16 March 2009 | Programming |
Ruby on Rails has become a rather popular framework that many have used to easily and quickly create some pretty powerful web sites. As with any web programming language or framework, it certainly does have its problems. For example, Rails has never been well-known for its incredibly speedy database layer. In fact, if you’re not careful, you can make a glorious application that will run your server into the ground because of all the heavy behind-the-scenes DB queries.
Another problem is that a lot of people get their Rails coding tips and tricks from others – basically what you’re doing right now! The solutions you find online aren’t always optimal, and are sometimes downright scary.
Take a custom 404 error page. It’s easy enough to make, but you have to be careful about how you actually implement it.
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22 February 2009 | Programming |
Say you have an application running on a Linux server using the ext2 or ext3 file systems. You set up a caching scheme in your application to store files like so:
/cache/stamps/1/main_content.cache
/cache/stamps/1/comments.cache
/cache/stamps/2/main_content.cache
/cache/stamps/2/comments.cache
/cache/stamps/3/main_content.cache
/cache/stamps/3/comments.cache
...
Eventually, you’re going to run into a problem: Your caching will stop working since your application won’t be able to write to the “stamps” directory any more. Instead, you’ll get an error message like this:
Couldn't create cache directory: /stamps/41134/main_content (Too many links - /var/www/your-app/tmp/cache/stamps/41134)
At that point, you’ll try to search for “too many links”, and probably you won’t find much information that is actually comprehensible to normal human beings. Fortunately, it really is quite simple to repair once you understand what’s going on.
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