diff --git a/src/shrpx_client_handler.cc b/src/shrpx_client_handler.cc
index 67bf9e50..e9cc311b 100644
--- a/src/shrpx_client_handler.cc
+++ b/src/shrpx_client_handler.cc
@@ -835,25 +835,27 @@ void ClientHandler::write_accesslog(Downstream *downstream) {
   upstream_accesslog(
       get_config()->accesslog_format,
       LogSpec{
-          downstream, ipaddr_.c_str(), http2::to_method_string(req.method),
+          downstream, ipaddr_, http2::to_method_string(req.method),
 
           req.method == HTTP_CONNECT
-              ? req.authority.c_str()
+              ? req.authority
               : (get_config()->http2_proxy || get_config()->client_proxy)
-                    ? construct_absolute_request_uri(req).c_str()
-                    : req.path.empty() ? req.method == HTTP_OPTIONS ? "*" : "-"
-                                       : req.path.c_str(),
+                    ? construct_absolute_request_uri(req)
+                    : req.path.empty()
+                          ? req.method == HTTP_OPTIONS
+                                ? StringAdaptor::from_lit("*")
+                                : StringAdaptor::from_lit("-")
+                          : req.path,
 
-          alpn_.c_str(),
-          nghttp2::ssl::get_tls_session_info(&tls_info, conn_.tls.ssl),
+          alpn_, nghttp2::ssl::get_tls_session_info(&tls_info, conn_.tls.ssl),
 
           std::chrono::system_clock::now(),          // time_now
           downstream->get_request_start_time(),      // request_start_time
           std::chrono::high_resolution_clock::now(), // request_end_time
 
           req.http_major, req.http_minor, resp.http_status,
-          downstream->response_sent_body_length, port_.c_str(),
-          get_config()->port, get_config()->pid,
+          downstream->response_sent_body_length, port_, get_config()->port,
+          get_config()->pid,
       });
 }
 
@@ -863,21 +865,20 @@ void ClientHandler::write_accesslog(int major, int minor, unsigned int status,
   auto highres_now = std::chrono::high_resolution_clock::now();
   nghttp2::ssl::TLSSessionInfo tls_info;
 
-  upstream_accesslog(get_config()->accesslog_format,
-                     LogSpec{
-                         nullptr, ipaddr_.c_str(),
-                         "-", // method
-                         "-", // path,
-                         alpn_.c_str(), nghttp2::ssl::get_tls_session_info(
-                                            &tls_info, conn_.tls.ssl),
-                         time_now,
-                         highres_now,  // request_start_time TODO is
-                                       // there a better value?
-                         highres_now,  // request_end_time
-                         major, minor, // major, minor
-                         status, body_bytes_sent, port_.c_str(),
-                         get_config()->port, get_config()->pid,
-                     });
+  upstream_accesslog(
+      get_config()->accesslog_format,
+      LogSpec{
+          nullptr, ipaddr_,
+          StringAdaptor::from_lit("-"), // method
+          StringAdaptor::from_lit("-"), // path,
+          alpn_, nghttp2::ssl::get_tls_session_info(&tls_info, conn_.tls.ssl),
+          time_now,
+          highres_now,  // request_start_time TODO is
+                        // there a better value?
+          highres_now,  // request_end_time
+          major, minor, // major, minor
+          status, body_bytes_sent, port_, get_config()->port, get_config()->pid,
+      });
 }
 
 ClientHandler::ReadBuf *ClientHandler::get_rb() { return &rb_; }
diff --git a/src/shrpx_log.cc b/src/shrpx_log.cc
index 10c398b4..e880caa0 100644
--- a/src/shrpx_log.cc
+++ b/src/shrpx_log.cc
@@ -182,6 +182,14 @@ std::pair<OutputIterator, size_t> copy(const std::string &src, size_t avail,
 }
 } // namespace
 
+namespace {
+template <typename OutputIterator>
+std::pair<OutputIterator, size_t> copy(const StringAdaptor &src, size_t avail,
+                                       OutputIterator oitr) {
+  return copy(src.c_str(), src.size(), avail, oitr);
+}
+} // namespace
+
 namespace {
 template <size_t N, typename OutputIterator>
 std::pair<OutputIterator, size_t> copy_l(const char(&src)[N], size_t avail,
diff --git a/src/shrpx_log.h b/src/shrpx_log.h
index 2fae8d04..018206ab 100644
--- a/src/shrpx_log.h
+++ b/src/shrpx_log.h
@@ -36,6 +36,9 @@
 
 #include "shrpx_log_config.h"
 #include "ssl.h"
+#include "template.h"
+
+using namespace nghttp2;
 
 #define ENABLE_LOG 1
 
@@ -139,10 +142,10 @@ struct LogFragment {
 
 struct LogSpec {
   Downstream *downstream;
-  const char *remote_addr;
-  const char *method;
-  const char *path;
-  const char *alpn;
+  StringAdaptor remote_addr;
+  StringAdaptor method;
+  StringAdaptor path;
+  StringAdaptor alpn;
   const nghttp2::ssl::TLSSessionInfo *tls_info;
   std::chrono::system_clock::time_point time_now;
   std::chrono::high_resolution_clock::time_point request_start_time;
@@ -150,7 +153,7 @@ struct LogSpec {
   int major, minor;
   unsigned int status;
   int64_t body_bytes_sent;
-  const char *remote_port;
+  StringAdaptor remote_port;
   uint16_t server_port;
   pid_t pid;
 };
diff --git a/src/template.h b/src/template.h
index 25c0828e..d0314679 100644
--- a/src/template.h
+++ b/src/template.h
@@ -254,6 +254,11 @@ struct StringAdaptor {
   StringAdaptor(const T &s)
       : base(s.c_str()), len(s.size()) {}
   StringAdaptor(const char *s) : base(s), len(strlen(s)) {}
+  StringAdaptor(const char *s, size_t n) : base(s), len(n) {}
+
+  template <size_t N> static StringAdaptor from_lit(const char(&s)[N]) {
+    return StringAdaptor(s, N - 1);
+  }
 
   const char *c_str() const { return base; }
   size_t size() const { return len; }