ymww_backend/vendor/maennchen/zipstream-php/guides/Symfony.rst

Usage with Symfony
===============

Overview for using ZipStream in Symfony
--------

Using ZipStream in Symfony requires use of Symfony's ``StreamedResponse`` when
used in controller actions.

Wrap your call to the relevant ``ZipStream`` stream method (i.e. ``addFile``,
``addFileFromPath``, ``addFileFromStream``) in Symfony's ``StreamedResponse``
function passing in any required arguments for your use case.

Using Symfony's ``StreamedResponse`` will allow Symfony to stream output from
ZipStream correctly to users' browsers and avoid a corrupted final zip landing
on the users' end.

Example for using ``ZipStream`` in a controller action to zip stream files
stored in an AWS S3 bucket by key:

.. code-block:: php

    use Symfony\Component\HttpFoundation\StreamedResponse;
    use Aws\S3\S3Client;
    use ZipStream;

    //...

    /**
    * @Route("/zipstream", name="zipstream")
    */
    public function zipStreamAction()
    {
        //sample test file on s3
        $s3keys = array(
        "ziptestfolder/file1.txt"
        );

        $s3Client = $this->get('app.amazon.s3'); //s3client service
        $s3Client->registerStreamWrapper(); //required

        //using StreamedResponse to wrap ZipStream functionality for files on AWS s3.
        $response = new StreamedResponse(function() use($s3keys, $s3Client)
        {
            // Define suitable options for ZipStream Archive.
            $options = new \ZipStream\Option\Archive();
            $options->setContentType('application/octet-stream');
            // this is needed to prevent issues with truncated zip files
            $options->setZeroHeader(true);
            $options->setComment('test zip file.');

            //initialise zipstream with output zip filename and options.
            $zip = new ZipStream\ZipStream('test.zip', $options);

            //loop keys - useful for multiple files
            foreach ($s3keys as $key) {
                // Get the file name in S3 key so we can save it to the zip
                //file using the same name.
                $fileName = basename($key);

                //concatenate s3path.
                $bucket = 'bucketname'; //replace with your bucket name or get from parameters file.
                $s3path = "s3://" . $bucket . "/" . $key;

                //addFileFromStream
                if ($streamRead = fopen($s3path, 'r')) {
                $zip->addFileFromStream($fileName, $streamRead);
                } else {
                die('Could not open stream for reading');
                }
            }

            $zip->finish();

        });

        return $response;
    }

In the above example, files on AWS S3 are being streamed from S3 to the Symfon
application via ``fopen`` call when the s3Client has ``registerStreamWrapper``
applied. This stream is then passed to ``ZipStream`` via the
``addFileFromStream`` function, which ZipStream then streams as a zip to the
client browser via Symfony's ``StreamedResponse``. No Zip is created server
side, which makes this approach a more efficient solution for streaming zips to
the client browser especially for larger files.

For the above use case you will need to have installed
`aws/aws-sdk-php-symfony <https://github.com/aws/aws-sdk-php-symfony>`_ to
support accessing S3 objects in your Symfony web application. This is not
required for locally stored files on you server you intend to stream via
``ZipStream``.

See official Symfony documentation for details on
`Symfony's StreamedResponse <https://symfony.com/doc/current/components/http_foundation.html#streaming-a-response>`_ 
``Symfony\Component\HttpFoundation\StreamedResponse``.

Note from `S3 documentation <https://docs.aws.amazon.com/sdk-for-php/v3/developer-guide/s3-stream-wrapper.html>`_:

    Streams opened in "r" mode only allow data to be read from the stream, and
    are not seekable by default. This is so that data can be downloaded from
    Amazon S3 in a truly streaming manner, where previously read bytes do not
    need to be buffered into memory. If you need a stream to be seekable, you
    can pass seekable into the stream context options of a function.

Make sure to configure your S3 context correctly!

Uploading a file
--------

You need to add correct permissions
(see `#120 <https://github.com/maennchen/ZipStream-PHP/issues/120>`_)

**example code**


.. code-block:: php

    $path = "s3://{$adapter->getBucket()}/{$this->getArchivePath()}";

    // the important bit
    $outputContext = stream_context_create([
        's3' => ['ACL' => 'public-read'],
    ]);

    fopen($path, 'w', null, $outputContext);