finfo_open

finfo::__construct

(PHP >= 5.3.0, PECL fileinfo >= 0.1.0)

finfo_open -- finfo::__construct — 创建一个 fileinfo 资源

说明

过程化风格

resource finfo_open ([ int $options = FILEINFO_NONE [, string $magic_file = NULL ]] )

面向对象风格（构造器）：

public finfo::__construct ([ int $options = FILEINFO_NONE [, string $magic_file = NULL ]] )

本函数打开一个魔数数据库并且返回它的资源。

参数

options

一个 Fileinfo 常量或多个 Fileinfo 常量进行逻辑或运算。

magic_file

魔数数据库文件名称，通常是 /path/to/magic.mime。如果未指定，则使用 MAGIC 环境变量。如果未指定此环境变量，则使用 PHP 绑定的魔数数据库。

传入 NULL 或者空字符串，等同于使用默认值。

返回值

（仅适用于过程化风格）如果成功则返回一个表示魔数数据库的资源，或者在失败时返回 FALSE 。

注释

Warning

在 PHP 5.3.11 和 5.4.1 中预期的魔数数据库格式发生了变动，所以，内置的魔数数据库被更新。如果使用了外部魔数数据库，可能会由于格式不同导致读取失败。同时，一些 mime 类型的文字表示也发生了变化，例如，PHP 文件的 mime 类型由 “"PHP script text” 变为“PHP script, ASCII text”。

Note:

通常来说，使用 PHP 绑定的魔数数据库（设置 magic_file 参数为空，不设置 MAGIC 环境变量）是最好的选择，除非你确实需要一个自定义的魔数数据库。

范例

Example #1 面向对象风格

  <?php
$finfo  = new  finfo ( FILEINFO_MIME ,  "/usr/share/misc/magic" );  // 返回 mime 类型


 $filename  =  "/usr/local/something.txt" ;
echo  $finfo -> file ( $filename );

 ?>

Example #2 过程化风格

  <?php
$finfo  =  finfo_open ( FILEINFO_MIME ,  "/usr/share/misc/magic" );  // 返回 mime 类型

 if (! $finfo ) {
    echo  "Opening fileinfo database failed" ;
    exit();
}

 
 $filename  =  "/usr/local/something.txt" ;
echo  finfo_file ( $finfo ,  $filename );

 
 finfo_close ( $finfo );
 ?>

以上例程会输出：

text/plain; charset=us-ascii

参见

finfo_close() - 关闭 fileinfo 资源

用户评论:

[#1] Anonymous [2013-07-04 19:41:50]

For most common image files:
<?php function minimime($fname) { $fh=fopen($fname,'rb'); if ($fh) { $bytes6=fread($fh,6); fclose($fh); if ($bytes6===false) return false; if (substr($bytes6,0,3)=="\xff\xd8\xff") return 'image/jpeg'; if ($bytes6=="\x89PNG\x0d\x0a") return 'image/png'; if ($bytes6=="GIF87a" || $bytes6=="GIF89a") return 'image/gif'; return 'application/octet-stream'; } return false; } ?>

[#2] illusivefingers at gmail dot com [2012-02-06 00:53:36]

I am running Windows 7 with Apache. It took hours to figure out why it was not working.

First, enable the php_fileinfo.dll extension in you php.ini. You'll also need the four magic files that are found in the following library:

http://sourceforge.net/projects/gnuwin32/files/file/4.23/file-4.23-bin.zip/download

An environment variable or a direct path to the file named "magic" is necessary, without any extension.

Then, make sure that xdebug is either turned off or set the ini error_reporting to not display notices or warnings for the script.

Hope this saves someone a few hours of frustration!

[#3] olivier dot berger at it-sudparis dot eu [2011-03-09 12:02:24]

On my Debian squeeze system, the path needed is like :
<?php $finfo = new finfo(FILEINFO_MIME, "/usr/share/misc/magic.mgc"); ?>

[#4] franssen dot roland at gmail dot com [2010-05-11 00:23:30]

Notice FileInfo::__construct() has strange behavior in PHP < 5.3.1 when a 2nd parameter is set explicitly, e.g.;

<?php $fileInfo = new finfo(FILEINFO_MIME, null); ?>

Expected result:
----------------
object(finfo)#2 (0) { }

Actual result:
--------------
Warning: finfo::finfo(): Failed to load magic database at ''. in *** on line ***
object(finfo)#2 (0) { }

See http://bugs.php.net/bug.php?id=51732

[#5] mark at dynom dot nl [2008-11-09 12:34:08]

It seems there is quite some inconsistency in distributions and loading of magic files.

On Archlinux, the file is located here:
/usr/share/misc/file/magic.mgc

But this:

<?php $fi = new finfo(FILEINFO_MIME, '/usr/share/misc/file/magic'); $fi->file('/tmp/fubar.txt'); ?>

Actually segfaults, where if I type the full name (including the file extension:)

<?php $fi = new finfo(FILEINFO_MIME, '/usr/share/misc/file/magic.mgc'); // added ".mgc" $fi->file('/tmp/fubar.txt'); ?>

It works as expected, so I guess something goes wrong with "A .mime and/or .mgc suffix is added if needed."

[#6] php at brudaswen dot de [2008-09-15 03:13:53]

Since it costed me some time to find the needed magic database files for Windows, just a hint:

The last release of the GnuWin32 project with both needed files (magic and magic.mime) currently was "file-4.23".
All releases after 4.23 to 4.25-1 did not contain both needed files.

Hope that helps.

[#7] dario dot borreguero at gmail dot com [2008-04-16 03:15:42]

Platform: WinXP-SP2, PHP5.2.5, MySQL 5.0, Apache 2.2.8

After reading former notes, I wasn't able to load my magic database: 'magic.mime' file (donwloaded from GnuWin32 project, zipped with the binary files v4.21). I always got an invalid $finfo object or finfo_open(...) returned FALSE.

In order to be able to load the 'magic.mime' file, Fileinfo library (bundled in PHP5.2.5) also requires 'magic' file.

For example:
1. Database:
  c:\php\magic.mime
  c:\php\magic

2. PHP Code:
<?php   $filname = 'c:\php\php.ini';   $finfo = new finfo(FILEINFO_MIME, 'c:\php\magic');   if (!$finfo) return false;   echo $finfo->file($filename); ?>

For further info see: http://pecl.php.net/bugs/bug.php?id=7555

Pay attention to comments added by 'christophe dot charron dot xul at gmail dot com'

NOTE: Before upgrading to PHP5.2.5, I was working with PHP5.2.1 and it only required 'magic.mime' file.

[#8] php at kingsquare dot nl [2008-01-23 07:41:40]

The current version (1.04) doesnt support a different mime.magic database than the server default.

(the documentation is thus not correct)
Ubuntu default location is '/usr/share/file/magic'. In order for the examples to work all finfo_open()-commands must be issued with the extra location accordingly:
<?php $file = "/path/to/file.jpg"; $handle = finfo_open(FILEINFO_MIME, '/usr/share/file/magic'); $mime_type = finfo_file($handle,$file); ?>

[#9] ian at createanet dot co dot uk [2007-11-02 08:50:55]

Couldn't get finfo to return the mimetype in the way expected so i made a function to do it with system()

<?php function get_mime_type($filepath) { ob_start(); system("file -i -b {$filepath}"); $output = ob_get_clean(); $output = explode("; ",$output); if ( is_array($output) ) { $output = $output[0]; } return $output; } ?>

hope it works for other people too

[#10] tularis at php dot net [2007-05-06 12:55:55]

On Windows systems people might find that this always returns "application/x-dpkg".
There are 2 ways of solving this problem:
1. Get the mime-magic database file from GnuWin32 at <http://sourceforge.net/projects/gnuwin32/>
2. You can manually "fix" the mime-magic file by editing it and escaping all lines starting with !, thus changing each one to \!