php - Duplicate Filename Protection by Incrementation -


first post, , rather asking question proposing answer 1 couldn't find answer for, may else.

the issue saving file uploads locally, , trying find nice way handle duplicate file names.

given filename of filename.ext can form, give first filename of form filename-\d+.ext doesn't exist

   $file = "upload.jpg";     while(is_file($file))     {         preg_match("/\d+\.[^.]*$/", $file, $matches);         if (!$matches)         {             $file = preg_replace('/(\.[^.]*)$/', '-1${1}', $file);             echo $file."<br>";         }         else         {             list($i, $extension) = explode(".",$matches[0]);              $file = preg_replace('/(\d+\.[^.]*)$/', ++$i.".".$extension, $file);         }  }    echo $file;

hope might someone

this algorithm not scalable. uploading n files same name cause o(n) behavior in algorithm, leading o(n²) total running time, including o(n²) filesystem accesses. that's not pretty server app. can't fixed because of how filesystems work.

better solutions:

  1. store filenames have been used in db table, mapping them use count.
  2. put high-granularity timestamp in filename.
  3. use sha1 (or md5) hash of contents filename. prevents duplicate files being uploaded, if that's important.

use database map filenames human-readable names, if necessary.


Comments

Post a Comment

Popular posts from this blog

apache - Add omitted ? to URLs -

i working on website cms reads page name of query string, e.g. http://exmaple.com/?pagename . trying create rewrite rule rewrite ? . so, user types in /pagename , taken /?pagename try this: rewriteengine on rewritecond %{request_filename} !-d rewritecond %{request_filename} !-f rewriterule ^/?(.*) index.php?$1 [l]
Read more

redirect - bbPress Forum - rewrite to wwww.mysite prohibits login -

i using bbpress installation without wordpress integration. the redirect of rewriteengine @ forum site works: rewriteengine on rewritecond %{http_host} ^forum.mysite.com$ rewriterule (.*)$ http://www.forum.mysite.com/$1 [r=301,l] the problem login pppress. bbpress login not recognize: http://www.forum.mysite/bb-login.php . it redirects to: http://forum.mysite.com/bb-login.php . i tried permalink settings none , name based, same issue. does uses redirect in bbpress or how can eliminate "double" content , redirect permanently www.? i redirected www.forum.mysite.com forum.mysite.com , achieved eliminate "double" content.
Read more

php - How can I stop spam on my custom forum/blog? -

so have custom built forum & blog system of late has been dealing lot of spam. if wordpress use akismet, if different common platform i'm sure i'd find plugin. there kind of static class can download this? using php. i'd still go akismet, if it. uses outside of wordpress, may have pay fee it, depending on use -- check terms , conditions -- it's option , easy implement in php using api. use api key wordpress. com account access. basically, grab whichever php client library takes fancy -- use alex potsides' php5 library -- plug in key, , it's handful of lines of code. here's bare bones of validation straight 1 of live sites: ... if ($akismet) { $akismet->setcommentauthor($name); $akismet->setcommentauthoremail($session->userinfo["email"]); $akismet->setcommentauthorurl(""); $akismet->setcommentcontent($sentence);...
Read more