Clout

Clout is a library for matching Ring HTTP requests. It uses the same routing syntax as used by popular Ruby web frameworks like Ruby on Rails and Sinatra.

Installation

Add the following to your project.clj dependencies:

[clout "2.2.1"]

Usage

Require Clout in the normal way:

(require '[clout.core :as clout])

These following examples also make use of the Ring-Mock library to generate Ring request maps:

(require '[ring.mock.request :as mock])

Routes can match by keyword:

(clout/route-matches
 "/article/:title"
 (mock/request :get "/article/clojure"))

=> {:title "clojure"}

Or with wildcards:

(clout/route-matches
 "/public/*"
 (mock/request :get "/public/style/screen.css"))
 
=> {:* "style/screen.css"}

Clout can also match absolute routes:

(clout/route-matches
 "http://subdomain.example.com/"
 (mock/request :get "http://subdomain.example.com/"))

=> {}

And scheme-relative routes:

(clout/route-matches
 "//subdomain.example.com/"
 (mock/request :get "http://subdomain.example.com/"))

=> {}

(clout/route-matches
 "//subdomain.example.com/"
 (mock/request :get "https://subdomain.example.com/"))
 
=> {}

Clout supports both keywords and wildcards. Keywords (like ":title") will match any character but the following: / . , ; ?. Wildcards (*) will match anything.

If a route does not match, nil is returned:

(clout/route-matches "/products" (mock/request :get "/articles"))

=> nil

For additional performance, you can choose to pre-compile a route:

(def user-route
  (clout/route-compile "/user/:id"))

(clout/route-matches user-route (mock/request :get "/user/10"))

=> {:id "10"}

When compiling a route, you can specify a map of regular expressions to use for different keywords. This allows more specific routing:

(def user-route
  (clout/route-compile "/user/:id" {:id #"\d+"}))

(clout/route-matches user-route (mock/request :get "/user/10"))

=> {:user "10"}

(clout/route-matches user-route (mock/request :get "/user/jsmith"))

=> nil

You can also specify regular expressions inline in braces after the keyword:

(def user-route
  (clout/route-compile "/user/:id{\\d+}"))

Note that regular expression escape sequences (like \d) need to be double-escaped when placed inline in a string.

License

Copyright © 2018 James Reeves

Distributed under the Eclipse Public License either version 1.0 or (at your option) any later version.