Clean up TransactionTransmitter (Consensys#206)

Author: rain-on

ethsigner/core/src/main/java/tech/pegasys/ethsigner/core/requesthandler/sendtransaction/TransactionTransmitter.java

@@ -27,12 +27,14 @@
 
 import java.net.SocketException;
 import java.net.SocketTimeoutException;
+import java.util.Optional;
 
 import io.vertx.core.buffer.Buffer;
 import io.vertx.core.http.HttpClient;
 import io.vertx.core.http.HttpClientRequest;
 import io.vertx.core.http.HttpClientResponse;
 import io.vertx.core.http.HttpServerRequest;
+import io.vertx.core.json.EncodeException;
 import io.vertx.core.json.Json;
 import io.vertx.ext.web.RoutingContext;
 import org.apache.logging.log4j.LogManager;
@@ -62,21 +64,48 @@ public TransactionTransmitter(
   }
 
   public void send() {
-    createSignedTransactionBody();
-  }
+    final Optional<JsonRpcRequest> request = createSignedTransactionBody();
+
+    if (request.isEmpty()) {
+      return;
+    }
 
-  private void createSignedTransactionBody() {
-    final String signedTransactionHexString;
     try {
-      if (!transaction.isNonceUserSpecified()) {
-        transaction.updateNonce();
+      sendTransaction(Json.encodeToBuffer(request.get()));
+    } catch (final IllegalArgumentException | EncodeException e) {
+      LOG.debug("JSON Serialization failed for: {}", request, e);
+      routingContext.fail(BAD_REQUEST.code(), new JsonRpcException(INTERNAL_ERROR));
+    }
+  }
+
+  private Optional<JsonRpcRequest> createSignedTransactionBody() {
+
+    if (!transaction.isNonceUserSpecified()) {
+      if (!populateNonce()) {
+        return Optional.empty();
       }
+    }
 
+    final String signedTransactionHexString;
+    try {
       signedTransactionHexString = transactionSerializer.serialize(transaction);
     } catch (final IllegalArgumentException e) {
       LOG.debug("Failed to encode transaction: {}", transaction, e);
       routingContext.fail(BAD_REQUEST.code(), new JsonRpcException(JsonRpcError.INVALID_PARAMS));
-      return;
+      return Optional.empty();
+    } catch (final Throwable thrown) {
+      LOG.debug("Failed to encode transaction: {}", transaction, thrown);
+      routingContext.fail(BAD_REQUEST.code(), new JsonRpcException(INTERNAL_ERROR));
+      return Optional.empty();
+    }
+
+    return Optional.of(transaction.jsonRpcRequest(signedTransactionHexString, transaction.getId()));
+  }
+
+  private boolean populateNonce() {
+    try {
+      transaction.updateNonce();
+      return true;
     } catch (final RuntimeException e) {
       LOG.warn("Unable to get nonce from web3j provider.", e);
       final Throwable cause = e.getCause();
@@ -86,21 +115,8 @@ private void createSignedTransactionBody() {
       } else {
         routingContext.fail(GATEWAY_TIMEOUT.code(), new JsonRpcException(INTERNAL_ERROR));
       }
-      return;
-    } catch (final Throwable thrown) {
-      LOG.debug("Failed to encode/serialize transaction: {}", transaction, thrown);
-      routingContext.fail(BAD_REQUEST.code(), new JsonRpcException(INTERNAL_ERROR));
-      return;
-    }
-
-    final JsonRpcRequest rawTransaction =
-        transaction.jsonRpcRequest(signedTransactionHexString, transaction.getId());
-    try {
-      sendTransaction(Json.encodeToBuffer(rawTransaction));
-    } catch (final IllegalArgumentException e) {
-      LOG.debug("JSON Serialization failed for: {}", rawTransaction, e);
-      routingContext.fail(BAD_REQUEST.code(), new JsonRpcException(INTERNAL_ERROR));
     }
+    return false;
   }
 
   private void sendTransaction(final Buffer bodyContent) {