php 文件上传类
<?php /** * php 文件上传类 * www.jbxue.com */ class UploadFile { /** * 允许的上传文件类型 * @var array $allowFileTypes * @access private */ private $allowFileTypes = array('jpeg','jpg','gif','bmp','png'); /** * 允许的上传文件大小,单位字节 * @var int $maxFileSize * @access public */ public $maxFileSize = 8388608; /** * 构造函数 */ public function __construct() { } /** * 设置允许的文件类型 * @param mixed $fileTypes 文件类型列表可以是数组和字符串,用“,”号隔开 * @return void * @access public */ public function setAllowFileType($fileTypes) { if (!is_array($fileTypes)) { $this->allowFileTypes = explode(',', $fileTypes); } else { $this->allowFileTypes = $fileTypes; } return; } /** * 上传文件 * @param string $fileField 要上传的文件如$_FILES['file'] * @param string $destFolder 上传的目录,会自动建立 * @param string $fileTypes 上传后文件命名方式0使用原文件名1使用当前时间戳作为文件名 * @return int * @access public */ public function upload($fileField, $destFolder = './', $fileNameType = 1) { switch ($fileField['error']) { case UPLOAD_ERR_OK : //其值为 0,没有错误发生,文件上传成功。 $upload_succeed = true; break; case UPLOAD_ERR_INI_SIZE : //其值为 1,上传的文件超过了 php.ini 中 upload_max_filesize 选项限制的值。 case UPLOAD_ERR_FORM_SIZE : //其值为 2,上传文件的大小超过了 HTML 表单中 MAX_FILE_SIZE 选项指定的值。 $errorMsg = '文件上传失败!失败原因:文件大小超出限制!'; $errorCode = -103; $upload_succeed = false; break; case UPLOAD_ERR_PARTIAL : //值:3; 文件只有部分被上传。 $errorMsg = '文件上传失败!失败原因:文件只有部分被上传!'; $errorCode = -101; $upload_succeed = false; break; case UPLOAD_ERR_NO_FILE : //值:4; 没有文件被上传。 $errorMsg = '文件上传失败!失败原因:没有文件被上传!'; $errorCode = -102; $upload_succeed = false; break; case UPLOAD_ERR_NO_TMP_DIR : //其值为 6,找不到临时文件夹。PHP 4.3.10 和 PHP 5.0.3 引进。 $errorMsg = '文件上传失败!失败原因:找不到临时文件夹!'; $errorCode = -102; $upload_succeed = false; break; case UPLOAD_ERR_CANT_WRITE : //其值为 7,文件写入失败。PHP 5.1.0 引进。 $errorMsg = '文件上传失败!失败原因:文件写入失败!'; $errorCode = -102; $upload_succeed = false; break; default : //其它错误 $errorMsg = '文件上传失败!失败原因:其它!'; $errorCode = -100; $upload_succeed = false; break; } if ($upload_succeed) { if ($fileField['size']>$this->maxFileSize) { $errorMsg = '文件上传失败!失败原因:文件大小超出限制!'; $errorCode = -103; $upload_succeed = false; } if ($upload_succeed) { $fileExt = FileSystem::fileExt($fileField['name']); if (!in_array(strtolower($fileExt),$this->allowFileTypes)) { $errorMsg = '文件上传失败!失败原因:文件类型不被允许!'; $errorCode = -104; $upload_succeed = false; } } } if ($upload_succeed) { if (!is_dir($destFolder) && $destFolder!='./' && $destFolder!='../') { $dirname = ''; $folders = explode('/',$destFolder); foreach ($folders as $folder) { $dirname .= $folder . '/'; if ($folder!='' && $folder!='.' && $folder!='..' && !is_dir($dirname)) { mkdir($dirname); } } chmod($destFolder,0777); } switch ($fileNameType) { case 1: $fileName = date('YmdHis'); $dot = '.'; $fileFullName = $fileName . $dot . $fileExt; $i = 0; //判断是否有重名文件 while (is_file($destFolder . $fileFullName)) { $fileFullName = $fileName . $i++ . $dot . $fileExt; } break; case 2: $fileFullName = date('YmdHis'); $i = 0; //判断是否有重名文件 while (is_file($destFolder . $fileFullName)) { $fileFullName = $fileFullName . $i++; } break; default: $fileFullName = $fileField['name']; break; } //die($destFolder . $fileFullName); $tempfile = str_replace('\\','\',$fileField['tmp_name']); //$files = if (move_uploaded_file($tempfile, $destFolder . $fileFullName)) { return $fileFullName; } else { $errorMsg = $destFolder.$fileFullName." 文件上传失败!失败原因:本地文件系统读写权限出错!"; $errorCode = -105; $upload_succeed = false; } } if (!$upload_succeed) { throw new Exception($errorMsg,$errorCode); } }

The main advantages of using database storage sessions include persistence, scalability, and security. 1. Persistence: Even if the server restarts, the session data can remain unchanged. 2. Scalability: Applicable to distributed systems, ensuring that session data is synchronized between multiple servers. 3. Security: The database provides encrypted storage to protect sensitive information.

Implementing custom session processing in PHP can be done by implementing the SessionHandlerInterface interface. The specific steps include: 1) Creating a class that implements SessionHandlerInterface, such as CustomSessionHandler; 2) Rewriting methods in the interface (such as open, close, read, write, destroy, gc) to define the life cycle and storage method of session data; 3) Register a custom session processor in a PHP script and start the session. This allows data to be stored in media such as MySQL and Redis to improve performance, security and scalability.

SessionID is a mechanism used in web applications to track user session status. 1. It is a randomly generated string used to maintain user's identity information during multiple interactions between the user and the server. 2. The server generates and sends it to the client through cookies or URL parameters to help identify and associate these requests in multiple requests of the user. 3. Generation usually uses random algorithms to ensure uniqueness and unpredictability. 4. In actual development, in-memory databases such as Redis can be used to store session data to improve performance and security.

Managing sessions in stateless environments such as APIs can be achieved by using JWT or cookies. 1. JWT is suitable for statelessness and scalability, but it is large in size when it comes to big data. 2.Cookies are more traditional and easy to implement, but they need to be configured with caution to ensure security.

To protect the application from session-related XSS attacks, the following measures are required: 1. Set the HttpOnly and Secure flags to protect the session cookies. 2. Export codes for all user inputs. 3. Implement content security policy (CSP) to limit script sources. Through these policies, session-related XSS attacks can be effectively protected and user data can be ensured.

Methods to optimize PHP session performance include: 1. Delay session start, 2. Use database to store sessions, 3. Compress session data, 4. Manage session life cycle, and 5. Implement session sharing. These strategies can significantly improve the efficiency of applications in high concurrency environments.

Thesession.gc_maxlifetimesettinginPHPdeterminesthelifespanofsessiondata,setinseconds.1)It'sconfiguredinphp.iniorviaini_set().2)Abalanceisneededtoavoidperformanceissuesandunexpectedlogouts.3)PHP'sgarbagecollectionisprobabilistic,influencedbygc_probabi

In PHP, you can use the session_name() function to configure the session name. The specific steps are as follows: 1. Use the session_name() function to set the session name, such as session_name("my_session"). 2. After setting the session name, call session_start() to start the session. Configuring session names can avoid session data conflicts between multiple applications and enhance security, but pay attention to the uniqueness, security, length and setting timing of session names.


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