PHPePub\Core\Structure\Opf::finalize PHP Method

    function finalize()
    {
        $metadata = $this->metadata->finalize($this->bookVersion, $this->date);
        foreach ($this->metadata->namespaces as $ns => $nsuri) {
            $this->addNamespace($ns, $nsuri);
        }
        $opf = "<?xml version=\"1.0\" encoding=\"utf-8\"?>\n" . "<package xmlns=\"http://www.idpf.org/2007/opf\"\n";
        foreach ($this->namespaces as $ns => $uri) {
            $opf .= "\txmlns:{$ns}=\"{$uri}\"\n";
        }
        if ($this->bookVersion === EPub::BOOK_VERSION_EPUB3 && sizeof($this->prefixes) > 0) {
            $opf .= "\tprefix=\"";
            $addSpace = false;
            foreach ($this->prefixes as $name => $uri) {
                if ($addSpace) {
                    $opf .= " ";
                } else {
                    $addSpace = true;
                }
                $opf .= "{$name}: {$uri}";
            }
            $opf .= "\"\n";
        }
        $opf .= "\tunique-identifier=\"" . $this->ident . "\" version=\"" . $this->bookVersion . "\">\n";
        $opf .= $metadata;
        $opf .= $this->manifest->finalize($this->bookVersion);
        $opf .= $this->spine->finalize();
        if ($this->guide->length() > 0) {
            $opf .= $this->guide->finalize();
        }
        return $opf . "</package>\n";
    }