ScalarDL Node Client SDK

This is a library for Node.js applications by which the applications can interact with a ScalarDL network.

Node version used for development and testing

This package has been developed and tested using Node LTS v14.16.0. named "fermium". This means we cannot guarantee the package nominal behaviour when using other Node versions.

Install

We can use any NPM package manager to install this library. For example, to install with NPM:

npm install @scalar-labs/scalardl-node-client-sdk

HOWTO

Create ClientService instance

ClientService class is the main class of this package. It provides following functions to request ScalarDL network.

Name	use
registerCertificate	To register a client's certificate on a ScalarDL network
registerContract	To register a contract (of a registered client) on the ScalarDL network
listContracts	To list the client's registered contracts
executeContract	To execute a client's registered contract
validateLedger	To validate an asset on the ScalarDL network to determine if it has been tampered

If an error occurs when executing one of the above methods, a ClientError will be thrown. The ClientError.code provides additional error context. Please refer to the Runtime error section below for the status code specification.

Use the code snippet below to create a ClientService instance.

const { ClientService } = require('@scalar-labs/scalardl-node-client-sdk');
const clientService = new ClientService(clientProperties);

The clientProperties argument is mandatory for the constructor. This is a properties example that a user foo@example.com would use to try to connect to the server scalardl-server.example.com:50051 of the ScalarDL network.

{
    'scalar.dl.client.server.host': 'scalardl-server.example.com',
    'scalar.dl.client.server.port': 50051,
    'scalar.dl.client.server.privileged_port': 50052,
    'scalar.dl.client.cert_holder_id': 'foo@example.com',
    'scalar.dl.client.private_key_pem': '-----BEGIN EC PRIVATE KEY-----\nMHc...',
    // scalar.dl.client.private_key_path is applied when scalar.dl.client.private_key_pem is not given
    'scalar.dl.client.private_key_path': 'path-to-key-file',
    'scalar.dl.client.cert_pem': '-----BEGIN CERTIFICATE-----\nMIICjTCCAj...\n',
    // scalar.dl.client.cert_path is applied when scalar.dl.client.cert_pem is not given
    'scalar.dl.client.cert_path': 'path-to-certificate-file',
    'scalar.dl.client.cert_version': 1,
    'scalar.dl.client.tls.enabled': false,
    'scalar.dl.client.tls.ca_root_cert_pem': '-----BEGIN CERTIFICATE-----\n...\n',
    // scalar.dl.client.tls.ca_root_cert_path is applied when scalar.dl.client.tls.ca_root_cert_pem is not given
    'scalar.dl.client.tls.ca_root_cert_path': 'path-to-ca-root-certificate-file',
    'scalar.dl.client.authorization.credential': '...',
    'scalar.dl.client.proxy.server': '...',
}

If the auditor capability is enabled on the ScalarDL network, specify additional properties like the following example. In this example, the client interacts with the auditor scalardl-auditor.example.com and detects Byzantine faults including data tampering when executing contracts.

{
    'scalar.dl.client.auditor.enabled': true,
    'scalar.dl.client.auditor.host': 'scalardl-auditor.example.com',
    'scalar.dl.client.auditor.port': 40051,
    'scalar.dl.client.auditor.privileged_port': 40052,
}

In what follows assume that we have a clientService instance.

Register the certificate

Use the registerCertificate function to register a certificate on the ScalarDL network.

await clientService.registerCertificate();

Register contracts

Use the registerContract function to register a contract.

await clientService.registerContract('contractId', 'com.example.contract.contractName', contractUint8Array, propertiesObject);

Register functions

Use the registerFunction function to register a function.

await clientService.registerFunction('functionId', 'com.example.function.functionName', functionUint8Array);

List registered contracts

Use listContracts function to list all registered contracts.

const constracts = await clientService.listContracts();

Execute a contract

Use executeContract function to execute a registered contract. It will also execute a function if _functions_ is given in the argument.

const response = await clientService.executeContract('contractId', argumentObject);
const executionResult = response.getResult();
const proofsList = response.getProofs();

const response = await clientService.executeContract('contractId', { 'arg1': 'a', '_functions_': [functionId] }, { 'arg2': 'b' });

{ 'arg1': 'a', will be passed via contractArgument, while { 'arg2': 'b' } will be passed via functionArgument.

Validate an asset

Use the validateLedger function to validate an asset in the ScalarDL network.

const response = await clientService.validateLedger('assetId');
const statusCode = response.getCode();
const proof = response.getProof();

Validate an asset linearizably

The default ledger validation in a Auditor-enabled ScalarDL network is non-linearizable; i.e., there might be cases where Ledger and Auditor look inconsistent temporarily. ScalarDL supports linearizable ledger validation. To use it, we can configure the properties as follows

{
    'scalar.dl.client.auditor.enabled': true,
    ...
    'scalar.dl.client.auditor.linearizable_validation.enabled': true,
    'scalar.dl.client.auditor.linearizable_validation.contract_id': '<choose a contract ID>',
}

and, register the ValidateLedger contract as the contract ID we specified in the properties. Then, the ClientService.validateLedger function can provide linearizable ledger validation.

Runtime error

Error thrown by the client present a status code.

try {
    await clientService.registerCertificate();
} catch (clientError) {
    const message = clientError.message;
    const statusCode = clientError.code;
}

StatusCode = {
  OK: 200,
  INVALID_HASH: 300,
  INVALID_PREV_HASH: 301,
  INVALID_CONTRACT: 302,
  INVALID_OUTPUT: 303,
  INVALID_NONCE: 304,
  INCONSISTENT_STATES: 305,
  INVALID_SIGNATURE: 400,
  UNLOADABLE_KEY: 401,
  UNLOADABLE_CONTRACT: 402,
  CERTIFICATE_NOT_FOUND: 403,
  CONTRACT_NOT_FOUND: 404,
  CERTIFICATE_ALREADY_REGISTERED: 405,
  CONTRACT_ALREADY_REGISTERED: 406,
  INVALID_REQUEST: 407,
  CONTRACT_CONTEXTUAL_ERROR: 408,
  ASSET_NOT_FOUND: 409,
  FUNCTION_NOT_FOUND: 410,
  UNLOADABLE_FUNCTION: 411,
  INVALID_FUNCTION: 412,
  DATABASE_ERROR: 500,
  UNKNOWN_TRANSACTION_STATUS: 501,
  RUNTIME_ERROR: 502,
  CLIENT_IO_ERROR: 600,
  CLIENT_DATABASE_ERROR: 601,
  CLIENT_RUNTIME_ERROR: 602,
};

Create raw gRPC requests

You can also create a raw gRPC request in byte array (JavaScript Uint8Array) too. Note that the name of functions are different from usual functions such as executeContract but the parameters are exactly the same.

Register the certificate

const binary = await ClientService.createSerializedCertificateRegistrationRequest();

Register contracts

const binary = await clientService.createSerializedContractRegistrationRequest('contractId', 'com.example.contract.contractName', contractUint8Array, propertiesObject);

Register functions

const binary = await clientService.createSerializedFunctionRegistrationRequest('functionId', 'com.example.function.functionName', functionUint8Array);

List registered contracts

const binary = await clientService.createSerializedContractsListingRequest();

Execute a contract

const binary = await clientService.createSerializedContractExecutionRequest('contractId', argumentObject);

Validate an asset

const binary = await clientService.createSerializedLedgerValidationRequest('assetId');

Send the raw gRPC requests to ScalarDL servers

The SDK has another ClientServiceWithBinary class for you to send the byte array of a request to ScalarDL network.

const { ClientServiceWithBinary } = require('@scalar-labs/scalardl-node-client-sdk');
const clientService = new ClientServiceWithBinary(clientProperties);

Register the certificate

const binary = await ClientService.createSerializedCertificateRegistrationRequest();
await ClientService.registerCertificate(binary);

Register contracts

const binary = await clientService.createSerializedContractRegistrationRequest('contractId', 'com.example.contract.contractName', contractUint8Array, propertiesObject);
await ClientService.registerContract(binary);

Register functions

const binary = await clientService.createSerializedFunctionRegistrationRequest('functionId', 'com.example.function.functionName', functionUint8Array);
await clientService.registerFunction(binary);

List registered contracts

const binary = await clientService.createSerializedContractsListingRequest();
const contracts = await clientService.listContracts(binary);

Execute a contract

const binary = await clientService.createSerializedContractExecutionRequest('contractId', argumentObject);
const response = await clientService.executeContract(binary);
const executionResult = response.getResult();
const proofsList = response.getProofs();

Validate an asset

const binary = await clientService.createSerializedLedgerValidationRequest('assetId');
const response = await clientService.validateLedger(binary);
const statusCode = response.getCode();
const proof = response.getProof();

Contributing

This library is mainly maintained by the Scalar Engineering Team, but of course we appreciate any help.

• For asking questions, finding answers and helping other users, please go to stackoverflow and use scalardl tag.
• For filing bugs, suggesting improvements, or requesting new features, help us out by opening an issue.

License

ScalarDL Node client SDK is dual-licensed under both the AGPL (found in the LICENSE file in the root directory) and a commercial license. You may select, at your option, one of the above-listed licenses. Regarding the commercial license, please contact us for more information.