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Analyze the use of $_FILES in PHP and precautions

Analyze the use of $_FILES in PHP and precautions

Updated: July 5, 2013 17:23:11 Author:
$_FILES: A variable submitted to the script via an HTTP POST file upload. Similar to the old array $HTTP_POST_FILES array (still valid, but against use)

The contents of the $_FILES array are as follows:
$_FILES['myFile']['name'] The original name of the client file.
The MIME type of the $_FILES['myFile']['type'] file requires the browser to provide support for this information, such as "image/gif".
$_FILES['myFile']['size'] The size of the uploaded file, in bytes.
$_FILES['myFile']['tmp_name'] The temporary file name stored on the server after the file is uploaded, which is generally the system default. It can be specified in upload_tmp_dir, but setting it with putenv() function does not work.
$_FILES['myFile']['error'] error code related to uploading this file. ['error'] was added in PHP 4.2.0 version.

Here is its description: (They became constants after PHP3.0)
UPLOAD_ERR_OK Value: 0; No error occurred and file upload was successful.
UPLOAD_ERR_INI_SIZE Value: 1; The uploaded file exceeds the value limit of the upload_max_filesize option in .
UPLOAD_ERR_FORM_SIZE Value: 2; The uploaded file size exceeds the value specified by the MAX_FILE_SIZE option in the HTML form.
UPLOAD_ERR_PARTIAL Value: 3; Only partial files are uploaded.
UPLOAD_ERR_NO_FILE Value: 4; No file was uploaded. Value: 5; Upload file size is 0.

Note:
1. After the file is uploaded, it is stored in the temporary directory by default. At this time, it must be deleted from the temporary directory or moved to another place. If not, it will be deleted. That is, regardless of whether the upload is successful or not, the files in the temporary directory will definitely be deleted after the script is executed. Therefore, before deleting, you need to use PHP's copy() function to copy it to another location. Only then can the file upload process be considered complete.

2. Prior to PHP 4.1.0, the array had the name of $HTTP_POST_FILES, which was not an automatic global variable like $_FILES. PHP 3 does not support $HTTP_POST_FILES arrays.

3. When uploading files with form, be sure to add the attribute content enctype="multipart/form-data", otherwise an exception will be reported when using $_FILES[filename] to obtain file information.
<form enctype="multipart/form-data" action="URL" method="post">
<input name="myFile" type="file">
<input type="submit" value="upload file">
</form>

  • PHP
  • $ FILES
  • use

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