Fabric is a distributed ledger platform that provides an easy way to build blockchain applications. If you want to use RS erasure code in fabric, you can follow the steps below to integrate:
- First, a new chaincode (chaincode) needs to be defined in the fabric to implement the logic of the RS erasure code. Chaincode can be written in Java and then deployed in the fabric network.
- In the chain code, you need to use the Java library to implement the algorithm of the RS erasure code. You can use open source libraries such as Jerasure or ErasureCode, or implement the algorithm yourself.
- In chaincode, a function needs to be defined to encode and decode data. The encoding function splits the original data into multiple data blocks, and uses the RS erasure code algorithm to generate some redundant data blocks. The decoding function combines data blocks and redundant data blocks to restore the original data.
- Finally, call the encoding and decoding functions in the chaincode in the application program to realize the RS erasure code function. The chaincode can be accessed using fabric’s Java SDK.
Integrating RS erasure codes requires certain programming skills and algorithm knowledge. If you are not familiar with this knowledge, it is recommended to study relevant courses and literature first, and then try to implement RS erasure code in fabric.
The following is a simple example to demonstrate how to implement RS erasure coding in fabric using Java.
1. First, a new chaincode needs to be defined in the fabric. Chaincode can be written in Java, for example:
public class RSEncodingChaincode implements Chaincode {<!-- -->
@Override
public Response init(ChaincodeStub stub) {<!-- -->
return newSuccessResponse();
}
@Override
public Response invoke(ChaincodeStub stub) {<!-- -->
String func = stub. getFunction();
List<String> args = stub. getParameters();
if ("encode".equals(func)) {<!-- -->
return encode(stub, args);
} else if ("decode".equals(func)) {<!-- -->
return decode(stub, args);
} else {<!-- -->
return newErrorResponse("Invalid function name");
}
}
private Response encode(ChaincodeStub stub, List<String> args) {<!-- -->
// TODO: Implement RS encoding algorithm
return newSuccessResponse();
}
private Response decode(ChaincodeStub stub, List<String> args) {<!-- -->
// TODO: Implement RS decoding algorithm
return newSuccessResponse();
}
}
2. In the chain code, you need to use the Java library to implement the RS erasure code algorithm. You can use open source libraries such as Jerasure or ErasureCode, or implement the algorithm yourself. For example, using the Jerasure library:
import org.apache.commons.codec.binary.Base64;
import org.koka.erasure.Encoder;
private Response encode(ChaincodeStub stub, List<String> args) {<!-- -->
String data = args. get(0);
int k = Integer. parseInt(args. get(1));
int m = Integer. parseInt(args. get(2));
byte[][] dataBlocks = splitData(data, k);
byte[][] parityBlocks = new byte[m][dataBlocks[0].length];
Encoder encoder = new Encoder(k, m);
encoder.encode(dataBlocks, parityBlocks);
List<String> blocks = new ArrayList<>();
for (byte[] block : dataBlocks) {<!-- -->
blocks.add(Base64.encodeBase64String(block));
}
for (byte[] block : parityBlocks) {<!-- -->
blocks.add(Base64.encodeBase64String(block));
}
return newSuccessResponse(blocks);
}
private Response decode(ChaincodeStub stub, List<String> args) {<!-- -->
List<String> blocks = args.subList(0, Integer.parseInt(args.get(1)) + Integer.parseInt(args.get(2)));
int k = Integer. parseInt(args. get(1));
int m = Integer. parseInt(args. get(2));
byte[][] dataBlocks = new byte[k][];
byte[][] parityBlocks = new byte[m][];
int i = 0;
for (String block : blocks) {<!-- -->
if (i < k) {<!-- -->
dataBlocks[i] = Base64. decodeBase64(block);
} else {<!-- -->
parityBlocks[i - k] = Base64. decodeBase64(block);
}
i + + ;
}
Encoder encoder = new Encoder(k, m);
int[] erasures = encoder.decode(dataBlocks, parityBlocks);
if (erasures != null) {<!-- -->
return newErrorResponse("Failed to decode data");
}
byte[] data = joinData(dataBlocks);
return newSuccessResponse(Base64. encodeBase64String(data));
}
private byte[][] splitData(String data, int k) {<!-- -->
byte[] bytes = data. getBytes();
int n = (bytes. length + k - 1) / k;
byte[][] blocks = new byte[k][n];
for (int i = 0; i < bytes. length; i ++ ) {<!-- -->
blocks[i % k][i / k] = bytes[i];
}
return blocks;
}
private byte[] joinData(byte[][] blocks) {<!-- -->
int n = blocks[0].length;
byte[] bytes = new byte[blocks. length * n];
for (int i = 0; i < bytes. length; i ++ ) {<!-- -->
bytes[i] = blocks[i % blocks. length][i / blocks. length];
}
return bytes;
}
3. In the chaincode, a function needs to be defined to encode and decode data. The encoding function splits the original data into multiple data blocks, and uses the RS erasure code algorithm to generate some redundant data blocks. The decoding function combines data blocks and redundant data blocks to restore the original data. For example:
private Response encode(ChaincodeStub stub, List<String> args) {<!-- -->
String data = args. get(0);
int k = Integer. parseInt(args. get(1));
int m = Integer. parseInt(args. get(2));
byte[][] dataBlocks = splitData(data, k);
byte[][] parityBlocks = new byte[m][dataBlocks[0].length];
Encoder encoder = new Encoder(k, m);
encoder.encode(dataBlocks, parityBlocks);
List<String> blocks = new ArrayList<>();
for (byte[] block : dataBlocks) {<!-- -->
blocks.add(Base64.encodeBase64String(block));
}
for (byte[] block : parityBlocks) {<!-- -->
blocks.add(Base64.encodeBase64String(block));
}
return newSuccessResponse(blocks);
}
private Response decode(ChaincodeStub stub, List<String> args) {<!-- -->
List<String> blocks = args.subList(0, Integer.parseInt(args.get(1)) + Integer.parseInt(args.get(2)));
int k = Integer. parseInt(args. get(1));
int m = Integer. parseInt(args. get(2));
byte[][] dataBlocks = new byte[k][];
byte[][] parityBlocks = new byte[m][];
int i = 0;
for (String block : blocks) {<!-- -->
if (i < k) {<!-- -->
dataBlocks[i] = Base64. decodeBase64(block);
} else {<!-- -->
parityBlocks[i - k] = Base64. decodeBase64(block);
}
i + + ;
}
Encoder encoder = new Encoder(k, m);
int[] erasures = encoder.decode(dataBlocks, parityBlocks);
if (erasures != null) {<!-- -->
return newErrorResponse("Failed to decode data");
}
byte[] data = joinData(dataBlocks);
return newSuccessResponse(Base64. encodeBase64String(data));
}
private byte[][] splitData(String data, int k) {<!-- -->
byte[] bytes = data. getBytes();
int n = (bytes. length + k - 1) / k;
byte[][] blocks = new byte[k][n];
for (int i = 0; i < bytes. length; i ++ ) {<!-- -->
blocks[i % k][i / k] = bytes[i];
}
return blocks;
}
private byte[] joinData(byte[][] blocks) {<!-- -->
int n = blocks[0].length;
byte[] bytes = new byte[blocks. length * n];
for (int i = 0; i < bytes. length; i ++ ) {<!-- -->
bytes[i] = blocks[i % blocks. length][i / blocks. length];
}
return bytes;
}
4. Finally, call the encoding and decoding functions in the chaincode in the application program to realize the RS erasure code function. For example:
public static void main(String[] args) throws Exception {<!-- -->
HFClient client = HFClient.createNewInstance();
client.setCryptoSuite(CryptoSuite.Factory.getCryptoSuite());
User user = new UserImpl();
client.setUserContext(user);
Channel channel = client. newChannel("mychannel");
channel.addPeer(client.newPeer("peer0.org1.example.com", "grpc://localhost:7051"));
channel.addOrderer(client.newOrderer("orderer.example.com", "grpc://localhost:7050"));
channel. initialize();
ChaincodeID ccId = ChaincodeID.newBuilder().setName("rs-encoding").build();
String data = "hello world";
int k = 3;
int m = 2;
TransactionProposalRequest request = client.newTransactionProposalRequest();
request.setChaincodeID(ccId);
request.setFcn("encode");
request.setArgs(Arrays.asList(data, String.valueOf(k), String.valueOf(m)));
Collection<ProposalResponse> responses = channel. sendTransactionProposal(request);
for (ProposalResponse response : responses) {<!-- -->
if (response. getStatus() == ProposalResponse. Status. SUCCESS) {<!-- -->
List<String> blocks = Arrays.asList(response.getChaincodeActionResponsePayload().toStringUtf8().split("\s + "));
System.out.println("Encoded blocks: " + blocks);
} else {<!-- -->
System.out.println("Failed to encode data: " + response.getMessage());
}
}
List<String> blocks = Arrays.asList("block1", "block2", "block3", "block4", "block5");
request = client.newTransactionProposalRequest();
request.setChaincodeID(ccId);
request.setFcn("decode");
request.setArgs(blocks);
responses = channel. sendTransactionProposal(request);
for (ProposalResponse response : responses) {<!-- -->
if (response. getStatus() == ProposalResponse. Status. SUCCESS) {<!-- -->
String result = response.getChaincodeActionResponsePayload().toStringUtf8();
System.out.println("Decoded data: " + result);
} else {<!-- -->
System.out.println("Failed to decode data: " + response.getMessage());
}
}
}
This is a simple example that demonstrates how to implement RS erasure coding in a fabric using Java. In practical applications, more complex algorithms and more complete functions may be required.