PHP Warning: fclose(): supplied resource is not a valid stream resource #311

IT-Experte · 2016-12-14T15:51:49Z

PHP 7.0.8
mongo-php-library 1.1.0 (final)

PHP Warning: fclose(): supplied resource is not a valid stream resource in .../src/GridFS/ReadableStream.php on line 78

This is my php code. It reads images from a MongoDB collection and display each file.

<?php
// include Composer (mongodb) extension
require '/src/composer/vendor/autoload.php';

class GridFS {

        private $client;

        public function __construct() {
                $this->client = new MongoDB\Client("mongodb://localhost:27017");
        }

        public function Image($id) {

                $db = $this->client->selectDatabase("myfiles");
                $bucket = $db->selectGridFSBucket();

                $stream = $bucket->openDownloadStream($id);
                header("Content-type: image/jpg;");
                echo stream_get_contents($stream);
                exit;
        }

        public function FindFiles($limit) {

                $collection = $this->client->selectCollection("myfiles", "fs.files");
                $filter = [];
                $options = ['limit' => $limit];
                return $collection->find($filter, $options);
        }
}

$id = isset($_GET['id']) ? urldecode($_GET['id']) : null;


$gfs = new GridFS();

if(isset($id)) {
        $gfs->Image($id);
}

?>

<html>
<head><title>ImageFiles</title></head>
<body>

<?php

$files = $gfs->FindFiles(10);

foreach ($files as $file) {
        $id = $file["_id"];
        echo "<h2>ID: $id</h2>\r\n";
        echo "<img src='?id=$id' border='0' alt='' /><br /> \r\n";
}
?>

</body>
</html>

My solution is, to hide the warning...

public function close()
{
    if (is_resource($this->buffer)) {
        @fclose($this->buffer);
    }
}

The text was updated successfully, but these errors were encountered:

…ream resource

jmikola · 2016-12-14T16:28:52Z

Can you share a PHP script that reproduces this warning?

Based on the code, it's not clear to me how this warning would be triggered unless ReadableStream::close() was invoked multiple times, which itself sounds like a bug in our StreamWrapper implementation.

IT-Experte · 2016-12-15T15:28:58Z

I have inserted my example php code. You need some image files into mongo database "myfiles". I think, Close(); was invoked multiple times (for each image).

jmikola · 2016-12-15T21:59:38Z

I was able to test this a bit and it appears to be specific to PHP 7.x. Our StreamWrapper's close() method is still only called once, but the in-memory stream we use for buffering appears to be closed before the GridFS stream that encapsulates it. When the exit; statement is moved out of the Image() method, the script completes without any warning:

if(isset($id)) {
    $gfs->Image($id);
    exit; // relocated from GridFS::Image()
}

This makes sense, as our stream goes out of scope when Image() returns and is closed naturally.

I'm currently in the midst of refactoring the StreamWrappers to not use streams for buffer (see: #304), so this will be resolved. In the meantime, feel free to use the above work-around.

IT-Experte · 2016-12-16T12:59:49Z

Many thanks for your help. I've looked your refactoring and your benchmarks. It is surprising that a string buffer is faster than writing it directly into RAM.

jmikola · 2016-12-16T16:25:05Z

It is surprising that a string buffer is faster than writing it directly into RAM.

Strings are in RAM as well. I was a bit surprised to find that the php://memory stream was nearly 4x slower, but I suppose that may be overhead of PHP's APIs (e.g. fwrite()). There is definitely a use case for php://memory, as in our tests when we want to quickly feed strings into GridFS without creating a file on disk; however, there wasn't a compelling reason to keep it in our StreamWrappers.

jmikola · 2017-01-06T20:24:00Z

This should be fixed by #304 and will be resolved in the next 1.1.x release.

jmikola · 2017-01-12T20:44:22Z

Correction: #304 pertained only to WritableStream refactoring. This was actually resolved by ReadableStream refactoring in #323 (PHPLIB-247).

IT-Experte added a commit to IT-Experte/mongo-php-library that referenced this issue Dec 14, 2016

Fix Issue mongodb#311 PHP Warning supplied resource is not a valid st…

9583105

…ream resource

jmikola added the bug label Dec 15, 2016

jmikola closed this as completed Jan 6, 2017

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PHP Warning: fclose(): supplied resource is not a valid stream resource #311

PHP Warning: fclose(): supplied resource is not a valid stream resource #311

IT-Experte commented Dec 14, 2016 •

edited by jmikola

jmikola commented Dec 14, 2016

IT-Experte commented Dec 15, 2016

jmikola commented Dec 15, 2016

IT-Experte commented Dec 16, 2016

jmikola commented Dec 16, 2016 •

edited

jmikola commented Jan 6, 2017

jmikola commented Jan 12, 2017

PHP Warning: fclose(): supplied resource is not a valid stream resource #311

PHP Warning: fclose(): supplied resource is not a valid stream resource #311

Comments

IT-Experte commented Dec 14, 2016 • edited by jmikola

PHP 7.0.8 mongo-php-library 1.1.0 (final)

PHP Warning: fclose(): supplied resource is not a valid stream resource in .../src/GridFS/ReadableStream.php on line 78

jmikola commented Dec 14, 2016

IT-Experte commented Dec 15, 2016

jmikola commented Dec 15, 2016

IT-Experte commented Dec 16, 2016

jmikola commented Dec 16, 2016 • edited

jmikola commented Jan 6, 2017

jmikola commented Jan 12, 2017

IT-Experte commented Dec 14, 2016 •

edited by jmikola

PHP 7.0.8
mongo-php-library 1.1.0 (final)

jmikola commented Dec 16, 2016 •

edited