[ic] Out of memory problems with Downloadable products.

[interchange-users@icdevgroup.org (Nathan Pitts)]

Thank you very much. I was about to go into a bad mode of trying to 
stream the file myself with sysreads and the like, but this is a much 
more simple method. I appreciate the help, and the time you spent typing 
this prompt response.

Nathan



Paul Jordan wrote:

>>Quoting Nathan Pitts (npitts@cybernet.com):
>>    
>>
>>>Hello.
>>>  I have recently put Interchange online as the ecommerce application
>>>for my company. We are offering our software products for download,
>>>available as CD-ROM ISO images.
>>>  Each time that a customer attempts to download a product, the
>>>webserver runs out of  memory.
>>>  I have figured out what the problem is, but not how to fix it.
>>>  It appears that in /usr/lib/interchange/bin/interchange, a
>>>      
>>>
>>download is
>>    
>>
>>>handled by a subroutine called do_deliver. This do_deliver sub
>>>      
>>>
>>is a call
>>    
>>
>>>to /usr/lib/interchange/lib/Vend/Util.pm->readfile and then a call
>>>to /usr/lib/interchange/lib/Vend/Server.pm->respond.
>>>  The problem is that Util::readfile performs a "slurp" on the file to
>>>be delivered, meaning it tries to read the entire file into memory
>>>before delivering it. With a 650 MB ISO image, this is not a viable
>>>solution, especially considering that more than one user may be
>>>downloading at 1 time.
>>>  Has anyone out there used Interchange to serve large downloads? Is it
>>>possible?
>>>      
>>>
>>You have to have interchange symlink in the ISO and hand it off to
>>HTTP or FTP. There have been multiple examples of this on this list over
>>the years.
>>
>>--
>>Mike Heins
>>    
>>
>
>
>Mike wrote one for us Nathan. Here is the usertag:
>
>UserTag enable-download Order resource
>UserTag enable-download addAttr
>UserTag enable-download Routine <<EOR
> sub {
> my ($resource, $opt) = @_;
> my $docroot = $opt->{document_root} || $::Variable->{DOCROOT};
> my $dl_dir  = $opt->{base_dir} || 'tmp_download';
> my $server  = $opt->{server}   || $::Variable->{SERVER_NAME};
> ## Routine comes from Vend::Util
> ## We will use session ID, but this would make totally random
> #my $random = random_string();
>
> my $random = $Vend::Session->{id};
>
> require File::Path;
>
> my $dir = "$docroot/$dl_dir/$random";
>
> if(-d $dir) {
>
> # Must have been made previously
>
> }
>
> elsif ( File::Path::mkpath($dir)
> ) {
> ## Need to ensure readable for HTTP download
> chmod 0755, $dir;
> }
> else {
> logError("Unable to make user download directory %s", $dir);
> return undef;
> }
> # Routine comes from Vend::Util
> unless ( file_name_is_absolute($resource) ) {
> $resource = "$Vend::Cfg->{VendRoot}/$resource";
> }
>
> # Get the base file name
> my $filebase = $resource;
> $filebase =~ s,.*/,,;
> ## Now do the symlink
> symlink $resource, "$dir/$filebase"
> or do {
> logError("Unable to symlink %s to %s", $resource, $dir);
> return undef;
> };
> ## Return the URL of the now-symlinked resource
> return "http://$server/$dl_dir/$random/$filebase";;
> }
>
>EOR
>
>
>This should be accompanied by a cron job which runs every half hour
>or so:
>
>	## Wherever that temporary base is
>	BASEDIR=/var/www/html/tmp_download
>	find $BASEDIR -type l -mmin +60 -exec rm '{}' ';'
>	find $BASEDIR -type d -depth -mindepth 1 -empty -exec rmdir '{}' ';'
>
>
>You can call the download script with:
>[enable-download resource="/path/to/download/dir/[item-code].zip"]
>
>-------------
>You may have to edit up that xxx/xxx/xx/[item-code].zip to fit your needs.
>-------------
>
>This was all written by Mike Heins, in like 4 seconds :)
>
>
>Paul
>
>
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>