High Performance Web Sites

Alternatives to Redirects

Redirects are an easy way to solve many problems, but it's better to use alternative solutions that don't slow down page loading. The following sections discuss some of the typical situations in which redirects are used, and alternatives that are better for your users.

Missing Trailing Slash

One of the most wasteful redirects happens frequently and web developers are generally not aware of it. It occurs when a trailing slash (/) is missing from a URL that should otherwise have one. For example, the redirect illustrated in Figure 13-1 was generated by going to http://astrology.yahoo.com/astrology. This request results in a 301 response containing a redirect to http://astrology.yahoo.com/astrology/. The only difference is the addition of a trailing slash.

There are good reasons for sending a redirect when the trailing slash is missing: it allows autoindexing (going to the index.html by default) and makes it possible to retrieve URLs in the page that are relative to the current directory (e.g., logo.gif). However, many popular web pages don't rely on autoindexing, instead relying on specific URLs and handlers. Additionally, URLs are often relative to the root and not to the current directory.

Note that a redirect does not happen if the trailing slash is missing after the hostname. For example, http://www.yahoo.com does not generate a redirect. However, the resultant URL seen in your browser does contain the trailing slash: http://www.yahoo.com/. The automatic ...