How to write php file upload code

How to write the php file upload code

When we first learned php, we couldn’t understand the php file upload code , as well as the upload logic, the following code is written from a beginner's perspective, I hope it will be helpful to everyone!

Required knowledge:

Super global array: the value of $_FILES

$_FILES['myfile']['name'] Is: The file name of the client file system

$_FILES['myfile']['type'] The value is: The file type passed by the client

$_FILES['myfile'] The value of ['size'] is: the byte size of the file

The value of $_FILES['myflie']['tmp_name '] is: the temporary full path stored on the server after the file is uploaded

$_FILES['myfile']['error'] is: the error code of file upload

The value stored in $_FILES['myfile']['error']

A value of 0: indicates that no error occurred.

A value of 1: indicates that the size of the uploaded file exceeds the agreed value. The maximum file size is specified in the PHP configuration file. The instruction is: upload_max_filesize

The value is 2: Indicates that the uploaded file size exceeds the maximum value specified by the MAX_FILE_SIZE element of the HTML form hidden field attribute

A value of 3: Indicates that the file was only partially uploaded

A value of 4: Indicates that no files were uploaded

A value of 6: Indicates that the temporary folder cannot be found

The value is 7: Indicates that the file writing failed.

The error value corresponds to the constant

UPLOAD_ERR_OK: The corresponding value is 0

UPLOAD_ERR_INI_SIZE: The corresponding value is 1

UPLOAD_ERR_FORM_SIZE: Corresponding value 2

UPLOAD_ERR_PARTIAL: Corresponding value 3

UPLOAD_ERR_NO_FILE: Corresponding value 4

UPLOAD_ERR_NO_TMP_DIR: Corresponding value 6

UPLOAD_ERR_CANT_WRITE: Corresponding Value 7

upload.html The code is as follows

upload.php The code is as follows

 1024 * 1024 * 8) //以字节为主 1024*1024是1M { exit('上传的文件太大'); } //设置新文件名 $filename = date('YmdHis',strtotime('now')).rand(1000,9999); //获取上传文件的后缀名 $name = $file['pic']['name']; //得到文件名字符串 $filestr = explode('.',$name); $ext = array_pop($filestr); //拼接新文件名 $newfilename = $filename.'.'.$ext; //拼接上传文件的路径 $path = './uploads/'; //绝对路径 $abspath = $path.$newfilename; if(move_uploaded_file($file['pic']['tmp_name'],$abspath)) { echo '上传成功'; }else{ echo '上传失败'; } }

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