(PHP 5 >= 5.2.0, PHP 7, PHP 8)
image_type_to_extension — 取得图像类型的文件后缀
根据给定的常量 IMAGETYPE_* 返回后缀名。
根据指定的图像类型返回对应的后缀名， 或者在失败时返回 false。
示例 #1 image_type_to_extension() 示例
<?php
// 创建图像实例
$im = imagecreatetruecolor(100, 100);
// 保存图像
imagepng($im, './test' . image_type_to_extension(IMAGETYPE_PNG));
?>注意:
此函数不需要 GD 图象库。
If you would like to get the extension from a filename (string), the following should save you any frustration with exploding the string into parts (be sure to read the documentation warnings for pathinfo):
<?php
$filename = "wallpaper.jpg";
$extension = pathinfo( $filename, PATHINFO_EXTENSION );
echo $extension; // "jpg"
?>To: mail at spybreak dot de
I noted your solution was for mime_type_to_extension which is flawed because the MIME types to extensions are not unique. See my example to consider what I have observed.
This function performs image type or mime type to extension. With limitation it will not attempt to handle duplicated MIME types. NOT DEFINITIVE!
<?php
if(!function_exists('image_type_to_extension')){
$extension;
function image_type_or_mime_type_to_extension($image_type, $include_dot) {
define ("INVALID_IMAGETYPE", '');
$extension = INVALID_IMAGETYPE; /// Default return value for invalid input
$image_type_identifiers = array ( ### These values correspond to the IMAGETYPE constants
array (IMAGETYPE_GIF => 'gif', "mime_type" => 'image/gif'), ### 1 = GIF
array (IMAGETYPE_JPEG => 'jpg', "mime_type" => 'image/jpeg'), ### 2 = JPG
array (IMAGETYPE_PNG => 'png', "mime_type" => 'image/png'), ### 3 = PNG
array (IMAGETYPE_SWF => 'swf', "mime_type" => 'application/x-shockwave-flash'), ### 4 = SWF // A. Duplicated MIME type
array (IMAGETYPE_PSD => 'psd', "mime_type" => 'image/psd'), ### 5 = PSD
array (IMAGETYPE_BMP => 'bmp', "mime_type" => 'image/bmp'), ### 6 = BMP
array (IMAGETYPE_TIFF_II => 'tiff', "mime_type" => 'image/tiff'), ### 7 = TIFF (intel byte order)
array (IMAGETYPE_TIFF_MM => 'tiff', "mime_type" => 'image/tiff'), ### 8 = TIFF (motorola byte order)
array (IMAGETYPE_JPC => 'jpc', "mime_type" => 'application/octet-stream'), ### 9 = JPC // B. Duplicated MIME type
array (IMAGETYPE_JP2 => 'jp2', "mime_type" => 'image/jp2'), ### 10 = JP2
array (IMAGETYPE_JPX => 'jpf', "mime_type" => 'application/octet-stream'), ### 11 = JPX // B. Duplicated MIME type
array (IMAGETYPE_JB2 => 'jb2', "mime_type" => 'application/octet-stream'), ### 12 = JB2 // B. Duplicated MIME type
array (IMAGETYPE_SWC => 'swc', "mime_type" => 'application/x-shockwave-flash'), ### 13 = SWC // A. Duplicated MIME type
array (IMAGETYPE_IFF => 'aiff', "mime_type" => 'image/iff'), ### 14 = IFF
array (IMAGETYPE_WBMP => 'wbmp', "mime_type" => 'image/vnd.wap.wbmp'), ### 15 = WBMP
array (IMAGETYPE_XBM => 'xbm', "mime_type" => 'image/xbm') ### 16 = XBM
);
if((is_int($image_type)) AND (IMAGETYPE_GIF <= $image_type) AND (IMAGETYPE_XBM >= $image_type)){
$extension = $image_type_identifiers[$image_type-1]; // -1 because $image_type_identifiers array starts at [0]
$extension = $extension[$image_type];
}
elseif(is_string($image_type) AND (($image_type != 'application/x-shockwave-flash') OR ($image_type != 'application/octet-stream'))){
$extension = match_mime_type_to_extension($image_type, $image_type_identifiers);
}
else
{
$extension = INVALID_IMAGETYPE;
}
if(is_bool($include_dot)){
if((false != $include_dot) AND (INVALID_IMAGETYPE != $extension)){
$extension = '.' . $extension;
}
}
else
{
$extension = INVALID_IMAGETYPE;
}
return $extension;
}
}
function match_mime_type_to_extension($image_type, $image_type_identifiers){
// Return from loop on a match
foreach($image_type_identifiers as $_key_outer_loop => $_val_outer_loop){
foreach($_val_outer_loop as $_key => $_val){
if(is_int ($_key)){ // Keep record of extension for mime check
$extension = $_val;
}
if($_key == 'mime_type'){
if($_val === $image_type){ // Found match no need to continue looping
return $extension; ### Return
}
}
}
}
// Compared all values without match
return $extension = INVALID_IMAGETYPE;
}
$extension = image_type_or_mime_type_to_extension($image_type, $include_dot);
return $extension;
}
?>// if you just want to find the format from the file path name without creating any images
// image path name
$image_name = "image name.png";
// After the last point is naturally the format.
$dots = explode(".",$image_name);
// We assign the last data of $dots to the variable $type.
$type = $dots[(count($dots)-1)];
// The output will be written without a dot.
echo "without dot : ".$type;
//for dotted
$type = ".".$type;
echo "dotted : ".$type;When I was writing a script for my photo website, it was necessary to write such function, which can get the extension of uploaded file (image), so the function is:
<?php
function get_extension($imagetype)
{
if(empty($imagetype)) return false;
switch($imagetype)
{
case 'image/bmp': return '.bmp';
case 'image/cis-cod': return '.cod';
case 'image/gif': return '.gif';
case 'image/ief': return '.ief';
case 'image/jpeg': return '.jpg';
case 'image/pipeg': return '.jfif';
case 'image/tiff': return '.tif';
case 'image/x-cmu-raster': return '.ras';
case 'image/x-cmx': return '.cmx';
case 'image/x-icon': return '.ico';
case 'image/x-portable-anymap': return '.pnm';
case 'image/x-portable-bitmap': return '.pbm';
case 'image/x-portable-graymap': return '.pgm';
case 'image/x-portable-pixmap': return '.ppm';
case 'image/x-rgb': return '.rgb';
case 'image/x-xbitmap': return '.xbm';
case 'image/x-xpixmap': return '.xpm';
case 'image/x-xwindowdump': return '.xwd';
case 'image/png': return '.png';
case 'image/x-jps': return '.jps';
case 'image/x-freehand': return '.fh';
default: return false;
}
}
?>
It's useful for those, who upload files on server.2006-09-29
A few notes about some contributions on this page.
1. It seemed to me that on the face it of all of the offerings to emulate "image_type_to_extension" function fell short of the mark in one way or another (See my comments below). That's why I wrote my own and submitted to this page below. In respect of my work any comments, bugs noted or improvements would be gratefully received.
2. Avoid using the Switch statement in an unconventional method to "Break" (I note the use of the return statement!). Also even if it does nothing at the inception of our code - Still put in the default case (It lets others realise that a default is not required or at worst forgotton.
3. In an environment that is under your control the risk of an error by determining the content by its extension or MIME type may seem an attractive solution to a problem. However, in the real world there's no guarantee that a MIME type or file extension is correct for it's associated file.
Consider using functions to get the image type:
getimagesize or (This is available without GD)
exif_imagetype
4. There's more to coding than just putting something together to do a job!!! But whatever is done is worthwhile - Hence expletives have no place in this forum!!
5. The idea from "oridan at hotmail dot com" is a very slick idea. I will be taking a closer look at this for my own project.