Move ring.core.protocols into its own library

Move the ring.core.protocols namespace into its own library, thereby
allowing third-party adapters to use the core Ring protocols without
needing to depend on all of the ring/ring-core package.

Add a dependency on the new org.ring-clojure/ring-core-protocols
library to ring/ring-core to maintain backward compatibility.

.github/workflows/test.yml

@@ -25,6 +25,10 @@ jobs:
           key: cljdeps-${{ hashFiles('project.clj', 'ring-*/project.clj') }}
           restore-keys: cljdeps-
 
+      - name: Install core protocols project locally
+        run: lein install
+        working-directory: ./ring-core-protocols
+
       - name: Install websocket protocols project locally
         run: lein install
         working-directory: ./ring-websocket-protocols

ring-core-protocols/project.clj

@@ -0,0 +1,9 @@
+(defproject org.ring-clojure/ring-core-protocols "1.11.0"
+  :description "Ring core protocols."
+  :url "https://github.com/ring-clojure/ring"
+  :scm {:dir ".."}
+  :license {:name "The MIT License"
+            :url "http://opensource.org/licenses/MIT"}
+  :dependencies []
+  :profiles
+  {:dev {:dependencies [[org.clojure/clojure "1.7.0"]]}})

ring-core/src/ring/core/protocols.clj → ring-core-protocols/src/ring/core/protocols.clj

@@ -2,8 +2,7 @@
   "Protocols necessary for Ring."
   {:added "1.6"}
   (:import [java.io Writer OutputStream])
-  (:require [clojure.java.io :as io]
-            [ring.util.response :as response]))
+  (:require [clojure.java.io :as io]))
 
 (defprotocol ^{:added "1.6"} StreamableResponseBody
   "A protocol for writing data to the response body via an output stream."
@@ -12,8 +11,27 @@
     will be closed after the value had been written. The stream may be written
     asynchronously."))
 
-(defn- ^Writer response-writer [response output-stream]
-  (if-let [charset (response/get-charset response)]
+;; The following private functions are replicated from ring.util.response in
+;; order to allow third-party adapters to use StreamableResponseBody without the
+;; need for a ring-core dependency.
+
+(def ^:private re-charset
+  #"(?x);(?:.*\s)?(?i:charset)=(?:
+      ([!\#$%&'*\-+.0-9A-Z\^_`a-z\|~]+)|  # token
+      \"((?:\\\"|[^\"])*)\"               # quoted
+    )\s*(?:;|$)")
+
+(defn- find-charset-in-content-type [content-type]
+  (when-let [m (re-find re-charset content-type)]
+    (or (m 1) (m 2))))
+
+(defn- response-charset [response]
+  (some->> (:headers response)
+           (some #(when (.equalsIgnoreCase "content-type" (key %)) (val %)))
+           (find-charset-in-content-type)))
+
+(defn- response-writer ^Writer [response output-stream]
+  (if-let [charset (response-charset response)]
     (io/writer output-stream :encoding charset)
     (io/writer output-stream)))
 

ring-core-protocols/test/ring/assets/hello world.txt

@@ -0,0 +1 @@
+Hello World

ring-core/project.clj

@@ -5,6 +5,7 @@
   :license {:name "The MIT License"
             :url "http://opensource.org/licenses/MIT"}
   :dependencies [[org.clojure/clojure "1.7.0"]
+                 [org.ring-clojure/ring-core-protocols "1.11.0"]
                  [org.ring-clojure/ring-websocket-protocols "1.11.0"]
                  [ring/ring-codec "1.2.0"]
                  [commons-io "2.15.0"]