Support imports in solcjs CLI

[lukehedger]

Given the following directory structure:

contracts/
  Source.sol
  Imported.sol

Where Source.sol:

pragma solidity ^0.4.0;

import './Imported.sol';

contract Source {
}

Running the following command:

solcjs --optimize --bin contracts/Source.sol

Based on the docs, I would expect the compiler to resolve the import but instead it throws:

contracts/Source.sol:3:1: Error: Source "contracts/Imported.sol" not found: File not supplied initially.
import './Imported.sol';
^---------------------^

If I include Imported.sol as a source file it will compile without error:

solcjs --optimize --bin contracts/Source.sol contracts/Imported.sol

Could you clarify my understanding here or is this a bug? Thanks! 🙃

[lukehedger]

Just seen this note in readme:

Note that all input files that are imported have to be supplied, the compiler will not load any additional files on its own.

Which answers my question!

What's the reason for this/any scope for improving it in the future?

[axic]

@lukehedger someone needs to do implement it. If you are interested adding support for it, please make a PR and we're happy to help to finish and include that feature.

[lukehedger]

Happy to look at adding support but would you be able to point me in the right direction to get started? Would the feature be added to the JS bindings or to the compiler itself?

[axic]

This is a feature missing in the solcjs tool included in this repository. The solc.compile method supports a callback to read external files, see https://github.com/ethereum/solc-js#from-version-021

[lukehedger]

Just came across this tool which may be of use in the meantime: https://github.com/TiesNetwork/solidify

[mimitc123]

how to use https://github.com/TiesNetwork/solidify @lukehedger

[Suhail]

I solved this by doing the below as things have been improved as of 0.2.1:

var solc = require('solc');
var fs = require('fs');

var inputs = {
    'auction.sol': fs.readFileSync('auction.sol').toString(),
};

// Assumes imported files are in the same folder/local path
function findImports(path) {
    return {
        'contents': fs.readFileSync(path).toString()
    }
}

var compiledCode = solc.compile({sources: inputs}, 1, findImports)

fs.writeFile('compiled.json', JSON.stringify(compiledCode), function(err) {
    if (err) throw err;
    console.log('Compiled & saved');
});

I then read in compiled.json later in a .js file using web3 to use it via a browser using browserify:

compiledCode =  JSON.parse(fs.readFileSync('compiled.json').toString());

//console.log(compiledCode);

abi = JSON.parse(compiledCode.contracts['auction.sol:ContractName'].interface);
bytecode = compiledCode.contracts['auction.sol:ContractName'].bytecode;

Hope this is helpful to someone else.

[arashkiani]

so writing import is just a fun activity that solc dont understand ?

[aj0strow]

It looks like if findImports(path) had a second parameter, the source file that is calling import, it would be easy to generalize this.

var fs = require('fs')
var path = require('path')

function findImports(importPath, sourcePath) {
  try {
    var filePath = path.resolve(sourcePath, importPath)
    return { contents: fs.readFileSync(filePath).toString() }
  } catch (e) {
    return { error: e.message }
  }
}

solc.compile(..., findImports)

Is there a way to receive the source path too? I tried looking in the soljson.js file but it looks like it is already compiled from somewhere else.

[flcoder]

@aj0strow 👍

[kangdao]

solcjs --abi contract.sol
Tell me how to generate bytecode

[wangjj9219]

@kangdao try it： solcjs --bin contract.sol

[uluhonolulu]

@axic I tried to include all imported contracts, but it still fails for me (Windows, version 0.5.4+commit.9549d8ff.Emscripten.clang):

> solcjs .\contracts\StorageController.sol .\contracts\Owned.sol .\contracts\SafeMath.sol .\contracts\Owned.sol --bin
.\contracts\StorageController.sol:4:1: ParserError: Source "BaseContract.sol" not found: File import callback not supported
import "./BaseContract.sol";
^--------------------------^

.\contracts\StorageController.sol:5:1: ParserError: Source "Owned.sol" not found: File import callback not supported
import "./Owned.sol";
^-------------------^

.\contracts\StorageController.sol:6:1: ParserError: Source "SafeMath.sol" not found: File import callback not supported
import "./SafeMath.sol";

[axic]

The feature is not implemented yet. Passing multiple contracts will work unfortunately.

[fasidOnGit]

Bingo! I have a fix that works!! This will simply compile all the .sol files in the directory and its sub-directories and feed it into solc.compile

//uitls.js

const fs = require('fs');
const path = require('path');
const findImports = (dir) => {
    const files = walkSync(dir);
    return (fileName) => {
        const fileNames = Object.keys(files);
        for(const key in files) {
            if(key.indexOf(fileName) > -1) {
                return { contents: files[key]};
            }
        }
        return {error: fileName + 'not Found'};
    }
};

const walkSync = (dir, filelist) => {
    var fs = fs || require('fs'),
        files = fs.readdirSync(dir);
    filelist = filelist || [];
    files.forEach(function(file) {
        if (fs.statSync(dir + '/' + file).isDirectory()) {
            console.log('Directory:', dir + '/' + file);
            filelist = walkSync(dir + '/' + file, filelist);
        }
        else {
            if(file.indexOf('.sol') > 0) {
                console.log('File: ', dir + '/' + file)
                // filelist.push({[file]: fs.readFileSync(dir + '/' + file, 'utf-8')});
                filelist[dir + '/' + file] = fs.readFileSync(dir + '/' + file, 'utf-8')
            }
        }
    });
    return filelist;
};

module.exports = {
    findImports
};

and in solc.compile just pass this as the last parameter like so

//compile.js
const {findImports} = require('./utils');
...
const input = YOUR_INPUT_JSON_TO_COMPILE;
solc.compile(JSON.stringify(input), findImports(__dirname + '/contracts'));
...
...

[akiabi]

Bingo! I have a fix that works!! This will simply compile all the .sol files in the directory and its sub-directories and feed it into solc.compile

//uitls.js

const fs = require('fs');
const path = require('path');
const findImports = (dir) => {
    const files = walkSync(dir);
    return (fileName) => {
        const fileNames = Object.keys(files);
        for(const key in files) {
            if(key.indexOf(fileName) > -1) {
                return { contents: files[key]};
            }
        }
        return {error: fileName + 'not Found'};
    }
};

const walkSync = (dir, filelist) => {
    var fs = fs || require('fs'),
        files = fs.readdirSync(dir);
    filelist = filelist || [];
    files.forEach(function(file) {
        if (fs.statSync(dir + '/' + file).isDirectory()) {
            console.log('Directory:', dir + '/' + file);
            filelist = walkSync(dir + '/' + file, filelist);
        }
        else {
            if(file.indexOf('.sol') > 0) {
                console.log('File: ', dir + '/' + file)
                // filelist.push({[file]: fs.readFileSync(dir + '/' + file, 'utf-8')});
                filelist[dir + '/' + file] = fs.readFileSync(dir + '/' + file, 'utf-8')
            }
        }
    });
    return filelist;
};

module.exports = {
    findImports
};

and in solc.compile just pass this as the last parameter like so

//compile.js
const {findImports} = require('./utils');
...
const input = YOUR_INPUT_JSON_TO_COMPILE;
solc.compile(JSON.stringify(input), findImports(__dirname + '/contracts'));
...
...

wer shld be the utilis.js and compile.js shld be added?

[fasidOnGit]

@akiabi Could be at the project root dir?

[Garito]

Hi
I use the remappings option in settings to do this in python
Why is here different or am I losing something?

[bakeiro]

Hi!

I'm getting a Invalid callback object specified all the time, seems that the second parameter needs to be an object and not a callback (solc 8.10)

does anyone knows more about this? thanks!

[chriseth]

Can you come to the solidity gitter / matrix channel as described in the readme: https://github.com/ethereum/solidity#readme ?

[jonathansmirnoff]

Hi!

I'm getting a Invalid callback object specified all the time, seems that the second parameter needs to be an object and not a callback (solc 8.10)

does anyone knows more about this? thanks!

did you find a way to solve this?