Fileinfo 函数
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finfo_open

finfo::__construct

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

finfo_open -- finfo::__construct — Create a new fileinfo resource

说明

过程化风格

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

面向对象风格 (constructor):

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

This function opens a magic database and returns its resource.

参数

options

One or disjunction of more Fileinfo constants.

magic_file

Name of a magic database file, usually something like /path/to/magic.mime. If not specified, the MAGIC environment variable is used. If this variable is not set either, /usr/share/misc/magic is used by default. A .mime and/or .mgc suffix is added if needed.

Passing NULL or an empty string will be equivalent to the default value.

返回值

(Procedural style only) Returns a magic database resource on success 或者在失败时返回 FALSE.

范例

Example #1 面向对象风格

<?php
$finfo = new finfo(FILEINFO_MIME, "/usr/share/misc/magic"); // return mime type ala mimetype extension

/* get mime-type for a specific file */
$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"); // return mime type ala mimetype extension

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

/* get mime-type for a specific file */
$filename = "/usr/local/something.txt";
echo finfo_file($finfo, $filename);

/* close connection */
finfo_close($finfo);
?>

以上例程会输出：

text/plain; charset=us-ascii

参见

Fileinfo 函数
在线手册：中文 英文
PHP手册
PHP手册 - N: Create a new fileinfo resource

用户评论:

illusivefingers at gmail dot com (06-Feb-2012 08:53)

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!

olivier dot berger at it-sudparis dot eu (09-Mar-2011 08:02)

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

franssen dot roland at gmail dot com (11-May-2010 08:23)

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

mark at dynom dot nl (09-Nov-2008 08:34)

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."

php at brudaswen dot de (15-Sep-2008 11:13)

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.

dario dot borreguero at gmail dot com (16-Apr-2008 11:15)

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.

php at kingsquare dot nl (23-Jan-2008 03:41)

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);
?>

ian at createanet dot co dot uk (02-Nov-2007 04:50)

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

tularis at php dot net (06-May-2007 08:55)

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 \!