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File upload PHP function: move_uploaded_file(): Move the uploaded file file_exists(): Check whether the file exists is_uploaded_file(): Check whether the file is uploaded through HTTP POST getimagesize(): Get the size and type of the image file mime_content_type(): Get the MIME type of the file
Application of PHP function in file upload
File upload is a common function in Web development. PHP provides a variety of functions to easily handle file upload tasks.
Function
Practical Case: File Upload Script
We create a simple script that allows users to upload image files.
<?php // 检查文件是否存在 if (isset($_FILES["image"])) { // 检查文件大小 if ($_FILES["image"]["size"] > 2097152) { echo "文件过大,请上传小于 2MB 的图像。"; } else { // 获取图像信息 $imageInfo = getimagesize($_FILES["image"]["tmp_name"]); // 验证图像类型 if ($imageInfo[0] > 1920 || $imageInfo[1] > 1920) { echo "图像尺寸太大,请上传小于 1920x1920 的图像。"; } else if (!in_array($imageInfo[2], [IMAGETYPE_JPEG, IMAGETYPE_PNG])) { echo "图像格式不支持,请上传 JPEG 或 PNG 格式的图像。"; } else { // 获取 MIME 类型 $mimeType = mime_content_type($_FILES["image"]["tmp_name"]); // 移动文件 if (move_uploaded_file($_FILES["image"]["tmp_name"], "uploads/" . $_FILES["image"]["name"])) { echo "图像上传成功。"; } else { echo "图像上传失败。"; } } } } ?>
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