Deleting a file

kilbey1

What can I use besides unlink and unset to delete a file from a directory? I've been searching through the manual and nothing seems to quite fit.

Thanks,
Eve

feldon23

If unlink isn't working, it's because PHP scripts run with the same permissions as the web browser and so don't have the privileges to delete public files on your site.

Either CHMOD the files so they are publicly writable or work around this some other way.

kilbey1

I would do that, but then I should probably have been more specific.

In my case, I am creating a thumbnail of an image that is assigned a temporary name (using tempnam). The thumbnail image is pushed to a browser to be viewed. Now, my goal is to get rid of the temporary name.

else if($action == "thumbnail")
{
   echo "<B>Thumbnail preview:</B><BR>";
   $tmpfname = tempnam ("$dir", "$userfile_name");
   system("convert $file -resize \"200>\" \"$tmpfname\".jpg");
   echo "<img src=\"$tmpfname.jpg\"><br>";

   unlink(trim($tmpfname));
   unset($tmpfname);
}

I see my image in the browser as tHujby.jpg (original name 243.jpg), but then in examining the directory, tHujby.jpg now exists and I can't get rid of it. Unlink and Unset don't do the trick.

kilbey1

Of course, I could probably move the temporary name to a directory and flush the files from that directory later on, but I don't want to run the risk of two users viewing the same temporary name at the same time. I want it deleted right away. Sure, a user could still download the image since it's in the browser cache - that's fine.

feldon23

There was another thread this week describing the exact same problem.

Perhaps fclose(); ?

Weedpacket

Do you mean to say you regenerate the thumbnail every time it's requested?

If you want to continue to do that, can you instead retrieve the actual jpg data from the "convert" program instead of directing it to a file? Then the image tag's src URL can be to a script that will serve the binary directly - no need to stash it in a temporary file.

kilbey1

Originally posted by Weedpacket
Do you mean to say you regenerate the thumbnail every time it's requested?

Yes, that's exactly what I'm trying to do.

If you want to continue to do that, can you instead retrieve the actual jpg data from the "convert" program instead of directing it to a file? Then the image tag's src URL can be to a script that will serve the binary directly - no need to stash it in a temporary file. [/B]

Well, the 'convert' program is a command line from Image Magick. I would think if I use 'convert' on the original, it's going to change my original. If I did that, though, it'd look something like this:

system("convert $file -resize \"200>\" \"$file\".jpg");
echo "<img src=\"$file.jpg\"><br>";

But I bet I'd get an error... since $file is already "MyImage.jpg" and it would merely spit it out to "MyImage.jpg.jpg".

I'll check it out.

feldon23

Now what would be really cool is if your thumbnail script checked /yourdir/images/thumbs to see if there is a matching thumbnail for the jpeg being displayed.

If it exists, display it, if not, then run the commandline and move the jpeg it creates to /yourdir/images/thumbs.

kilbey1

Yeah... but... I really didn't want to have all those extra thumbnails cluttering things up. 🙂

kilbey1

The answer might be TMPFILE instead of TEMPNAM. As per the manual:

Creates a temporary file with an unique name in write mode, returning a file handle similar to the one returned by fopen(). The file is automatically removed when closed (using fclose()), or when the script ends.

I'll test it out and keep you posted.

Thanks,
Eve

kilbey1

Can any of you folks tell me, when using tmpfile, why I'd pull back Resource%20id%20#1.jpg? Code below:

$temp = tmpfile();
//fwrite($temp, $userfile_name);
system("convert $file -resize \"200>\" \"$temp\".jpg");
echo "<img src=\"$temp.jpg\"><br><br>";
fclose($temp); // this removes the file

Thanks,
Eve

feldon23

$temp is the file pointer, not the filename.

I don't know if you can do what you are wanting to do. I think temporary files are not meant to be available to the public. I could be wrong though.

kilbey1

Ideally, I'd like to:

a. open my image for reading
b. copy the image and assign it a temporary name
or perhaps write it into the temporary filename
c. manipulate the temporary file image (leaves original image intact)
d. output image to browser
e. delete temporary filename

How?

feldon23

Ok, I think you're going to have to go back to tmpnam since you want to display the file for the viewer.

tmpfile writes files to an inaccessible part of the server's hard drive.

I am still wondering why you don't create a folder of thumbnails and let this script create a thumbnail for each image if it's not already in the thumbnails dir.

Are users allowed to choose the size of the thumbnail they are asking for meaning that each image would have an endless number of thumbnails?

I am thinking your webhost is going to get upset if your site is generating 50 thumbnails per page x 3 pages x 50 visitors a day. That's a lot of CPU and disk activity for one site to be requesting.

kilbey1

Originally posted by feldon23
Ok, I think you're going to have to go back to tmpnam since you want to display the file for the viewer. tmpfile writes files to an inaccessible part of the server's hard drive.

I am still wondering why you don't create a folder of thumbnails and let this script create a thumbnail for each image if it's not already in the thumbnails dir.

Hmm. Ok (about the tmpnam). As for why I don't create a folder of thumbnails - well, it really doesn't matter. My idea was that for most sites we'd use this tool for, only 1 thumbnail is on a page (showcasing thumbnail of product). Yes, each time the viewer requested the page, there would be a thumbnail generated.... but not, say, 50 thumbnails to a page.

Originally posted by feldon23
Are users allowed to choose the size of the thumbnail they are asking for meaning that each image would have an endless number of thumbnails?

Nah, nothing like that. In fact, to see it, view here:
http://www.izzymillerfurniture.com/
- click on Online Showroom, Bedroom Sets, and Log Cabin Bed.
- You'll see PICTURE HERE where the thumbnail is meant to be, and will be linked to the larger image.

What this utility is for is a back-end, allowing users to upload their graphic. The graphic will get resized to fit. I can, of course, create a thumbnail as well as the original - I was just hoping that when the user when to the PRODUCTS page, the thumbnail would only be generated when requested, and then deleted when they left the page. Other suggestions are welcome!

Originally posted by feldon23
I am thinking your webhost is going to get upset if your site is generating 50 thumbnails per page x 3 pages x 50 visitors a day. That's a lot of CPU and disk activity for one site to be requesting.

Well, you tell me. Since I'm not a web admin, do you think the potential traffic generated could get this high?

Thanks,
Eve

feldon23

Why not generate the thumbnail in the Graphic Upload handling script in the Admin control panel that the client uses?

My admin page is a long table with two columns in each row. The left column is the thumbnail for the images (each fish has 2 images). The right column is the details for that fish with the name, the latin name, the alternate names, description, the price if you bought that fish in a store, etc. That's the first form with "Update Fish" and "Delete Fish" as buttons.

I wish they'd turn on IMG code here. 🙁
http://www.feldoncentral.com/Sachs/fishpanel.gif

Then the second form is a "file" field to upload a file. In this case, it's two separate pictures they can upload so there's no thumbnails here.

So with this form, the user can create a new fish object, change the contents of an existing fish object (including uploading a new photo), or delete any fish object.

So what does this have to do with file uploads and thumbnails?

Because of the way the form is written, I do not have a generic image upload script. Instead, each spot to upload a file is tied to a specific object so I know what that object's name is.

So what I do is strip special characters and spaces out of the name and write the JPEG to the site. I am ignoring the filename they are giving me and renaming it to a controlled name.

So if the object name is "Serta Perfect Sleeper", I could write:
/images/SertaPerfectSleeper.jpg

and then with GD, create a thumbnail and write it to:
/images/thumbs/SertaPerfectSleeper.jpg

automatically in the Admin script. This way you never worry about not having a thumbnail. On your viewing pages, you would just refer to /images/<product name with spaces and special characters stripped>.jpg and /images/thumbs/<product name with spaces and special characters stripped>

This would also allow you to make the site more graphical with perhaps 2-3 random thumbnails (by getting a list of all the files in /image/thumbs/ and randomly picking 3 of them) on different pages throughout the site.

kilbey1

Mmm. I see where you're coming from. I could then also delete out of the database the image and thumbnail where it's related to that product id, when the admin wants to remove products?

Can you give me an idea of what I'd use to associate the original file name with the thumb file name? Would this be done via php string comparisons, or just plop the filename into the database (or both)?

Thanks,
Eve

feldon23

Well I am not doing any MySQL yet. The admin script just writes JPEGs directly to the public site. I don't know how secure this is.

The filenames are completely determined by object names. If there isn't a file there with the same name as the object, you get a red X.