php对文件进行hash运算的方法

2024-05-04 22:37:51

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本文实例讲述了php对文件进行hash运算的方法。分享给大家供大家参考。具体如下：

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。

<html><head>  <title>Hash (Check) Files</title>  <style type='text/css'>   #ok{color:green;}   #nono{color:red;}  </style></head><body> <?php   if(!empty($_FILES)){   if ($_FILES["file"]["error"] > 0){    switch($_FILES["file"]["error"]){     case 1:     echo "<b id='nono'>Error: The uploaded file exceeds the upload_max_filesize directive in php.ini</b><br>";     break;     case 2:     echo "<b id='nono'>Error: The uploaded file exceeds the MAX_FILE_SIZE directive that was specified in the HTML form.</b><br>";     break;     case 3:     echo "<b id='nono'>Error: The uploaded file was only partially uploaded.</b><br>";     break;     case 4:     echo "<b id='nono'>Error: No file was uploaded.</b><br>";     break;     case 6:     echo "<b id='nono'>Error: Missing a temporary folder.</b><br>";     break;     case 7:     echo "<b id='nono'>Error: Failed to write file to disk.</b><br>";     break;     case 8:     echo "<b id='nono'>Error: A PHP extension stopped the file upload.</b><br>";     break;     default:     echo "<b id='nono'>Unknown error occured.</b><br>";    }   } else {    echo 'Upload: ' . $_FILES['file']['name'] . '<br>';    echo 'Type: ' . $_FILES['file']['type'] . '<br>';    echo 'Size: ' . (round($_FILES['file']['size'] / 1024, 2)) . ' Kb<br><br>';    if(array_search($_POST['algo'], hash_algos())===false){    echo 'Unknown hashing algorithm requested.<br>';    } else {    echo 'Hashing Algorithm: '. $_POST['algo'] . '<br>';    $hash = hash_file($_POST['algo'], $_FILES['file']['tmp_name']);    echo 'Calculated hash: ' . $hash . '<br>';    if($_POST['exphash']!=='none' && !empty($_POST['exphash'])){      echo 'Expected hash:   ' . $_POST['exphash'] . '<br><br>';      echo ($hash==$_POST['exphash'])? '<b id="ok">Hash matched expected value.</b>' : '<b id="nono">Hash did not match expected value.</b>';      echo '<br>';    }    }   }   ?>   <br>   <button onClick="document.location.reload(true)">Again</button>    <?php   } else {  ?>  <form action="" method="post" enctype="multipart/form-data">   <input type="hidden" name="exphash" value="none">   <label for="file">Filename:</label>   <input type="file" name="file" id="file">   <input type="submit" name="submit" value="Submit" /><br>   <label>Expected hash(optional): <input type="text" name="exphash" size="100"></label>   <br><br>Choose an algorithm (This is the list of all the available algorithms in your php installation)<br>   <?php   foreach(hash_algos() as $algo){    if($algo=='md5'){    echo "<label><input type='radio' name='algo' value='$algo' checked='checked'>$algo</label><br>";    } else {    echo "<label><input type='radio' name='algo' value='$algo'>$algo</label><br>";    }   }   ?>  </form> <?php   }  ?></body></html>

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