Errors – Thesis Hosting

Resolving WordPress Plugin Activation Error “Characters of Unexpected Output During Activation” & “Headers Already Sent” Php Error

“The plugin generated 3 characters of unexpected output during activation. If you notice “headers already sent” messages, problems with syndication feeds or other issues, try deactivating or removing this plugin.” – WordPress Error

Not good, right? This was the error message I ran into updating a WordPress plugin that I happen to really like. Worse, it indeed generated the “Warning: Cannot modify header information – headers already sent by…” error message when my caching plugin was active. While things worked without my cache plugin, my cache plugin definitely took priority over the lightweight image box plugin that was throwing the errors.

I did the obligatory searching for blank spaces at the beginning and ending of implicated php files for the “headers already sent” error to no avail. A little more research led me to a quick solution, though.

Resolving the Unexpected Output During Activation Error

It appears this happens because straight UTF has a few invisible bytes in the encoding that identifies it as UTF, known as BOM. This confuses PHP. (Like my technical talk here? Har!) But it’s easy to fix.

Grab the free Notepad ++, open the offending php file from the plugin folder–identified via your error messages–and using the “Encoding” option on the Notepad ++ menu, change the encoding from UTF-8 to Encode in UTF-8 (without BOM). Save and replace it in the plugin folder. Woot!

Hope this helps somebody!

Changing Directory Ownership via Command Line

Trying to replace, delete or change files via FTP, you may notice you get insufficient permissions errors. If you haven’t seen this a lot, your first instinct is to try to change the permissions on the directories in question, in which case you will continue to get mooned. This issue is less about permissions per se than about directory ownership. If you’re running on a server that has some directories owned by nobody/99, that means the server itself is considered “owner” and individual users won’t be able to change or delete these. ((If your server requires 777 permissions for certain functions, then you most likely will have some directories “owned” by the server/nobody.))

chown -Rv username:groupname *

The username/groupname should be replaced with your info–but you don’t know this already, best to get out of there and get tech support to help you–and these two will normally be the same. The R makes it recursive, changing the files inside the directory as well as the directory you run the command on, and the v gives you verbose output so you can see what got changed.

Disabling WordPress Plugins When You Cannot Access Admin Area

When you cannot access the admin of a WordPress installation because of a plugin issue, you can delete the plugins directly from a database management tool like PHPmyAdmin. (And if you can’t access the WP backend, there’s a good chance it is because of a plugin issue.)

This helpful tidbit comes from the WP FAQ

In the table wp_options, under the option_name column (field) find the active_plugins row

Change the option_value field to: a:0:{}

If you have FTP access, you can also rename your original plugin folder (/wp-contents/plugins) and and add an empty plugin folder. After you sign on to your WP admin area, you can delete the dummy folder and rename the plugin folder back to “plugins,” as it will have deactivated all your plugins when you signed on with the empty folder.

Happy WordPressing!

Solving FTP Deletion Error “550 Prohibited file name”

Trying to delete a file via FTP and unable to? Getting a “550 Prohibited file name” error? Annoying! But also very easy to fix. Create a php file called “unlink.php” with this code, replacing the “YOUR-FILENAME-HERE” with–what else?–your undeleteable file name.

<?php unlink('YOUR-FILENAME-HERE');?>

Upload it to the directory with the file in question, and visit the script in your web browser. It will remove the previously unruly file. ((Thanks to irasmith’s forum post for this solution.))

PHP noobs, please remember to have NO blank spaces before or after the beginning of your code in PHP files, or you’re liable to get a “Cannot modify header information/Headers already sent” error. You can create the file in a text program and simply rename it with a .php extension.