From 4dd2f3d03dcad28c267ecee85560a9ff151bcb66 Mon Sep 17 00:00:00 2001
From: Congcong Cai <congcong.cai@bmw.com>
Date: Thu, 7 Mar 2024 19:07:39 +0800
Subject: [PATCH 1/2] fix ambiguous for HandlerWithResponse and Handler in
 set_error_handler

using lambda expression as Handler in set_error_handler will cause ambiguous.
Template forwarding can forward HandlerWithResponse to the correct overloading function
---
 httplib.h | 19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

diff --git a/httplib.h b/httplib.h
index cabdb48..74c034e 100644
--- a/httplib.h
+++ b/httplib.h
@@ -231,6 +231,7 @@ using socket_t = int;
 #include <string>
 #include <sys/stat.h>
 #include <thread>
+#include <type_traits>
 #include <unordered_map>
 #include <unordered_set>
 #include <utility>
@@ -871,8 +872,13 @@ public:
   Server &set_default_file_mimetype(const std::string &mime);
   Server &set_file_request_handler(Handler handler);
 
-  Server &set_error_handler(HandlerWithResponse handler);
-  Server &set_error_handler(Handler handler);
+  template <class ErrorHandlerFunc>
+  Server &set_error_handler(ErrorHandlerFunc &&handler) {
+    return set_error_handler_impl(
+        std::forward<ErrorHandlerFunc>(handler),
+        std::is_convertible<ErrorHandlerFunc, HandlerWithResponse>{});
+  }
+
   Server &set_exception_handler(ExceptionHandler handler);
   Server &set_pre_routing_handler(HandlerWithResponse handler);
   Server &set_post_routing_handler(Handler handler);
@@ -934,6 +940,9 @@ protected:
   size_t payload_max_length_ = CPPHTTPLIB_PAYLOAD_MAX_LENGTH;
 
 private:
+  Server &set_error_handler_impl(HandlerWithResponse handler, std::true_type);
+  Server &set_error_handler_impl(Handler handler, std::false_type);
+
   using Handlers =
       std::vector<std::pair<std::unique_ptr<detail::MatcherBase>, Handler>>;
   using HandlersForContentReader =
@@ -5797,12 +5806,14 @@ inline Server &Server::set_file_request_handler(Handler handler) {
   return *this;
 }
 
-inline Server &Server::set_error_handler(HandlerWithResponse handler) {
+inline Server &Server::set_error_handler_impl(HandlerWithResponse handler,
+                                              std::true_type) {
   error_handler_ = std::move(handler);
   return *this;
 }
 
-inline Server &Server::set_error_handler(Handler handler) {
+inline Server &Server::set_error_handler_impl(Handler handler,
+                                              std::false_type) {
   error_handler_ = [handler](const Request &req, Response &res) {
     handler(req, res);
     return HandlerResponse::Handled;

From 07288888ad39004ddcdfefadfdd666c3a8737a5c Mon Sep 17 00:00:00 2001
From: yhirose <yuji.hirose.bug@gmail.com>
Date: Thu, 11 Apr 2024 22:26:30 -0400
Subject: [PATCH 2/2] Code cleanup

---
 httplib.h | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/httplib.h b/httplib.h
index 698849c..4c446d9 100644
--- a/httplib.h
+++ b/httplib.h
@@ -231,7 +231,6 @@ using socket_t = int;
 #include <string>
 #include <sys/stat.h>
 #include <thread>
-#include <type_traits>
 #include <unordered_map>
 #include <unordered_set>
 #include <utility>
@@ -874,7 +873,7 @@ public:
 
   template <class ErrorHandlerFunc>
   Server &set_error_handler(ErrorHandlerFunc &&handler) {
-    return set_error_handler_impl(
+    return set_error_handler_core(
         std::forward<ErrorHandlerFunc>(handler),
         std::is_convertible<ErrorHandlerFunc, HandlerWithResponse>{});
   }
@@ -940,9 +939,6 @@ protected:
   size_t payload_max_length_ = CPPHTTPLIB_PAYLOAD_MAX_LENGTH;
 
 private:
-  Server &set_error_handler_impl(HandlerWithResponse handler, std::true_type);
-  Server &set_error_handler_impl(Handler handler, std::false_type);
-
   using Handlers =
       std::vector<std::pair<std::unique_ptr<detail::MatcherBase>, Handler>>;
   using HandlersForContentReader =
@@ -952,6 +948,9 @@ private:
   static std::unique_ptr<detail::MatcherBase>
   make_matcher(const std::string &pattern);
 
+  Server &set_error_handler_core(HandlerWithResponse handler, std::true_type);
+  Server &set_error_handler_core(Handler handler, std::false_type);
+
   socket_t create_server_socket(const std::string &host, int port,
                                 int socket_flags,
                                 SocketOptions socket_options) const;
@@ -5817,13 +5816,13 @@ inline Server &Server::set_file_request_handler(Handler handler) {
   return *this;
 }
 
-inline Server &Server::set_error_handler_impl(HandlerWithResponse handler,
+inline Server &Server::set_error_handler_core(HandlerWithResponse handler,
                                               std::true_type) {
   error_handler_ = std::move(handler);
   return *this;
 }
 
-inline Server &Server::set_error_handler_impl(Handler handler,
+inline Server &Server::set_error_handler_core(Handler handler,
                                               std::false_type) {
   error_handler_ = [handler](const Request &req, Response &res) {
     handler(req, res);