Posted by flyerhzm on February 10, 2012
It's very common for a rails developer to use time_ago_in_words to display time like "5 minutes ago", but it's too expensive to calculate the time in server side, you should utilize client cpu to calculate the time ago.
Rails provides a helper method time_ago_in_words to display the distance between one time and now, like "5 minute ago", it's very useful.
<%= times_ago_in_words(comment.created_at) %>
It looks fine, but we have some room to improve.
- Your servers have to calculate the time ago for each request, it wastes the cpu capability on server side, why not move the calculation to client side.
- If we calculate the time ago on server side, it gets difficult to cache the page. e.g. after you create a comment, the time ago of the comment shows "5 seconds ago", if you cache the page, the time ago still show "5 second ago" after 3 minute (depends on your cache strategy).
<abbr class="timeago" title="<%= comment.created_at.getutc.iso8601 %>"> <%= comment.created_at.to_s %> </abbr>
Now, you save the server cpu capability and make your page easier to cache.