If you want to copy one file at a time and remove the folder name that is stored in the ZIP file, so you don't have to create directories from the ZIP itself, then use this snippet (basically collapses the ZIP file into one Folder).

<?php

$path = 'zipfile.zip'

$zip = new ZipArchive;
if ($zip->open($path) === true) {
    for($i = 0; $i < $zip->numFiles; $i++) {
        $filename = $zip->getNameIndex($i);
        $fileinfo = pathinfo($filename);
        copy("zip://".$path."#".$filename, "/your/new/destination/".$fileinfo['basename']);
    }                   
    $zip->close();                   
}

?>

* On a side note, you can also use $_FILES['userfile']['tmp_name'] as the $path for an uploaded ZIP so you never have to move it or extract a uploaded zip file.

Cheers!

ProNeticas Dev Team

If you want to extract the files just to the current folder, simply use
$zip->extractTo(".");

It took me hours to figure this out.

The extractTo() method does not offer any parameter to allow extracting files and folders recursively from another (parent) folder inside the ZIP archive. With the following method it is possible:

<?php
  class my_ZipArchive extends ZipArchive
  {
    public function extractSubdirTo($destination, $subdir)
    {
      $errors = array();

      // Prepare dirs
      $destination = str_replace(array("/", "\\"), DIRECTORY_SEPARATOR, $destination);
      $subdir = str_replace(array("/", "\\"), "/", $subdir);

      if (substr($destination, mb_strlen(DIRECTORY_SEPARATOR, "UTF-8") * -1) != DIRECTORY_SEPARATOR)
        $destination .= DIRECTORY_SEPARATOR;

      if (substr($subdir, -1) != "/")
        $subdir .= "/";

      // Extract files
      for ($i = 0; $i < $this->numFiles; $i++)
      {
        $filename = $this->getNameIndex($i);

        if (substr($filename, 0, mb_strlen($subdir, "UTF-8")) == $subdir)
        {
          $relativePath = substr($filename, mb_strlen($subdir, "UTF-8"));
          $relativePath = str_replace(array("/", "\\"), DIRECTORY_SEPARATOR, $relativePath);

          if (mb_strlen($relativePath, "UTF-8") > 0)
          {
            if (substr($filename, -1) == "/")  // Directory
            {
              // New dir
              if (!is_dir($destination . $relativePath))
                if (!@mkdir($destination . $relativePath, 0755, true))
                  $errors[$i] = $filename;
            }
            else
            {
              if (dirname($relativePath) != ".")
              {
                if (!is_dir($destination . dirname($relativePath)))
                {
                  // New dir (for file)
                  @mkdir($destination . dirname($relativePath), 0755, true);
                }
              }

              // New file
              if (@file_put_contents($destination . $relativePath, $this->getFromIndex($i)) === false)
                $errors[$i] = $filename;
            }
          }
        }
      }

      return $errors;
    }
  }
?>

Example:
<?php
  echo "<pre>";

  $zip = new my_ZipArchive();
  if ($zip->open("test.zip") === TRUE)
  {
    $errors = $zip->extractSubdirTo("C:/output", "folder/subfolder/");
    $zip->close();

    echo 'ok, errors: ' . count($errors);
  }
  else
  {
    echo 'failed';
  }
?>

If you want to extract one file at a time, you can use this:

<?php

$path = 'zipfile.zip'

$zip = new ZipArchive;
if ($zip->open($path) === true) {
                    
    for($i = 0; $i < $zip->numFiles; $i++) {
                         
        $zip->extractTo('path/to/extraction/', array($zip->getNameIndex($i)));
                        
        // here you can run a custom function for the particular extracted file
                        
    }
                    
    $zip->close();
                    
}

?>

Please be aware of the fact that using this function has OVERWRITE true.

an old file will be overwritten if the achieve (zipped file) contains file matching the same old file name.

old files that has no match in the zip, will be kept as is.

hopefully the someone will explain how to avoid overwriting old files.

This function will flatten a zip file using the ZipArchive class.  

It will extract all the files in the zip and store them in a single destination directory.  That is, no sub-directories will be created.

If anyone knows a better way to determine if an entry is a directory, please chime in.  I feel dirty checking for a trailing slash.

<?php
// dest shouldn't have a trailing slash
function zip_flatten ( $zipfile, $dest='.' )
{
    $zip = new ZipArchive;
    if ( $zip->open( $zipfile ) ) 
    {
        for ( $i=0; $i < $zip->numFiles; $i++ ) 
        {
            $entry = $zip->getNameIndex($i);
            if ( substr( $entry, -1 ) == '/' ) continue; // skip directories
            
            $fp = $zip->getStream( $entry );
            $ofp = fopen( $dest.'/'.basename($entry), 'w' );
            
            if ( ! $fp ) 
                throw new Exception('Unable to extract the file.');
            
            while ( ! feof( $fp ) ) 
                fwrite( $ofp, fread($fp, 8192) );
            
            fclose($fp);
            fclose($ofp);
        }

                $zip->close();
    }
    else
        return false;
    
    return $zip;
}

/*
Example Usage:

zip_flatten( 'test.zip', 'my/path' );
*/
?>

[EDIT BY danbrown AT php DOT net: Added $zip-close() per indication by original poster in follow-up note on 18-APR-2010.]

// Handling ERROR file by file !!

<?php

$ERROR_UNZIP = false;
$dest = "../";
$zipfile = "test.zip";

$zip = new ZipArchive;

if ($zip->open("$zipfile") === true) {
    
    for ($i = 0; $i < $zip -> numFiles; $i++) {
        $RETVAL = false;

        $filename = $zip->getNameIndex($i);

        $RETVAL = $zip->extractTo($dest,$filename);

        if ($RETVAL) {
            print "$filename ... [ OK ]<br>";
        } else {
            print "$filename ... [ ERROR ]<br>";
            $ERROR_UNZIP = true;
        }
    }

    // close
    $zip -> close();

    // retval
    if ($ERROR_UNZIP) {
        print "<p>ERROR unziping ${zipfile}</p>";
    } else {
        print "<p>Unzip OK</p>";
    }
} else {
    print "<p>ERROR opening ${zipfile}</p>";
}

?>

Please note that the path can not be to long! I am not sure what the maximum length is, didnt find any information about that. But i kept getting issues when using extractTo().

Than after google i found this little comment: https://github.com/composer/composer/issues/2824#issuecomment-308201902

CopyPasted comment:
===
I had this path in my machine:

C:/xampp5.0/htdocs/project-recordando-symfony/project-recordando-symfony
Then I ran composer install or/and composer update and it returned this error:

ErrorException ZipArchive::extractTo...

That error is because your path is too much long, I changed to:

C:/xampp5.0/htdocs/p-symfony/*
and worked!
===

<?php 
    
    // This version allows to see which file will be decompressed and to keep 
    // a follow-up on decompression

    define( 'FILEPATH',     dirname(__FILE__)     . '\\' );
    define( 'TEST',         FILEPATH             . 'test\\' );

$za = new ZipArchive();

$za->open(FILEPATH . 'test.zip');
print_r($za);
var_dump($za);
echo "Nombre de fichiers : " . $za->numFiles . "\n";
echo "Statut : " . $za->status  . "\n";
echo "Statut du système : " . $za->statusSys . "\n";
echo "Nom du fichier : " . $za->filename . "\n";
echo "Commentaire : " . $za->comment . "\n";

/*  in $za->statIndex($i)

    [name] => data/x.luac
    [index] => 451
    [crc] => -1266183263
    [size] => 2936
    [mtime] => 1464790482
    [comp_size] => 976
    [comp_method] => 8
*/

for ($i=0; $i<$za->numFiles;$i++) {
    echo "index : $i\n";
    $name = $za->statIndex($i)['name'];
    $size = $za->statIndex($i)['size'];
    $comp_size = $za->statIndex($i)['comp_size'];
    print_r($name . ' [ ' . $size . '>' . $comp_size . ']' );
    $za->extractTo(TEST,$name);
}
echo "Nombre de fichiers :" . $za->numFiles . "\n";    

?>

This script will search for ".txt" file(any file name) inside test.zip archive. Suppose, 'example.txt' file is found then the script will copy 'example.txt' to "txt_files" directory and rename it to 'test.zip.txt' and will remove all the blank lines from 'test.zip.txt' and resave and will exit the loop without searching remaining entries. 
This script can be useful to extract .DIZ and GIF files to display ZIP archive details in your script.
<?php 
   $value="test.zip"; 
   $filename="zip_files/$value"; 
   $zip = new ZipArchive;
     if ($zip->open($filename) === true) {
      echo "Generating TEXT file.";
          for($i = 0; $i < $zip->numFiles; $i++) { 
             $entry = $zip->getNameIndex($i);
               if(preg_match('#\.(txt)$#i', $entry))
                {
                ////This copy function will move the entry to the root of "txt_files" without creating any sub-folders unlike "ZIP->EXTRACTO" function.
                copy('zip://'.dirname(__FILE__).'/zip_files/'.$value.'#'.$entry, 'txt_files/'.$value.'.txt'); 
                $content = file_get_contents("txt_files/$value.txt");
                $newcontent = preg_replace("/(^[\r\n]*|[\r\n]+)[\s\t]*[\r\n]+/", "\n", $content);
                file_put_contents("txt_files/$value.txt", "$newcontent");
                break;
                } 
              }  
             $zip->close();
            }
    else{
         echo "ZIP archive failed";
        }
?>

enjoy PHP programming.
Sachin Yadav

This function, at least from my experience, maintains/forces the directory structure within the ZIP file.

ie. if you have FOLDER1/File1.txt in the zip file and you use
$zip->extractTo('/extract', 'FOLDER1/File1.txt');
the location of the extracted file will be:
/extract/FOLDER1/File1.txt

Note, in Linux (possibly other *nix platforms too) there is no way to extract hidden files ( aka filename starting with a '.') from a Zip archive.

Para casos donde sea necesario descomprimir archivos sin saber si el nombre está en mayúsculas o minúsculas:

$zip = new ZipArchive;
if ($zip->open('myfile.zip') === TRUE) {
    //no funciona
    //$zip->extractTo('./', array( 'file1.XML', 'file1.xml'));
    //funciona
    $zip->extractTo('./', 'file1.XML' );
    $zip->extractTo('./', 'file1.xml' );
    $zip->close();
}

WARNING!!!!

if you are running php under Apache, a .htaccess file inside the zip file may fail the extractTo() method.

I found it useful to add this to a function.

<?php
/**
*  Extracts a ZIP archive to the specified extract path
*
*  @param string $file The ZIP archive to extract (including the path)    
*  @param string $extractPath The path to extract the ZIP archive to
*
*  @return boolean TURE if the ZIP archive is successfully extracted, FALSE if there was an errror 
*  
*/
function zip_extract($file, $extractPath) {

    $zip = new ZipArchive;
    $res = $zip->open($file);
    if ($res === TRUE) {
        $zip->extractTo($extractPath);
        $zip->close();
        return TRUE;
    } else {
        return FALSE;
    }

} // end function
?>