> The headers with original casing. */ private array $headers = []; /** * @var array Map of lowercase header names to actual header names. */ private array $headersMap = []; /** * Constructor. * * @since 0.1.0 * * @param array> $headers Initial headers. */ public function __construct(array $headers = []) { foreach ($headers as $name => $value) { $this->set($name, $value); } } /** * Gets a specific header value. * * @since 0.1.0 * * @param string $name The header name (case-insensitive). * @return list|null The header value(s) or null if not found. */ public function get(string $name): ?array { $lowerName = strtolower($name); if (!isset($this->headersMap[$lowerName])) { return null; } $actualName = $this->headersMap[$lowerName]; return $this->headers[$actualName]; } /** * Gets all headers. * * @since 0.1.0 * * @return array> All headers with their original casing. */ public function getAll(): array { return $this->headers; } /** * Gets header values as a comma-separated string. * * @since 0.1.0 * * @param string $name The header name (case-insensitive). * @return string|null The header values as a comma-separated string or null if not found. */ public function getAsString(string $name): ?string { $values = $this->get($name); return $values !== null ? implode(', ', $values) : null; } /** * Checks if a header exists. * * @since 0.1.0 * * @param string $name The header name (case-insensitive). * @return bool True if the header exists, false otherwise. */ public function has(string $name): bool { return isset($this->headersMap[strtolower($name)]); } /** * Sets a header value, replacing any existing value. * * @since 0.1.0 * * @param string $name The header name. * @param string|list $value The header value(s). * @return void */ private function set(string $name, $value): void { if (is_array($value)) { $normalizedValues = array_values($value); } else { // Split comma-separated string into array $normalizedValues = array_map('trim', explode(',', $value)); } $lowerName = strtolower($name); // If header exists with different casing, remove the old casing if (isset($this->headersMap[$lowerName])) { $oldName = $this->headersMap[$lowerName]; if ($oldName !== $name) { unset($this->headers[$oldName]); } } // Always use the new casing $this->headers[$name] = $normalizedValues; $this->headersMap[$lowerName] = $name; } /** * Returns a new instance with the specified header. * * @since 0.1.0 * * @param string $name The header name. * @param string|list $value The header value(s). * @return self A new instance with the header. */ public function withHeader(string $name, $value): self { $new = clone $this; $new->set($name, $value); return $new; } }