353 lines (303 sloc) 11.2 KB
(ns compojure.core
"A DSL for building Ring handlers from smaller routes.
Compojure routes are semantically the same as Ring handlers, with the
exception that routes may return `nil` to indicate they do not match.
This namespace provides functions and macros for concisely constructing
routes and combining them together to form more complex functions."
(:require [compojure.response :as response]
[ :as macro]
[clout.core :as clout]
[ring.middleware.head :refer [wrap-head]]
[ring.util.codec :as codec]
[medley.core :refer [map-vals]]))
(defn- form-method [request]
(or (get-in request [:form-params "_method"])
(get-in request [:multipart-params "_method"])))
(defn- method-matches? [request method]
(or (nil? method)
(let [request-method (:request-method request)]
(case request-method
(or (= method :head) (= method :get))
(if-let [fm (form-method request)]
(.equalsIgnoreCase (name method) fm)
(= method :post))
(= request-method method)))))
(defn- head-response [response request method]
(if (and response (= :get method) (= :head (:request-method request)))
(assoc response :body nil)
(defn- decode-route-params [params]
(map-vals codec/url-decode params))
(defn- assoc-route-params [request params]
(merge-with merge request {:route-params params, :params params}))
(defn- route-matches [route request]
(let [path (:compojure/path request)]
(clout/route-matches route (cond-> request path (assoc :path-info path)))))
(defn- route-request [request route]
(if-let [params (route-matches route request)]
(assoc-route-params request (decode-route-params params))))
(defn- literal? [x]
(if (coll? x)
(every? literal? x)
(not (or (symbol? x) (list? x)))))
(defn- prepare-route [route]
(string? route)
(clout/route-compile route)
(and (vector? route) (literal? route))
(first route)
(apply hash-map (rest route)))
(vector? route)
~(first route)
~(apply hash-map (rest route)))
`(if (string? ~route)
(clout/route-compile ~route)
(defn- and-binding [req binds]
`(dissoc (:params ~req) ~@(map keyword (keys binds)) ~@(map str (keys binds))))
(defn- symbol-binding [req sym]
`(get-in ~req [:params ~(keyword sym)] (get-in ~req [:params ~(str sym)])))
(defn- application-binding [req sym func]
`(~func ~(symbol-binding req sym)))
(defn- vector-bindings [args req]
(loop [args args, binds {}]
(if (seq args)
(let [[x y z] args]
(= '& x)
(recur (nnext args) (assoc binds y (and-binding req binds)))
(= :as x)
(recur (nnext args) (assoc binds y req))
(and (symbol? x) (= :<< y) (nnext args))
(recur (drop 3 args) (assoc binds x (application-binding req x z)))
(symbol? x)
(recur (next args) (assoc binds x (symbol-binding req x)))
(throw (Exception. (str "Unexpected binding: " x)))))
(mapcat identity binds))))
(defn- warn-on-*-bindings! [bindings]
(when (and (vector? bindings) (contains? (set bindings) '*))
(binding [*out* *err*]
(println "WARNING: * should not be used as a route binding."))))
(defn- application-symbols [args]
(loop [args args, syms '()]
(if (seq args)
(let [[x y] args]
(if (and (symbol? x) (= :<< y))
(recur (drop 3 args) (conj syms x))
(recur (next args) syms)))
(seq syms))))
(defmacro ^:no-doc let-request [[bindings request] & body]
(warn-on-*-bindings! bindings)
(if (vector? bindings)
`(let [~@(vector-bindings bindings request)]
~(if-let [syms (application-symbols bindings)]
`(if (and ~@(for [s syms] `(not (nil? ~s)))) (do ~@body))
`(do ~@body)))
`(let [~bindings ~request] ~@body)))
(defn- wrap-route-middleware [handler]
(if-let [mw (:route-middleware request)]
((mw handler) request)
(handler request)))
([request respond raise]
(if-let [mw (:route-middleware request)]
((mw handler) request respond raise)
(handler request respond raise)))))
(defn- wrap-route-info [handler route-info]
(handler (assoc request :compojure/route route-info)))
([request respond raise]
(handler (assoc request :compojure/route route-info) respond raise))))
(defn- wrap-route-matches [handler method path]
(if (method-matches? request method)
(if-let [request (route-request request path)]
(-> (handler request)
(head-response request method)))))
([request respond raise]
(if (method-matches? request method)
(if-let [request (route-request request path)]
(handler request #(respond (head-response % request method)) raise)
(respond nil))
(respond nil)))))
(defn- wrap-response [handler]
(response/render (handler request) request))
([request respond raise]
(response/send (handler request) request respond raise))))
(defn make-route
"Returns a function that will only call the handler if the method and path
match the request."
[method path handler]
(-> handler
(wrap-route-info [(or method :any) (str path)])
(wrap-route-matches method path)))
(defn compile-route
"Compile a route in the form `(method path bindings & body)` into a function.
Used to create custom route macros."
[method path bindings body]
~(prepare-route path)
(fn [request#]
(let-request [~bindings request#] ~@body))))
(defn routing
"Apply a list of routes to a Ring request map."
[request & handlers]
(some #(% request) handlers))
(defn routes
"Create a Ring handler by combining several handlers into one."
[& handlers]
(apply routing request handlers))
([request respond raise]
(letfn [(f [handlers]
(if (seq handlers)
(let [handler (first handlers)
respond' #(if % (respond %) (f (rest handlers)))]
(handler request respond' raise))
(respond nil)))]
(f handlers)))))
(defmacro defroutes
"Define a Ring handler function from a sequence of routes. The name may
optionally be followed by a doc-string and metadata map."
[name & routes]
(let [[name routes] (macro/name-with-attributes name routes)]
`(def ~name (routes ~@routes))))
(defmacro GET "Generate a `GET` route."
[path args & body]
(compile-route :get path args body))
(defmacro POST "Generate a `POST` route."
[path args & body]
(compile-route :post path args body))
(defmacro PUT "Generate a `PUT` route."
[path args & body]
(compile-route :put path args body))
(defmacro DELETE "Generate a `DELETE` route."
[path args & body]
(compile-route :delete path args body))
(defmacro HEAD "Generate a `HEAD` route."
[path args & body]
(compile-route :head path args body))
(defmacro OPTIONS "Generate an `OPTIONS` route."
[path args & body]
(compile-route :options path args body))
(defmacro PATCH "Generate a `PATCH` route."
[path args & body]
(compile-route :patch path args body))
(defmacro ANY "Generate a route that matches any method."
[path args & body]
(compile-route nil path args body))
(defn ^:no-doc make-rfn [handler]
(-> handler
(defmacro rfn "Generate a route that matches any method and path."
[args & body]
`(make-rfn (fn [request#] (let-request [~args request#] ~@body))))
(defn- remove-suffix [path suffix]
(subs path 0 (- (count path) (count suffix))))
(defn- context-request [request route]
(if-let [params (clout/route-matches route request)]
(let [uri (:uri request)
path (:path-info request uri)
context (or (:context request) "")
subpath (:__path-info params)
params (dissoc params :__path-info)]
(-> request
(assoc-route-params (decode-route-params params))
(assoc :path-info (if (= subpath "") "/" subpath)
:context (remove-suffix uri subpath))))))
(defn- context-route [route]
(let [re-context {:__path-info #"|/.*"}]
(string? route)
(clout/route-compile (str route ":__path-info") re-context)
(and (vector? route) (literal? route))
(str (first route) ":__path-info")
(merge (apply hash-map (rest route)) re-context))
(vector? route)
(str ~(first route) ":__path-info")
~(merge (apply hash-map (rest route)) re-context))
`(clout/route-compile (str ~route ":__path-info") ~re-context))))
(defn ^:no-doc make-context [route make-handler]
(letfn [(handler
((make-handler request) request))
([request respond raise]
((make-handler request) request respond raise)))]
(if (#{":__path-info" "/:__path-info"} (:source route))
(if-let [request (context-request request route)]
(handler request)))
([request respond raise]
(if-let [request (context-request request route)]
(handler request respond raise)
(respond nil)))))))
(defmacro context
"Give all routes in the form a common path prefix and set of bindings.
The following example demonstrates defining two routes with a common
path prefix ('/user/:id') and a common binding ('id'):
(context \"/user/:id\" [id]
(GET \"/profile\" [] ...)
(GET \"/settings\" [] ...))"
[path args & routes]
~(context-route path)
(fn [request#]
(let-request [~args request#]
(routes ~@routes)))))
(defmacro let-routes
"Takes a vector of bindings and a body of routes.
Equivalent to:
(let [...] (routes ...))"
[bindings & body]
`(let ~bindings (routes ~@body)))
(defn- pre-init [middleware]
(let [proxy (middleware
((:route-handler request) request))
([request respond raise]
((:route-handler request) request respond raise))))]
(fn [handler]
(let [prep-request #(assoc % :route-handler handler)]
(proxy (prep-request request)))
([request respond raise]
(proxy (prep-request request) respond raise)))))))
(defn wrap-routes
"Apply a middleware function to routes after they have been matched."
([handler middleware]
(let [middleware (pre-init middleware)
prep-request (fn [request]
(let [mw (:route-middleware request identity)]
(assoc request :route-middleware (comp mw middleware))))]
(handler (prep-request request)))
([request respond raise]
(handler (prep-request request) respond raise)))))
([handler middleware & args]
(wrap-routes handler #(apply middleware % args))))