Fix #7 Expose path-parameter function to get path parameter from URI

Author: Johnny Ruiz

README.org

@@ -83,7 +83,7 @@
   (define-get "/" ()                                          ; (2)
     (ok "alive"))                                             ; (3)
   (define-get "/accounts/:account-id" (request)               ; (4)
-    (let ((account-id (path-param request :account-id)))      ; (5)
+    (let ((account-id (path-parameter request :account-id)))  ; (5)
       (ok (format nil "Your account id: ~a." account-id))))   ; (6)
   (define-any "*" ()                                          ; (7)
     (not-found "not-found")))                                 ; (8)

src/middleware/path-template.lisp

@@ -10,10 +10,13 @@
                 #:scan-to-strings)
   (:import-from :tiny-routes.request
                 #:request-append
+                #:request-get
                 #:path-info)
   (:import-from :tiny-routes.util
                 #:compose)
-  (:export #:wrap-request-path-info-matcher
+  (:export #:path-parameter
+           #:with-path-parameters
+           #:wrap-request-path-info-matcher
            #:wrap-request-matches-path-template))
 
 (in-package :tiny-routes.middleware.path-template)
@@ -87,15 +90,16 @@ then it is made available to the request under `:path-parameters'."
   "Wrap HANDLER such that it is called only if the request path matches
 the PATH-TEMPLATE.
 
-If PATH-TEMPLATE is t, nil, or an empty string, then return HANDLER
-unchanged.
+If PATH-TEMPLATE is t, nil, the empty string, or \"*\", then return
+HANDLER unchanged.
 
 If REGEX is non-nil, then interpret path-template as a regular
 expression."
   (check-type path-template (or symbol string))
   (cond ((or (null path-template)
              (eq path-template t)
-             (string= path-template ""))
+             (string= path-template "")
+             (string= path-template "*"))
          handler)
         ;; If regex is non-nil, then interpret path-info as a regex
         (regex
@@ -105,3 +109,15 @@ expression."
          (wrap-request-path-info-matcher handler (make-path-template-keyword-matcher path-template)))
         (t
          (wrap-request-path-info-matcher handler (make-path-template-exact-matcher path-template)))))
+
+(defun path-parameter (request path-parameter &optional default)
+  "Return the value mapped to PATH-PARAMETER from REQUEST or DEFAULT."
+  (getf (getf request :path-parameters) path-parameter default))
+
+(defmacro with-path-parameters (vars path-parameters &body body)
+  "Bind the variables in VARS to the corresponding values present in
+PATH-PARAMETERS."
+  (let ((gpath-parameters (gensym "path-parameters")))
+    `(let* ((,gpath-parameters ,path-parameters))
+       (destructuring-bind (&key ,@vars &allow-other-keys) ,gpath-parameters
+         ,@body))))

t/tiny-routes-test.lisp

@@ -120,3 +120,37 @@
     (is (null (funcall (define-post "/bar" () response) request)))
     (is (equalp response (funcall (define-post "/foo" () response) request)))
     (is (equalp response (funcall (define-post "/:foo" () response) request)))))
+
+(test route-matching1
+  (let ((request (mock-request :get "/accounts/A123/users/U42"))
+        (ok-response (make-response :status 200 :body "OK"))
+        (expected (list "A123" "U42")))
+    (is (equalp ok-response (funcall (define-any "*" () ok-response) request)))
+    (is (equalp expected
+                (funcall (define-get "/accounts/:account-id/users/:user-id" (request)
+                           (let ((account-id (path-parameter request :account-id))
+                                 (user-id (path-parameter request :user-id)))
+                             (list account-id user-id)))
+                         request)))
+    (is (equalp expected
+                (funcall (define-get "/accounts/:account-id/users/:user-id" (request)
+                           (with-request (path-parameters) request
+                             (with-path-parameters (account-id user-id) path-parameters
+                               (list account-id user-id))))
+                         request)))))
+
+(test readme-example
+  (let ((app (routes
+              (define-get "/" ()
+                (ok "alive"))
+              (define-get "/accounts/:account-id" (request)
+                (let ((account-id (path-parameter request :account-id)))
+                  (ok (format nil "Your account id: ~a." account-id))))
+              (define-any "*" ()
+                (not-found "not-found")))))
+    (is (equalp '(200 NIL ("alive"))
+                (funcall app (mock-request :get "/"))))
+    (is (equalp '(200 NIL ("Your account id: A123."))
+                (funcall app (mock-request :get "/accounts/A123"))))
+    (is (equalp '(404 NIL ("not-found"))
+                (funcall app (mock-request :get "/unknown"))))))