PHP single file and multiple file upload examples explained-PHP Tutorial-php.cn

This article gives you a detailed analysis of the code and problem solutions for single file upload and multi-file upload in PHP. Let’s learn and refer to it together.

$_FILES When is an empty array?

When the form submission enctype is not equal to multipart/form-data in the php.ini configuration file, file_uploads = Off and the uploaded file size > the maximum upload size configured in the php.ini configuration file

As long as $_FILES is an empty array, the above problems may occur and must be fixed!

If you click the "Upload Button" immediately without selecting any file, $_FILES will be an array with elements. Each attribute in the element is an empty string, and the error attribute is 4

Single file upload

##$_FILES data structure

array( 'filename' => array( 'name' => 'xxx.png', 'type' => 'image/png', 'size' => 2548863, 'tmp_name' => '/img/sdsdsd.png', 'error' => 0 ) )

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Whether it is

Single fileorMultiple file upload, there will be 5 fixed attributes: name / size / type / tmp_name / error

Multiple file upload

Compared with single file upload, multi-file upload is much more complicated to process. The two forms of multi-file upload on the front end

//name相同     
 //name不同（简单点）

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The back-end

$_FILEScorresponds to different data structures

//name相同 array (size=1) 'wt' => array (size=5) 'name' => array (size=2) 0 => string '新建文本文档 (2).txt' (length=26) 1 => string '新建文本文档.txt' (length=22) 'type' => array (size=2) 0 => string 'text/plain' (length=10) 1 => string 'text/plain' (length=10) 'tmp_name' => array (size=2) 0 => string 'C:\Windows\php1D64.tmp' (length=22) 1 => string 'C:\Windows\php1D65.tmp' (length=22) 'error' => array (size=2) 0 => int 0 1 => int 0 'size' => array (size=2) 0 => int 0 1 => int 1820 //name不同（简单点） array (size=2) 'wt' => array (size=5) 'name' => string '新建文本文档 (2).txt' (length=26) 'type' => string 'text/plain' (length=10) 'tmp_name' => string 'C:\Windows\php39C7.tmp' (length=22) 'error' => int 0 'size' => int 0 'mmt' => array (size=5) 'name' => string '新建文本文档.txt' (length=22) 'type' => string 'text/plain' (length=10) 'tmp_name' => string 'C:\Windows\php39D8.tmp' (length=22) 'error' => int 0 'size' => int 1820

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Field Error purpose

Value: 1 The uploaded file exceeds the value limited by the upload_max_filesize option in php.ini.

Value: 2 The size of the uploaded file exceeds the value specified by the MAX_FILE_SIZE option in the HTML form.

Value: 3 The file was only partially uploaded.

Value: 4 No files were uploaded. Value: 5 The upload file size is 0.

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