使用ajax请求访问文件后如何删除文件？

Question

我将我的站点文件保存在 ftp 服务器中。在以下代码中，用户可以通过 ajax 请求访问 ftp 文件。

HTML

<a onclick="attach('354.tif')"><i class="fa fa-paperclip" aria-hidden="true"></i></a>

JavaScript

function attach(fileLink) {
var xmlhttp = new XMLHttpRequest();
var ajaxResponse;
xmlhttp.onreadystatechange = function() {
    if (this.readyState == 4 && this.status == 200) {
        ajaxResponse = this.responseText;
        var response = JSON.parse(ajaxResponse);
        if(response.location){
            window.location.href = response.location;
        }
    }
};
xmlhttp.open("GET", "/ajax/ftp-download.php?q=" + fileLink, true);
xmlhttp.send();
}

ftp-download.php

<?php
define('__ROOT__',dirname(dirname(__FILE__)));
require_once __ROOT__.'/config/ftpconfig.php'; 
require_once __ROOT__.'/functions/file-process/tiff-to-pdf.php';    
$ftp_file = '/'.$_REQUEST["q"];
$ftp_file_ext = pathinfo($ftp_file, PATHINFO_EXTENSION);

// set up basic connection
$conn_id = ftp_connect($ftp_server, $ftp_port) or die(err_handler(ftp_connect_error)); 

// login with username and password
$login_result = ftp_login($conn_id, $ftp_user_name, $ftp_user_pass);
ftp_pasv($conn_id, true);

$downloaded_file = $_SERVER['DOCUMENT_ROOT']."/user-files/".mt_rand(1000, 999999).".".$ftp_file_ext;

// try to download $ftp_file and save to $local_file
if (ftp_get($conn_id, $downloaded_file, $ftp_file, FTP_BINARY)) {
    if (strcasecmp($ftp_file_ext,"tif") == 0 or strcasecmp($ftp_file_ext,"tiff") == 0) {
        $output_file = "/user-files/".convert_tif_to_pdf($downloaded_file);     
    } else {
        $output_file = "/user-files/".basename($downloaded_file).PHP_EOL;
    }
    header('Content-Type: application/json');
    echo json_encode(['location'=>$output_file]);
} 
// close the connection
ftp_close($conn_id);
?>

我想知道在用户访问文件后是否可以删除 $downloaded_file 和 $output_file？

谢谢。

Answer 1

您无需将文件保存到网络服务器上的临时物理文件中。

您可以直接发送给客户端。

见Download file via PHP script from FTP server to browser with Content-Length header without storing the file on the web server。

Answer 2

谢谢马丁，终于我在你的帮助下解决了我的问题。 我想分享我的代码，也许它会帮助其他人。

使用以下代码，您可以从 ftp 服务器下载文件，并使用 PHP Imagick 类将非 PDF 文件转换为 PDF 并在浏览器窗口中查看文件

HTML 元素

<a onclick="attach('354.tif')"><i class="fa fa-paperclip" aria-hidden="true"></i></a>

<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.4.1/jquery.min.js"></script>
<!-- jQuery Modal -->
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.0.0/jquery.min.js"></script>
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/jquery-modal/0.9.1/jquery.modal.min.css" />

新建 ftp-download.php 文件

<?php

    $ftp_file = "/".$_REQUEST["q"];
    $ftp_file_ext = pathinfo($ftp_file, PATHINFO_EXTENSION);

    $pdfFile = get_ftpfile_blob($ftp_file);


    if (strcasecmp($ftp_file_ext, 'pdf') != 0) {
        $pdfFile = convert_tif_to_pdf($pdfFile);    
    }

function get_ftpfile_blob($file) {

    require_once $_SERVER['DOCUMENT_ROOT'].'/config/ftpconfig.php'; // this file contain ftp configuration

        $conn_id = ftp_connect($ftp_server, $ftp_port); 
        ftp_login($conn_id, $ftp_user_name, $ftp_user_pass);
        ftp_pasv($conn_id, true);

        ob_start();
        $result = ftp_get($conn_id, "php://output", $file, FTP_BINARY);
        $data = ob_get_contents();
        ob_end_clean();

        ftp_close($conn_id);

        if ($result) {
            return $data;
        } else {
            die('');
        }
}

function convert_tif_to_pdf($inputFile) {
    $document = new Imagick();
    $document->readImageBlob($inputFile);
    $document->setFormat("pdf");
    return $document->getImagesBlob();  
}

    echo base64_encode($pdfFile);
    die();
?>

新 jquery

function attach(fileLink) {
    $.get("/ajax/ftp-download.php", 
        {
            q: fileLink
        } , 
        function(data){
            // Display the returned data in browser
            if (data == "") {
                var modalWindow = '<div id="saveMsg" class="modal">' +
                                  '<p>File Not Found!</p>' +
                                  '<a href="#" rel="modal:close"></a>' +
                                  '</div>';
                $('body').append(modalWindow);
                $('#saveMsg').modal({fadeDuration: 100});
                return;
            }
            var link = document.createElement('a');
            link.href = 'data:application/pdf;base64,' + data;
            document.body.appendChild(link);
            window.open(link);
        }
    );
}