From 6d5bf64833c28fdbdfb9ef94182433e829c526dc Mon Sep 17 00:00:00 2001
From: Pauli Jaakkola <pauli.jaakkola@metosin.fi>
Date: Mon, 2 Dec 2019 15:33:55 +0200
Subject: [PATCH] Implement encoding of multi-valued query params.

---
 modules/reitit-core/src/reitit/impl.cljc | 13 +++++++++----
 test/cljc/reitit/impl_test.cljc          | 12 +++++-------
 2 files changed, 14 insertions(+), 11 deletions(-)

diff --git a/modules/reitit-core/src/reitit/impl.cljc b/modules/reitit-core/src/reitit/impl.cljc
index 5f41802c..c99d593b 100644
--- a/modules/reitit-core/src/reitit/impl.cljc
+++ b/modules/reitit-core/src/reitit/impl.cljc
@@ -73,7 +73,7 @@
 
 (defn resolve-routes [raw-routes {:keys [coerce] :as opts}]
   (cond->> (->> (walk raw-routes opts) (map-data merge-data))
-           coerce (into [] (keep #(coerce % opts)))))
+    coerce (into [] (keep #(coerce % opts)))))
 
 (defn path-conflicting-routes [routes opts]
   (-> (into {}
@@ -239,14 +239,19 @@
   [params]
   (maybe-map-values #(url-encode (into-string %)) params))
 
+(defn- query-parameter [k v]
+  (str (form-encode (into-string k))
+       "="
+       (form-encode (into-string v))))
+
 (defn query-string
   "shallow transform of query parameters into query string"
   [params]
   (->> params
        (map (fn [[k v]]
-              (str (form-encode (into-string k))
-                   "="
-                   (form-encode (into-string v)))))
+              (if (or (sequential? v) (set? v))
+                (str/join "&" (map query-parameter (repeat k) v))
+                (query-parameter k v))))
        (str/join "&")))
 
 (defmacro goog-extend [type base-type ctor & methods]
diff --git a/test/cljc/reitit/impl_test.cljc b/test/cljc/reitit/impl_test.cljc
index d8ff062f..1b2165c5 100644
--- a/test/cljc/reitit/impl_test.cljc
+++ b/test/cljc/reitit/impl_test.cljc
@@ -51,13 +51,11 @@
     {:a 1} "a=1"
     {:a nil} "a="
     {:a :b :c "d"} "a=b&c=d"
-    {:a "b c"} "a=b+c"))
-
-; TODO: support seq values?
-;{:a ["b" "c"]} "a=b&a=c"
-;{:a ["c" "b"]} "a=c&a=b"
-;{:a (seq [1 2])} "a=1&a=2"
-;{:a #{"c" "b"}} "a=b&a=c"
+    {:a "b c"} "a=b+c"
+    {:a ["b" "c"]} "a=b&a=c"
+    {:a ["c" "b"]} "a=c&a=b"
+    {:a (seq [1 2])} "a=1&a=2"
+    {:a #{"c" "b"}} "a=b&a=c"))
 
 ;; test from https://github.com/playframework/playframework -> UriEncodingSpec.scala