Silverstripe CMS gives File size zero error - error-handling

Question

I have designed a page that has upload attachments ... one image and another PDF.
The data is created in the database, however, when trying to upload a file of either type I get a server error "File Size is zero bytes".
A search of this forum yielded entries that indicate it is a permission issue of site assets folder or assets/Uploads folder. I have checked both and the permissions are correct.
The search on other platforms seems to indicate file size issues are from the PHP5.6 php.ini file settings. Both are correct and set to a value well above the 8Mb default.
The Apache2 log looks like:
[Tue Jun 06 15:11:57.167558 2017] [:error] [pid 26971] [client 192.168.1.73:50192] PHP Warning: mkdir(): Permission denied in /var/www/html/ss/framework/filesystem/Filesystem.php on line 53, referer: http://192.168.1.70/ss/index.php/admin/pages/edit/show/23
[Tue Jun 06 15:11:57.170810 2017] [:error] [pid 26971] [client 192.168.1.73:50192] PHP Warning: copy(/var/www/html/ss/assets/Uploads/news-attachments/the-satern-ring.pdf): failed to open stream: Permission denied in /var/www/html/ss/framework/filesystem/Upload.php on line 207, referer: http://192.168.1.70/ss/index.php/admin/pages/edit/show/23
This code also seems to indicate a permission issue. The folders all have the owner as root group as root and drw-rw----, files can be uploaded manually but not through the CMS.
So where do I look now?
Environment:
SS v3.6.0 theme bootstrap
OS Linux Mint 18.1
Apache 2.4 PHP 5.6

Answer 1

This can occur when framework does not have permission to write files to the server. If this is the case, when we upload images through the CMS the file can not be written to assets and the CMS returns a "File size zero error". The website also cannot combine files (such as JavaScript and CSS files) and cannot create new resampled images.
To help investigate this problem we can run the SilverStripe install wizard. The install wizard will notify us of issues preventing SilverStripe from running correctly.
To run the install wizard we visit http://www.example.com/install.php
The install.php is usually deleted after the site is installed, so if it is missing we will need to replace it. We can download the file from github. Here is the install.php file for SilverStripe 3.6: https://github.com/silverstripe/silverstripe-installer/blob/3.6/install.php
Once downloaded we upload this to the root directory of our webserver. Once this is done we can visit the install.php URL.
Here is a screenshot showing an example of the file permission issue warnings that the install wizard outputs:
What we want to do now is fix up all the warnings that the install wizard is reporting.
If this is a shared hosting environment we might not have the ability to fix these issues ourselves. In this case we should be able to send the install.php link to hosting support asking them fix the issues.
Once all the issues are fixed the site should work correctly. Make sure to delete the install.php when we are done.