How can the EVA principle be applied in PHP coding to prevent issues with headers and output?

When using the EVA principle in PHP coding to prevent issues with headers and output, it is important to ensure that all headers are sent before any output is generated. This can be achieved by following the EVA principle, which stands for Establish, Validate, and Act. By establishing headers first, validating any conditions that may affect headers, and then acting accordingly, you can prevent common issues such as "headers already sent" errors. 

<?php
// Establish headers
header('Content-Type: text/html');

// Validate conditions
if ($condition) {
    header('Location: newpage.php');
    exit;
}

// Act
echo "Hello, World!";
?>

Keywords

EVA principle PHP coding headers output prevent issues

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