About URI Templates

Probably one of the most interesting projects related to URL Design on which anyone is currently working is the URI Templates project spearheaded by Joe Gregorio of IBM. While not sexy and not something most end users will ever see, infrastructure developers writing blogs, wikis, forums, content management systems, and ideally even web servers, proxies, and routers will be able to utilize URI Templates for configuration and more. Well, once URI Templates are finalized and made an IETF standard that is.

Examples uses could include URL Rewriting Rules, URL Virtualization Configuration, REST’s Hypermedia Requirement, within future HTTP Headers and HTML LINK Elements, and even for Sitemaps (in a hopeful revision to Sitemap.org’s Sitemap protocol.) URI Templates will provide Internet professionals far more flexibility in dealing with URLs such as making it possible to employ URL Construction in a controlled manner without violating that nastly little URI Opacity Axiom.

Unlike most URL Rewriting Tools, URI Templates are very easy to use and, with the possible exception of certain esoteric edge cases that are still being finalized, accessible to mere mortals. URI Templates are certainly nowhere near as difficult as the requirement to master regular expressions and their complex interations when using Apache’s mod_rewrite and IIS’ (3rd Party) ISAPI Rewrite. Almost certainly anyone who has managed to language their own website will have no trouble at all mastering the most common use-cases for URI Templates.

URI Templates use a simple syntax where braces denote variables to be replaced when the templates are converted to actual URLs. For example, if this blog were using URI Templates to configure this page, the URI Template would most certainly look like this:


When the template variables have the following values (as they do for this post):

year: 2007
month: 01
day: 03
post-slug: introducing-uri-templates

The resultant URL upon conversion will be:


Pretty simple, huh?

However, be aware that before URI Templates can become an IETF standard there needs to be at least two interoperable implementations, if not a lot more. Mark Nottingham of Yahoo has implemented a URI Template parser in Javascript, but I don’t know for certain if that one will qualify for the purposes of standardization. Whatever the case, if you are working on any projects or products that could benefit from URI Templates I encourage you to participate in the URI working group via their mailing list and then implement the specification in your software projects or products.

Although it may appear to be a boring subject from the outside looking in, the standardization of URI Templates will be probably the most positive thing to happen for URL Design in over a decade.

This entry was posted in Internet Professionals, Proposals, REST, Sitemaps, SoapBox, Software Vendors, URI Templates, URL Rewriters, URL Virtualization. Bookmark the permalink.

2 Responses to About URI Templates

  1. This ain’t a new concept, and for years and years, developers were creating URLs on the fly using for-loops.

    It’s more like binding a data-source (the parameters and values of the URLs) to a given template, and let a template engine do the for-loop part instead of you.

    I think it won’t be adapted and implemented by the community, because the syntax is not that easy, and the learning overhead makes many developers continue using the old, easy, for-loops to create URLs.

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