Clean Coding with Classes: Understanding SRP in PHP | CodeSignal Learn

Clean Coding with Classes: Understanding SRP in PHP | CodeSignal Learn

Let's explore what happens when a class doesn't follow the Single Responsibility Principle by examining a practical code snippet. Consider the following Report class:

PHP

class Report {
    public function generateReport() {
        // Generate report logic
        return "Report";
    }

    public function print($reportContent) {
        // Print report logic
        echo $reportContent . "\n";
    }

    public function saveToFile($reportContent, $filePath) {
        // Save report logic
        echo "Saving report to " . $filePath . "...\n";
    }

    public function sendByEmail($email, $reportContent) {
        // Send email logic
        echo "Sending email to " . $email . "\n";
    }
}

Here, the Report class handles report generation, printing, saving, and emailing, which are distinct responsibilities. This violation of the SRP results in increased complexity; changes in one area may unintentionally affect others, making maintenance more challenging.

To better align with the Single Responsibility Principle, we need to refactor the Report class into multiple classes, each handling a single responsibility. Let's examine a refactored version:

PHP

class Report {
    public function generate() {
        // Generate report logic
        return "Report";
    }
}

class ReportPrinter {
    public function print($reportContent) {
        // Print report logic
        echo $reportContent . "\n";
    }
}

class ReportSaver {
    public function saveToFile($reportContent, $filePath) {
        // Save report logic
        echo "Saving report to " . $filePath . "...\n";
    }
}

class EmailSender {
    public function sendByEmail($email, $reportContent) {
        // Send email logic
        echo "Sending email to " . $email . "\n";
    }
}

In this refactoring, each class is responsible for only one task: Report generates the report, ReportPrinter handles printing, ReportSaver takes care of saving to a file, and EmailSender manages email sending. This division improves the modularity and testability of our code. Each class can now be understood, modified, and reused independently, reducing unintended side effects.