PHP-按URL获取文件类型

Question

我希望通过URL使用PHP获取文件类型(例如.image/gif).我试过了

<?php
$image_path="http://fc04.deviantart.net/fs71/f/2010/227/4/6/PNG_Test_by_Destron23.png";
exif_imagetype($image_path);
?>

上面的代码给了我一个空白页面,下面的代码返回"3":

<?php
$image_path="http://fc04.deviantart.net/fs71/f/2010/227/4/6/PNG_Test_by_Destron23.png";
echo exif_imagetype($image_path);
?>

我哪里错了？解决:使用Fileinfo获取内容类型

Answer 1

我理解的最好方法

if (!function_exists('getUrlMimeType')) {
    function getUrlMimeType($url)
    {
        $buffer = file_get_contents($url);
        $finfo = new finfo(FILEINFO_MIME_TYPE);
        return $finfo->buffer($buffer);
    }
}

是创建依赖于finfo 类的函数

Answer 2

<?php
 $image_path="http://fc04.deviantart.net/fs71/f/2010/227/4/6/PNG_Test_by_Destron23.png";
 echo exif_imagetype($image_path);
?>

它返回3是因为pngmaciej 所说的响应类型。

试试这个得到这样的image/png：

echo mime_content_type($image_path);

尝试这个：

$finfo = finfo_open(FILEINFO_MIME_TYPE); // return mime type ala mimetype extension   
echo finfo_file($finfo, $image_path) . "\n";
finfo_close($finfo);

Answer 3

你在任何地方都不会出错。exif_imagetype返回图像类型常量之一的值：http : //php.net/manual/en/image.constants.php

如果要将其转换为扩展字符串，可以使用 switch 语句：

$typeString = null;
$typeInt = exif_imagetype($image_path);
switch($typeInt) {
  case IMG_GIF:
    $typeString = 'image/gif';
    break;
  case IMG_JPG:
    $typeString = 'image/jpg';
    break;
  case IMG_JPEG:
    $typeString = 'image/jpeg';
    break;
  case IMG_PNG:
    $typeString = 'image/png';
    break;
  case IMG_WBMP:
    $typeString = 'image/wbmp';
    break;
  case IMG_XPM:
    $typeString = 'image/xpm';
    break;
  default: 
    $typeString = 'unknown';
}

您可能希望将顺序更改为最频繁到最不常见，以获得更好的性能。

Answer 4

这是我想出的一个PHP函数：

/**
 * @param $image_path
 * @return bool|mixed
 */
function get_image_mime_type($image_path)
{
    $mimes  = array(
        IMAGETYPE_GIF => "image/gif",
        IMAGETYPE_JPEG => "image/jpg",
        IMAGETYPE_PNG => "image/png",
        IMAGETYPE_SWF => "image/swf",
        IMAGETYPE_PSD => "image/psd",
        IMAGETYPE_BMP => "image/bmp",
        IMAGETYPE_TIFF_II => "image/tiff",
        IMAGETYPE_TIFF_MM => "image/tiff",
        IMAGETYPE_JPC => "image/jpc",
        IMAGETYPE_JP2 => "image/jp2",
        IMAGETYPE_JPX => "image/jpx",
        IMAGETYPE_JB2 => "image/jb2",
        IMAGETYPE_SWC => "image/swc",
        IMAGETYPE_IFF => "image/iff",
        IMAGETYPE_WBMP => "image/wbmp",
        IMAGETYPE_XBM => "image/xbm",
        IMAGETYPE_ICO => "image/ico");

    if (($image_type = exif_imagetype($image_path))
        && (array_key_exists($image_type ,$mimes)))
    {
        return $mimes[$image_type];
    }
    else
    {
        return FALSE;
    }
}