原生js下载服务器文件，js和php分别怎么写

Question

原生js下载服务器文件要怎么写呢，js需要怎么写，php里面又应该怎么弄，我自学，搞不明白，有没有朋友帮我写个例子，万分感谢。

Answer 1

您可以在前端使用Ajax请求下载服务器文件。

JavaScript：

var xhr = new XMLHttpRequest();
xhr.open("GET", "/download-file", true);
xhr.responseType = "blob";
xhr.onload = function () {
    if (this.status === 200) {
        var blob = new Blob([this.response], {type: "application/octet-stream"});
        var link = document.createElement("a");
        link.href = window.URL.createObjectURL(blob);
        link.download = "file.txt";
        link.click();
    }
};
xhr.send();

PHP:

<?php
if (isset($_GET['download-file'])) {
    $file = "file.txt";
    header("Content-Type: application/octet-stream");
    header("Content-Disposition: attachment; filename=" . urlencode($file));   
    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); 
}

这个例子可以帮助您理解原理。希望对您有所帮助！