how to get the extension of a image file with known filename not extension

Question

I have a simple upload image function where user gets to choose what image to be uploaded for the profile pic. The image function allows every type of image. Once the user uploads the image file, it will save in a directory specified by me in the public folder where the name will change to something like this.

if the userId = 32
then the image will be stored as 32.ext

where "ext" is the image's extension.

My question is when retrieving the image when the user finished uploading and goes to the profile page. I can only do one type of filetype say jpg not png or any extension.

<img src="<?php echo "/public/images/event/".$userDetails->id.".jpg";?>" />

My question is how to check for extension and depending upon the extension it will show up like that itself. Say the user uploaded a png file, the output will be 32.png , but right now I am hardcoding the file extension to be jpg.

veelen · Accepted Answer · 2013-06-06T07:44:23.050

1

You can find the file extension in php like this:

$file_parts = pathinfo($filename);

$file_extension = $file_parts['extension'];

Or if you don't know the extension, you have tot do something like this:

$dirname  = "./somedir/"; 
$filename = "myfile"; 
$iterator = new RegexIterator(new DirectoryIterator($dirname), '/^' . preg_quote($filename) . '\.[^.]+$/iD'); 

// Any matching files? 
if (iterator_count($iterator) > 0) { 
    echo "Matches found:\n"; 
} else { 
    echo "No matches found.\n"; 
} 

// Get extensions of matching files 
foreach ($iterator as $fileinfo) { 
    printf("%s -> %s\n", $fileinfo, pathinfo($fileinfo, PATHINFO_EXTENSION)); 
}

As seen on http://www.sitepoint.com/forums/showthread.php?631513-possible-check-if-file-filename-exists-w-o-knowing-its-extension

edited Jun 06 '13 at 07:44

answered Jun 06 '13 at 07:25

veelen

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Are you sure the file is found, and has an extension? – veelen Jun 06 '13 at 07:32
veelen: the file is saved like this userid.extension . so when i do $filename = imagepath/userid , it wont give me the extension cause i dont know what type is that and for that it says null – Pranaya Behera Jun 06 '13 at 07:36
I've modified my answer for you. – veelen Jun 06 '13 at 07:44
veelen: This works. But one downside of this script is the foreach loop will kill the system . I have the userid , i just need to append the extension. – Pranaya Behera Jun 06 '13 at 08:07
How does it kill your system? – veelen Jun 06 '13 at 08:34
veelen: not like that. if i have 100 or 1000 images it willsearch everyimage i guess. – Pranaya Behera Jun 06 '13 at 08:45
You are right. It will scan the whole directory for all files, and filter out all that do not match the regex. This is very much unneeded overhead. I wouldn't accept this as a solution. – Sven Jun 06 '13 at 09:33
@Pranaya Behera have you found a better solution? – veelen Jun 07 '13 at 10:13
@veelen: I never said it is not working. But this is not the best solution. That's why I removed as accepted ans. – Pranaya Behera Jun 07 '13 at 10:42
I was just curious, no hard feelings! :) – veelen Jun 07 '13 at 10:44
BTW I am still searching for the same though. As of now I have disabled uploading other mime types , only jpeg mime types are allowed. – Pranaya Behera Jun 07 '13 at 10:56
As I did not find any solution to this. I am marking this as the solution as a workaround. But not a suitable one though. – Pranaya Behera Jun 13 '13 at 12:47

score 0 · Answer 2 · answered Jun 06 '13 at 07:29

0

You can use $_FILES or pathinfo() in server side

$extension = $_FILES["file"]["type"];

or

$extension = pathinfo($filename, PATHINFO_EXTENSION);

answered Jun 06 '13 at 07:29

curious_coder

2,392
4
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It has to be included in the server side where you are processing the uploaded image. – curious_coder Jun 06 '13 at 07:33

score 0 · Answer 3 · answered Jun 06 '13 at 08:21

0

<?php

$directory_path="/public/images/event/";

$matches = glob($directory_path.$userDetails->id.".*");

//assuming there is only one user id expect only one file in the array 
$image_file=$matches[0];

$extension=pathinfo($image_file, PATHINFO_EXTENSION);
echo "<img src='".$directory_path.$userDetails->id.$extension."' />";

answered Jun 06 '13 at 08:21

Bere

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2
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Bere: Nopes. Its not working. The extension its not picking up. Its only picking up the id. – Pranaya Behera Jun 06 '13 at 08:44

score 0 · Answer 4 · answered Jun 06 '13 at 09:31

You have several solutions at hand.

Convert every image to the one format you support, even if it seems to be in that format already. This has the benefit of added security, as the conversion will hopefully not be affected by malicious payload inside the image, but only transform or copy the pixel info, but otherwise create an entirely new image.
Ignoring the security implications of offering user uploaded content, you could also just get the file type by using getimagesize() on the file when it is uploaded and store the detected file type in your database as well as use this info for the filename extension itself. Note that browsers might have fallback mechanism implemented that treat a JPG as a JPG even if the server says that the extension is ".gif" and the mime type is "image/png". Users can and will fail uploading images with the correct extension matching the real content. Expect to get all kinds of strange formats.
You could also change the way you get to know the image name completely. Just store it in the database - this is only slightly more overhead than storing only the extension. You cannot however simply create the image name just by knowing the user id then.
There is no need for an extension in the URL alltogether. The only requirement from a browser is that there should be a mimetype matching the content. But autodetection is implemented, you might end up getting an image displayed even with a wrong mimetype, but also the Apache webserver might have mime-magic detection implemented and will send the correct mimetype for every image served without having a file extension.

As of now I have disabled uploading other than jpeg files. But will try to come up with an ans. Thanks for the info though. Helpful but not implemented as of now in my code base. — Pranaya Behera, Jun 07 '13 at 11:03

how to get the extension of a image file with known filename not extension

4 Answers4