Fix #8 unhandled exception when parsing malformed body

Author: LukasRychtecky

src/duct/handler/static.clj

@@ -49,6 +49,11 @@
 (defmethod ig/init-key ::bad-request [_ response]
   (make-handler (assoc response :status 400)))
 
+(defmethod ig/init-key ::bad-request-malformed [_ response]
+  (let [handler (make-handler (assoc response :status 400))]
+    (fn [_ _ request]
+      (handler request))))
+
 (defmethod ig/init-key ::not-found [_ response]
   (make-handler (assoc response :status 404)))
 

src/duct/middleware/web.clj

@@ -1,5 +1,6 @@
 (ns duct.middleware.web
-  (:require [duct.logger :as logger]
+  (:require [cheshire.core :as cheshire]
+            [duct.logger :as logger]
             [integrant.core :as ig]
             [muuntaja.core :as mc]
             [muuntaja.middleware :as mm]
@@ -129,5 +130,15 @@
     (merge-with deep-merge a b)
     b))
 
-(defmethod ig/init-key ::format [_ options]
-  #(mm/wrap-format % (deep-merge mc/default-options options)))
+(defmethod ig/init-key ::format [_ {:keys [malformed-handler]
+                                    :as options
+                                    :or {malformed-handler
+                                         (fn [error content-type request]
+                                           (let [handler (or (:malformed-handler options)
+                                                             (:default-malformed-handler options))]
+                                             (-> (handler error content-type request)
+                                                 (update :body cheshire/generate-string)
+                                                 (assoc-in [:headers "Content-Type"] "application/json"))))}}]
+  #(mm/wrap-exception
+     (mm/wrap-format % (deep-merge mc/default-options options))
+     malformed-handler))

src/duct/module/web.clj

@@ -70,6 +70,7 @@
 
 (def ^:private base-config
   {:duct.handler.static/bad-request           (plaintext-response "Bad Request")
+   :duct.handler.static/bad-request-malformed (plaintext-response "Bad Request Malformed")
    :duct.handler.static/not-found             (plaintext-response "Not Found")
    :duct.handler.static/method-not-allowed    (plaintext-response "Method Not Allowed")
    :duct.handler.static/internal-server-error (plaintext-response "Internal Server Error")
@@ -80,11 +81,12 @@
 
 (def ^:private api-config
   {:duct.handler.static/bad-request           {:body ^:displace {:error :bad-request}}
+   :duct.handler.static/bad-request-malformed {:body ^:displace {:error :malformed-request-body}}
    :duct.handler.static/not-found             {:body ^:displace {:error :not-found}}
    :duct.handler.static/method-not-allowed    {:body ^:displace {:error :method-not-allowed}}
    :duct.handler.static/internal-server-error
    {:body ^:displace {:error :internal-server-error}}
-   :duct.middleware.web/format   {}
+   :duct.middleware.web/format   {:default-malformed-handler (ig/ref :duct.handler.static/bad-request-malformed)}
    :duct.middleware.web/defaults base-ring-defaults
    :duct.core/handler
    {:middleware ^:distinct [(ig/ref :duct.middleware.web/not-found)
@@ -113,6 +115,7 @@
 
 (defn- site-config [project-ns]
   {:duct.handler.static/bad-request           (html-response error-400)
+   :duct.handler.static/bad-request-malformed (html-response error-400)
    :duct.handler.static/not-found             (html-response error-404)
    :duct.handler.static/method-not-allowed    (html-response error-405)
    :duct.handler.static/internal-server-error (html-response error-500)

test/duct/module/web_test.clj

@@ -58,6 +58,9 @@
           :duct.handler.static/bad-request
           {:headers {"Content-Type" "text/plain; charset=UTF-8"}
            :body    "Bad Request"}
+          :duct.handler.static/bad-request-malformed
+          {:headers {"Content-Type" "text/plain; charset=UTF-8"}
+           :body "Bad Request Malformed"}
           :duct.handler.static/not-found
           {:headers {"Content-Type" "text/plain; charset=UTF-8"}
            :body    "Not Found"}
@@ -102,13 +105,16 @@
            :logger  (ig/ref :duct/logger)}
           :duct.handler.static/bad-request
           {:body {:error :bad-request}}
+          :duct.handler.static/bad-request-malformed
+          {:body {:error :malformed-request-body}}
           :duct.handler.static/not-found
           {:body {:error :not-found}}
           :duct.handler.static/method-not-allowed
           {:body {:error :method-not-allowed}}
           :duct.handler.static/internal-server-error
           {:body {:error :internal-server-error}}
-          :duct.middleware.web/format     {}
+          :duct.middleware.web/format
+          {:default-malformed-handler (ig/ref :duct.handler.static/bad-request-malformed)}
           :duct.middleware.web/stacktrace {}
           :duct.middleware.web/hide-errors
           {:error-handler (ig/ref :duct.handler.static/internal-server-error)}
@@ -155,6 +161,9 @@
           :duct.middleware.web/webjars    {}
           :duct.middleware.web/stacktrace {}
           :duct.handler.static/bad-request
+          {:headers {"Content-Type" "text/html; charset=UTF-8"}
+           :body    (io/resource "duct/module/web/errors/400.html")}
+          :duct.handler.static/bad-request-malformed
           {:headers {"Content-Type" "text/html; charset=UTF-8"}
            :body    (io/resource "duct/module/web/errors/400.html")}
           :duct.handler.static/not-found