PHP single file and multiple file upload examples_php examples

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 structure

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

Whether it is a

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, multiple

file 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>

The back end

$_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

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 uploaded file size is 0.

The above is all the content of

PHP file upload, I hope it will be helpful to everyone! !

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