Posted by Shailesh Humbad on 10/09/63 11:36

Gordon Burditt wrote:
>> Here is an advanced PHP question. Can anyone think of a way to detect
>> the number of bytes written to output when a script is aborted?
>
> What are you going to use that information for?
>
>> I am sending a large file to the client, and I want to record how many
>> bytes are actually sent.
>
> Bytes sent != bytes received. Why is there a problem with the
> script aborting? Modem drops carrier? Spontaneous Windows reboot?
> Browser crash?
>
>> I can detect abort of the script using a
>> shutdown handler. In the shutdown handler, I tried ob_get_length, but
>> it returns false. I tried to read the server's log file, but it is does
>> not contain the information until the script fully quits. I tried to
>> use fwrite to php://output, and then get the bytes written return value.
>> However, if the script aborts in the middle of the write, then bytes
>> written is never returned.
>
> If one end of a TCP connection quietly goes away, you might be
> able to write 64k more bytes before you realize it has gone away.
>
>> The only thing that worked was writing one byte at a time using
>> fread/fwrite. But this also made the processor load 100% and download
>> speed very slow (700KB/sec versus 24MB/sec on localhost using wget).
>
> What do you intend to use this for? If you're trying to figure out
> where to restart sending the file, it won't be accurate.
>
> Gordon L. Burditt

TCP is a reliable transport, meaning that at the application layer, one
always know exactly how much data the client received, and this is
always equal to how much was successfully sent. I don't care how many
bytes were transferred by TCP in the data link layer.

I don't want to restart sending the file. I also do not care why the
script aborted. Of course, it must be from a network/client abort, not
a server reboot or such, because the script must finish executing. I
only want to be able to track how many bytes were sent to the client,
which equals the value that is eventually written to the server log file.

The reason I need it is because in this system, I want to be able to
show the user how many bytes the server sent them. This will tell them
how much data transfer they have used.

I need the status of bytes sent as soon as possible after the script
completes or aborts. Thanks.

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