Character encoding headaches

I recently worked on a project with a strange character encoding issue. The application in question was an old CMS system which had originally been developed using a Latin–1 character set both for storing it’s data and in regards to the pages being served by Apache. More recently it had been updated to use UTF8 to eliminate lots of encoding problems which were arising, especially as more non English speaking users started to utilise the system.

There was however an odd issue occurring; the database and it’s tables had been setup correctly to store everything as UTF8; PHP and Apache had been configured to correctly serve UTF8 content and the application itself had been updated to use PHP’s set of [mb_ string functions][]. However when I viewed the database using Navicat it still looked like the data was being stored as Latin–1.

After a bit of digging I discovered that when the connection to the database was being made, [mysql_set_charset()][] wasnt being called which meant PHP was defaulting to Latin–1. I fixed this but in doing so, Latin–1 characters were being displayed as UTF8, and everything ended up looking like a mess. I set about writing a script to fix the data in MySQL and came across this great snippet on stackoverflow:

UPDATE table SET col = CONVERT(CONVERT(CONVERT(col USING latin1) USING binary) using utf8);

I wrote a quick PHP script which iterated over the database ran this query on any text, varchar or char columns and the problem was solved. There are other ways to achieve the same effect which involve dumping the database without any encoding information and then re-importing it, specifying UTF8 but I prefer this approach. As a word of warning, remember to backup any databases before running this. Also be aware if you have a lot of data it could take some time.

James Moss

I’m a freelance full-stack engineer with over 15 years experience. Currently taking on new React based opportunities, drop me a line 👋