返回一个 xml 文件，避免回显它

Question

我知道不应该echo在控制器中使用，但我不明白我应该使用什么来返回 xml 以便下载它。请注意，它不是服务器上的文件，它只是一个字符串：public function export(){    $this->autoRender = false;    $id = $this->request->getQuery('id');    $invoice = $this->Invoices->get($id, ['contain' => ['Customers', 'ItemInvoices' => ['ItemProformas' => ['ItemDeliveryNotes' => ['ItemOrders' => ['Orders' => ['Customers']]]]]]]);    $fpr = new ExportInvoice();    $fpr->SetInvoice($invoice);    header('Content-type: text/xml');    header('Content-Disposition: attachment; filename="' . $fpr->getFilename() . '"');    $xml = $fpr->asXML();    echo $xml;}它实际上按预期工作：浏览器下载具有给定文件名的文件，其内容是$xml值。但在文件末尾有关于标题的警告：Warning (512): Unable to emit headers. Headers sent in file=/home/mark/myproject/src/Controller/InvoicesController.php line=130 [CORE/src/Http/ResponseEmitter.php, line 51]Warning (2): Cannot modify header information - headers already sent by (output started at /home/mark/myproject/src/Controller/InvoicesController.php:130) [CORE/src/Http/ResponseEmitter.php, line 152]Warning (2): Cannot modify header information - headers already sent by (output started at /home/mark/myproject/src/Controller/InvoicesController.php:130) [CORE/src/Http/ResponseEmitter.php, line 181]Warning (2): Cannot modify header information - headers already sent by (output started at /home/mark/myproject/src/Controller/InvoicesController.php:130) [CORE/src/Http/ResponseEmitter.php, line 181]据我所知，这是由于使用了echoin 控制器。在发送标头之前可能会发生输出，然后是警告。替换功能的正确方法是echo什么？

Answer 1

在文档之前，您可以使用该框架，查看如何将字符串作为文件发送

public function export()

{

    $this->autoRender = false;

    $id = $this->request->getQuery('id');

    $invoice = $this->Invoices->get($id, ['contain' => ['Customers', 'ItemInvoices' => ['ItemProformas' => ['ItemDeliveryNotes' => ['ItemOrders' => ['Orders' => ['Customers']]]]]]]);

    $fpr = new ExportInvoice();

    $fpr->SetInvoice($invoice);

    // header('Content-type: text/xml');

    // header('Content-Disposition: attachment; filename="' . $fpr->getFilename() . '"');

    $xml = $fpr->asXML();

    $response = $this->response;

    $response = $response->withStringBody($xml);

    // use $response->body($xml); for versions before 3.4.0

    $response = $response->withType('xml');

    $response = $response->withDownload($fpr->getFilename());

    return $response;

}

Answer 2

只需使用die()或exit()

public function export()

{

    $this->autoRender = false;

    $id = $this->request->getQuery('id');

    $invoice = $this->Invoices->get($id, ['contain' => ['Customers', 'ItemInvoices' => ['ItemProformas' => ['ItemDeliveryNotes' => ['ItemOrders' => ['Orders' => ['Customers']]]]]]]);

    $fpr = new ExportInvoice();

    $fpr->SetInvoice($invoice);

    if (!headers_sent())

    {

        header('Content-type: text/xml');

        header('Content-Disposition: attachment; filename="' . $fpr->getFilename() . '"');

    }

    else

    {

        //Do something else to let them know they can't expect a file

        die();

    }

    die($fpr->asXML());

}