Fixes #21: Override Timestamp using from-pg-value.

src/postgres/async.clj

@@ -6,13 +6,20 @@
            [com.github.pgasync.impl.conversion DataConverter]))
 
 (defmulti from-pg-value (fn [oid value] oid))
+(defmethod from-pg-value :default [oid value] ::raw-value)
+
 (defprotocol IPgParameter
   (to-pg-value [value]))
 
 (defn- create-converter []
   (proxy [DataConverter] []
-    (toConvertable [oid value]
-      (from-pg-value oid value))
+    (toObject [oid value]
+      (when value
+        (let [val (from-pg-value oid value)]
+          (if (= ::raw-value val)
+            (proxy-call-with-super #(.toObject ^DataConverter this oid value)
+                                   this "toObject")
+            val))))
     (fromConvertable [value]
       (to-pg-value value))))
 

test/postgres/async_test.clj

@@ -66,6 +66,21 @@
       (is (instance? SqlException (<!! c)))
       (is (nil? (<!! c)))))
 
+(deftest query-for-overridden-types
+
+  (defmethod from-pg-value com.github.pgasync.impl.Oid/TIMESTAMP [oid ^bytes value]
+    (String. value "utf-8"))
+
+  (testing "timestamp can be returned as string"
+    (let [c (query-rows! *db* ["select $1::TIMESTAMP as ts"
+                               "2016-05-01T12:00:00.001"])]
+      (is (= {:ts "2016-05-01 12:00:00.001"} (<!! c)))))
+
+  (testing "unsupported type throws an exception"
+    (let [c (query-rows! *db* ["select '<x/>'::xml"])
+          ^Throwable ex (<!! c)]
+      (is (= "Unknown conversion source: XML" (.getMessage ex))))))
+
 (deftest inserts
 
   (testing "insert returns row count"