file_put_contents php permissions

Question

This is a question about my system configuration and how apache/php can be affected by that. Code that was working on my dev server failed to work when I moved to production and here is the problem I boiled the error down to. I want to use file_put_contents in php to simply make a file on my system. Here is the very simple code I am using:

print file_put_contents("testfile.txt","this is my test")?"made file":"failed";

No errors are thrown but it always prints "failed". When I run it in the normal directory no file is made but when I move it to a directory with 777 permission, it will make the file but still print "failed" and save nothing into it. If I change the php file itself to have 777 permission nothing changes. If I change the target file (testtext.txt) to have 777 permission nothing changes.

The when I change the owner of the php file to be the same as the created testfile.txt nothing changes. When I try relative vs. absolute paths nothing changes. For some reason I can have php make the file but it is always empty and using file_put_contents I can't write anything in.

The created file is in the owner and group of 'www-data' while I am acting as root if that helps. What can I do to get this working? I think that my version of php is using the suhosin extension if this could have anything to do with it (or if you think there is a way to fix this in php or suhosin ini files I can do that too).

I've been hunting this for hours the last few days.

EDIT: updates based on the comments below. When I run it in CLI mode it does work but since I need to run it through apache how can I use this fact? Does this tell us something about where or what is stopping the file writing? Also the file_put_contents call is actually returning "false" and not zero.

Solution 1

You have to set permissions as 777 for the apache user. Apache also needs to be able to 'create' new files. I'm sure that if you tried writing to a file with 777 permissions that it would work.

Solution 2

The function returns the number of bytes that were written to the file, or FALSE on failure.

Make sure that mydir is writable (by the apache user - apache2 or www-data). To check if content was written to file use the === operator:

$file = "mydir/testfile.txt";

$result = file_put_contents($file,"this is my test");

if ($result === false)
{
  echo "failed to write to $file";
}
else
{
  echo "successfully written $result bytes to $file";
}

For debugging i recommend to define this at the top of your php file:

error_reporting(-1);
ini_set('display_errors', true);

Comments

[jolivier]

has the www-data user +w and +x rights on the folder which will contain this file? can you su as www-data and try to write to this file?

[Mitya]

file_put_contents() returns the number of bytes written on successful write. If it's creating an empty file, this is presumably 0 bytes, which would evaluate to a falsy. That's why you're seeing the "failed" message. Try the fopen() / fwrite() route instead. I wouldn't anticipate any change but good to check.

[Tucker]

Does the script work when you run it CLI?

[hackartist]

Yes I just ran it in CLI and it did work -- what does this mean for how the permissions are set, since I have to get the apache version to work? It is actually returning false and not 0 when I modified to check the type it was returning by doing print file_put_contents("testfile.txt","this is my test")===false?"failed":"made file";

[Stano]

echo (file_exists('testfile.txt')?'y':'n').getcwd();

[hackartist]

Yes it seems since CLI works but apache does not, that this is some issue with permissions. In Ubuntu Unix, how does one give permissions to a user -- not a specific file or folder which I am used to doing with chmod?

[Adam F]

Not Sure. I'm using linux mint and in my natalus it gives me the option to modify the permissions for all the machines users, with WWW-Data being right there.

[hackartist]

Well even though I have not yet been able to get it to work I am now about 95% sure that it is a permissions issue with apache not having the right permissions to write these files so I will accept this answer.

[arkascha]

A permission of 0777 is nearly never required and rarely a good idea. Instead one should typically use the group memberships of those accounts who need access to the files or even create a new, custom crafted user group for special purposes and grant ownership and access permissions to that group.