

src/main/java/org/qortal/arbitrary/ArbitraryDataTransactionBuilder.java

@@ -46,6 +46,7 @@ public class ArbitraryDataTransactionBuilder {
     private static final double MAX_FILE_DIFF = 0.5f;
 
     private final String publicKey58;
+    private final long fee;
     private final Path path;
     private final String name;
     private Method method;
@@ -64,11 +65,12 @@ public class ArbitraryDataTransactionBuilder {
     private ArbitraryTransactionData arbitraryTransactionData;
     private ArbitraryDataFile arbitraryDataFile;
 
-    public ArbitraryDataTransactionBuilder(Repository repository, String publicKey58, Path path, String name,
+    public ArbitraryDataTransactionBuilder(Repository repository, String publicKey58, long fee, Path path, String name,
                                            Method method, Service service, String identifier,
                                            String title, String description, List<String> tags, Category category) {
         this.repository = repository;
         this.publicKey58 = publicKey58;
+        this.fee = fee;
         this.path = path;
         this.name = name;
         this.method = method;
@@ -261,7 +263,7 @@ public class ArbitraryDataTransactionBuilder {
             }
 
             final BaseTransactionData baseTransactionData = new BaseTransactionData(now, Group.NO_GROUP,
-                    lastReference, creatorPublicKey, 0L, null);
+                    lastReference, creatorPublicKey, fee, null);
             final int size = (int) arbitraryDataFile.size();
             final int version = 5;
             final int nonce = 0;

src/main/java/org/qortal/block/BlockChain.java

@@ -78,7 +78,8 @@ public class BlockChain {
 		onlineAccountMinterLevelValidationHeight,
 		selfSponsorshipAlgoV1Height,
 		feeValidationFixTimestamp,
-		chatReferenceTimestamp;
+		chatReferenceTimestamp,
+		arbitraryOptionalFeeTimestamp;
 	}
 
 	// Custom transaction fees
@@ -522,6 +523,10 @@ public class BlockChain {
 		return this.featureTriggers.get(FeatureTrigger.chatReferenceTimestamp.name()).longValue();
 	}
 
+	public long getArbitraryOptionalFeeTimestamp() {
+		return this.featureTriggers.get(FeatureTrigger.arbitraryOptionalFeeTimestamp.name()).longValue();
+	}
+
 
 	// More complex getters for aspects that change by height or timestamp
 

src/main/java/org/qortal/transaction/ArbitraryTransaction.java

@@ -88,6 +88,12 @@ public class ArbitraryTransaction extends Transaction {
 		if (this.transactionData.getFee() < 0)
 			return ValidationResult.NEGATIVE_FEE;
 
+		// After the feature trigger, we require the fee to be sufficient if it's not 0.
+		// If the fee is zero, then the nonce is validated in isSignatureValid() as an alternative to a fee
+		if (this.arbitraryTransactionData.getTimestamp() >= BlockChain.getInstance().getArbitraryOptionalFeeTimestamp() && this.arbitraryTransactionData.getFee() != 0L) {
+			return super.isFeeValid();
+		}
+
 		return ValidationResult.OK;
 	}
 
@@ -208,10 +214,14 @@ public class ArbitraryTransaction extends Transaction {
 			// Clear nonce from transactionBytes
 			ArbitraryTransactionTransformer.clearNonce(transactionBytes);
 
-			// We only need to check nonce for recent transactions due to PoW verification overhead
-			if (NTP.getTime() - this.arbitraryTransactionData.getTimestamp() < HISTORIC_THRESHOLD) {
-				int difficulty = ArbitraryDataManager.getInstance().getPowDifficulty();
-				return MemoryPoW.verify2(transactionBytes, POW_BUFFER_SIZE, difficulty, nonce);
+			// As of feature-trigger timestamp, we only require a nonce when the fee is zero
+			boolean beforeFeatureTrigger = this.arbitraryTransactionData.getTimestamp() < BlockChain.getInstance().getArbitraryOptionalFeeTimestamp();
+			if (beforeFeatureTrigger || this.arbitraryTransactionData.getFee() == 0L) {
+				// We only need to check nonce for recent transactions due to PoW verification overhead
+				if (NTP.getTime() - this.arbitraryTransactionData.getTimestamp() < HISTORIC_THRESHOLD) {
+					int difficulty = ArbitraryDataManager.getInstance().getPowDifficulty();
+					return MemoryPoW.verify2(transactionBytes, POW_BUFFER_SIZE, difficulty, nonce);
+				}
 			}
 		}
 

src/main/resources/blockchain.json

@@ -85,7 +85,8 @@
 		"onlineAccountMinterLevelValidationHeight": 1092000,
 		"selfSponsorshipAlgoV1Height": 1092400,
 		"feeValidationFixTimestamp": 1671918000000,
-		"chatReferenceTimestamp": 1674316800000
+		"chatReferenceTimestamp": 1674316800000,
+		"arbitraryOptionalFeeTimestamp": 9999999999999
 	},
 	"checkpoints": [
 		{ "height": 1136300, "signature": "3BbwawEF2uN8Ni5ofpJXkukoU8ctAPxYoFB7whq9pKfBnjfZcpfEJT4R95NvBDoTP8WDyWvsUvbfHbcr9qSZuYpSKZjUQTvdFf6eqznHGEwhZApWfvXu6zjGCxYCp65F4jsVYYJjkzbjmkCg5WAwN5voudngA23kMK6PpTNygapCzXt" }