How to query a namespace programmatically
I am working on a Liberator project in Clojure. I have defined a number of routes that return JSON data computed by logic in a different namespace. I would like to be able to change the namespace that implements the logic programmatically, so I can do something like this:
JAVA_OPTS='-DgameLogicNamespace=foo.logic.mock' lein ring server-headless 8080
I am currently doing it like this:
(ns foo.routes
(:require [compojure.core :refer :all]
[liberator.core :as lib :refer [defresource request-method-in]]
[liberator.representation :refer [ring-response]]))
(require
(vec
(cons (symbol (System/getProperty "gameLogicNamespace" "foo.logic.real"))
'[:as logic])))
It works, but feels a little awkward. Is there an idiomatic way to accomplish what I want?
One of my main motivations is actually for unit test routes with mock data, so if there is a good solution for providing mock logic only in tests (not as a property of the JVM system) suggestions are welcome.
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One of my main motivations is actually for unit test routes with mock data, so if there is a good solution for providing mock logic only in tests (not as a property of the JVM system) suggestions are welcome.
If you haven't already, take a look at ring-mock for some useful mock-request utilities to test Ring handlers.
If you are interested in providing mock versions of functions that provide logic for your application during unit tests, consider using with-redefs
; it is pretty much custom made for this purpose.
(ns my-app.handlers-test
(:require [clojure.test]
[my-app.handlers :as h]
[my-app.logic :as l]
[ring.mock.request :as r]))
(deftest test-simple-handler
(with-redefs [l/my-complicated-logic #(update-in % [:a] inc)]
(is (= {:a 2}
(h/my-handler (r/request :post "/foo" {:a 1}))))))
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