README

PHP implementation of the SCALE (Simple Concatenated Aggregate Little-Endian) codec used in Substrate-based blockchains like Polkadot, Kusama, and Substrate-native chains.

Features

• ✅ Full SCALE codec implementation
• ✅ All primitive types (U8-U128, I8-I128, Bool, String)
• ✅ Compact integer encoding
• ✅ Compound types (Vec, Option, Tuple, Struct, Enum)
• ✅ Metadata v12-v15 support
• ✅ Extrinsic building and signing
• ✅ Event parsing
• ✅ polkadot.js compatible

Installation

composer require gmajor/substrate-codec-php

Requirements

• PHP 8.2+
• ext-gmp (for large integer handling)
• ext-json
• ext-sodium

Quick Start

Basic Encoding/Decoding

<?php

require_once 'vendor/autoload.php';

use Substrate\ScaleCodec\Types\TypeRegistry;
use Substrate\ScaleCodec\Bytes\ScaleBytes;

// Create type registry
$registry = new TypeRegistry();

// Encode a U32 value
$u32 = $registry->get('U32');
$encoded = $u32->encode(12345);
echo $encoded->toHex(); // 0x39300000

// Decode it back
$bytes = ScaleBytes::fromHex('0x39300000');
$decoded = $u32->decode($bytes);
echo $decoded; // 12345

Compact Integers

$compact = $registry->get('Compact');

// Small values (0-63): 1 byte
echo $compact->encode(42)->toHex(); // 0xa8

// Medium values (64-16383): 2 bytes
echo $compact->encode(100)->toHex(); // 0x9101

// Large values
echo $compact->encode(1000000)->toHex(); // 0x02c0843d00

Boolean

$bool = $registry->get('Bool');

$encoded = $bool->encode(true);  // 0x01
$encoded = $bool->encode(false); // 0x00

String/Text

$string = $registry->get('String');
$encoded = $string->encode('Hello, Substrate!');
// 0x2048656c6c6f2c2053756273747261746521

Vectors

// Vec<U8>
$vecU8 = (new VecType($registry))->setElementType($registry->get('U8'));
$encoded = $vecU8->encode([1, 2, 3, 4, 5]);
// 0x140102030405

$decoded = $vecU8->decode(ScaleBytes::fromHex('0x140102030405'));
// [1, 2, 3, 4, 5]

Options

$optionU32 = (new OptionType($registry))->setInnerType($registry->get('U32'));

// Some value
$encoded = $optionU32->encode(42); // 0x012a000000

// None value
$encoded = $optionU32->encode(null); // 0x00

Structs

$struct = (new StructType($registry))->setFields([
    'id' => $registry->get('U32'),
    'name' => $registry->get('String'),
    'active' => $registry->get('Bool'),
]);

$encoded = $struct->encode([
    'id' => 1,
    'name' => 'Alice',
    'active' => true,
]);

Advanced Usage

Metadata Parsing

use Substrate\ScaleCodec\Metadata\MetadataParser;

$parser = new MetadataParser();
$metadata = $parser->parse($metadataHex);

// Access pallets
$systemPallet = $metadata->getPallet('System');

// Get events
$events = $metadata->getPalletEvents('Balances');

Extrinsic Building

use Substrate\ScaleCodec\Extrinsic\ExtrinsicBuilder;

$builder = new ExtrinsicBuilder($registry);
$extrinsic = $builder
    ->setVersion(4)
    ->setPallet('Balances')
    ->setFunction('transfer')
    ->setArgs([
        'dest' => $accountId,
        'value' => 1000000000,
    ])
    ->sign($keypair)
    ->build();

Working with Large Integers

U64 and U128 return strings for values exceeding PHP_INT_MAX:

$u64 = $registry->get('U64');

// Max U64 value
$encoded = $u64->encode('18446744073709551615');
$decoded = $u64->decode($bytes);
echo $decoded; // '18446744073709551615' (string)

Documentation

• API Reference - Complete API documentation
• Types Reference - Detailed type documentation
• Static Analysis - PHPStan configuration

Testing

# Run unit tests
make test

# Run with coverage
make coverage

# Run compatibility tests
make compat

# Run static analysis
make stan

# Run code style check
make sniff

Compatibility

This library maintains compatibility with polkadot.js SCALE codec. Run compatibility tests:

php compat/tests/php-compatibility-test.php

Benchmarks

make bench        # Standard benchmarks
make bench-quick  # Quick benchmarks
make bench-full   # Full benchmarks

Contributing

1. Fork the repository
2. Create a feature branch: git checkout -b feature/my-feature
3. Run tests: make test
4. Run static analysis: make stan
5. Run code style: make sniff
6. Commit changes: git commit -am "feat: my feature"
7. Push and create a PR

License

MIT License. See LICENSE for details.

Related

• SCALE Codec Specification
• Substrate Documentation
• polkadot.js API