Are there benefits to using {site_url} rather than a relative path?

Question

Should I use {site_url}? I prefer to use relative paths in my templates.

Example:

/resources/glossary/category/{category_url_title}

Rather than:

{site_url}/resources/glossary/category/{category_url_title}

I was wondering if anyone could provide an argument of why one should be used over the other? Is it a personal preference thing? Should I always use {site_url}? Should I never use {site_url}?

My reasoning for not using it is because I believe it takes less resources to use a relative path. Logically, one would think that because EE doesn't have to replace {site_url} with http://www.example.com in every template, the page would load faster?

I'm using FocusLab Master Config on all of my sites.

Answer 1

In most cases, using relative paths are fine, though you won't see any performance gain there (replacing global variables like {site_url} is the tiniest of tasks).

But in the cases where you do want a full URL generated, {site_url} is not the best way to do it - instead, you should use {path=""}, {permalink=""}, {title_permalink=""}, etc. This way you'll never run into issues with slashed/unslashed URLs, and it's much cleaner.

So when would you want to use {path}? If you have some parts of your site which run under SSL, this will prevent all of your nav links, etc, from being linked to with an https URL when leaving those SSL-protected areas.

Answer 2

I would like to point out that your first example is not a relative path - it's an absolute path with a variable domain. This crucial difference explains why the full path in your second example is the preferred form.

If you have a page at example.com/foo.html, and a page at example.com/bar/baz.html, there's a few ways to link to the second page from the first:

• Absolute path with site_url: { site_url }/bar/baz.html
• Absolute path without site_url: /bar/baz.html
• Relative path: bar/baz.html

In this case, it's pretty straightforward. Now imagine the reverse - how exactly will baz.html link back to foo.html?

• Absolute path with site_url: { site_url }/foo.html
• Absolute path without site_url: /foo.html
• Relative path: ../foo.html

The relative paths for the pages have an entirely different format, because they're relative to where the linking page is. This is bad, it means your URL formatters have to be context-sensitive. So that's out.

So either form of absolute path looks good, right? Not quite. Imagine you wrote your code on a server that gives you the subdomain user.example.com, and you used the second form, that doesn't use site_url, because it was simplest at the time. Everything will work perfectly.

Then, later, you have to migrate to a server that puts your account at the url example.com/user/.

Well, crap. Now all your links are going to go to example.com/foo.html instead of the required example.com/user/foo.html. You can go through and update every single reference, but that's unnecessary work.

If you'd written them using { site_url } from the start, you only have to change that one setting.

Answer 3

Speed wise I would go for the relative paths (less DNS lookups) Also for java and css (minified) I would use relative paths. (major speed increase)

So basically if you are running one website with EE, I would go for relative paths. Speed increase is not due to the fact that EE needs to enter the domain in every {site_url} tag. it's due to the DNS lookups/requests.