warning feof()期望参数1是资源

Question

我的错误日志失控,出现以下两个错误

warning feof() expects parameter 1 to be resource

和

warning fread() expects parameter 1 to be resource

负责的代码是

<?php
    $file = '../upload/files/' . $filex;
    header("Content-Disposition: attachment; filename=" . urlencode($file));
    header("Content-Type: application/force-download");
    header("Content-Type: application/octet-stream");
    header("Content-Type: application/download");
    header("Content-Description: File Transfer");
    header("Content-Length: " . filesize($file));
    flush(); // this doesn't really matter.

    $fp = fopen($file, "r");
    while (!feof($fp)) {
        echo fread($fp, 65536);
        flush(); // this is essential for large downloads
    }
    fclose($fp);
?> 

我使用这个代码进行标题下载,但它现在吓坏了 - 在任何人询问我尝试过之前,我试过google但仍然不完全理解错误消息.

Answer 1

fopen失败并返回false.false不是资源,因此是警告.

在将其作为类似资源的参数注入之前,最好测试$ fp:

if(($fp = fopen($file, "r"))) {
    [...]
}