HTML/PHP多文件上传故障求助：单文件正常多文件报错

尝试用HTML/PHP实现多文件上传，单文件上传功能正常，但多文件上传时$_FILES变量完全无响应，try-catch语句也未捕获到异常，参考大量示例后仍无法解决问题。

HTML代码 #

<form id="NewImages" method="POST" action="../cgi-bin/saveImages.php?action=add">
    <section id="ActionsBar" class ="actions-bar">
        <div class="files-upload">
                <input id="SelectFiles" name="selectfiles[]" type="file" accept="image/*" onchange="previewAll(this)" multiple>
            <label id="FilesLabel" class="form-label">Solo se permiten archivos tipo imagen (jpg|png|bmp|gif)</label>
        </div>
        <div style="display:inline-block; vertcial-align:top;">
            <button id="UploadButton" name="uploadbutton" class="side-button" type="button" onclick="document.getElementById('Add').click()" disabled>Agregar Imagenes</button>             
        </div>
    </section>
    <section id="Preview" class="flex-box">
        <input id="Add" type="submit" style="display:none;">
        <!--  div id="Loader" class="inner-box">-->
        <div id="pBox-0" class="service-box">
            <figure id="pFigure-0">
                <img id="pImage-0" src="../images/icon-house.png" alt="AGR Bienes Raices compra, venta y renta de casas en Querétaro">
            </figure>                   
            <span id="pFile-0" class="file-name">*Nombre del archivo*</span>
            <div id="pDiv-0">
                <div id="pDivInp1-0" class="div-input"><label id="pLabel1-0" class="form-label" for="pFrontPage-0">Mostrar en <abbr id="pAbbr1-0" title="Mostrar en pagina de bienvenida de AGR bienes raices">portada </abbr></label> <input id="pFrontPage-0" type="checkbox" class="form-input"></div>   
                <div id="pDivInp2-0" class="div-input"><label id="pLabel2-0" class="form-label" for="pShowPicture-0">Mostrar en <abbr id="pAbbr2-0" title="Mostrar imágen en el catálogo de AGR bienes raices">catalogo </abbr></label> <input id="pShowPicture-0" type="checkbox" class="form-input"></div>    
                <input id="pOrder-0" type="text" class="form-input-text" placeholder="1,2,3,..">    
                <input id="pExclude-0" type="button" class="no-button" value="Excluir" onclick="excludeBox(0)">
            </div>
        </div>
        <!--  /div>-->
    </section>
</form>

PHP代码（saveImages.php） #

<?php
session_start();
try{
    $action=$_GET["action"];
    include '/home/k3mq6hsrski5/agr/php/loadImage.php';
    $logfile= '/home/k3mq6hsrski5/public_html/users/logs/user-' . date("Y-m-d") . '.log';
    file_put_contents($logfile, date("H:i:s") . "*-- saveImage.php started --*\n", FILE_APPEND);
    $err ="";
    if ($_SERVER["REQUEST_METHOD"] == "POST") {
        if($action == "add")
        {
            $vFile = basename($_FILES["selectfiles"]["name"][0]);
            file_put_contents($logfile, date("H:i:s") . "-- Location:" . $_SESSION["location"] . ", Section:" . $_SESSION["section"] . ", file:$vFile\n", FILE_APPEND);
            $nFiles= count($_FILES['selectfiles']['name']);
            file_put_contents($logfile, date("H:i:s") . "-- Files to read:$nFiles --\n", FILE_APPEND);
            for ($i = 0; $i < $nFiles; $i++) {
                $vFile = basename($_FILES["selectfiles"]["name"][$i]);
                file_put_contents($logfile, date("H:i:s") . "-- Processing file:$vFile --\n", FILE_APPEND);
                if (uploadImg('selectfiles',$vFile,true,$i)!=true){
                    $err .= $_SESSION["err"];
                }
            }
            header("Location: ../actions/images.php?asset=" . $_SESSION['currasset']);
        }
        elseif ($action == "save")
        {
            header("Location: ../actions/catalogue.php");
        }
        else
        {
            header("Location: ../actions/images.php?asset=" . $_SESSION['currasset']);
        }
    }
}
catch (Exception $e)
{
    $_SESSION["err"]= "Program saveImages.php failed and threw an excpetion.";
    $_SESSION["log"]= $e->getMessage();
    header("Location: ../actions/userAck.php?target=/actions/images");    
}
?>

问题排查与解决方案 #

1. 表单缺少关键属性（核心问题） #

文件上传表单必须添加enctype="multipart/form-data"属性，否则服务器无法解析POST请求中的文件数据，导致$_FILES为空。

修正后的

<form id="NewImages" method="POST" action="../cgi-bin/saveImages.php?action=add" enctype="multipart/form-data">

file_put_contents($logfile, date("H:i:s") . "-- \$_FILES content: " . print_r($_FILES, true) . "\n", FILE_APPEND);