Tell JSON encoder what to do with BSON IDs

src/metabase/middleware/format.clj

@@ -24,6 +24,9 @@
 ;; Do the same for PG arrays
 (add-encoder org.postgresql.jdbc4.Jdbc4Array encode-str)
 
+;; Encode BSON IDs like strings
+(add-encoder org.bson.types.ObjectId encode-str)
+
 ;; serialize sql dates (i.e., QueryProcessor results) like YYYY-MM-DD instead of as a full-blown timestamp
 (add-encoder java.sql.Date (fn [^java.sql.Date date ^com.fasterxml.jackson.core.JsonGenerator json-generator]
                              (.writeString json-generator (.toString date))))