How to improve downloading and add resume support?

[manis99]

Hi ,
I m using 2.0 rc3 on my forum http://myemobiles.com .
The prob. Is that smf default downloading is not resume supported. It sucks when u hv to download large file on slow connection. It doesn't even show the file size while downloading.

Is there anyway to solve it. It there anyway to show file size during downloading and make it resumable. What and where the coding is needed?

[Kill Em All]

There is no SMF default download manager. Which download mod are you using?

[manis99]

Yeah i know. M nt using any download mod. I mean to say the default simple downloading from smf based sites. The files we uploaded when we need to download it, then this happens.

[abhi]

Some webhosts coudnt support resume

[manis99]

its not the web host prob. bcz all other sites on that host support resuming. except smf.

u can test it with the official smf forum. it will also not give u resume support.

[Kill Em All]

What downloading are you using? You do mean by resume support? resume as in a job application type file?

[manis99]

resume mean to start the downloading file again from the break point.
in smf if u stopped the download in the middle or it got stopped due to network failure then the file will again start from the begining except from the breakpoint.
  want an eg. Then download any file from my forum or from smf itself and then stop it in the middle before completion and then see it will start from begining instead of the breakpoint. And then download anything from phpbb,mybb,vbulletin or other based forums and do the same with those files and then start again then see that will start from breakpoint.
    this is very irritating.

[Kill Em All]

Thats just how it is, there is really no getting around beginning a download from where you left off. I suppose it could be done, maybe if someone created a mod to allow something like utorrent to download the SMF attachment... it would be a difficult mod to code though I would imagine.

[manis99]

i need it very badly. Bcz my site is growing and members r having problems in downloading. I dont want to leave smf. But this one is pretty imp and if remain unsolved then will hv to move to other forum software.

[Kill Em All]

Every other forum software is gonna have this problem, the whole internet is gonna have this problem pretty much...

Have you considered changing web hosts to avoid disconnection issues?

[SlammedDime]

Adding Resume support isn't an easy task... it would require reworking SMF's download function quite a bit.... I'm thinking of adding this for the new Customize site... if I can get something in working form, I'll probably submit it as a modification... it probably would not be a default feature in SMF 2.0... perhaps the next version of SMF.

[manis99]

Adding Resume support isn't an easy task... it would require reworking SMF's download function quite a bit.... I'm thinking of adding this for the new Customize site... if I can get something in working form, I'll probably submit it as a modification... it probably would not be a default feature in SMF 2.0... perhaps the next version of SMF.

That's why i m afraid , its still no final version of 2.0 then how can we expect for other next versions. Btw it is the only thing i don't like in smf .

hope u get succed soon.. plz post a reply here when u r done.

or any other member can help me then plz....

[Kill Em All]

It would def be something that would probably rely heavily on cookies too, which could be a possible slowdown if it relies to much on them.

[SlammedDime]

Naw, cookies aren't needed for it... nothing extra is needed except a server that supports it (I'd imagine that apache probably does) and the code to make it work in PHP.

[Kill Em All]

Really? How would it keep track then of where someone left of downloading?

[SlammedDime]

The browser or download manager itself keeps track, and if you try to 'resume' the download, it sends a 'HTTP_RANGE' header that includes the amount that has been downloaded so far, then in the PHP script, you break apart the header to determine where it left off, then you 'seek' to that place in the file and start sending the download from there.  It's not difficult to do, but because of the way SMF does downloads, it will take some reworking.

[SlammedDime]

Update: I have successfully added Resume support on the new customize site I'm writing... I'll work on getting it packaged into a modification for SMF... unfortunately it might take more work on SMF itself... I'm using a heavily modified version of SMF's attachment download function on the new cust site.

Update 2: I found a different way to do it using the same code on both the new cust site and my test SMF install... Just need to verify it works on SMF and I'll post some code for anyone to test out...

Update 3:  Try the following:

Update 4: Code deleted - see below.

[SlammedDime]

I forgot an important piece of code that could cause issues with some resume requests... use the code below:

File: Sources/Display.php

Code (Find) Select Expand

// Since we don't do output compression for files this large...
if (filesize($filename) > 4194304 || !empty($resuming))
{
// Forcibly end any output buffering going on.
if (function_exists('ob_get_level'))
{
while (@ob_get_level() > 0)
@ob_end_clean();
}
else
{
@ob_end_clean();
@ob_end_clean();
@ob_end_clean();
}

$fp = fopen($filename, 'rb');
while (!feof($fp))
{
if (isset($callback))
echo $callback(fread($fp, 8192));
else
echo fread($fp, 8192);
flush();
}
fclose($fp);
}


Code (Replace) Select Expand

// Resume support?
$filesize = filesize($filename);
if (!in_array('ob_gzhandler', ob_list_handlers()) && !isset($callback)  && isset($_SERVER['HTTP_RANGE']) && preg_match('~bytes=(\d+)-(\d*)~i', $_SERVER['HTTP_RANGE'], $range))
{
list(, $seek_start, $seek_end) = $range;

$seek_end = empty($seek_end) ? $filesize - 1 : min(abs(intval($seek_end)), $filesize - 1);
$seek_start = empty($seek_start) || $seek_end < abs(intval($seek_start)) ? 0 : max(abs(intval($seek_start)), 0);

if ($seek_start > 0 || $seek_end < $filesize - 1)
{
header('HTTP/1.1 206 Partial Content');
header('Content-Range: bytes ' . $seek_start . '-' . $seek_end . '/' . $filesize);
$filesize = $seek_end - $seek_start + 1;
header('Content-Length: ' . $filesize);
$resuming = TRUE;
}
}

// Since we don't do output compression for files this large...
if ($filesize > 4194304 || !empty($resuming))
{
// Forcibly end any output buffering going on.
if (function_exists('ob_get_level'))
{
while (@ob_get_level() > 0)
@ob_end_clean();
}
else
{
@ob_end_clean();
@ob_end_clean();
@ob_end_clean();
}

$fp = fopen($filename, 'rb');
if (!empty($resuming))
fseek($fp, $seek_start);
while (!feof($fp) && $filesize > 0)
{
$read_length = $filesize < 8192 ? $filesize : 8192;
if (isset($callback))
echo $callback(fread($fp, $read_length));
else
echo fread($fp, $read_length);
flush();
$filesize -= $read_length;
}
fclose($fp);
}


[manis99]

This doesnt work.........
still the same thing happen . it doesn't even show the filesize.
and also no resume support.

[SlammedDime]

How are you testing it?  What are you using to download with?  And what specifically are you downloading?

I should have probably clarified what it will and will not work with...

If the file is greater than or equal to 4MB, it will always work unless the following is true:
   If the file is 'txt', 'css', 'htm', 'html', 'php', 'xml' and $modSettings['attachmentRecodeLineEndings'] is set

If the file is less than 4MB, it will work unless the following is true:
   If the file is 'txt', 'html', 'htm', 'js', 'doc', 'pdf', 'docx', 'rtf', 'css', 'php', 'log', 'xml', 'sql', 'c', 'java' and $modSettings['enableCompressedOutput'] is set.

I tested using FireFox and a 35MB zip file and it worked flawlessly.