In the following snippet of code:


use CGI;    
sub write_file {
    $filename = $query->param('portrait');
open (OUTFILE, "> directory/file.xxx");
    while ($bytesread = read ($filename, $buffer, 1024)) {
        print OUTFILE $buffer;
    }
    close $filename;
    close OUTFILE;
}

[download]
...the $filename variable is getting set to the value of a <input type="file" name="portrait" field> from a "ENCTYPE=multipart/form-data" form which allowed the user to browse their computer and select a file for upload. No big deal.

What I don't understand is how that $filename variable suddenly becomes a filehandle argument for the read function. Doesn't the $filename contain only the path the user selected on their computer? How the hell does the server upload the file given only this information? There has to be a lot more happening with "ENCTYPE=multipart/form-data" forms that's invisible to me. What is it?

$PM = "Perl Monk's";
$MCF = "Most Clueless Friar";
$nysus = $PM . $MCF;

In reply to How does file uploading work in multipart form? by nysus

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