Leveraging Blockchain in PHP for Supply Chain Management

In a previous post, we explored the basics of building a blockchain using PHP. Now, let's dive deeper into how this technology can be applied specifically to supply chain management (SCM). We'll discuss practical implementations, benefits, and real-world examples of blockchain in SCM, all while using PHP as our primary development language.

Enhancing Our PHP Blockchain for SCM

To adapt our basic blockchain for supply chain management, we need to modify our Block class to include SCM-specific data:

class SupplyChainBlock extends Block {
    public $productId;

    public $location;

    public $timestamp;

    public $temperature;

    public $humidity;

    public $handlerInfo;

    public function __construct($index, $timestamp, $data, $previousHash = '')
    {
        parent::__construct($index, $timestamp, $data, $previousHash);
        $this->productId = $data['productId'];
        $this->location = $data['location'];
        $this->temperature = $data['temperature'];
        $this->humidity = $data['humidity'];
        $this->handlerInfo = $data['handlerInfo'];
    }

    public function calculateHash()
    {
        return hash('sha256', $this->index . $this->timestamp . json_encode($this->data) . 
                    $this->previousHash . $this->productId . $this->location . 
                    $this->temperature . $this->humidity . json_encode($this->handlerInfo));
    }
}

This extended class now includes crucial supply chain data points such as product ID, location, environmental conditions, and handler information.

Implementing SCM-Specific Features

1. Product Traceability

To implement product traceability, we can create a method to retrieve the entire history of a specific product:

class SupplyChainBlockchain extends Blockchain
{
    public function getProductHistory($productId)
    {
        $history = [];

        foreach ($this->chain as $block) {
            if ($block->productId === $productId) {
                $history[] = $block;
            }
        }

        return $history;
    }
}

2. Quality Assurance Checks

We can add a method to verify if a product has maintained required conditions throughout its journey:

public function verifyProductQuality($productId, $maxTemp, $maxHumidity)
{
    $history = $this->getProductHistory($productId);

    foreach ($history as $block) {
        if ($block->temperature > $maxTemp || $block->humidity > $maxHumidity) {
            return false;
        }
    }

    return true;
}

3. Smart Contracts for Automated Payments

While PHP isn't typically used for smart contracts, we can simulate this functionality:

public function processPayment($productId, $buyerId, $sellerId, $amount)
{
    if ($this->verifyProductQuality($productId, 25, 60)) {
        // Simulate payment processing
        echo "Payment of $amount processed from $buyerId to $sellerId for product $productId";
        return true;
    }

    echo "Payment failed due to quality issues";
    return false;
}

Real-World Application: Farm-to-Table Tracking

Let's consider a farm-to-table scenario where we track organic produce from farm to restaurant:

$supplyChain = new SupplyChainBlockchain();

// Farmer harvests tomatoes
$supplyChain->addBlock(new SupplyChainBlock(1, date('Y-m-d H:i:s'), [
    'productId' => 'TOM001',
    'location' => 'Farm A',
    'temperature' => 20,
    'humidity' => 55,
    'handlerInfo' => ['name' => 'John Farmer', 'role' => 'Harvester']
]));

// Tomatoes in transit
$supplyChain->addBlock(new SupplyChainBlock(2, date('Y-m-d H:i:s'), [
    'productId' => 'TOM001',
    'location' => 'In Transit',
    'temperature' => 18,
    'humidity' => 60,
    'handlerInfo' => ['name' => 'Alice Trucker', 'role' => 'Transporter']
]));

// Tomatoes arrive at restaurant
$supplyChain->addBlock(new SupplyChainBlock(3, date('Y-m-d H:i:s'), [
    'productId' => 'TOM001',
    'location' => 'Restaurant B',
    'temperature' => 22,
    'humidity' => 50,
    'handlerInfo' => ['name' => 'Bob Chef', 'role' => 'Receiver']
]));

// Verify product journey
$tomatoHistory = $supplyChain->getProductHistory('TOM001');
foreach ($tomatoHistory as $block) {
    echo "Location: " . $block->location . ", Temp: " . $block->temperature . "°C, Humidity: " . $block->humidity . "%\n";
}

// Check quality and process payment
if ($supplyChain->verifyProductQuality('TOM001', 25, 70)) {
    $supplyChain->processPayment('TOM001', 'Restaurant B', 'Farm A', 100);
}

Benefits of Blockchain in SCM

1. Enhanced Traceability: Every step of the product journey is recorded and easily accessible.

2. Improved Quality Control: Real-time monitoring of environmental conditions ensures product quality.

3. Increased Efficiency: Automated processes reduce paperwork and speed up transactions.

4. Greater Transparency: All stakeholders have access to the same, immutable information.

5. Reduced Fraud: The immutable nature of blockchain makes it difficult to falsify records.

Conclusion

By integrating blockchain technology into supply chain management using PHP, we can create a more transparent, efficient, and secure system. While our example is simplified, it demonstrates the potential of blockchain in SCM. As this technology continues to evolve, we can expect to see more sophisticated implementations that further revolutionize supply chain processes.

Remember, while PHP is great for prototyping and understanding blockchain concepts, production-level blockchain systems often require more specialized tools and frameworks. However, the principles we've explored here form the foundation for understanding and implementing blockchain solutions in supply chain management.