folio/templates/contact.php

<?php
// Session pour CSRF et rate-limit
if (session_status() === PHP_SESSION_NONE) {
    session_start();
}

$contactEmail = $_ENV['CONTACT_EMAIL'] ?? '';
$error   = null;
$success = false;

if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    // CSRF
    $token = $_POST['_token'] ?? '';
    if (!hash_equals($_SESSION['contact_csrf'] ?? '', $token)) {
        $error = 'Requête invalide. Veuillez réessayer.';
    }

    // Honeypot (champ caché que les bots remplissent)
    if (!$error && ($_POST['_hp'] ?? '') !== '') {
        $error = 'Requête invalide.';
    }

    // Rate-limit : 1 message par 5 minutes par session
    if (!$error) {
        $lastSent = $_SESSION['contact_last_sent'] ?? 0;
        if (time() - $lastSent < 300) {
            $error = 'Merci d\'attendre quelques minutes avant d\'envoyer un nouveau message.';
        }
    }

    // Validation des champs
    $name    = trim($_POST['name']    ?? '');
    $from    = trim($_POST['email']   ?? '');
    $subject = trim($_POST['subject'] ?? 'Contact depuis varlog');
    $body    = trim($_POST['message'] ?? '');

    if (!$error) {
        if ($name === '' || mb_strlen($name) > 100) {
            $error = 'Nom invalide.';
        } elseif (!filter_var($from, FILTER_VALIDATE_EMAIL)) {
            $error = 'Adresse e-mail invalide.';
        } elseif ($body === '' || mb_strlen($body) > 5000) {
            $error = 'Message vide ou trop long (max 5000 caractères).';
        }
    }

    if (!$error && $contactEmail !== '') {
        $subjectClean = mb_encode_mimeheader(
            '[' . siteTitle() . ' contact] ' . mb_strimwidth($subject, 0, 100, '…'),
            'UTF-8',
            'B'
        );
        $nameClean = mb_encode_mimeheader($name, 'UTF-8', 'B');

        $fromEmail = $_ENV['CONTACT_FROM_EMAIL'] ?? ('noreply@' . (parse_url(APP_URL, PHP_URL_HOST) ?? 'localhost'));
        $headers  = 'From: =?UTF-8?B?' . base64_encode(siteTitle() . ' contact') . "?= <{$fromEmail}>\r\n";
        $headers .= "Reply-To: {$nameClean} <{$from}>\r\n";
        $headers .= "Content-Type: text/plain; charset=UTF-8\r\n";
        $headers .= "Content-Transfer-Encoding: 8bit\r\n";

        $fullBody = "De : {$name} <{$from}>\n\n{$body}\n\n---\nEnvoyé depuis varlog";

        if (@mail($contactEmail, $subjectClean, $fullBody, $headers)) {
            $_SESSION['contact_last_sent'] = time();
            $success = true;
        } else {
            $error = 'Erreur lors de l\'envoi. Veuillez réessayer plus tard.';
        }
    } elseif (!$error) {
        $error = 'Formulaire de contact non configuré.';
    }
}

// Génère un nouveau token CSRF à chaque affichage du formulaire
if (!$success) {
    $_SESSION['contact_csrf'] = bin2hex(random_bytes(16));
}

ob_start();
?>

<div class="posts-list">
    <h1 class="mb-1">Contact</h1>
    <p class="text-muted mb-4">Envoyez-moi un message. Votre adresse e-mail ne sera pas publiée.</p>

    <?php if ($success): ?>

        <div class="alert alert-success" role="alert">
            Message envoyé. Je vous répondrai dès que possible.
        </div>

    <?php else: ?>

        <?php if ($error): ?>
            <div class="alert alert-danger" role="alert"><?= htmlspecialchars($error) ?></div>
        <?php endif; ?>

        <div class="card">
            <div class="card-body">
                <form method="POST" action="/?action=contact" novalidate>
                    <input type="hidden" name="_token" value="<?= htmlspecialchars($_SESSION['contact_csrf']) ?>">
                    <!-- Honeypot -->
                    <div style="display:none" aria-hidden="true">
                        <input type="text" name="_hp" tabindex="-1" autocomplete="off">
                    </div>

                    <div class="mb-3">
                        <label for="contact-name" class="form-label">Nom <span class="text-danger">*</span></label>
                        <input type="text" class="form-control" id="contact-name" name="name"
                               value="<?= htmlspecialchars($_POST['name'] ?? '') ?>"
                               maxlength="100" required autocomplete="name">
                    </div>

                    <div class="mb-3">
                        <label for="contact-email" class="form-label">Adresse e-mail <span class="text-danger">*</span></label>
                        <input type="email" class="form-control" id="contact-email" name="email"
                               value="<?= htmlspecialchars($_POST['email'] ?? '') ?>"
                               required autocomplete="email">
                    </div>

                    <div class="mb-3">
                        <label for="contact-subject" class="form-label">Sujet</label>
                        <input type="text" class="form-control" id="contact-subject" name="subject"
                               value="<?= htmlspecialchars($_POST['subject'] ?? '') ?>"
                               maxlength="150" autocomplete="off">
                    </div>

                    <div class="mb-4">
                        <label for="contact-message" class="form-label">Message <span class="text-danger">*</span></label>
                        <textarea class="form-control" id="contact-message" name="message"
                                  rows="7" maxlength="5000" required><?= htmlspecialchars($_POST['message'] ?? '') ?></textarea>
                    </div>

                    <button type="submit" class="btn btn-success">Envoyer</button>
                </form>
            </div>
        </div>

    <?php endif; ?>
</div>

<?php
$content = ob_get_clean();
$title   = 'Contact — ' . siteTitle();
include __DIR__ . '/layout.php';