What is the php file upload process?

php file upload process: first configure the PHP file and set the front-end form; then save the temporary file in the set directory by default; then judge and process the error attribute in the file array; finally, in the front-end you can Limit the type and size of uploaded files.

The operating environment of this tutorial: Windows 7 system, PHP version 5.6, DELL G3 computer. This method is suitable for all brands of computers.

php file upload process:

1. PHP configuration file

The file uploads section in the php.ini file defines the relevant file upload configuration.

• file_uploads = On Turn on file uploads

• upload_tmp_dir =Temporary directory

• upload_max_filesize = 2M maximum Upload size

• max_file_uploads = 20 Maximum number of files uploaded at a time

2. Front-end form

When using the file When uploading the form of the control, the enctype of the form must be set to "multipart/form-data".

You can limit the size and type of uploaded files on the client side:

3. Background processing

After uploading, you will get a$_FILES on the server sideThe file array is as follows:

The temporary files uploaded to the server are saved by default in the directory set byupload_tmp_dirin php.ini, we need Move the file to the specified location:

        

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4. Error handling

Judge and process the error attribute in the file array:

$error=$myfile['myfile']['error']; if ($error==0){//为0，代表上传成功 if (move_uploaded_file($tmp,"userpic/".$picname)) { echo "移动文件成功"; }else{ echo "移动文件失败"; } }else{//不为0，匹配错误信息 switch ($error){ case 1: echo "超过文件最大上传限制";//php.ini中upload_max_filesize break; case 2: echo "超过表单文件大小限制";//HTML表单中MAX_FILE_SIZE选项 break; case 3: echo "文件部分被上传"; break; case 4: echo "未选择上传文件"; break; case 7://文件写入失败 case 8: echo "系统错误"; break; } }

5. Upload restrictions

On the front end, you can limit the type and size of uploaded files:

Note that the limit is in bytes

There are also response restrictions on the server side:

$size=$myfile['size'];//获取文件大小 $MaxSize=2097152;//设置最大允许字节 $type=$myfile['type'];//获取图片类型 $AllowTypr=array('image/jpeg','image/png','image/gif');//允许类型数组 if ($error==0){//为0，代表上传成功 if ($size>$MaxSize){ echo ""; echo ""; exit(); } if (!in_array($type,$AllowTypr)){ echo ""; echo ""; exit(); }

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