File upload and multi-file upload in PHP are like a nightmare for PHP beginners who are just getting started. This article gives you a detailed analysis of PHP Code to implement single file upload and multiple file upload as well as problem solutions. If you don’t understand PHP file upload, please be optimistic! !
$_FILES When is an empty array?
When the form submission enctype is not equal to multipart/form-data, in php.iniConfiguration file, file_uploads = Off The size of the uploaded file> is specified in the php.ini configuration file When the maximum upload size is configured
As long as $_FILES is an empty array, the above problem may occur and must be fixed!
If you click the "Upload Button" immediately without selecting any file, $_FILES will be an array with elements, and each attribute in the element will be empty String, error attribute For 4
##Single file upload
$_FILES data structurearray( 'filename' => array( 'name' => 'xxx.png', 'type' => 'image/png', 'size' => 2548863, 'tmp_name' => '/img/sdsdsd.png', 'error' => 0 ) )
single file Or
Multiple file upload, there will be 5 fixed attributes: name / size / type / tmp_name / error
Multiple file upload
Compared with single file upload, multiplefile upload processing is much more complicated. The two forms of multi-file upload on the front end
//name相同 <form method="post" enctype="multipart/form-data"> <input type="file" name="wt[]"/> <input type="file" name="wt[]"/> <input type="submit" value="提交"/> </form> //name不同(简单点) <form method="post" enctype="multipart/form-data"> <input type="file" name="wt"/> <input type="file" name="mmt"/> <input type="submit" value="提交"/> </form>
$_FILES The corresponding data structures are different
//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
PHP file upload, I hope it will be helpful to everyone! !
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