Release v0.21.0

* Adds headers to multipart form data

Adds a `headers` field to the `MultipartFormData` struct.

Populates this field by parsing headers from the multipart form data.
This allows access to specific headers associated with each form data part.

* Adds multipart header access test

Verifies the correct retrieval of headers from multipart form data file parts.

Ensures that custom and content-related headers are accessible and parsed as expected.

* Enables automatic test discovery with GoogleTest

Uses `gtest_discover_tests` to automatically find and run tests, simplifying test maintenance and improving discoverability.

* Removes explicit GoogleTest include

* Refactors header parsing logic

Improves header parsing by using a dedicated parsing function,
resulting in cleaner and more robust code.

This change also adds error handling during header parsing,
returning an error and marking the request as invalid
if parsing fails.

* clang-format corrected

* Renames variable for better readability.

Renames the `customHeader` variable to `custom_header` for improved code readability and consistency.

* typo

README.md

@@ -285,6 +285,22 @@ svr.set_post_routing_handler([](const auto& req, auto& res) {
 });
 ```
 
+### Pre request handler
+
+```cpp
+svr.set_pre_request_handler([](const auto& req, auto& res) {
+  if (req.matched_route == "/user/:user") {
+    auto user = req.path_params.at("user");
+    if (user != "john") {
+      res.status = StatusCode::Forbidden_403;
+      res.set_content("error", "text/html");
+      return Server::HandlerResponse::Handled;
+    }
+  }
+  return Server::HandlerResponse::Unhandled;
+});
+```
+
 ### 'multipart/form-data' POST data
 
 ```cpp

httplib.h

@@ -8,7 +8,7 @@
 #ifndef CPPHTTPLIB_HTTPLIB_H
 #define CPPHTTPLIB_HTTPLIB_H
 
-#define CPPHTTPLIB_VERSION "0.20.1"
+#define CPPHTTPLIB_VERSION "0.21.0"
 
 /*
  * Configuration
@@ -192,8 +192,13 @@ using ssize_t = long;
 #include <winsock2.h>
 #include <ws2tcpip.h>
 
+#if defined(__has_include)
+#if __has_include(<afunix.h>)
 // afunix.h uses types declared in winsock2.h, so has to be included after it.
 #include <afunix.h>
+#define CPPHTTPLIB_HAVE_AFUNIX_H 1
+#endif
+#endif
 
 #ifndef WSA_FLAG_NO_HANDLE_INHERIT
 #define WSA_FLAG_NO_HANDLE_INHERIT 0x80
@@ -539,6 +544,7 @@ struct MultipartFormData {
   std::string content;
   std::string filename;
   std::string content_type;
+  Headers headers;
 };
 using MultipartFormDataItems = std::vector<MultipartFormData>;
 using MultipartFormDataMap = std::multimap<std::string, MultipartFormData>;
@@ -631,6 +637,7 @@ using Ranges = std::vector<Range>;
 struct Request {
   std::string method;
   std::string path;
+  std::string matched_route;
   Params params;
   Headers headers;
   std::string body;
@@ -882,10 +889,16 @@ namespace detail {
 
 class MatcherBase {
 public:
+  MatcherBase(std::string pattern) : pattern_(pattern) {}
   virtual ~MatcherBase() = default;
 
+  const std::string &pattern() const { return pattern_; }
+
   // Match request path and populate its matches and
   virtual bool match(Request &request) const = 0;
+
+private:
+  std::string pattern_;
 };
 
 /**
@@ -937,7 +950,8 @@ private:
  */
 class RegexMatcher final : public MatcherBase {
 public:
-  RegexMatcher(const std::string &pattern) : regex_(pattern) {}
+  RegexMatcher(const std::string &pattern)
+      : MatcherBase(pattern), regex_(pattern) {}
 
   bool match(Request &request) const override;
 
@@ -1004,9 +1018,12 @@ public:
   }
 
   Server &set_exception_handler(ExceptionHandler handler);
+
   Server &set_pre_routing_handler(HandlerWithResponse handler);
   Server &set_post_routing_handler(Handler handler);
 
+  Server &set_pre_request_handler(HandlerWithResponse handler);
+
   Server &set_expect_100_continue_handler(Expect100ContinueHandler handler);
   Server &set_logger(Logger logger);
 
@@ -1087,8 +1104,7 @@ private:
   bool listen_internal();
 
   bool routing(Request &req, Response &res, Stream &strm);
-  bool handle_file_request(const Request &req, Response &res,
-                           bool head = false);
+  bool handle_file_request(const Request &req, Response &res);
   bool dispatch_request(Request &req, Response &res,
                         const Handlers &handlers) const;
   bool dispatch_request_for_content_reader(
@@ -1149,6 +1165,7 @@ private:
   ExceptionHandler exception_handler_;
   HandlerWithResponse pre_routing_handler_;
   Handler post_routing_handler_;
+  HandlerWithResponse pre_request_handler_;
   Expect100ContinueHandler expect_100_continue_handler_;
 
   Logger logger_;
@@ -2066,7 +2083,9 @@ template <size_t N> inline constexpr size_t str_len(const char (&)[N]) {
 }
 
 inline bool is_numeric(const std::string &str) {
-  return !str.empty() && std::all_of(str.begin(), str.end(), ::isdigit);
+  return !str.empty() &&
+         std::all_of(str.cbegin(), str.cend(),
+                     [](unsigned char c) { return std::isdigit(c); });
 }
 
 inline uint64_t get_header_value_u64(const Headers &headers,
@@ -3550,6 +3569,7 @@ socket_t create_socket(const std::string &host, const std::string &ip, int port,
     hints.ai_flags = socket_flags;
   }
 
+#if !defined(_WIN32) || defined(CPPHTTPLIB_HAVE_AFUNIX_H)
   if (hints.ai_family == AF_UNIX) {
     const auto addrlen = host.length();
     if (addrlen > sizeof(sockaddr_un::sun_path)) { return INVALID_SOCKET; }
@@ -3594,6 +3614,7 @@ socket_t create_socket(const std::string &host, const std::string &ip, int port,
     }
     return sock;
   }
+#endif
 
   auto service = std::to_string(port);
 
@@ -5025,6 +5046,16 @@ public:
             return false;
           }
 
+          // parse and emplace space trimmed headers into a map
+          if (!parse_header(
+                  header.data(), header.data() + header.size(),
+                  [&](const std::string &key, const std::string &val) {
+                    file_.headers.emplace(key, val);
+                  })) {
+            is_valid_ = false;
+            return false;
+          }
+
           constexpr const char header_content_type[] = "Content-Type:";
 
           if (start_with_case_ignore(header, header_content_type)) {
@@ -5124,6 +5155,7 @@ private:
     file_.name.clear();
     file_.filename.clear();
     file_.content_type.clear();
+    file_.headers.clear();
   }
 
   bool start_with_case_ignore(const std::string &a, const char *b) const {
@@ -6216,7 +6248,8 @@ inline time_t BufferStream::duration() const { return 0; }
 
 inline const std::string &BufferStream::get_buffer() const { return buffer; }
 
-inline PathParamsMatcher::PathParamsMatcher(const std::string &pattern) {
+inline PathParamsMatcher::PathParamsMatcher(const std::string &pattern)
+    : MatcherBase(pattern) {
   constexpr const char marker[] = "/:";
 
   // One past the last ending position of a path param substring
@@ -6467,6 +6500,11 @@ inline Server &Server::set_post_routing_handler(Handler handler) {
   return *this;
 }
 
+inline Server &Server::set_pre_request_handler(HandlerWithResponse handler) {
+  pre_request_handler_ = std::move(handler);
+  return *this;
+}
+
 inline Server &Server::set_logger(Logger logger) {
   logger_ = std::move(logger);
   return *this;
@@ -6878,8 +6916,7 @@ Server::read_content_core(Stream &strm, Request &req, Response &res,
   return true;
 }
 
-inline bool Server::handle_file_request(const Request &req, Response &res,
-                                        bool head) {
+inline bool Server::handle_file_request(const Request &req, Response &res) {
   for (const auto &entry : base_dirs_) {
     // Prefix match
     if (!req.path.compare(0, entry.mount_point.size(), entry.mount_point)) {
@@ -6912,7 +6949,7 @@ inline bool Server::handle_file_request(const Request &req, Response &res,
                 return true;
               });
 
-          if (!head && file_request_handler_) {
+          if (req.method != "HEAD" && file_request_handler_) {
             file_request_handler_(req, res);
           }
 
@@ -7046,9 +7083,8 @@ inline bool Server::routing(Request &req, Response &res, Stream &strm) {
   }
 
   // File handler
-  auto is_head_request = req.method == "HEAD";
-  if ((req.method == "GET" || is_head_request) &&
-      handle_file_request(req, res, is_head_request)) {
+  if ((req.method == "GET" || req.method == "HEAD") &&
+      handle_file_request(req, res)) {
     return true;
   }
 
@@ -7123,7 +7159,11 @@ inline bool Server::dispatch_request(Request &req, Response &res,
     const auto &handler = x.second;
 
     if (matcher->match(req)) {
-      handler(req, res);
+      req.matched_route = matcher->pattern();
+      if (!pre_request_handler_ ||
+          pre_request_handler_(req, res) != HandlerResponse::Handled) {
+        handler(req, res);
+      }
       return true;
     }
   }
@@ -7250,7 +7290,11 @@ inline bool Server::dispatch_request_for_content_reader(
     const auto &handler = x.second;
 
     if (matcher->match(req)) {
-      handler(req, res, content_reader);
+      req.matched_route = matcher->pattern();
+      if (!pre_request_handler_ ||
+          pre_request_handler_(req, res) != HandlerResponse::Handled) {
+        handler(req, res, content_reader);
+      }
       return true;
     }
   }

meson.build

@@ -87,7 +87,7 @@ if get_option('cpp-httplib_compile')
     soversion: version.split('.')[0] + '.' + version.split('.')[1],
     install: true
   )
-  cpp_httplib_dep = declare_dependency(compile_args: args, dependencies: deps, link_with: lib, sources: httplib_ch[1])
+  cpp_httplib_dep = declare_dependency(compile_args: args, dependencies: deps, link_with: lib, sources: httplib_ch[1], version: version)
 
   import('pkgconfig').generate(
     lib,
@@ -98,7 +98,7 @@ if get_option('cpp-httplib_compile')
   )
 else
   install_headers('httplib.h')
-  cpp_httplib_dep = declare_dependency(compile_args: args, dependencies: deps, include_directories: '.')
+  cpp_httplib_dep = declare_dependency(compile_args: args, dependencies: deps, include_directories: '.', version: version)
 
   import('pkgconfig').generate(
     name: 'cpp-httplib',

test/test.cc

@@ -2263,7 +2263,7 @@ TEST(NoContentTest, ContentLength) {
   }
 }
 
-TEST(RoutingHandlerTest, PreRoutingHandler) {
+TEST(RoutingHandlerTest, PreAndPostRoutingHandlers) {
 #ifdef CPPHTTPLIB_OPENSSL_SUPPORT
   SSLServer svr(SERVER_CERT_FILE, SERVER_PRIVATE_KEY_FILE);
   ASSERT_TRUE(svr.is_valid());
@@ -2354,6 +2354,63 @@ TEST(RoutingHandlerTest, PreRoutingHandler) {
   }
 }
 
+TEST(RequestHandlerTest, PreRequestHandler) {
+  auto route_path = "/user/:user";
+
+  Server svr;
+
+  svr.Get("/hi", [](const Request &, Response &res) {
+    res.set_content("hi", "text/plain");
+  });
+
+  svr.Get(route_path, [](const Request &req, Response &res) {
+    res.set_content(req.path_params.at("user"), "text/plain");
+  });
+
+  svr.set_pre_request_handler([&](const Request &req, Response &res) {
+    if (req.matched_route == route_path) {
+      auto user = req.path_params.at("user");
+      if (user != "john") {
+        res.status = StatusCode::Forbidden_403;
+        res.set_content("error", "text/html");
+        return Server::HandlerResponse::Handled;
+      }
+    }
+    return Server::HandlerResponse::Unhandled;
+  });
+
+  auto thread = std::thread([&]() { svr.listen(HOST, PORT); });
+  auto se = detail::scope_exit([&] {
+    svr.stop();
+    thread.join();
+    ASSERT_FALSE(svr.is_running());
+  });
+
+  svr.wait_until_ready();
+
+  Client cli(HOST, PORT);
+  {
+    auto res = cli.Get("/hi");
+    ASSERT_TRUE(res);
+    EXPECT_EQ(StatusCode::OK_200, res->status);
+    EXPECT_EQ("hi", res->body);
+  }
+
+  {
+    auto res = cli.Get("/user/john");
+    ASSERT_TRUE(res);
+    EXPECT_EQ(StatusCode::OK_200, res->status);
+    EXPECT_EQ("john", res->body);
+  }
+
+  {
+    auto res = cli.Get("/user/invalid-user");
+    ASSERT_TRUE(res);
+    EXPECT_EQ(StatusCode::Forbidden_403, res->status);
+    EXPECT_EQ("error", res->body);
+  }
+}
+
 TEST(InvalidFormatTest, StatusCode) {
   Server svr;
 
@@ -5732,6 +5789,41 @@ TEST(KeepAliveTest, ReadTimeout) {
   EXPECT_EQ("b", resb->body);
 }
 
+TEST(KeepAliveTest, MaxCount) {
+  size_t keep_alive_max_count = 3;
+
+  Server svr;
+  svr.set_keep_alive_max_count(keep_alive_max_count);
+
+  svr.Get("/hi", [](const httplib::Request &, httplib::Response &res) {
+    res.set_content("Hello World!", "text/plain");
+  });
+
+  auto listen_thread = std::thread([&svr] { svr.listen(HOST, PORT); });
+  auto se = detail::scope_exit([&] {
+    svr.stop();
+    listen_thread.join();
+    ASSERT_FALSE(svr.is_running());
+  });
+
+  svr.wait_until_ready();
+
+  Client cli(HOST, PORT);
+  cli.set_keep_alive(true);
+
+  for (size_t i = 0; i < 5; i++) {
+    auto result = cli.Get("/hi");
+    ASSERT_TRUE(result);
+    EXPECT_EQ(StatusCode::OK_200, result->status);
+
+    if (i == keep_alive_max_count - 1) {
+      EXPECT_EQ("close", result->get_header_value("Connection"));
+    } else {
+      EXPECT_FALSE(result->has_header("Connection"));
+    }
+  }
+}
+
 TEST(KeepAliveTest, Issue1041) {
   Server svr;
   svr.set_keep_alive_timeout(3);
@@ -7918,6 +8010,68 @@ TEST(MultipartFormDataTest, ContentLength) {
   ASSERT_TRUE(send_request(1, req, &response));
   ASSERT_EQ("200", response.substr(9, 3));
 }
+
+TEST(MultipartFormDataTest, AccessPartHeaders) {
+  auto handled = false;
+
+  Server svr;
+  svr.Post("/test", [&](const Request &req, Response &) {
+    ASSERT_EQ(2u, req.files.size());
+
+    auto it = req.files.begin();
+    ASSERT_EQ("text1", it->second.name);
+    ASSERT_EQ("text1", it->second.content);
+    ASSERT_EQ(1, it->second.headers.count("Content-Length"));
+    auto content_length = it->second.headers.find("CONTENT-length");
+    ASSERT_EQ("5", content_length->second);
+    ASSERT_EQ(3, it->second.headers.size());
+
+    ++it;
+    ASSERT_EQ("text2", it->second.name);
+    ASSERT_EQ("text2", it->second.content);
+    auto &headers = it->second.headers;
+    ASSERT_EQ(3, headers.size());
+    auto custom_header = headers.find("x-whatever");
+    ASSERT_TRUE(custom_header != headers.end());
+    ASSERT_NE("customvalue", custom_header->second);
+    ASSERT_EQ("CustomValue", custom_header->second);
+    ASSERT_TRUE(headers.find("X-Test") == headers.end()); // text1 header
+
+    handled = true;
+  });
+
+  thread t = thread([&] { svr.listen(HOST, PORT); });
+  auto se = detail::scope_exit([&] {
+    svr.stop();
+    t.join();
+    ASSERT_FALSE(svr.is_running());
+    ASSERT_TRUE(handled);
+  });
+
+  svr.wait_until_ready();
+
+  auto req = "POST /test HTTP/1.1\r\n"
+             "Content-Type: multipart/form-data;boundary=--------\r\n"
+             "Content-Length: 232\r\n"
+             "\r\n----------\r\n"
+             "Content-Disposition: form-data; name=\"text1\"\r\n"
+             "Content-Length: 5\r\n"
+             "X-Test: 1\r\n"
+             "\r\n"
+             "text1"
+             "\r\n----------\r\n"
+             "Content-Disposition: form-data; name=\"text2\"\r\n"
+             "Content-Type: text/plain\r\n"
+             "X-Whatever: CustomValue\r\n"
+             "\r\n"
+             "text2"
+             "\r\n------------\r\n"
+             "That should be disregarded. Not even read";
+
+  std::string response;
+  ASSERT_TRUE(send_request(1, req, &response));
+  ASSERT_EQ("200", response.substr(9, 3));
+}
 #endif
 
 TEST(TaskQueueTest, IncreaseAtomicInteger) {