Blockchain as a Service:Solidity contract compiler

Prerequisites

Before you begin, make sure you have:

• Node.js installed

Download and install solc-js

1. Download the installation package: alipay-solc-0.1.10.tgz (~1.76 MB).

2. Run the following command in the directory where you downloaded the package to install solc-js globally:

   npm i -g alipay-solc-0.1.10.tgz

After installation, solcjs is available in your terminal. Run solcjs --help to see all supported options.

CLI reference

Usage: /usr/local/bin/solcjs [options] <FILE_NAME>

solc-js does not support --bin-runtime. To compile runtime bytecode for contract updates, use the solc binary compiler.

Compile a contract

The examples below use the following sample contract (hello.sol):

pragma solidity ^0.4.20;

contract Hello {

    string name;
    identity id; // identity is an Ant Blockchain type similar to address in standard Solidity

    constructor() public {
        name = 'Hello world!';
    }

    function hello() view public returns (identity, string) {
        return (msg.sender, name);
    }
}

solcjs --bin hello.sol

solcjs --abi hello.sol

Compile in JavaScript code

Use the following steps to compile a contract programmatically and get both the ABI and bytecode.

1. Create a solcjs-test directory, run npm init inside it, and move alipay-solc-0.1.10.tgz into the directory.

2. Install solc-js as a local dependency:

   npm i alipay-solc-0.1.10.tgz --save

3. Create index.js with the following code. The second argument to solc.compile() activates the optimizer when set to 1.

   var solc = require('@alipay/solc')
   var input = 'contract test { function g(identity a) {} }'
   // Setting 1 as the second parameter activates the optimizer
   var output = solc.compile(input, 1)
   for (var contractName in output.contracts) {
       // Print the bytecode and ABI for each contract
       console.log(contractName + ': ' + output.contracts[contractName].bytecode)
       console.log(contractName + ': ' + output.contracts[contractName].interface)
   }

4. Run the script:

   node index.js

   The output contains the compiled bytecode and ABI:

   :test: 6080604052348015600f57600080fd5b5060898061001e6000396000f300608060405260043610603e5763ffffffff7c010000000000000000000000000000000000000000000000000000000060003504166338a1231d81146043575b600080fd5b348015604e57600080fd5b506058600435605a565b005b505600a165627a7a7230582008d3450904d4f09535ba76326aae5ecd2f61113b791d633dbb3c0799ff75b3ad0029
   :test: [{"constant":false,"inputs":[{"name":"a","type":"identity"}],"name":"g","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"}]

Deploy and call a contract with the JS SDK

After compiling, pass the ABI and bytecode directly to the JS SDK to deploy and invoke the contract. For details, see JS SDK Introduction.

--bin vs --bin-runtime

For contract updates, compile with --bin-runtime:

solc --bin-runtime <your-contract.sol>

Pass the resulting bytecode to the JS SDK's update contract operation. For details, see JS SDK Introduction.

Download solc

Both versions are compatible with Solidity syntax prior to version 0.4.24 and support --bin-runtime.