TASK-006: Replace #define constants with httpserver::constants

Move every value-form #define from public headers into
inline constexpr declarations under httpserver::constants:

- DEFAULT_WS_PORT      -> std::uint16_t (9898)
- DEFAULT_WS_TIMEOUT   -> int           (180 seconds)
- DEFAULT_MASK_VALUE   -> std::uint16_t (0xFFFF)
- NOT_FOUND_ERROR      -> std::string_view ("Not Found")
- METHOD_ERROR         -> std::string_view ("Method not Allowed")
- NOT_METHOD_ERROR     -> std::string_view ("Method not Acceptable")
- GENERIC_ERROR        -> std::string_view ("Internal Error")

The new header src/httpserver/constants.hpp uses the established
two-token gate (_HTTPSERVER_HPP_INSIDE_ + HTTPSERVER_COMPILATION),
is re-exported from <httpserver.hpp>, and is registered in
nobase_include_HEADERS so it ships in the install layout.

Internal callers in webserver.cpp, http_utils.cpp,
create_webserver.hpp, and http_utils.hpp are migrated to the
namespaced names. The string_response call sites materialize a
std::string from the string_view to satisfy the existing ctor
signature.

A new unit test (test/unit/constants_test.cpp) pins the values
and types via static_assert, and uses #ifdef sentinels to
witness that the v1 macro names no longer leak into consumer
namespace after #include <httpserver.hpp>.

NOT_METHOD_ERROR has no in-tree caller; retained for v1 API
parity per the v2.0 mechanical-migration policy.

Acceptance:
- 23/23 tests pass (release + debug -Werror -Wall -Wextra)
- Filtered grep on src/httpserver/*.hpp shows no leftover
  value-constant #defines (include guards, _WINDOWS,
  _WIN32_WINNT, and COMPARATOR are out of scope per plan §2)
- Installed-header layout includes httpserver/constants.hpp

Closes TASK-006.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: etr

src/Makefile.am

@@ -24,7 +24,7 @@ libhttpserver_la_SOURCES = string_utilities.cpp webserver.cpp http_utils.cpp fil
 # Detail headers (httpserver/details/*.hpp) live here so they cannot leak to
 # downstream consumers — the public surface comes in through <httpserver.hpp>.
 noinst_HEADERS = httpserver/string_utilities.hpp httpserver/details/modded_request.hpp httpserver/details/http_endpoint.hpp gettext.h
-nobase_include_HEADERS = httpserver.hpp httpserver/create_webserver.hpp httpserver/webserver.hpp httpserver/http_utils.hpp httpserver/file_info.hpp httpserver/http_request.hpp httpserver/http_response.hpp httpserver/http_resource.hpp httpserver/string_response.hpp httpserver/digest_auth_fail_response.hpp httpserver/deferred_response.hpp httpserver/file_response.hpp httpserver/pipe_response.hpp httpserver/empty_response.hpp httpserver/feature_unavailable.hpp httpserver/iovec_entry.hpp httpserver/iovec_response.hpp httpserver/http_arg_value.hpp httpserver/http_method.hpp
+nobase_include_HEADERS = httpserver.hpp httpserver/constants.hpp httpserver/create_webserver.hpp httpserver/webserver.hpp httpserver/http_utils.hpp httpserver/file_info.hpp httpserver/http_request.hpp httpserver/http_response.hpp httpserver/http_resource.hpp httpserver/string_response.hpp httpserver/digest_auth_fail_response.hpp httpserver/deferred_response.hpp httpserver/file_response.hpp httpserver/pipe_response.hpp httpserver/empty_response.hpp httpserver/feature_unavailable.hpp httpserver/iovec_entry.hpp httpserver/iovec_response.hpp httpserver/http_arg_value.hpp httpserver/http_method.hpp
 
 if HAVE_BAUTH
 libhttpserver_la_SOURCES += basic_auth_fail_response.cpp

src/http_utils.cpp

@@ -18,6 +18,7 @@
      USA
 */
 
+#include "httpserver/constants.hpp"
 #include "httpserver/http_utils.hpp"
 
 #if defined(_WIN32) && !defined(__CYGWIN__)
@@ -373,12 +374,12 @@ ip_representation::ip_representation(const struct sockaddr* ip) {
             pieces[i] = (reinterpret_cast<const u_char*>(sin_addr6_pt))[i];
         }
     }
-    mask = DEFAULT_MASK_VALUE;
+    mask = constants::DEFAULT_MASK_VALUE;
 }
 
 ip_representation::ip_representation(const std::string& ip) {
     std::vector<std::string> parts;
-    mask = DEFAULT_MASK_VALUE;
+    mask = constants::DEFAULT_MASK_VALUE;
     std::fill(pieces, pieces + 16, 0);
     if (ip.find(':') != std::string::npos) {  // IPV6
         ip_version = http_utils::IPV6;

src/httpserver.hpp

@@ -30,6 +30,7 @@
 #ifdef HAVE_BAUTH
 #include "httpserver/basic_auth_fail_response.hpp"
 #endif  // HAVE_BAUTH
+#include "httpserver/constants.hpp"
 #include "httpserver/deferred_response.hpp"
 #ifdef HAVE_DAUTH
 #include "httpserver/digest_auth_fail_response.hpp"

src/httpserver/constants.hpp

@@ -0,0 +1,83 @@
+/*
+     This file is part of libhttpserver
+     Copyright (C) 2011-2019 Sebastiano Merlino
+
+     This library is free software; you can redistribute it and/or
+     modify it under the terms of the GNU Lesser General Public
+     License as published by the Free Software Foundation; either
+     version 2.1 of the License, or (at your option) any later version.
+
+     This library is distributed in the hope that it will be useful,
+     but WITHOUT ANY WARRANTY; without even the implied warranty of
+     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+     Lesser General Public License for more details.
+
+     You should have received a copy of the GNU Lesser General Public
+     License along with this library; if not, write to the Free Software
+     Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301
+     USA
+*/
+
+#if !defined (_HTTPSERVER_HPP_INSIDE_) && !defined (HTTPSERVER_COMPILATION)
+#error "Only <httpserver.hpp> or <httpserverpp> can be included directly."
+#endif
+
+#ifndef SRC_HTTPSERVER_CONSTANTS_HPP_
+#define SRC_HTTPSERVER_CONSTANTS_HPP_
+
+#include <cstdint>
+#include <string_view>
+
+// Public, namespaced replacements for the v1 #define wall. Each constant
+// here was previously a value-form macro in a public header (see PRD-CFG-
+// REQ-002 / architecture §4.9 for the rationale). The identifiers
+// preserve their v1 spellings so the migration is mechanical: only the
+// namespace qualifier changes at call sites.
+//
+// `inline constexpr` (C++17+, project floor is C++20 per TASK-001) gives
+// each symbol a single ODR-stable definition usable from any TU that
+// includes this header.
+namespace httpserver::constants {
+
+// Default TCP port the webserver binds to when no `port()` is set on the
+// create_webserver builder. Replaces v1 `#define DEFAULT_WS_PORT 9898`.
+inline constexpr std::uint16_t DEFAULT_WS_PORT = 9898;
+
+// Default per-connection timeout in seconds. Replaces v1
+// `#define DEFAULT_WS_TIMEOUT 180`. Type is `int` to match the
+// `create_webserver._connection_timeout` field exactly — no implicit
+// conversion at the assignment site, no -Wconversion noise. The value
+// is non-negative by construction.
+inline constexpr int DEFAULT_WS_TIMEOUT = 180;
+
+// Bitmask sentinel used by ip_representation when no explicit CIDR mask
+// has been parsed (all 16 nibbles "present"). Replaces v1
+// `#define DEFAULT_MASK_VALUE 0xFFFF`.
+inline constexpr std::uint16_t DEFAULT_MASK_VALUE = 0xFFFFu;
+
+// Default body for a 404 response when no not_found_resource is set on
+// the webserver. Replaces v1 `#define NOT_FOUND_ERROR "Not Found"`.
+// std::string_view keeps storage non-allocating; call sites materialize
+// a std::string via the string_response constructor.
+inline constexpr std::string_view NOT_FOUND_ERROR = "Not Found";
+
+// Default body for a 405 response when no method_not_allowed_resource
+// is set. Replaces v1 `#define METHOD_ERROR "Method not Allowed"`.
+// The name is preserved (rather than renamed to METHOD_NOT_ALLOWED_ERROR)
+// to keep the migration mechanical — the namespacing is the API change,
+// not a rename.
+inline constexpr std::string_view METHOD_ERROR = "Method not Allowed";
+
+// Default body for a 406 response. Replaces v1
+// `#define NOT_METHOD_ERROR "Method not Acceptable"`. Currently unused
+// by any in-tree caller (verified by grep across src/, test/, examples/);
+// retained for v1 API parity per the v2.0 mechanical-migration policy.
+inline constexpr std::string_view NOT_METHOD_ERROR = "Method not Acceptable";
+
+// Default body for a 500 response when no internal_error_resource is
+// set. Replaces v1 `#define GENERIC_ERROR "Internal Error"`.
+inline constexpr std::string_view GENERIC_ERROR = "Internal Error";
+
+}  // namespace httpserver::constants
+
+#endif  // SRC_HTTPSERVER_CONSTANTS_HPP_

src/httpserver/create_webserver.hpp

@@ -33,12 +33,10 @@
 #include <variant>
 #include <vector>
 
+#include "httpserver/constants.hpp"
 #include "httpserver/http_response.hpp"
 #include "httpserver/http_utils.hpp"
 
-#define DEFAULT_WS_TIMEOUT 180
-#define DEFAULT_WS_PORT 9898
-
 namespace httpserver {
 
 class webserver;
@@ -480,13 +478,13 @@ class create_webserver {
     }
 
  private:
-     uint16_t _port = DEFAULT_WS_PORT;
+     uint16_t _port = constants::DEFAULT_WS_PORT;
      http::http_utils::start_method_T _start_method = http::http_utils::INTERNAL_SELECT;
      int _max_threads = 0;
      int _max_connections = 0;
      int _memory_limit = 0;
      size_t _content_size_limit = std::numeric_limits<size_t>::max();
-     int _connection_timeout = DEFAULT_WS_TIMEOUT;
+     int _connection_timeout = constants::DEFAULT_WS_TIMEOUT;
      int _per_IP_connection_limit = 0;
      log_access_ptr _log_access = nullptr;
      log_error_ptr _log_error = nullptr;

src/httpserver/http_utils.hpp

@@ -56,10 +56,9 @@
 #include <string>
 #include <vector>
 
+#include "httpserver/constants.hpp"
 #include "httpserver/http_arg_value.hpp"
 
-#define DEFAULT_MASK_VALUE 0xFFFF
-
 
 namespace httpserver {
 
@@ -370,7 +369,7 @@ struct ip_representation {
 
     explicit ip_representation(http_utils::IP_version_T ip_version) :
         ip_version(ip_version) {
-            mask = DEFAULT_MASK_VALUE;
+            mask = constants::DEFAULT_MASK_VALUE;
             std::fill(pieces, pieces + 16, 0);
     }
 

src/httpserver/webserver.hpp

@@ -25,11 +25,6 @@
 #ifndef SRC_HTTPSERVER_WEBSERVER_HPP_
 #define SRC_HTTPSERVER_WEBSERVER_HPP_
 
-#define NOT_FOUND_ERROR "Not Found"
-#define METHOD_ERROR "Method not Allowed"
-#define NOT_METHOD_ERROR "Method not Acceptable"
-#define GENERIC_ERROR "Internal Error"
-
 #include <microhttpd.h>
 #include <pthread.h>
 #include <stdarg.h>
@@ -54,6 +49,7 @@
 #include <gnutls/gnutls.h>
 #endif  // HAVE_GNUTLS
 
+#include "httpserver/constants.hpp"
 #include "httpserver/http_utils.hpp"
 #include "httpserver/create_webserver.hpp"
 #include "httpserver/details/http_endpoint.hpp"

src/webserver.cpp

@@ -56,6 +56,7 @@
 #include <utility>
 #include <vector>
 
+#include "httpserver/constants.hpp"
 #include "httpserver/create_webserver.hpp"
 #include "httpserver/details/http_endpoint.hpp"
 #include "httpserver/details/modded_request.hpp"
@@ -1019,23 +1020,23 @@ std::shared_ptr<http_response> webserver::not_found_page(details::modded_request
     if (not_found_resource != nullptr) {
         return not_found_resource(*mr->dhr);
     } else {
-        return std::make_shared<string_response>(NOT_FOUND_ERROR, http_utils::http_not_found);
+        return std::make_shared<string_response>(std::string{constants::NOT_FOUND_ERROR}, http_utils::http_not_found);
     }
 }
 
 std::shared_ptr<http_response> webserver::method_not_allowed_page(details::modded_request* mr) const {
     if (method_not_allowed_resource != nullptr) {
         return method_not_allowed_resource(*mr->dhr);
     } else {
-        return std::make_shared<string_response>(METHOD_ERROR, http_utils::http_method_not_allowed);
+        return std::make_shared<string_response>(std::string{constants::METHOD_ERROR}, http_utils::http_method_not_allowed);
     }
 }
 
 std::shared_ptr<http_response> webserver::internal_error_page(details::modded_request* mr, bool force_our) const {
     if (internal_error_resource != nullptr && !force_our) {
         return internal_error_resource(*mr->dhr);
     } else {
-        return std::make_shared<string_response>(GENERIC_ERROR, http_utils::http_internal_server_error);
+        return std::make_shared<string_response>(std::string{constants::GENERIC_ERROR}, http_utils::http_internal_server_error);
     }
 }
 

test/Makefile.am

@@ -26,7 +26,7 @@ LDADD += -lcurl
 
 AM_CPPFLAGS = -I$(top_srcdir)/src -I$(top_srcdir)/src/httpserver/ -DHTTPSERVER_COMPILATION
 METASOURCES = AUTO
-check_PROGRAMS = basic file_upload http_utils threaded nodelay string_utilities http_endpoint ban_system ws_start_stop authentication deferred http_resource http_response create_webserver new_response_types daemon_info uri_log feature_unavailable header_hygiene_iovec iovec_entry iovec_response http_method
+check_PROGRAMS = basic file_upload http_utils threaded nodelay string_utilities http_endpoint ban_system ws_start_stop authentication deferred http_resource http_response create_webserver new_response_types daemon_info uri_log feature_unavailable header_hygiene_iovec iovec_entry iovec_response http_method constants
 
 MOSTLYCLEANFILES = *.gcda *.gcno *.gcov
 
@@ -56,6 +56,7 @@ header_hygiene_iovec_SOURCES = unit/header_hygiene_iovec_test.cpp
 iovec_entry_SOURCES = unit/iovec_entry_test.cpp
 iovec_response_SOURCES = unit/iovec_response_test.cpp
 http_method_SOURCES = unit/http_method_test.cpp
+constants_SOURCES = unit/constants_test.cpp
 
 noinst_HEADERS = littletest.hpp
 AM_CXXFLAGS += -Wall -fPIC -Wno-overloaded-virtual