php对文件进行hash运算的方法_PHP

这段代码非常有用，如果你下载了一个文件，网站提供了hash结果，你可以对你下载下来的文件进行hash运算，以验证下载的文件是否正确。

  
  


 <?php
   if(!empty($_FILES)){
   if ($_FILES["file"]["error"] > 0){
    switch($_FILES["file"]["error"]){
     case 1:
     echo "Error: The uploaded file exceeds the upload_max_filesize directive in php.ini
";
     break;
     case 2:
     echo "Error: The uploaded file exceeds the MAX_FILE_SIZE directive that was specified in the HTML form.
";
     break;
     case 3:
     echo "Error: The uploaded file was only partially uploaded.
";
     break;
     case 4:
     echo "Error: No file was uploaded.
";
     break;
     case 6:
     echo "Error: Missing a temporary folder.
";
     break;
     case 7:
     echo "Error: Failed to write file to disk.
";
     break;
     case 8:
     echo "Error: A PHP extension stopped the file upload.
";
     break;
     default:
     echo "Unknown error occured.
";
    }
   } else {
    echo 'Upload: ' . $_FILES['file']['name'] . '
';
    echo 'Type: ' . $_FILES['file']['type'] . '
';
    echo 'Size: ' . (round($_FILES['file']['size'] / 1024, 2)) . ' Kb

';
    if(array_search($_POST['algo'], hash_algos())===false){
    echo 'Unknown hashing algorithm requested.
';
    } else {
    echo 'Hashing Algorithm: '. $_POST['algo'] . '
';
    $hash = hash_file($_POST['algo'], $_FILES['file']['tmp_name']);
    echo 'Calculated hash: ' . $hash . '
';
    if($_POST['exphash']!=='none' && !empty($_POST['exphash'])){
      echo 'Expected hash:   ' . $_POST['exphash'] . '

';
      echo ($hash==$_POST['exphash'])? 'Hash matched expected value.' : 'Hash did not match expected value.';
      echo '
';
    }
    }
   }
   ?>
   

   Again
    <?php
   } else {
  ?>
  
 <?php
   }
  ?>

希望本文所述对大家的php程序设计有所帮助。