MongoDB GridFS PHP附加文本

Question

I'm trying to make a log system using mongodb in php and GridFS. I can initially write data to my file but once I close the stream I don't know how to append data later to it. This is how I write to it:

    $bucket= DB::connection('mongodb')->getMongoDB()->selectGridFSBucket();
    $stream = $bucket->openUploadStream('my-file-name.txt');
    $contents = 'whatever text here \n';
    fwrite($stream, $contents);
    fclose($stream);

I tried retreiving it and appending data to the stream but it doesn't work. This is attempt:

    $bucket= DB::connection('mongodb')->getMongoDB()->selectGridFSBucket();
    $stream = $bucket->openDownloadStreamByName('my-file-name.txt');
    fwrite($stream, $contents);

also tried fopen on the stream but no luck. I also don't know how to retrieve this file Id after writing data to it.

Answer 1

I couldn't find a simple solution to append so I ended up replacing the previous file with a new file and deleting the old one.

$stream = $bucket->openDownloadStream($this->file_id);
$prev_content = stream_get_contents($stream);

//delete old data chunks
DB::connection('mongodb')->collection('fs.chunks')->where('files_id',$this->file_id)->delete();
//delete old file
DB::connection('mongodb')->collection('fs.files')->where('_id',$this->file_id)->delete();


$new_content =$prev_content.$dt.$msg."\n"; // append to log body
$new_filename = $filename_prefix;
$stream = $bucket->openUploadStream($new_filename);
fwrite($stream, $new_content);
fclose($stream);

$new_file = DB::connection('mongodb')->collection('fs.files')->where('filename',$new_filename)->first();

UPDATE: For future readers, after using this system for few months I realized this is not a good solution. Files & chunks can get corrupted and also the process is super slow. I simply switched to logging in a txt file and just storing a reference to my file in mongodb much better :)