Anonymous Monk has asked for the wisdom of the Perl Monks concerning the following question:

Hi Monks!

I am having a bug problem on this part of my code where I am uploading a PDF file from a html form and checking in the directory where all my PDF(s) will be to see if I have a duplicated file name in there, if its a “YES” I am trying to rename the file been uploaded using a random number, also to avoid further duplication of file names I am trying to rename any submitted file with a unique name, using the random number variable as well.
I can not get the code to rename the file am I missing something because I am dealing with a binary file, or its just something I can't not see any more, thanks for the help!!!
Here is part of the code.

...code here
#Random Number
my $n_range = 100000;
my $n_minimum = 1;
my $random_num = int(rand($n_range)) + $n_minimum;
#@ext will have my valid extension, I am looking for .pdf
my $file_in = param('manual'); # This parameter is from the upload for
+m.

if ($file_in){

     foreach $ext (@ext){
        if (grep /$ext$/i,$file_in){
         $match=1;
        }
    }
        if ($match){
            opendir(DIRCHCK, $dir) or die $!;
            while ($check_file = readdir(DIRCHCK)) {
                #chomp $check_file;
                                $check_file=~ s/\s+$//;
                        # Only files
                        next unless (-f "$dir$check_file");
                        # Find files ending in .pdf
                        next unless ($check_file =~ m/\.pdf$/);
                   

                        $file_in =~ s/.*[\/\\](.*)/$1/;

                        if($check_file=~/\b$file_in\b/gi){

                 rename "$file_in", "$random_num"."$file_in" or warn "
+Couldn't rename file: $!\n";
                                                                  
                }
                } #end while
                
                closedir(DIRCHCK);
                
            #call upload 
            &upload;
        }else {
        
                        &go_bk;
                        
                 }
}

[download]

Replies are listed 'Best First'.
Re: Rename Uploaded File
by pc88mxer (Vicar) on Feb 12, 2008 at 19:32 UTC 

    rename "$file_in", "$random_num"."$file_in" or warn "Couldn't rename f
+ile: $!\n";

    [download]

    I would put the random number at the end of the file name. Could $file_in have any slashes in it? If it does, then the path you're trying to move it to won't exist.

    Also, I would simplify your code by just directly checking to see if the file exists -- no need to iterate through the directory: 

    if (-e $file_in) {
    rename($file_in, "$file_in.$random_num");
}

    [download]

    Of course, you probably want to check if "$file_in.$random_num" already exists: 

    my $f = $file_in;
while (-e $f) {
    $f = "$file_in." . int(rand(100000));
}
rename($file_in, $f);

    [download]

    But this doesn't protect you against race conditions - like, what if two people upload the same file at the same time. To protect against that you'll need to find an identifier that uniquely identifies this upload.

[reply]
[d/l]
[select]
      But if the file name is file.pdf using this
      rename($file_in, "$file_in.$random_num");
      the new file name will be file.pdf.56786

      Dont you need some regular expression to insert the random number before .pdf ?
[reply]
[d/l]
      Thanks, for the uniqueness of the files I already have a unique id in the DB.
[reply]

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