Php write buffer to file

I am having trouble with an update script. It runs for a few hours so I would like it to output live to a text file.

I start the document with

ob_start();

Then within the while loop (as it iterates through the records of the database) I have this

$size=ob_get_length();
if ($size > 0)
{
    $content = ob_get_contents();
    logit($contents);
    ob_clean();
}

And finally the logit function

function logit($data)
{
    file_put_contents('log.txt', $data, FILE_APPEND);
}

However the log file remains empty. What am I doing wrong?

asked Jul 22, 2010 at 11:02

2

try

logit($content);
//           ^^ Note the missing s

answered Jul 22, 2010 at 11:05

jigfoxjigfox

17.9k3 gold badges56 silver badges73 bronze badges

0

$contents is not the same variable as $content.

answered Jul 22, 2010 at 11:07

Ahmed AmanAhmed Aman

2,3431 gold badge19 silver badges33 bronze badges

For anyone coming here looking for a function for this, I wrote a nice one today:

//buffer php outout between consecutive calls and optionally store it to a file:
function buffer( $toFilePath=0, $appendToFile=0 ){
    $status = ob_get_status ();
    if($status['level']===1) return ob_start(); //start the buffer
    $res = ob_get_contents();
    ob_end_clean();
    if($toFilePath) file_put_contents($toFilePath, $res, ($appendToFile ? FILE_APPEND : null));
    return $res;
}

Sample usage:

buffer(); //start the buffer

echo(12345); //log some stuff
echo(678910);

$log = buffer('mylog.txt',1); //add these lines to a file (optional)

echo('Heres the latest log:'.$log);

answered May 17, 2018 at 13:02

cronokleecronoklee

6,0548 gold badges48 silver badges75 bronze badges

The stream_set_write_buffer() function has been broken since PHP 4.3.0. As a workaround, I would suggest using a php_user_filter as an output buffer. By using the following class I have measured over 50% performance improvements with scripts that generate large text files by writing them one line at a time:

class my_output_buffer extends php_user_filter
{
    protected static $BUFFER_SIZE = 4096;

    function onCreate( ) {
        $this->bff = [];
        $this->len = 0;
        return true;
    }

    public function filter($in, $out, &$consumed, $closing)
    {
        $rv = PSFS_FEED_ME; /* assume no output */

        /* process input */
        while ($bucket = stream_bucket_make_writeable($in)) {

            /* bucket is too big for the buffer? */
            $space = static::$BUFFER_SIZE - $this->len;

            if ($bucket->datalen >= $space) {
                /* consume data by placing it into internal buffers */
                $this->bff[] = substr($bucket->data, 0, $space);
                $this->len += $space;
                $overflow = substr($bucket->data, $space);
                $ovfl_len = $bucket->datalen - $space;
                $consumed += $bucket->datalen;

                assert($this->len == static::$BUFFER_SIZE);

                /* make one big bucket */
                $bucket->data = implode('', $this->bff);
                $bucket->datalen = static::$BUFFER_SIZE;
                stream_bucket_append($out, $bucket);
                $rv = PSFS_PASS_ON; /* we have output! */

                /* handle overflow */
                $this->bff = [$overflow];
                $this->len = $ovfl_len;
            }
            else {
                /* consume data by placing it into internal buffers */
                $this->bff[] = $bucket->data;
                $this->len += $bucket->datalen;
                $consumed += $bucket->datalen;
            }
        }

        /* stream is closing and we have data? */
        if ($closing && $this->len > 0) {
            /* make one last bucket */
            $data = implode('', $this->bff);
            $bucket = stream_bucket_new($this->stream, $data);
            stream_bucket_append($out, $bucket);
            $rv = PSFS_PASS_ON; /* we have output! */

            /* clear internal buffer */
            $this->bff = [];
            $this->len = 0;
        }

        return $rv;
    }
}

$fp = fopen('foobar.txt', 'w');

/* enable filtering */
stream_filter_register('output.buffer', 'my_output_buffer');
stream_filter_append($fp, 'output.buffer');

/* a lot of small writes */
for ($i = 0; $i < 10000; $i++) {
    fwrite($fp, 'x');
}

fclose($fp);