Symfony2 StreamedResponse不允许我循环或设置变量

Question

我正在尝试设置一个StreamedResponse，以便导出一个csv文件。但是，除了静态数组之外，我没有其他东西可以进入流中。

此功能不起作用

public function exampleCsvAction(Request $request)
{
    $tests = array(
        array('one', 'two', 'three'),
        array('one', 'two', 'three'),
        array('one', 'two', 'three')
    );

    $response = new StreamedResponse();
    $response->setCallback(function () {
        $handle = fopen('php://output', 'w+');
        fputcsv( $handle, array('ONE', 'TWO', 'THREE'), ',');

        // THIS LOOP BREAKS THE RESPONSE
        foreach ($tests as $test) {
            fputcsv($handle, $test, ',');
        }

        fclose($handle);
    });

    $response->setStatusCode(200);
    $response->headers->set('Content-Type', 'application/force-download');
    $response->headers->set('Content-Disposition', 'attachment; filename="example.csv"');
    return $response;
}

但是如果我去掉了前程循环，它就能工作了。

public function exampleCsvAction(Request $request)
{
    $tests = array(
        array('one', 'two', 'three'),
        array('one', 'two', 'three'),
        array('one', 'two', 'three')
    );

    $response = new StreamedResponse();
    $response->setCallback(function () {
        $handle = fopen('php://output', 'w+');
        fputcsv( $handle, array('ONE', 'TWO', 'THREE'), ',');

        fclose($handle);
    });

    $response->setStatusCode(200);
    $response->headers->set('Content-Type', 'application/force-download');
    $response->headers->set('Content-Disposition', 'attachment; filename="example.csv"');
    return $response;
}

调用count()函数也会破坏它

public function exampleCsvAction(Request $request)
{
    $tests = array(
        array('one', 'two', 'three'),
        array('one', 'two', 'three'),
        array('one', 'two', 'three')
    );

    $response = new StreamedResponse();
    $response->setCallback(function () {
        $handle = fopen('php://output', 'w+');
        fputcsv( $handle, array('ONE', 'TWO', 'THREE'), ',');

        // THIS COUNT BREAKS THE RESPONSE
        $i = count($tests);

        fclose($handle);
    });

    $response->setStatusCode(200);
    $response->headers->set('Content-Type', 'application/force-download');
    $response->headers->set('Content-Disposition', 'attachment; filename="example.csv"');
    return $response;
}

编辑：

如果我尝试fputcsv其中一个$tests“行”，它也会中断。

public function exampleCsvAction(Request $request)
{
    $tests = array(
        array('one', 'two', 'three'),
        array('one', 'two', 'three'),
        array('one', 'two', 'three')
    );

    $response = new StreamedResponse();
    $response->setCallback(function () {
        $handle = fopen('php://output', 'w+');
        fputcsv( $handle, array('ONE', 'TWO', 'THREE'), ',');

        // THIS FPUTCSV BREAKS THE RESPONSE
        fputcsv($handle, $test[0], ',');

        fclose($handle);
    });

    $response->setStatusCode(200);
    $response->headers->set('Content-Type', 'application/force-download');
    $response->headers->set('Content-Disposition', 'attachment; filename="example.csv"');
    return $response;
}

但是，如果数组是内联的，我可以多次放置fputcsv。

public function exampleCsvAction(Request $request)
{
    $tests = array(
        array('one', 'two', 'three'),
        array('one', 'two', 'three'),
        array('one', 'two', 'three')
    );

    $response = new StreamedResponse();
    $response->setCallback(function () {
        $handle = fopen('php://output', 'w+');
        fputcsv( $handle, array('ONE', 'TWO', 'THREE'), ',');
        fputcsv( $handle, array('ONE', 'TWO', 'THREE'), ',');
        fputcsv( $handle, array('ONE', 'TWO', 'THREE'), ',');

        fclose($handle);
    });

    $response->setStatusCode(200);
    $response->headers->set('Content-Type', 'application/force-download');
    $response->headers->set('Content-Disposition', 'attachment; filename="example.csv"');
    return $response;
}

在不工作的情况下，将铬重定向到我操作的路由，并显示一条"ERR_INVALID_RESPONSE“消息

我如何使用StreamedResponse来做一些有用的事情？

Answer 1

我在这里看到了我错过的地方，我忘记使用回调函数之外的变量()

public function exampleCsvAction(Request $request)
{
    $tests = array(
        array('one', 'two', 'three'),
        array('one', 'two', 'three'),
        array('one', 'two', 'three')
    );

    $response = new StreamedResponse();
    $response->setCallback(function () use(&$tests) {
        $handle = fopen('php://output', 'w+');
        fputcsv( $handle, array('ONE', 'TWO', 'THREE'), ',');

        foreach ($tests as $test) {
            fputcsv($handle, $test, ',');
        }

        fclose($handle);
    });

    $response->setStatusCode(200);
    $response->headers->set('Content-Type', 'application/force-download');
    $response->headers->set('Content-Disposition', 'attachment; filename="example.csv"');
    return $response;
}