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    ethereum-input-data-decoder
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    0.3.2 • Public • Published


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    ethereum-input-data-decoder

    Ethereum smart contract transaction input data decoder

    License Build Status dependencies Status NPM version PRs Welcome

    Demo

    https://lab.miguelmota.com/ethereum-input-data-decoder

    Install

    npm install ethereum-input-data-decoder

    Getting started

    Pass ABI file path to decoder constructor:

    const InputDataDecoder = require('ethereum-input-data-decoder');
    const decoder = new InputDataDecoder(`${__dirname}/abi.json`);

    Alternatively, you can pass ABI array object to constructor;

    const abi = [{ ... }]
    const decoder = new InputDataDecoder(abi);

    example abi

    Then you can decode input data:

    const data = `0x67043cae0000000000000000000000005a9dac9315fdd1c3d13ef8af7fdfeb522db08f020000000000000000000000000000000000000000000000000000000058a20230000000000000000000000000000000000000000000000000000000000040293400000000000000000000000000000000000000000000000000000000000000a0f3df64775a2dfb6bc9e09dced96d0816ff5055bf95da13ce5b6c3f53b97071c800000000000000000000000000000000000000000000000000000000000000034254430000000000000000000000000000000000000000000000000000000000`;
    
    const result = decoder.decodeData(data);
    
    console.log(result);
    {
      "method": "registerOffChainDonation",
      "types": [
        "address",
        "uint256",
        "uint256",
        "string",
        "bytes32"
        ],
        "inputs": [
          <BN: 5a9dac9315fdd1c3d13ef8af7fdfeb522db08f02>,
          <BN: 58a20230>,
          <BN: 402934>,
          "BTC",
          <Buffer f3 df ... 71 c8>
        ],
        "names": [
          "addr",
          "timestamp",
          "chfCents",
          "currency",
          "memo"
        ]
    }
    

    Example using input response from web3.getTransaction:

    web3.eth.getTransaction(txHash, (error, txResult) => {
      const result = decoder.decodeData(txResult.input);
      console.log(result);
    });

    Decoding tuple and tuple[] types

    Where OrderData is

    struct OrderData {
      uint256 amount;
      address buyer;
    }

    Decoding input to a method someMethod(address,OrderData,OrderData[]) returns data in format

    {
      method: 'someMethod',
      types: ['address', '(uint256,address)', '(uint256,address)[]'],
      inputs: [
        '0x81c55017F7Ce6E72451cEd49FF7bAB1e3DF64d0C',
        [100, '0xA37dE6790861B5541b0dAa7d0C0e651F44c6f4D9']
        [[274, '0xea674fdde714fd979de3edf0f56aa9716b898ec8']]
      ],
      names: ['sender', ['order', ['amount', 'buyer']], ['allOrders', ['amount', 'buyer']]]
    }
    • In the types field, tuples are represented as a string containing types contained in the tuple
    • In the inputs field, tuples are represented as an array containing values contained in the tuple
    • In the names field, tuples are represented as an array with 2 items. Item 1 is the name of the tuple, item 2 is an array containing the names of the values contained in the tuple.

    Decoding Big Numbers

    All numbers are returned in big number format to preserve precision.

    Here's an example of how to convert the big number to a human readable format.

    console.log(result.inputs[0].toString(10)) // "5"
    console.log(result.inputs[0].toNumber()) // 55

    Please keep in mind that JavaScript only supports numbers up to 64 bits. Solidity numbers can be up to 256 bits, so you run the risk of truncation when casting or having the big number library error out when trying to parse a large number to a JavaScript Number type.

    const n = new BN("543534254523452352345234523455")
    console.log(n.toString(10)) // "543534254523452352345234523455"
    console.log(n.toNumber()) // ERROR!

    CLI

    Install

    npm install -g ethereum-input-data-decoder

    Usage

    $ ethereum_input_data_decoder --help
    
      Ethereum smart contract transaction input data decoder
    
      Usage
        $ ethereum_input_data_decoder [flags] [input]
    
      Options
        --abi, -a  ABI file path
        --input, -i Input data file path
    
      Examples
        $ ethereum_input_data_decoder --abi token.abi --input data.txt
        $ ethereum_input_data_decoder --abi token.abi "0x23b872dd..."

    Example

    Pass ABI file and input data as file:

    $ ethereum_input_data_decoder --abi abi.json --input data.tx
    
    method   registerOffChainDonation
    
    address  addr       0x5a9dac9315fdd1c3d13ef8af7fdfeb522db08f02
    uint256  timestamp  1487012400
    uint256  chfCents   4204852
    string   currency   BTC
    bytes32  memo       0xf3df64775a2dfb6bc9e09dced96d0816ff5055bf95da13ce5b6c3f53b97071c8

    Pass ABI file and input data as string:

    $ ethereum_input_data_decoder --abi abi.json 0x67043cae0...000000
    
    method   registerOffChainDonation
    
    address  addr       0x5a9dac9315fdd1c3d13ef8af7fdfeb522db08f02
    uint256  timestamp  1487012400
    uint256  chfCents   4204852
    string   currency   BTC
    bytes32  memo       0xf3df64775a2dfb6bc9e09dced96d0816ff5055bf95da13ce5b6c3f53b97071c8

    You can also pipe the input data:

    $ cat data.txt | ethereum_input_data_decoder --abi abi.json
    
    method   registerOffChainDonation
    
    address  addr       0x5a9dac9315fdd1c3d13ef8af7fdfeb522db08f02
    uint256  timestamp  1487012400
    uint256  chfCents   4204852
    string   currency   BTC
    bytes32  memo       0xf3df64775a2dfb6bc9e09dced96d0816ff5055bf95da13ce5b6c3f53b97071c8

    Test

    npm test

    Development

    1. Clone repository:
    git clone git@github.com:miguelmota/ethereum-input-data-decoder.git
    
    cd ethereum-input-data-decoder/
    1. Install dependencies:
    npm install
    1. Make changes.

    2. Run tests:

    npm test
    1. Run linter:
    npm run lint

    Contributing

    Pull requests are welcome!

    For contributions please create a new branch and submit a pull request for review.

    Many thanks to all the contributors for making this a better library for everyone 🙏

    FAQ

    • Q: How can I retrieve the ABI?

      • A: You can generate the ABI from the solidity source files using the Solidity Compiler.

        solc --abi MyContract.sol -o build
    • Q: Can this library decode contract creation input data?

      • A: Yes, it can decode contract creation input data.
    • Q: Does this library support ABIEncoderV2?

      • A: Yes, but it's buggy. Please submit a bug report if you encounter issues.

    License

    MIT

    Install

    npm i ethereum-input-data-decoder

    DownloadsWeekly Downloads

    2,076

    Version

    0.3.2

    License

    MIT

    Unpacked Size

    1.04 MB

    Total Files

    31

    Last publish

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