Release v0.32.0

* Fix compilation on BoringSSL by replacing ASN1_TIME_to_tm

BoringSSL doesn't expose `ASN1_TIME_to_tm`.
This patch switches to using `ASN1_TIME_diff` to calculate `time_t`.
This is supported by OpenSSL, LibreSSL, and BoringSSL, and also avoids
the platform-specific `timegm` vs `_mkgmtime` logic.

Signed-off-by: Adrien Gallouët <adrien@gallouet.fr>

* Format code

Signed-off-by: Adrien Gallouët <adrien@gallouet.fr>

* Use detail::scope_exit

Signed-off-by: Adrien Gallouët <adrien@gallouet.fr>

---------

Signed-off-by: Adrien Gallouët <adrien@gallouet.fr>

.github/workflows/test.yaml

@@ -75,21 +75,34 @@ jobs:
       (github.event_name == 'pull_request'  &&
        github.event.pull_request.head.repo.full_name != github.event.pull_request.base.repo.full_name) ||
       (github.event_name == 'workflow_dispatch' && github.event.inputs.test_linux == 'true')
+    strategy:
+      matrix:
+        tls_backend: [openssl, mbedtls]
+    name: ubuntu (${{ matrix.tls_backend }})
     steps:
       - name: checkout
         uses: actions/checkout@v4
-      - name: install libraries
+      - name: install common libraries
         run: |
-          sudo dpkg --add-architecture i386
           sudo apt-get update
-          sudo apt-get install -y libc6-dev${{ matrix.config.arch_suffix }} libstdc++-13-dev${{ matrix.config.arch_suffix }} \
-            libssl-dev${{ matrix.config.arch_suffix }} libcurl4-openssl-dev${{ matrix.config.arch_suffix }} \
-            zlib1g-dev${{ matrix.config.arch_suffix }} libbrotli-dev${{ matrix.config.arch_suffix }} \
-            libzstd-dev${{ matrix.config.arch_suffix }}
-      - name: build and run tests
-        run: cd test && make EXTRA_CXXFLAGS="${{ matrix.config.arch_flags }}"
+          sudo apt-get install -y libcurl4-openssl-dev zlib1g-dev libbrotli-dev libzstd-dev
+      - name: install OpenSSL
+        if: matrix.tls_backend == 'openssl'
+        run: sudo apt-get install -y libssl-dev
+      - name: install Mbed TLS
+        if: matrix.tls_backend == 'mbedtls'
+        run: sudo apt-get install -y libmbedtls-dev
+      - name: build and run tests (OpenSSL)
+        if: matrix.tls_backend == 'openssl'
+        run: cd test && make
+        env:
+          LSAN_OPTIONS: suppressions=lsan_suppressions.txt
+      - name: build and run tests (Mbed TLS)
+        if: matrix.tls_backend == 'mbedtls'
+        run: cd test && make test_split_mbedtls && make test_mbedtls && ./test_mbedtls
       - name: run fuzz test target
-        run: cd test && make EXTRA_CXXFLAGS="${{ matrix.config.arch_flags }}" fuzz_test
+        if: matrix.tls_backend == 'openssl'
+        run: cd test && make fuzz_test
 
   macos:
     runs-on: macos-latest
@@ -98,12 +111,26 @@ jobs:
       (github.event_name == 'pull_request'  &&
        github.event.pull_request.head.repo.full_name != github.event.pull_request.base.repo.full_name) ||
       (github.event_name == 'workflow_dispatch' && github.event.inputs.test_macos == 'true')
+    strategy:
+      matrix:
+        tls_backend: [openssl, mbedtls]
+    name: macos (${{ matrix.tls_backend }})
     steps:
       - name: checkout
         uses: actions/checkout@v4
-      - name: build and run tests
+      - name: install Mbed TLS
+        if: matrix.tls_backend == 'mbedtls'
+        run: brew install mbedtls@3
+      - name: build and run tests (OpenSSL)
+        if: matrix.tls_backend == 'openssl'
         run: cd test && make
+        env:
+          LSAN_OPTIONS: suppressions=lsan_suppressions.txt
+      - name: build and run tests (Mbed TLS)
+        if: matrix.tls_backend == 'mbedtls'
+        run: cd test && make test_split_mbedtls && make test_mbedtls && ./test_mbedtls
       - name: run fuzz test target
+        if: matrix.tls_backend == 'openssl'
         run: cd test && make fuzz_test
 
   windows:

.github/workflows/test_proxy.yaml

@@ -6,15 +6,28 @@ jobs:
   test-proxy:
     runs-on: ubuntu-latest
     if: github.event_name != 'pull_request' || github.event.pull_request.head.repo.full_name != github.event.pull_request.base.repo.full_name
-    
+    strategy:
+      matrix:
+        tls_backend: [openssl, mbedtls]
+    name: proxy (${{ matrix.tls_backend }})
+
     steps:
-    - uses: actions/checkout@v3
-    
-    - name: Install dependencies
+    - uses: actions/checkout@v4
+
+    - name: Install common dependencies
       run: |
         sudo apt-get update
-        sudo apt-get install -y build-essential libssl-dev zlib1g-dev libcurl4-openssl-dev libbrotli-dev libzstd-dev netcat-openbsd
-        
-    - name: Run proxy tests
-      run: |
-        cd test && make proxy
+        sudo apt-get install -y build-essential zlib1g-dev libcurl4-openssl-dev libbrotli-dev libzstd-dev netcat-openbsd
+    - name: Install OpenSSL
+      if: matrix.tls_backend == 'openssl'
+      run: sudo apt-get install -y libssl-dev
+    - name: Install Mbed TLS
+      if: matrix.tls_backend == 'mbedtls'
+      run: sudo apt-get install -y libmbedtls-dev
+
+    - name: Run proxy tests (OpenSSL)
+      if: matrix.tls_backend == 'openssl'
+      run: cd test && make proxy
+    - name: Run proxy tests (Mbed TLS)
+      if: matrix.tls_backend == 'mbedtls'
+      run: cd test && make proxy_mbedtls

.gitignore

@@ -33,9 +33,14 @@ example/*.pem
 test/httplib.cc
 test/httplib.h
 test/test
+test/test_mbedtls
+test/test_no_tls
 test/server_fuzzer
 test/test_proxy
+test/test_proxy_mbedtls
 test/test_split
+test/test_split_mbedtls
+test/test_split_no_tls
 test/test.xcodeproj/xcuser*
 test/test.xcodeproj/*/xcuser*
 test/*.o

CMakeLists.txt

@@ -5,6 +5,7 @@
 	* HTTPLIB_USE_ZLIB_IF_AVAILABLE (default on)
 	* HTTPLIB_USE_BROTLI_IF_AVAILABLE (default on)
 	* HTTPLIB_USE_ZSTD_IF_AVAILABLE (default on)
+	* HTTPLIB_BUILD_MODULES (default off)
 	* HTTPLIB_REQUIRE_OPENSSL (default off)
 	* HTTPLIB_REQUIRE_ZLIB (default off)
 	* HTTPLIB_REQUIRE_BROTLI (default off)
@@ -110,6 +111,15 @@ option(HTTPLIB_USE_CERTS_FROM_MACOSX_KEYCHAIN "Enable feature to load system cer
 option(HTTPLIB_USE_NON_BLOCKING_GETADDRINFO "Enables the non-blocking alternatives for getaddrinfo." ON)
 option(HTTPLIB_REQUIRE_ZSTD "Requires ZSTD to be found & linked, or fails build." OFF)
 option(HTTPLIB_USE_ZSTD_IF_AVAILABLE "Uses ZSTD (if available) to enable zstd support." ON)
+# C++20 modules support requires CMake 3.28 or later
+if(CMAKE_VERSION VERSION_GREATER_EQUAL "3.28")
+	option(HTTPLIB_BUILD_MODULES "Build httplib modules (requires HTTPLIB_COMPILE to be ON)." OFF)
+else()
+	set(HTTPLIB_BUILD_MODULES OFF CACHE INTERNAL "Build httplib modules disabled (requires CMake 3.28+)" FORCE)
+	if(DEFINED CACHE{HTTPLIB_BUILD_MODULES} AND HTTPLIB_BUILD_MODULES)
+		message(WARNING "HTTPLIB_BUILD_MODULES requires CMake 3.28 or later. Current version is ${CMAKE_VERSION}. Modules support has been disabled.")
+	endif()
+endif()
 # Defaults to static library but respects standard BUILD_SHARED_LIBS if set
 include(CMakeDependentOption)
 cmake_dependent_option(HTTPLIB_SHARED "Build the library as a shared library instead of static. Has no effect if using header-only."
@@ -240,6 +250,22 @@ if(HTTPLIB_COMPILE)
 		message(FATAL_ERROR "Failed when trying to split cpp-httplib with the Python script.\n${_httplib_split_error}")
 	endif()
 
+	# If building modules, also generate the module file
+	if(HTTPLIB_BUILD_MODULES)
+		# Put the generate_module script into the build dir
+		configure_file(generate_module.py "${CMAKE_CURRENT_BINARY_DIR}/generate_module.py"
+			COPYONLY
+		)
+		# Generate the module file
+		execute_process(COMMAND ${Python3_EXECUTABLE} "${CMAKE_CURRENT_BINARY_DIR}/generate_module.py"
+			WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}
+			ERROR_VARIABLE _httplib_module_error
+		)
+		if(_httplib_module_error)
+			message(FATAL_ERROR "Failed when trying to generate cpp-httplib module with the Python script.\n${_httplib_module_error}")
+		endif()
+	endif()
+
 	# split.py puts output in "out"
 	set(_httplib_build_includedir "${CMAKE_CURRENT_BINARY_DIR}/out")
 	add_library(${PROJECT_NAME} ${HTTPLIB_LIB_TYPE} "${_httplib_build_includedir}/httplib.cc")
@@ -248,6 +274,13 @@ if(HTTPLIB_COMPILE)
 			$<BUILD_INTERFACE:${_httplib_build_includedir}/httplib.h>
 			$<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}/httplib.h>
 	)
+	
+	# Add C++20 module support if requested
+	# Include from separate file to prevent parse errors on older CMake versions
+	if(CMAKE_VERSION VERSION_GREATER_EQUAL "3.28")
+		include(cmake/modules.cmake)
+	endif()
+	
 	set_target_properties(${PROJECT_NAME}
 		PROPERTIES
 			VERSION ${${PROJECT_NAME}_VERSION}
@@ -264,8 +297,12 @@ endif()
 # Only useful if building in-tree, versus using it from an installation.
 add_library(${PROJECT_NAME}::${PROJECT_NAME} ALIAS ${PROJECT_NAME})
 
-# Require C++11
-target_compile_features(${PROJECT_NAME} ${_INTERFACE_OR_PUBLIC} cxx_std_11)
+# Require C++11, or C++20 if modules are enabled
+if(HTTPLIB_BUILD_MODULES)
+	target_compile_features(${PROJECT_NAME} ${_INTERFACE_OR_PUBLIC} cxx_std_20)
+else()
+	target_compile_features(${PROJECT_NAME} ${_INTERFACE_OR_PUBLIC} cxx_std_11)
+endif()
 
 target_include_directories(${PROJECT_NAME} SYSTEM ${_INTERFACE_OR_PUBLIC}
 	$<BUILD_INTERFACE:${_httplib_build_includedir}>
@@ -337,7 +374,11 @@ if(HTTPLIB_INSTALL)
 	# Creates the export httplibTargets.cmake
 	# This is strictly what holds compilation requirements
 	# and linkage information (doesn't find deps though).
-	install(TARGETS ${PROJECT_NAME} EXPORT httplibTargets)
+	if(HTTPLIB_BUILD_MODULES)
+		install(TARGETS ${PROJECT_NAME} EXPORT httplibTargets FILE_SET CXX_MODULES DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/httplib/modules CXX_MODULES_BMI DESTINATION ${CMAKE_INSTALL_LIBDIR}/httplib/modules)
+	else()
+		install(TARGETS ${PROJECT_NAME} EXPORT httplibTargets)
+	endif()
 
 	install(FILES "${_httplib_build_includedir}/httplib.h" TYPE INCLUDE)
 
@@ -366,6 +407,10 @@ if(HTTPLIB_INSTALL)
 	include(CPack)
 endif()
 
+if(HTTPLIB_BUILD_MODULES AND NOT HTTPLIB_COMPILE)
+	message(FATAL_ERROR "HTTPLIB_BUILD_MODULES requires HTTPLIB_COMPILE to be ON.")
+endif()
+
 if(HTTPLIB_TEST)
 	include(CTest)
 	add_subdirectory(test)

README.md

@@ -50,19 +50,28 @@ if (auto res = cli.Get("/hi")) {
 }
 ```
 
-SSL Support
------------
+SSL/TLS Support
+---------------
 
-SSL support is available with `CPPHTTPLIB_OPENSSL_SUPPORT`. `libssl` and `libcrypto` should be linked.
+cpp-httplib supports multiple TLS backends through an abstraction layer:
+
+| Backend | Define | Libraries |
+| :------ | :----- | :-------- |
+| OpenSSL | `CPPHTTPLIB_OPENSSL_SUPPORT` | `libssl`, `libcrypto` |
+| Mbed TLS | `CPPHTTPLIB_MBEDTLS_SUPPORT` | `libmbedtls`, `libmbedx509`, `libmbedcrypto` |
 
 > [!NOTE]
-> cpp-httplib currently supports only version 3.0 or later. Please see [this page](https://www.openssl.org/policies/releasestrat.html) to get more information.
+> OpenSSL 3.0 or later is required. Please see [this page](https://www.openssl.org/policies/releasestrat.html) for more information.
+
+> [!NOTE]
+> Mbed TLS 2.x and 3.x are supported. The library automatically detects the version and uses the appropriate API.
 
 > [!TIP]
-> For macOS: cpp-httplib now can use system certs with `CPPHTTPLIB_USE_CERTS_FROM_MACOSX_KEYCHAIN`. `CoreFoundation` and `Security` should be linked with `-framework`.
+> For macOS: cpp-httplib can use system certs with `CPPHTTPLIB_USE_CERTS_FROM_MACOSX_KEYCHAIN`. `CoreFoundation` and `Security` should be linked with `-framework`.
 
 ```c++
-#define CPPHTTPLIB_OPENSSL_SUPPORT
+// Use either OpenSSL or Mbed TLS
+#define CPPHTTPLIB_OPENSSL_SUPPORT   // or CPPHTTPLIB_MBEDTLS_SUPPORT
 #include "path/to/httplib.h"
 
 // Server
@@ -83,15 +92,39 @@ cli.enable_server_certificate_verification(false);
 cli.enable_server_hostname_verification(false);
 ```
 
+### Windows Certificate Verification
+
+On Windows, cpp-httplib automatically performs additional certificate verification using the Windows certificate store via CryptoAPI (`CertGetCertificateChain` / `CertVerifyCertificateChainPolicy`). This works with both OpenSSL and Mbed TLS backends, providing:
+
+- Real-time certificate validation integrated with Windows Update
+- Certificate revocation checking
+- SSL/TLS policy verification using the system certificate store (ROOT and CA)
+
+This feature is enabled by default and can be controlled at runtime:
+
+```c++
+// Disable Windows certificate verification (use only OpenSSL/Mbed TLS verification)
+cli.enable_windows_certificate_verification(false);
+```
+
+To disable this feature at compile time, define:
+
+```c++
+#define CPPHTTPLIB_DISABLE_WINDOWS_AUTOMATIC_ROOT_CERTIFICATES_UPDATE
+```
+
 > [!NOTE]
 > When using SSL, it seems impossible to avoid SIGPIPE in all cases, since on some operating systems, SIGPIPE can only be suppressed on a per-message basis, but there is no way to make the OpenSSL library do so for its internal communications. If your program needs to avoid being terminated on SIGPIPE, the only fully general way might be to set up a signal handler for SIGPIPE to handle or ignore it yourself.
 
 ### SSL Error Handling
 
-When SSL operations fail, cpp-httplib provides detailed error information through two separate error fields:
+When SSL operations fail, cpp-httplib provides detailed error information through `ssl_error()` and `ssl_backend_error()`:
+
+- `ssl_error()` - Returns the TLS-level error code (e.g., `SSL_ERROR_SSL` for OpenSSL)
+- `ssl_backend_error()` - Returns the backend-specific error code (e.g., `ERR_get_error()` for OpenSSL, return value for Mbed TLS)
 
 ```c++
-#define CPPHTTPLIB_OPENSSL_SUPPORT
+#define CPPHTTPLIB_OPENSSL_SUPPORT  // or CPPHTTPLIB_MBEDTLS_SUPPORT
 #include "path/to/httplib.h"
 
 httplib::Client cli("https://example.com");
@@ -108,18 +141,18 @@ if (!res) {
       break;
 
     case httplib::Error::SSLLoadingCerts:
-      std::cout << "SSL cert loading failed, OpenSSL error: "
-                << std::hex << res.ssl_openssl_error() << std::endl;
+      std::cout << "SSL cert loading failed, backend error: "
+                << std::hex << res.ssl_backend_error() << std::endl;
       break;
 
     case httplib::Error::SSLServerVerification:
-      std::cout << "SSL verification failed, X509 error: "
-                << res.ssl_openssl_error() << std::endl;
+      std::cout << "SSL verification failed, verify error: "
+                << res.ssl_backend_error() << std::endl;
       break;
 
     case httplib::Error::SSLServerHostnameVerification:
-      std::cout << "SSL hostname verification failed, X509 error: "
-                << res.ssl_openssl_error() << std::endl;
+      std::cout << "SSL hostname verification failed, verify error: "
+                << res.ssl_backend_error() << std::endl;
       break;
 
     default:
@@ -128,6 +161,50 @@ if (!res) {
 }
 ```
 
+### Custom Certificate Verification
+
+You can set a custom verification callback using `tls::VerifyCallback`:
+
+```c++
+httplib::Client cli("https://example.com");
+
+cli.set_server_certificate_verifier(
+    [](const httplib::tls::VerifyContext &ctx) -> bool {
+      std::cout << "Subject CN: " << ctx.subject_cn() << std::endl;
+      std::cout << "Issuer: " << ctx.issuer_name() << std::endl;
+      std::cout << "Depth: " << ctx.depth << std::endl;
+      std::cout << "Pre-verified: " << ctx.preverify_ok << std::endl;
+
+      // Inspect SANs (Subject Alternative Names)
+      for (const auto &san : ctx.sans()) {
+        std::cout << "SAN: " << san.value << std::endl;
+      }
+
+      // Return true to accept, false to reject
+      return ctx.preverify_ok;
+    });
+```
+
+### Peer Certificate Inspection
+
+On the server side, you can inspect the client's peer certificate from a request handler:
+
+```c++
+httplib::SSLServer svr("./cert.pem", "./key.pem",
+                       "./client-ca-cert.pem");
+
+svr.Get("/", [](const httplib::Request &req, httplib::Response &res) {
+  auto cert = req.peer_cert();
+  if (cert) {
+    std::cout << "Client CN: " << cert.subject_cn() << std::endl;
+    std::cout << "Serial: " << cert.serial() << std::endl;
+  }
+
+  auto sni = req.sni();
+  std::cout << "SNI: " << sni << std::endl;
+});
+```
+
 Server
 ------
 
@@ -902,6 +979,12 @@ cli.set_write_timeout(5, 0); // 5 seconds
 cli.set_max_timeout(5000); // 5 seconds
 ```
 
+### Set maximum payload length for reading a response body
+
+```c++
+cli.set_payload_max_length(1024 * 1024 * 512); // 512MB
+```
+
 ### Receive content with a content receiver
 
 ```c++
@@ -1102,6 +1185,11 @@ httplib::Server svr;
 svr.listen("127.0.0.1", 8080);
 ```
 
+Payload Limit
+-------------
+
+The maximum payload body size is limited to 100MB by default for both server and client. You can change it with `set_payload_max_length()` or by defining `CPPHTTPLIB_PAYLOAD_MAX_LENGTH` at compile time. Setting it to `0` disables the limit entirely.
+
 Compression
 -----------
 

cmake/modules.cmake

@@ -0,0 +1,16 @@
+# This file contains C++20 module support requiring CMake 3.28+
+# Included conditionally to prevent parse errors on older CMake versions
+
+if(HTTPLIB_BUILD_MODULES)
+	if(POLICY CMP0155)
+		cmake_policy(SET CMP0155 NEW)
+	endif()
+
+	set(CMAKE_CXX_SCAN_FOR_MODULES ON)
+	
+	target_sources(${PROJECT_NAME}
+		PUBLIC
+			FILE_SET CXX_MODULES FILES
+				"${_httplib_build_includedir}/httplib.cppm"
+	)
+endif()

example/client.cc

@@ -30,7 +30,7 @@ int main(void) {
   } else {
     cout << "error code: " << res.error() << std::endl;
 #ifdef CPPHTTPLIB_OPENSSL_SUPPORT
-    auto result = cli.get_openssl_verify_result();
+    auto result = cli.get_verify_result();
     if (result) {
       cout << "verify error: " << X509_verify_cert_error_string(result) << endl;
     }

generate_module.py

@@ -0,0 +1,77 @@
+#!/usr/bin/env python3
+
+"""This script generates httplib.cppm module file from httplib.h."""
+
+import os
+import sys
+from argparse import ArgumentParser, Namespace
+from typing import List
+
+def main() -> None:
+    """Main entry point for the script."""
+
+    args_parser: ArgumentParser = ArgumentParser(description=__doc__)
+    args_parser.add_argument(
+        "-o", "--out", help="where to write the files (default: out)", default="out"
+    )
+    args: Namespace = args_parser.parse_args()
+
+    cur_dir: str = os.path.dirname(sys.argv[0])
+    if not cur_dir:
+        cur_dir = '.'
+    lib_name: str = "httplib"
+    header_name: str = f"/{lib_name}.h"
+    # get the input file
+    in_file: str = f"{cur_dir}{header_name}"
+    # get the output file
+    cppm_out: str = f"{args.out}/{lib_name}.cppm"
+
+    # if the modification time of the out file is after the in file,
+    # don't generate (as it is already finished)
+    do_generate: bool = True
+
+    if os.path.exists(cppm_out):
+        in_time: float = os.path.getmtime(in_file)
+        out_time: float = os.path.getmtime(cppm_out)
+        do_generate: bool = in_time > out_time
+
+    if do_generate:
+        with open(in_file) as f:
+            lines: List[str] = f.readlines()
+
+        os.makedirs(args.out, exist_ok=True)
+
+        # Find the Headers and Declaration comment markers
+        headers_start: int = -1
+        declaration_start: int = -1
+        for i, line in enumerate(lines):
+            if ' * Headers' in line:
+                headers_start = i - 1  # Include the /* line
+            elif ' * Declaration' in line:
+                declaration_start = i - 1  # Stop before the /* line
+                break
+
+        with open(cppm_out, 'w') as fm:
+            # Write module file
+            fm.write("module;\n\n")
+            
+            # Write global module fragment (from Headers to Declaration comment)
+            # Filter out 'using' declarations to avoid conflicts
+            if headers_start >= 0 and declaration_start >= 0:
+                for i in range(headers_start, declaration_start):
+                    line: str = lines[i]
+                    if 'using' not in line:
+                        fm.write(line)
+            
+            fm.write("\nexport module httplib;\n\n")
+            fm.write("export extern \"C++\" {\n")
+            fm.write(f"{' ' * 4}#include \"httplib.h\"\n")
+            fm.write("}\n")
+
+        print(f"Wrote {cppm_out}")
+    else:
+        print(f"{cppm_out} is up to date")
+
+
+if __name__ == "__main__":
+    main()

justfile

@@ -0,0 +1,24 @@
+set shell := ["bash", "-c"]
+
+default: list
+
+list:
+    @just --list --unsorted
+
+openssl:
+    @(cd test && make test && LSAN_OPTIONS=suppressions=lsan_suppressions.txt ./test)
+    @(cd test && make proxy)
+
+mbedtls:
+    @(cd test && make test_mbedtls && LSAN_OPTIONS=suppressions=lsan_suppressions.txt ./test_mbedtls)
+    @(cd test && make proxy_mbedtls)
+
+no_tls:
+    @(cd test && make test_no_tls && ./test_no_tls)
+
+fuzz:
+    @(cd test && make fuzz_test)
+
+build:
+    @(cd test && make test_split)
+    @(cd test && make test_split_mbedtls)

meson.build

@@ -39,11 +39,29 @@ endif
 deps = [dependency('threads')]
 args = []
 
-openssl_dep = dependency('openssl', version: '>=3.0.0', required: get_option('openssl'))
-if openssl_dep.found()
-  deps += openssl_dep
-  args += '-DCPPHTTPLIB_OPENSSL_SUPPORT'
-  if host_machine.system() == 'darwin'
+if get_option('tls').allowed()
+  tls_found = false
+  if get_option('tls_backend') == 'openssl'
+    openssl_dep = dependency('openssl', version: '>=3.0.0', required: get_option('tls'))
+    if openssl_dep.found()
+      deps += openssl_dep
+      args += '-DCPPHTTPLIB_OPENSSL_SUPPORT'
+      tls_found = true
+    endif
+  else
+    mbedtls_dep = dependency('mbedtls', required: get_option('tls'))
+    mbedtlsx509_dep = dependency('mbedx509', required: get_option('tls'))
+    mbedtlscrypto_dep = dependency('mbedcrypto', required: get_option('tls'))
+    if mbedtls_dep.found() and mbedtlsx509_dep.found() and mbedtlscrypto_dep.found()
+      deps += mbedtls_dep
+      deps += mbedtlsx509_dep
+      deps += mbedtlscrypto_dep
+      args += '-DCPPHTTPLIB_MBEDTLS_SUPPORT'
+      tls_found = true
+    endif
+  endif
+
+  if tls_found and host_machine.system() == 'darwin'
     macosx_keychain_dep = dependency('appleframeworks', modules: ['CFNetwork', 'CoreFoundation', 'Security'], required: get_option('macosx_keychain'))
     if macosx_keychain_dep.found()
         deps += macosx_keychain_dep

meson_options.txt

@@ -2,7 +2,8 @@
 #
 # SPDX-License-Identifier: MIT
 
-option('openssl', type: 'feature', value: 'auto', description: 'Enable OpenSSL support')
+option('tls',     type: 'feature', description: 'Enable TLS support')
+option('tls_backend', type: 'combo', choices: ['openssl', 'mbedtls'], value: 'openssl', description: 'Which TLS library to use')
 option('zlib',    type: 'feature', value: 'auto', description: 'Enable zlib support')
 option('brotli',  type: 'feature', value: 'auto', description: 'Enable Brotli support')
 option('zstd',    type: 'feature', value: 'auto', description: 'Enable zstd support')
@@ -12,6 +13,7 @@ option('compile', type: 'boolean', value: false,  description: 'Split the header
 option('test',    type: 'boolean', value: false,  description: 'Build tests')
 
 # Old option names
+option('openssl', type: 'feature', deprecated: 'tls')
 option('cpp-httplib_openssl', type: 'feature', deprecated: 'openssl')
 option('cpp-httplib_zlib',    type: 'feature', deprecated: 'zlib')
 option('cpp-httplib_brotli',  type: 'feature', deprecated: 'brotli')

split.py

@@ -7,15 +7,14 @@ import sys
 from argparse import ArgumentParser, Namespace
 from typing import List
 
+BORDER: str = '// ----------------------------------------------------------------------------'
 
 def main() -> None:
     """Main entry point for the script."""
-    BORDER: str = '// ----------------------------------------------------------------------------'
 
     args_parser: ArgumentParser = ArgumentParser(description=__doc__)
     args_parser.add_argument(
-        "-e", "--extension", help="extension of the implementation file (default: cc)",
-        default="cc"
+        "-e", "--extension", help="extension of the implementation file (default: cc)", default="cc"
     )
     args_parser.add_argument(
         "-o", "--out", help="where to write the files (default: out)", default="out"
@@ -25,14 +24,14 @@ def main() -> None:
     cur_dir: str = os.path.dirname(sys.argv[0])
     if not cur_dir:
         cur_dir = '.'
-    lib_name: str = 'httplib'
+    lib_name: str = "httplib"
     header_name: str = f"/{lib_name}.h"
     source_name: str = f"/{lib_name}.{args.extension}"
     # get the input file
-    in_file: str = cur_dir + header_name
+    in_file: str = f"{cur_dir}{header_name}"
     # get the output file
-    h_out: str = args.out + header_name
-    cc_out: str = args.out + source_name
+    h_out: str = f"{args.out}{header_name}"
+    cc_out: str = f"{args.out}{source_name}"
 
     # if the modification time of the out file is after the in file,
     # don't split (as it is already finished)
@@ -51,18 +50,23 @@ def main() -> None:
 
         in_implementation: bool = False
         cc_out: str = args.out + source_name
+        
         with open(h_out, 'w') as fh, open(cc_out, 'w') as fc:
-            fc.write('#include "httplib.h"\n')
-            fc.write('namespace httplib {\n')
+            # Write source file
+            fc.write("#include \"httplib.h\"\n")
+            fc.write("namespace httplib {\n")
+            
+            # Process lines for header and source split
             for line in lines:
                 is_border_line: bool = BORDER in line
                 if is_border_line:
                     in_implementation: bool = not in_implementation
                 elif in_implementation:
-                    fc.write(line.replace('inline ', ''))
+                    fc.write(line.replace("inline ", ""))
                 else:
                     fh.write(line)
-            fc.write('} // namespace httplib\n')
+            
+            fc.write("} // namespace httplib\n")
 
         print(f"Wrote {h_out} and {cc_out}")
     else:

test/Makefile

@@ -1,38 +1,44 @@
 CXX = clang++
-CXXFLAGS = -g -std=c++11 -I. -Wall -Wextra -Wtype-limits -Wconversion -Wshadow $(EXTRA_CXXFLAGS) -DCPPHTTPLIB_USE_NON_BLOCKING_GETADDRINFO # -fno-exceptions -DCPPHTTPLIB_NO_EXCEPTIONS -fsanitize=address
-
-PREFIX ?= $(shell brew --prefix)
-
-OPENSSL_DIR = $(PREFIX)/opt/openssl@3
-OPENSSL_SUPPORT = -DCPPHTTPLIB_OPENSSL_SUPPORT -I$(OPENSSL_DIR)/include -L$(OPENSSL_DIR)/lib -lssl -lcrypto
+CXXFLAGS = -g -std=c++11 -I. -Wall -Wextra -Wtype-limits -Wconversion -Wshadow $(EXTRA_CXXFLAGS) -DCPPHTTPLIB_USE_NON_BLOCKING_GETADDRINFO -fsanitize=address # -fno-exceptions -DCPPHTTPLIB_NO_EXCEPTIONS
 
 ifneq ($(OS), Windows_NT)
 	UNAME_S := $(shell uname -s)
 	ifeq ($(UNAME_S), Darwin)
+		PREFIX ?= $(shell brew --prefix)
+		OPENSSL_DIR = $(PREFIX)/opt/openssl@3
+		OPENSSL_SUPPORT = -DCPPHTTPLIB_OPENSSL_SUPPORT -I$(OPENSSL_DIR)/include -L$(OPENSSL_DIR)/lib -lssl -lcrypto
 		OPENSSL_SUPPORT += -DCPPHTTPLIB_USE_CERTS_FROM_MACOSX_KEYCHAIN -framework Security
+		MBEDTLS_DIR ?= $(shell brew --prefix mbedtls@3)
+		MBEDTLS_SUPPORT = -DCPPHTTPLIB_MBEDTLS_SUPPORT -I$(MBEDTLS_DIR)/include -L$(MBEDTLS_DIR)/lib -lmbedtls -lmbedx509 -lmbedcrypto
+		MBEDTLS_SUPPORT += -DCPPHTTPLIB_USE_CERTS_FROM_MACOSX_KEYCHAIN -framework Security
+	else
+		OPENSSL_SUPPORT = -DCPPHTTPLIB_OPENSSL_SUPPORT -lssl -lcrypto
+		MBEDTLS_SUPPORT = -DCPPHTTPLIB_MBEDTLS_SUPPORT -lmbedtls -lmbedx509 -lmbedcrypto
 	endif
 endif
 
 ZLIB_SUPPORT = -DCPPHTTPLIB_ZLIB_SUPPORT -lz
 
-BROTLI_DIR = $(PREFIX)/opt/brotli
-BROTLI_SUPPORT = -DCPPHTTPLIB_BROTLI_SUPPORT -I$(BROTLI_DIR)/include -L$(BROTLI_DIR)/lib -lbrotlicommon -lbrotlienc -lbrotlidec
-
-ZSTD_DIR = $(PREFIX)/opt/zstd
-ZSTD_SUPPORT = -DCPPHTTPLIB_ZSTD_SUPPORT -I$(ZSTD_DIR)/include -L$(ZSTD_DIR)/lib -lzstd
-
-LIBS = -lpthread -lcurl
 ifneq ($(OS), Windows_NT)
 	UNAME_S := $(shell uname -s)
 	ifeq ($(UNAME_S), Darwin)
-		LIBS += -framework CoreFoundation -framework CFNetwork
-	endif
-	ifneq ($(UNAME_S), Darwin)
-		LIBS += -lanl
+		# macOS: use Homebrew paths for brotli and zstd
+		BROTLI_DIR = $(PREFIX)/opt/brotli
+		BROTLI_SUPPORT = -DCPPHTTPLIB_BROTLI_SUPPORT -I$(BROTLI_DIR)/include -L$(BROTLI_DIR)/lib -lbrotlicommon -lbrotlienc -lbrotlidec
+		ZSTD_DIR = $(PREFIX)/opt/zstd
+		ZSTD_SUPPORT = -DCPPHTTPLIB_ZSTD_SUPPORT -I$(ZSTD_DIR)/include -L$(ZSTD_DIR)/lib -lzstd
+		LIBS = -lpthread -lcurl -framework CoreFoundation -framework CFNetwork
+	else
+		# Linux: use system paths
+		BROTLI_SUPPORT = -DCPPHTTPLIB_BROTLI_SUPPORT -lbrotlicommon -lbrotlienc -lbrotlidec
+		ZSTD_SUPPORT = -DCPPHTTPLIB_ZSTD_SUPPORT -lzstd
+		LIBS = -lpthread -lcurl -lanl
 	endif
 endif
 
 TEST_ARGS = gtest/src/gtest-all.cc gtest/src/gtest_main.cc -Igtest -Igtest/include $(OPENSSL_SUPPORT) $(ZLIB_SUPPORT) $(BROTLI_SUPPORT) $(ZSTD_SUPPORT) $(LIBS)
+TEST_ARGS_MBEDTLS = gtest/src/gtest-all.cc gtest/src/gtest_main.cc -Igtest -Igtest/include $(MBEDTLS_SUPPORT) $(ZLIB_SUPPORT) $(BROTLI_SUPPORT) $(ZSTD_SUPPORT) $(LIBS)
+TEST_ARGS_NO_TLS = gtest/src/gtest-all.cc gtest/src/gtest_main.cc -Igtest -Igtest/include $(ZLIB_SUPPORT) $(BROTLI_SUPPORT) $(ZSTD_SUPPORT) $(LIBS)
 
 # By default, use standalone_fuzz_target_runner.
 # This runner does no fuzzing, but simply executes the inputs
@@ -48,7 +54,7 @@ STYLE_CHECK_FILES = $(filter-out httplib.h httplib.cc, \
 	$(wildcard example/*.h example/*.cc fuzzing/*.h fuzzing/*.cc *.h *.cc ../httplib.h))
 
 all : test test_split
-	./test
+	LSAN_OPTIONS=suppressions=lsan_suppressions.txt ./test
 
 proxy : test_proxy
 	@echo "Starting proxy server..."
@@ -69,6 +75,25 @@ proxy : test_proxy
 	cd proxy && docker compose down; \
 	exit $$exit_code
 
+proxy_mbedtls : test_proxy_mbedtls
+	@echo "Starting proxy server..."
+	cd proxy && \
+	docker compose up -d
+	@echo "Waiting for proxy to be ready..."
+	@until nc -z localhost 3128 && nc -z localhost 3129; do sleep 1; done
+	@echo "Proxy servers are ready, waiting additional 5 seconds for full startup..."
+	@sleep 5
+	@echo "Checking proxy server status..."
+	@cd proxy && docker compose ps
+	@echo "Checking proxy server logs..."
+	@cd proxy && docker compose logs --tail=20
+	@echo "Running proxy tests (Mbed TLS)..."
+	./test_proxy_mbedtls; \
+	exit_code=$$?; \
+	echo "Stopping proxy server..."; \
+	cd proxy && docker compose down; \
+	exit $$exit_code
+
 test : test.cc include_httplib.cc ../httplib.h Makefile cert.pem
 	$(CXX) -o $@ -I.. $(CXXFLAGS) test.cc include_httplib.cc $(TEST_ARGS)
 	@file $@
@@ -78,6 +103,22 @@ test : test.cc include_httplib.cc ../httplib.h Makefile cert.pem
 test_split : test.cc ../httplib.h httplib.cc Makefile cert.pem
 	$(CXX) -o $@ $(CXXFLAGS) test.cc httplib.cc $(TEST_ARGS)
 
+# Mbed TLS backend targets
+test_mbedtls : test.cc include_httplib.cc ../httplib.h Makefile cert.pem
+	$(CXX) -o $@ -I.. $(CXXFLAGS) test.cc include_httplib.cc $(TEST_ARGS_MBEDTLS)
+	@file $@
+
+test_split_mbedtls : test.cc ../httplib.h httplib.cc Makefile cert.pem
+	$(CXX) -o $@ $(CXXFLAGS) test.cc httplib.cc $(TEST_ARGS_MBEDTLS)
+
+# No TLS
+test_no_tls : test.cc include_httplib.cc ../httplib.h Makefile
+	$(CXX) -o $@ -I.. $(CXXFLAGS) test.cc include_httplib.cc $(TEST_ARGS_NO_TLS)
+	@file $@
+
+test_split_no_tls : test.cc ../httplib.h httplib.cc Makefile
+	$(CXX) -o $@ $(CXXFLAGS) test.cc httplib.cc $(TEST_ARGS_NO_TLS)
+
 check_abi:
 	@./check-shared-library-abi-compatibility.sh
 
@@ -106,6 +147,9 @@ style_check: $(STYLE_CHECK_FILES)
 test_proxy : test_proxy.cc ../httplib.h Makefile cert.pem
 	$(CXX) -o $@ -I.. $(CXXFLAGS) test_proxy.cc $(TEST_ARGS)
 
+test_proxy_mbedtls : test_proxy.cc ../httplib.h Makefile cert.pem
+	$(CXX) -o $@ -I.. $(CXXFLAGS) test_proxy.cc $(TEST_ARGS_MBEDTLS)
+
 # Runs server_fuzzer.cc based on value of $(LIB_FUZZING_ENGINE).
 # Usage: make fuzz_test LIB_FUZZING_ENGINE=/path/to/libFuzzer
 fuzz_test: server_fuzzer
@@ -128,5 +172,5 @@ cert.pem:
 	./gen-certs.sh
 
 clean:
-	rm -rf test test_split test_proxy server_fuzzer *.pem *.0 *.o *.1 *.srl httplib.h httplib.cc _build* *.dSYM
+	rm -rf test test_split test_mbedtls test_split_mbedtls test_no_tls, test_split_no_tls test_proxy test_proxy_mbedtls server_fuzzer *.pem *.0 *.o *.1 *.srl httplib.h httplib.cc _build* *.dSYM
 

test/gen-certs.sh

@@ -14,5 +14,5 @@ openssl genrsa 2048 > client.key.pem
 openssl req -new -batch -config test.conf -key client.key.pem | openssl x509 -days 370 -req -CA rootCA.cert.pem -CAkey rootCA.key.pem -CAcreateserial > client.cert.pem
 openssl genrsa -passout pass:test123! 2048 > key_encrypted.pem
 openssl req -new -batch -config test.conf -key key_encrypted.pem | openssl x509 -days 3650 -req -signkey key_encrypted.pem > cert_encrypted.pem
-openssl genrsa -aes256 -passout pass:test012! 2048 > client_encrypted.key.pem
+openssl genrsa 2048 | openssl pkcs8 -topk8 -v1 PBE-SHA1-3DES -passout pass:test012! -out client_encrypted.key.pem
 openssl req -new -batch -config test.conf -key client_encrypted.key.pem -passin pass:test012! | openssl x509 -days 370 -req -CA rootCA.cert.pem -CAkey rootCA.key.pem -CAcreateserial > client_encrypted.cert.pem

test/lsan_suppressions.txt

@@ -0,0 +1,3 @@
+# OpenSSL 3.x internal caches (provider, cipher, keymgmt) are allocated
+# lazily and intentionally kept until process exit. These are not real leaks.
+leak:libcrypto

test/test_proxy.cc

@@ -26,7 +26,7 @@ TEST(ProxyTest, NoSSLBasic) {
   ProxyTest(cli, true);
 }
 
-#ifdef CPPHTTPLIB_OPENSSL_SUPPORT
+#ifdef CPPHTTPLIB_SSL_ENABLED
 TEST(ProxyTest, SSLBasic) {
   SSLClient cli("nghttp2.org");
   ProxyTest(cli, true);
@@ -51,7 +51,7 @@ void RedirectProxyText(T &cli, const char *path, bool basic) {
   if (basic) {
     cli.set_proxy_basic_auth("hello", "world");
   } else {
-#ifdef CPPHTTPLIB_OPENSSL_SUPPORT
+#ifdef CPPHTTPLIB_SSL_ENABLED
     cli.set_proxy_digest_auth("hello", "world");
 #endif
   }
@@ -67,7 +67,7 @@ TEST(RedirectTest, HTTPBinNoSSLBasic) {
   RedirectProxyText(cli, "/httpbin/redirect/2", true);
 }
 
-#ifdef CPPHTTPLIB_OPENSSL_SUPPORT
+#ifdef CPPHTTPLIB_SSL_ENABLED
 TEST(RedirectTest, HTTPBinNoSSLDigest) {
   Client cli("nghttp2.org");
   RedirectProxyText(cli, "/httpbin/redirect/2", false);
@@ -84,7 +84,7 @@ TEST(RedirectTest, HTTPBinSSLDigest) {
 }
 #endif
 
-#ifdef CPPHTTPLIB_OPENSSL_SUPPORT
+#ifdef CPPHTTPLIB_SSL_ENABLED
 TEST(RedirectTest, YouTubeNoSSLBasic) {
   Client cli("youtube.com");
   RedirectProxyText(cli, "/", true);
@@ -157,7 +157,7 @@ TEST(BaseAuthTest, NoSSL) {
   BaseAuthTestFromHTTPWatch(cli);
 }
 
-#ifdef CPPHTTPLIB_OPENSSL_SUPPORT
+#ifdef CPPHTTPLIB_SSL_ENABLED
 TEST(BaseAuthTest, SSL) {
   SSLClient cli("httpcan.org");
   BaseAuthTestFromHTTPWatch(cli);
@@ -166,7 +166,7 @@ TEST(BaseAuthTest, SSL) {
 
 // ----------------------------------------------------------------------------
 
-#ifdef CPPHTTPLIB_OPENSSL_SUPPORT
+#ifdef CPPHTTPLIB_SSL_ENABLED
 template <typename T> void DigestAuthTestFromHTTPWatch(T &cli) {
   cli.set_proxy("localhost", 3129);
   cli.set_proxy_digest_auth("hello", "world");
@@ -230,13 +230,13 @@ template <typename T> void KeepAliveTest(T &cli, bool basic) {
   if (basic) {
     cli.set_proxy_basic_auth("hello", "world");
   } else {
-#ifdef CPPHTTPLIB_OPENSSL_SUPPORT
+#ifdef CPPHTTPLIB_SSL_ENABLED
     cli.set_proxy_digest_auth("hello", "world");
 #endif
   }
 
   cli.set_follow_location(true);
-#ifdef CPPHTTPLIB_OPENSSL_SUPPORT
+#ifdef CPPHTTPLIB_SSL_ENABLED
   cli.set_digest_auth("hello", "world");
 #endif
 
@@ -274,7 +274,7 @@ template <typename T> void KeepAliveTest(T &cli, bool basic) {
   }
 }
 
-#ifdef CPPHTTPLIB_OPENSSL_SUPPORT
+#ifdef CPPHTTPLIB_SSL_ENABLED
 TEST(KeepAliveTest, NoSSLWithBasic) {
   Client cli("nghttp2.org");
   KeepAliveTest(cli, true);