Export Replacer type

middleware/replacer.go

@@ -8,17 +8,21 @@ import (
 	"time"
 )
 
-// replacer is a type which can replace placeholder
+// Replacer is a type which can replace placeholder
 // substrings in a string with actual values from a
 // http.Request and responseRecorder. Always use
 // NewReplacer to get one of these.
+type Replacer interface {
+	Replace(string) string
+}
+
 type replacer map[string]string
 
 // NewReplacer makes a new replacer based on r and rr.
 // Do not create a new replacer until r and rr have all
 // the needed values, because this function copies those
 // values into the replacer.
-func NewReplacer(r *http.Request, rr *responseRecorder) replacer {
+func NewReplacer(r *http.Request, rr *responseRecorder) Replacer {
 	rep := replacer{
 		"{method}": r.Method,
 		"{scheme}": func() string {