为什么zip文件在下载后无法打开但是通过手动传输很好？

Question

I searched and tried a few previous questions/example codes, but couldn't get this to work.

I'm trying to deliver the results to end-users via PHP code. Here is my code.

       $varZipFile = $varBaseNameParts[0] . '.' . $varDate . '.zip';
       $varZipDir = $varBaseNameParts[0] . '_' . $varDate;

       $zip = new ZipArchive();
       $zip->open($varZipFile, ZipArchive::CREATE | ZipArchive::OVERWRITE);
       $zip->addFile('008.csv');
       $zip->addFile('002.csv');
       $zip->close(); // mark line xxx

       header("Content-Type: application/zip");
       header("Content-disposition: attachment;filename=$varZipFile");
       header('Content-Length: ' . filesize($varZipFile)); // with or without this line, got the same error 
       header("Content-Type: application/force-download"); // with or without this line, got the same error 
       readfile($varZipFile);

I got the .zip file in my browser. However WinZip cannot open it, neither can 7-Zip. WinZip complains that "Error: Central directory not found".

Interestingly, when I manually transfer the file via WinSCP from my server to my Windows machine, I can open the file with either WinZip or 7-Zip. This indicates it works all fine to 'mark line xxx', and problems occurs in the header lines.

TIA!

Answer 1

Your ouput buffer may not be cleared before you try to serve the download. Try to clean the output buffer before serving the download with the ob_clean() function like this:

$zip->close(); // mark line xxx
ob_clean();