Raku interface for Ethereum blockchain

A Raku interface for interacting with the Ethereum blockchain and ecosystem via JSON RPC API.

Synopsys

Quick start: compile and deploy new contract

#!/usr/bin/env raku

use Net::Ethereum;

my $ne = Net::Ethereum.new(
    :api_url('http://127.0.0.1:8501'),
    :show_progress(True),
    :unlockpwd('ospasswd'),
);

my %h = $ne.compile_and_deploy_contract(
    :contract_path('./sample.sol'),
    :compile_output_path('./compile'),  # will be created automatically if it does not exist
);
%h.gist.say;

Net::Ethereum class attributes

• api_url - URL of Ethereum node RPC server (http://127.0.0.1:8501 by default, public mutable);

• abi - contents of .abi file generated by solidity compiler (public mutable);

• contract_id - contract address (e.g. 0xb3abfa488058dba76206071b3600ae6e0dec3205, public mutable);

• tx_wait_sec - method wait_for_transaction() waits for transactions to be mined in iterations, each iteration sleeping for $!tx_wait_sec seconds ([+ 15 +] by default).

• tx_wait_iters - maximum number of iterations for wait_for_transaction() ([+ 20 +] by default).

• keepalive - set to [+ True +] if you want to reuse HTTP connections when the underlying HTTP client supports it ([- False -] by default);

• solidity - path to solidity compiler (/usr/local/bin/solc by default);

• conn_name - connection name used by the HTTP::UserAgent backend when keep-alive is enabled; for the default HTTP::Tiny backend this is ignored ([+ local-ethereum-node +] by default);

• debug - debugging flag ([- False -] by default);

• return_raw_data - this flag enables including of raw data to Hash returned by unmarshal() method (it's useful while debugging);

• show_progress - if this flag is set you will see textual progress bar while transaction acceptance waiting ([- False -] by default);

• cleanup - this flag enables cleanup after compile_and_deploy_contract() method: unlink .abi and .bin files ([+ True +] by default);

• unlockpwd - password for account unlocking, this attribute is immutable and could be set in constructor;

• evmver - EVM code name to be used as a command line arg to Solidity compiler solc, ([+ paris +] by default);

• max_fee_per_gas_multiplier - additional multiplier to be applied on max fee per gas calculation, useful if you want to increase/decrease the fee ([+ 2.1 +] by default);

• max_fee_per_blob_multiplier - additional multiplier to be applied on max fee per blob calculation ([+ 1.1 +] by default);

• legacy_ua - switch between HTTP::Tiny and HTTP::UserAgent backends ([- False -] by default, means that HTTP::Tiny is used);

Fee and gas handling

Net::Ethereum derives fee data from the node and falls back gracefully on older or partially featured nodes:

• eth_gasPrice is always queried and exposed as gasPrice.

• If the latest block exposes baseFeePerGas (EIP-1559):

  • maxPriorityFeePerGas defaults to the result of eth_maxPriorityFeePerGas (or an internal default).

  • maxFeePerGas is computed from baseFeePerGas, maxPriorityFeePerGas, and max_fee_per_gas_multiplier.

• If baseFeePerGas is missing (legacy/pre-EIP-1559 nodes):

  • The module falls back to gasPrice for maxFeePerGas while still computing a reasonable maxPriorityFeePerGas.

• If blob gas fields (excessBlobGas, blobGasUsed) are present:

  • get_base_fee_per_blob_gas and max_fee_per_blob_multiplier are used to compute baseFeePerBlobGas and maxFeePerBlobGas.

See get_fee_data and get_base_fee_per_blob_gas in lib/Net/Ethereum.rakumod for details.

HTTP transport

All JSON-RPC calls in Net::Ethereum go through a small HTTP client abstraction (Net::Ethereum::HTTP::Client):

• By default, Net::Ethereum uses Net::Ethereum::HTTP::Client::Tiny, which is built on HTTP::Tiny and supports connection reuse via standard Connection: Keep-Alive headers.

• For legacy setups you can supply a Net::Ethereum::HTTP::Client::UserAgent instance, which wraps HTTP::UserAgent and preserves the older conn_name-based keep-alive semantics.

In normal usage you do not need to configure this explicitly; Net::Ethereum.new constructs a suitable HTTP client for you.

Dependencies and compatibility

This module is tested primarily against a Rakudo 6.d toolchain with the following Raku dependencies (declared in META6.json):

• Node::Ethereum::Keccak256::Native

• JSON::Fast

• HTTP::Tiny (default HTTP backend)

• Test::Mock (test-only)

• (Optional) HTTP::UserAgent:ver<1.1.58+>, HTTP::Request:ver<1.1.58+>, HTTP::Cookies:ver<1.1.58+> if you use the legacy Net::Ethereum::HTTP::Client::UserAgent adapter explicitly

A typical local setup is:

zef install .  # installs Net::Ethereum along with the dependencies above

You can also use a containerized environment (e.g. Docker) that:

• Provides Rakudo and zef.

• Installs this module and its dependencies (e.g. via zef install .).

• Runs an Ethereum node reachable at http://127.0.0.1:8501 and /usr/local/bin/solc inside the container.

Refer to CI configuration (e.g. .gitlab-ci.yml) for an example of such an environment.

API documentation

This module was ported from Perl5 Net::Ethereum with core refactoring and breaking changes. Original Perl5 documentation could be incompatible with Raku Net::Ethereum, so feel free to report issues.

Known API differences

In Perl5 Net::Ethereum there are wait_for_contract and wait_for_transaction subroutines. Quick look for source code shows that this functions are very similar. In Raku Net::Ethereum we have one common method wait_for_transaction().

method wait_for_transaction( :@hashes!, Int :$iters?, Bool :$contract? ) returns Array { ... }

Method arguments are:

• @hashes - array of transaction hashes to be mined;

• $iters - optional timeout iterations (overrides the tx_wait_iters attribute when provided).

• $contract - optional boolean: True if we're waiting for contract deploy transaction, False for other transactions;

By default, the effective maximum wait time is:

• tx_wait_iters × tx_wait_sec = 20 × 15 = 300 seconds (5 minutes).

Running tests from test-bundle

Tests from test-bundle are rather adjustable and full function testing is available if:

• ethereum node is running and available at http://127.0.0.1:8501;

• solidity compiler is installed, working properly and available at /usr/local/bin/solc;

If your node running on different port, use helper-script hooks/forward.sh for quick forwarding:

./hooks/forward.sh 8501 <your_actual_node_port>

Environment

You should set contract transaction hash at global env variable TXHASH:

export TXHASH=0x244409bb2cced62a2b93b2688167438ef47f60f1b5aa8b6c64e9de460ddec604

Run tests

Test could be ran with prove or prove6:

prove6 ./t

prove -ve 'raku -Ilib'

Author

Please contact me via Matrix or LinkedIn. Your feedback is welcome at narkhov.pro.

Perl5 Net::Ethereum

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Habrahabr

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