php对文件进行hash运算的方法
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>
<styletype='text/css'>
#ok{color:green;}
#nono{color:red;}
</style>
</head>
<body>
<?php
if(!empty($_FILES)){
if($_FILES["file"]["error"]>0){
switch($_FILES["file"]["error"]){
case1:
echo"<bid='nono'>Error:Theuploadedfileexceedstheupload_max_filesizedirectiveinphp.ini</b><br>";
break;
case2:
echo"<bid='nono'>Error:TheuploadedfileexceedstheMAX_FILE_SIZEdirectivethatwasspecifiedintheHTMLform.</b><br>";
break;
case3:
echo"<bid='nono'>Error:Theuploadedfilewasonlypartiallyuploaded.</b><br>";
break;
case4:
echo"<bid='nono'>Error:Nofilewasuploaded.</b><br>";
break;
case6:
echo"<bid='nono'>Error:Missingatemporaryfolder.</b><br>";
break;
case7:
echo"<bid='nono'>Error:Failedtowritefiletodisk.</b><br>";
break;
case8:
echo"<bid='nono'>Error:APHPextensionstoppedthefileupload.</b><br>";
break;
default:
echo"<bid='nono'>Unknownerroroccured.</b><br>";
}
}else{
echo'Upload:'.$_FILES['file']['name'].'<br>';
echo'Type:'.$_FILES['file']['type'].'<br>';
echo'Size:'.(round($_FILES['file']['size']/1024,2)).'Kb<br><br>';
if(array_search($_POST['algo'],hash_algos())===false){
echo'Unknownhashingalgorithmrequested.<br>';
}else{
echo'HashingAlgorithm:'.$_POST['algo'].'<br>';
$hash=hash_file($_POST['algo'],$_FILES['file']['tmp_name']);
echo'Calculatedhash:'.$hash.'<br>';
if($_POST['exphash']!=='none'&&!empty($_POST['exphash'])){
echo'Expectedhash: '.$_POST['exphash'].'<br><br>';
echo($hash==$_POST['exphash'])?'<bid="ok">Hashmatchedexpectedvalue.</b>':'<bid="nono">Hashdidnotmatchexpectedvalue.</b>';
echo'<br>';
}
}
}
?>
<br>
<buttononClick="document.location.reload(true)">Again</button>
<?php
}else{
?>
<formaction=""method="post"enctype="multipart/form-data">
<inputtype="hidden"name="exphash"value="none">
<labelfor="file">Filename:</label>
<inputtype="file"name="file"id="file">
<inputtype="submit"name="submit"value="Submit"/><br>
<label>Expectedhash(optional):<inputtype="text"name="exphash"size="100"></label>
<br><br>Chooseanalgorithm(Thisisthelistofalltheavailablealgorithmsinyourphpinstallation)<br>
<?php
foreach(hash_algos()as$algo){
if($algo=='md5'){
echo"<label><inputtype='radio'name='algo'value='$algo'checked='checked'>$algo</label><br>";
}else{
echo"<label><inputtype='radio'name='algo'value='$algo'>$algo</label><br>";
}
}
?>
</form>
<?php
}
?>
</body>
</html>
希望本文所述对大家的php程序设计有所帮助。