PHP - Manual: finfo_open

2024-12-22

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finfo_open

finfo::__construct

(PHP >= 5.3.0, PHP 7, PHP 8, PECL fileinfo >= 0.1.0)

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

说明

过程化风格

finfo_open(int $options = FILEINFO_NONE, string $magic_file = null): resource

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

警告

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”。

注意:
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

示例 #1 面向对象风格


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

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

?>

示例 #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();
}

/* 获取指定文件的 mime 类型 */
$filename = "/usr/local/something.txt";
echo finfo_file($finfo, $filename);

/* 关闭资源 */
finfo_close($finfo);
?>

以上例程会输出：

text/plain; charset=us-ascii

参见

finfo_close() - 关闭 fileinfo 资源

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User Contributed Notes 10 notes

down

Anonymous ¶

8 years ago


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;
}
?>

down

illusivefingers at gmail dot com ¶

10 years ago


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!

down

php at brudaswen dot de ¶

13 years ago


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.

down

olivier dot berger at it-sudparis dot eu ¶

11 years ago


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

down

ian at createanet dot co dot uk ¶

14 years ago


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

down

dario dot borreguero at gmail dot com ¶

14 years ago


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.

down

php at kingsquare dot nl ¶

14 years ago


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);
?>

down

-1

mark at dynom dot nl ¶

13 years ago


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."

down

-4

tularis at php dot net ¶

15 years ago


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 \!

down

-8

franssen dot roland at gmail dot com ¶

12 years ago


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

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官方地址：https://www.php.net/manual/en/function.finfo-open.php

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PHP官方手册 - 互联网笔记

finfo_open

finfo::__construct

说明

参数

返回值

注释

范例

参见

User Contributed Notes 10 notes