introduce string_view

webcc/response_builder.h

@@ -61,13 +61,13 @@ public:
     return *this;
   }
 
-  ResponseBuilder& MediaType(const std::string& media_type) {
-    media_type_ = media_type;
+  ResponseBuilder& MediaType(string_view media_type) {
+    media_type_ = ToString(media_type);
     return *this;
   }
 
-  ResponseBuilder& Charset(const std::string& charset) {
-    charset_ = charset;
+  ResponseBuilder& Charset(string_view charset) {
+    charset_ = ToString(charset);
     return *this;
   }
 
@@ -98,11 +98,7 @@ public:
   ResponseBuilder& File(const fs::path& path, bool infer_media_type = true,
                         std::size_t chunk_size = 1024);
 
-  ResponseBuilder& Header(const std::string& key, const std::string& value) {
-    headers_.push_back(key);
-    headers_.push_back(value);
-    return *this;
-  }
+  ResponseBuilder& Header(string_view key, string_view value);
 
   // Add the `Date` header to the response.
   ResponseBuilder& Date();