Where does PHP save temporary files during uploading? - php

I am using XAMPP on Windows. By printing $_FILES["file"]["tmp_name"], it seems that the temporary file was saved at C:\xampp\tmp\phpABCD.tmp. But I cannot see it on the filesystem of the server. However, the file can be moved or copied via move_uploaded_file(), rename(), or copy(). So where does PHP actually save temporary files during uploading?

It saves it at the path specified in $_FILES["file"]["tmp_name"], but deletes it after the script is done executing. It's up to you to move the file elsewhere if you want to preserve it.

Its specified in upload_tmp_dir in your php.ini file. It is deleted by the system automatically after use.

You can check where php is currently saving your temp files $_FILES["file"]["tmp_name"] by printing
sys_get_temp_dir()

Use move_uploaded_file(file, path), specify the file and the path where you want to store the file.
A copy of that file is created and gets stored.

php stores all temporary files, that includes uploaded files, in the temporary files directory as specified in the php.ini. Note that for uploads, those files might be removed as soon as the script the file was uploaded to was terminated (so unless you delay that script, you probably won't see the uploaded file). Another reason might be that the file is simply hidden on the file system.
So if you want to see the file, you might want to make sure you see all hidden files in the explorer and delay the script as long as you need to find the file.

from http://www.php.net/manual/en/features.file-upload.php#93602, "...the uploaded file will inherit the permissions of the directory specified in the directive upload_tmp_dir of php.ini. If this directive isn't set, the default of C:\Windows\Temp is used..."

Note that the file is saved binary in $_FILES["file"]["tmp_name"], so you may open it maybe with file_get_contents if it is an image or something like this...

IF you are asking the file location then it depend on the setting of server. but if you are asking whether it saved first in local system or in server. then answer is it save in temp folder in server.

Related

Do I NEED to use move_uploaded_file() function?

Am I enforced in some way to use move_uploaded_file() and/or delete the temporary file?
My application needs only to load the file contents in memory (eg. via file_get_contents()). Do I need to move it to another directory before? Otherwise, am I required to delete it at the end of the script?
If you don't want to save the uploaded file somewhere, you don't need to use move_uploaded_file(). Read from the file however you like; it'll be deleted automatically by PHP at the end of the request.
Yes, in cases when open_basedir or safe mode (hopefully safe_mode will go out of style eventually) otherwise prevent you to read from the location the uploaded file was saved to. The move_uploaded_file() is aware of those restrictions but only enforce them to the second parameter, so you can move files out of lets say /tmp/ while otherwise you couldn't read that directory.

What is point of a temporary file name during a file upload?

What is the point of $_FILES["file"]["tmp_name"]?
I know it is the name of the temporary copy of the file stored on the server but why do we need this when we have $_FILES["file"]["name"]?
I would assume it has to do with preventing name collisons, is that true? Are there other reasons? I'm using PHP syntax but I would guess the concept would apply to all the languages?
This is not a PHP syntax.
$_FILES['x']['name'] stores the name of the file on the user's filesystem - this is only extra information that is set up by the browser - just like $_FILES['x']['type'].
$_FILES['x']['tmp_name'] stores the name of the uploaded file on the server.
EDIT:
When you upload a file, it is phisically stored on the server's hard drive. A name to the file (not the entire path) will be available in your PHP under $_FILES['x']['tmp_name'] variable. You should move the file using move_uploaded_file() function. This function knows the path to the directory where the file is stored, so it's capable of moving the file to its new location.
$_FILE['x']['name'] / ['type'] are actually completely useless as the're being set by the browser during file upload, therefore they could store false information.
Because when someone uploads a file, until you save it somewhere, it's not really on disk under the 'name' until you explicitly save it somewhere else. Until then it's contents are only found in the temporary file.

Is it possible to receive uploaded files in PHP without storing them on the filesystem?

As far as I know, PHP stores all uploaded files in upload_tmp_dir (or the systems default tmp dir, if upload_tmp_dir is not set in the php.ini file).
Then the usual method is to move that file to another place using move_uploaded_file
My question is: Is there a way to to retrieve the file in a variable? So it does not need to be stored on the file system at any time?
Reasons are, that I don't have to clean up the files afterwards and don't have to care about file system permissions.
$contents = file_get_contents($_FILES['name']['tmp_name']);
It is generally safe to leave the temporary file as it is, PHP will take care to delete it at the end of the request (unless PHP crashes hard during your script).
You can probably read the temporary file, convert it to Base64 (for example) and store it on a variable..

move_uploaded_file not working

I'm uploading files via JS and storing the temp path in the session.
Than i use the following code to move the files.
if(move_uploaded_file($_SESSION['temp_img'][$key]['path'], $dest.$bigimg)){
$dest and $bigimg are defined earlier in the script with the id from the database.
Any Ideas or alternatives ?
MANCHUCK's answer was close but not quite there. You must call move_uploaded_file within the script where the file was uploaded. You cannot do what you're doing, that is, "storing temp path in the session" because that path is only valid for one request.
From the PHP manual:
The file will be deleted from the
temporary directory at the end of the
request if it has not been moved away
or renamed.
(Emphasis mine)
move_uploaded_file checks that a file has been uploaded to that page. You are actually uploading the file to a different PHP script then storing in a session. Instead of using move_upload_file use rename.
What is the output of $_SESSION['temp_img'][$key]['path'], also do you have permission to write to the web directory your placing the files. You may need to set it to 777 for some hosts to allow the webserver to write there.

'pass through' php upload to amazon's s3?

I've seen ways to upload files directly to S3 and I've seen ways to upload a file already on the server. I need to modify the file's name before sending it on to S3, but I don't want to store it locally and then upload it, if I can help it. Is there a way to put it in a buffer or something? Thx.
The file will always end up in the temporary directory first while the upload completes, even before you're able to work with the uploaded file. You get all the file's chunks before, and then it get rebuilt in the /tmp directory by default. So no, there's no "pass-through". But I guess you could re-upload directly from the temporary directory afterwards instead of moving it to another working directory.

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