I have been planning to deeply add support for URITemplates to RestKit for the last few months. Earlier today I came across CSURITemplate and was thrilled -- you've saved me the effort of having to implement the spec!

One feature that I need to be able to complete my integration is support for matching templates against fully formed URI's. For example, given a template @"/users/{username}/categories" and the URL http://whatever.com/users/blake/categories, evaluate the template as a positive or negative match and return a dictionary containing the matched variables.

I wanted to check in and see if you were interested in merging such a patch were I to tackle the development. It will come in with full documentation, tests and all that jazz and would then become a core dependency of RestKit.

This issue is to discuss potential designs for integrating CSURITemplate with NSURL for constructing relative and absolute URL's built from a pattern.

One design approach might look like the following:

@interface CSURITemplate (URLIntegration)

- (NSURL *)URLWithVariables:(NSDictionary *)variables relativeToURL:(NSURL *)baseURL error:(NSError **)error;

// or

- (NSURL *)URLWithVariables:(NSDictionary *)variables baseURL:(NSURL *)baseURL error:(NSError **)error;

@end

I somewhat hesitate on the relativeToURL: flavor because NSURL changes its behavior based on the presence/absence of a leading '/' when constructing URL's. I think most sane people expect that given a string "/foo/bar" with a baseURL of "http://foobar.com/baz" you would get "http://foobar.com/baz/foo/bar", but you get "http://foobar.com/foo/bar" instead.

Given how templates expansion can easily yield leading slashes, I'd probably argue for just doing an expansion, concatenating the strings, and calling [NSURL URLWithString:] instead of [NSURL URLWithString:relativeToURL:]