[FAB-3648] add getCreator() API

Change-Id: I854268bc3f20d8bece9d0ae3f4529e2a62bb67bf
Signed-off-by: Luis Sanchez <sanchezl@us.ibm.com>

Author: Luis Sanchez

shim/src/main/java/org/hyperledger/fabric/shim/ChaincodeStub.java

@@ -301,4 +301,12 @@ default void putStringState(String key, String value) {
 	 */
 	Instant getTxTimestamp();
 
+	/**
+	 * Returns the identity of the agent (or user) submitting the transaction.
+	 *
+	 * @return the bytes of the creator field of the proposal's signature
+	 *         header.
+	 */
+	byte[] getCreator();
+
 }

shim/src/main/java/org/hyperledger/fabric/shim/impl/ChaincodeStubImpl.java

@@ -9,8 +9,11 @@
 import com.google.protobuf.ByteString;
 import com.google.protobuf.InvalidProtocolBufferException;
 import com.google.protobuf.Timestamp;
+import org.hyperledger.fabric.protos.common.Common;
 import org.hyperledger.fabric.protos.common.Common.ChannelHeader;
 import org.hyperledger.fabric.protos.common.Common.Header;
+import org.hyperledger.fabric.protos.common.Common.HeaderType;
+import org.hyperledger.fabric.protos.common.Common.SignatureHeader;
 import org.hyperledger.fabric.protos.ledger.queryresult.KvQueryResult;
 import org.hyperledger.fabric.protos.ledger.queryresult.KvQueryResult.KV;
 import org.hyperledger.fabric.protos.peer.ChaincodeEventPackage.ChaincodeEvent;
@@ -40,6 +43,7 @@ class ChaincodeStubImpl implements ChaincodeStub {
 	private final List<ByteString> args;
 	private final SignedProposal signedProposal;
 	private final Instant txTimestamp;
+	private final ByteString creator;
 	private ChaincodeEvent event;
 
 	ChaincodeStubImpl(String txId, Handler handler, List<ByteString> args, SignedProposal signedProposal) {
@@ -48,20 +52,35 @@ class ChaincodeStubImpl implements ChaincodeStub {
 		this.args = Collections.unmodifiableList(args);
 		this.signedProposal = signedProposal;
 		if(this.signedProposal == null) {
+			this.creator = null;
 			this.txTimestamp = null;
 		} else {
 			try {
 				final Proposal proposal = Proposal.parseFrom(signedProposal.getProposalBytes());
 				final Header header = Header.parseFrom(proposal.getHeader());
 				final ChannelHeader channelHeader = ChannelHeader.parseFrom(header.getChannelHeader());
+				validateProposalType(channelHeader);
+				final SignatureHeader signatureHeader = SignatureHeader.parseFrom(header.getSignatureHeader());
+
 				final Timestamp timestamp = channelHeader.getTimestamp();
 				this.txTimestamp = Instant.ofEpochSecond(timestamp.getSeconds(), timestamp.getNanos());
+				this.creator = signatureHeader.getCreator();
 			} catch (InvalidProtocolBufferException e) {
 				throw new RuntimeException(e);
 			}
 		}
 	}
 
+	private void validateProposalType(ChannelHeader channelHeader) {
+		switch (Common.HeaderType.forNumber(channelHeader.getType())) {
+		case ENDORSER_TRANSACTION:
+		case CONFIG:
+			return;
+		default:
+			throw new RuntimeException(String.format("Unexpected transaction type: %s", HeaderType.forNumber(channelHeader.getType())));
+		}
+	}
+
 	@Override
 	public List<byte[]> getArgs() {
 		return args.stream().map(x -> x.toByteArray()).collect(Collectors.toList());
@@ -212,4 +231,9 @@ public Instant getTxTimestamp() {
 		return txTimestamp;
 	}
 
+	@Override
+	public byte[] getCreator() {
+		if(creator == null) return null;
+		return creator.toByteArray();
+	}
 }

shim/src/test/java/org/hyperledger/fabric/shim/impl/ChaincodeStubImplTest.java

@@ -11,6 +11,7 @@
 import org.hamcrest.Matchers;
 import org.hyperledger.fabric.protos.common.Common.ChannelHeader;
 import org.hyperledger.fabric.protos.common.Common.Header;
+import org.hyperledger.fabric.protos.common.Common.SignatureHeader;
 import org.hyperledger.fabric.protos.ledger.queryresult.KvQueryResult;
 import org.hyperledger.fabric.protos.ledger.queryresult.KvQueryResult.KV;
 import org.hyperledger.fabric.protos.peer.ChaincodeEventPackage.ChaincodeEvent;
@@ -373,4 +374,30 @@ public void testGetTxTimestampNullSignedProposal() {
 		final ChaincodeStubImpl stub = new ChaincodeStubImpl("txid", handler, new ArrayList<>(), null);
 		assertThat(stub.getTxTimestamp(), is(nullValue()));
 	}
+
+	@Test
+	public void testGetCreator() {
+		final Instant instant = Instant.now();
+		final byte[] creator = "CREATOR".getBytes(UTF_8);
+		final Timestamp timestamp = Timestamp.newBuilder().setSeconds(instant.getEpochSecond()).setNanos(instant.getNano()).build();
+		final SignedProposal signedProposal = SignedProposal.newBuilder()
+				.setProposalBytes(Proposal.newBuilder()
+						.setHeader(Header.newBuilder()
+								.setChannelHeader(ChannelHeader.newBuilder()
+										.setType(ENDORSER_TRANSACTION_VALUE)
+										.setTimestamp(timestamp)
+										.build().toByteString()
+								)
+								.setSignatureHeader(SignatureHeader.newBuilder()
+										.setCreator(ByteString.copyFrom(creator))
+										.build().toByteString()
+								)
+								.build().toByteString()
+						)
+						.build().toByteString()
+				).build();
+		final ChaincodeStubImpl stub = new ChaincodeStubImpl("txid", handler, new ArrayList<>(), signedProposal);
+		assertThat(stub.getCreator(), is(creator));
+	}
+
 }