Backend DevelopmentPHP TutorialPHP file upload - configure php.ini file and predefined variable $_FILES
php file upload - configure the php.inn file and the predefined variable $_FILES
##File upload can be achieved through the HTTP protocol. To use the file upload function, you must first make some upload settings in the php.ini configuration file, then understand the predefined variable $_FILES, make some restrictions and judgments on the uploaded files through the value of $_FILES, and finally use the move_uploaded_file() function to implement Upload! In the previous article, we introduced file operations, reading and writing, directory processing and advanced applications of file processing. Related articles: 《PHP File Processing-Writing Files And operation files》
《PHP directory processing-open/close directory》
《PHP directory processing-browse directory and operation directory》
《Advanced Application of PHP File Processing-Remote File Access and Locking Files》
《Advanced Application of PHP File Processing-File Pointer》
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Friends, you can check it out. Today we introduce PHP file uploading , predefined variables and configuration php.ini!1: Configure the php.ini file
To successfully implement the upload function, the first thing to do is to open the file in php.ini Upload and make reasonable settings for some parameters. Find the File Upioads item, and you can see that there are 3 attributes below, with the following meanings:- file_uploads: If the value is on, it means that the server supports uploading files; if it is off, it means that it does not support it. .
- upload_tem_dir: Temporary directory for uploading files. Before the file is successfully uploaded, the file is first stored in the temporary directory on the server. If you want to specify the location, you can set it here. Otherwise, just use the system default directory.
- upload_max_filesize: The maximum size of files allowed to be uploaded by the server, in MB. The system default is 2MB, and users can set it by themselves.
- max_execution_time: The maximum time that a command can be executed in PHP, in seconds;
- memory_limit: Allocated by a command in PHP There is no storage space, the unit is MB;
Instructions:
1. If you use the integrated Install the package to configure the PHP development environment. The configuration information described above has been configured by default!
2. If you want to upload very large files, you need to modify some parameters of php.ini, including upload_max_filesize, the maximum value of the files allowed to be uploaded by the server, and max_execution_time, which can be executed by one command. The maximum time and memory_limit memory space allocated by one instruction!
2: Predefined variable $_FLIES##$_FLIES variable stores information related to uploaded files. This information is useful for The upload function is very useful. This variable is a two-dimensional array. The description of the predefined variable $_FILES elements is as follows:
| Element name | Description |
| $_FILE[filename][name] | Save upload The file name of the file. For example: exam.txt, myDream.jpg, etc. |
| $_FILE[filename][size] | stores the file size in bytes. |
| $_FILE[filename][tmp_name] | When the file is uploaded, it is first saved as a temporary file in the temporary directory. This variable is the temporary file name |
| #$_FILE[filename][type] | The type of the uploaded file. |
| $_FILE[filename][error] | Stores the results of uploading files. If the value is 0, it means the file upload is successful. |
The following example creates an upload file field and outputs the uploaded file information through the $_FILES variable. The specific sample code is as follows;
<html>
<body>
<table width="500" border="1" cellpadding="0" cellspacing="0">
<!--上传文件的 form表单，必须有 enctype 属性-->
<form method="post" about="" enctype="multipart/form-data">
<tr>
<td width="150" height="30" align="right" valign="middle">请选择上传文件:</td>
<!--上传文件域，type类型为file-->
<td width="250"><input type="file" name="upfile"></td>
<!-- 提交按钮-->
<td width="100"><input type="submit" name="submit" value="上传"></td>
</tr>
</form>
</table>
</body>
</html>
<?php
header("Content-Type:text/html; charset=utf-8");
if(!empty($_FILES)){ //判断变量$_FILES是否为空
foreach ($_FILES['upfile'] as $name => $value){ //使用 foreach 循环输出上传文件信息的名称和值
echo $name,"=".$value."<br>";
}
}
?>The output result is:
In the next article, we will introduce the file upload function and multi-file upload. Please read the details. "PHP file upload-detailed explanation of the use of move_uploaded_file() function"
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