http_client_asio based on Botan's TLS implementation

Release/CMakeLists.txt

@@ -15,6 +15,16 @@ set(CPPREST_VERSION_REVISION 12)
 
 enable_testing()
 
+set(CPPREST_NO_OPENSSL OFF CACHE BOOL "Exclude OpenSSL. Implies CPPREST_EXCLUDE_WEBSOCKETS and CPPREST_EXCLUDE_LISTENER.")
+set(CPPREST_EXCLUDE_LISTENER OFF CACHE BOOL "Exclude listerner functionality.")
+
+if(CPPREST_NO_OPENSSL)
+  message(STATUS "OpenSSL disabled; disabling websockets and http listener.")
+  set(CPPREST_HTTP_LISTENER_IMPL none CACHE STRING "Internal use.")
+  set(CPPREST_EXCLUDE_WEBSOCKETS ON CACHE BOOL "Exclude websockets functionality.")
+  set(BUILD_SAMPLES OFF CACHE BOOL "Build sample applications.")
+endif()
+
 set(WERROR ON CACHE BOOL "Treat Warnings as Errors.")
 set(CPPREST_EXCLUDE_WEBSOCKETS OFF CACHE BOOL "Exclude websockets functionality.")
 set(CPPREST_EXCLUDE_COMPRESSION OFF CACHE BOOL "Exclude compression functionality.")
@@ -61,8 +71,12 @@ endif()
 
 include(cmake/cpprest_find_boost.cmake)
 include(cmake/cpprest_find_zlib.cmake)
-include(cmake/cpprest_find_openssl.cmake)
-include(cmake/cpprest_find_websocketpp.cmake)
+if(CPPREST_NO_OPENSSL)
+  include(cmake/cpprest_find_botan.cmake)
+else()
+  include(cmake/cpprest_find_openssl.cmake)
+  include(cmake/cpprest_find_websocketpp.cmake)
+endif()
 include(cmake/cpprest_find_brotli.cmake)
 include(CheckIncludeFiles)
 include(GNUInstallDirs)

Release/cmake/cpprest_find_botan.cmake

@@ -0,0 +1,90 @@
+function(cpprest_find_botan)
+  if(TARGET cpprestsdk_botan_internal)
+    return()
+  endif()
+
+  INCLUDE (FindPackageHandleStandardArgs)
+
+  SET (_BOTAN_POSSIBLE_DIRS ${BOTAN_ROOT_DIR})
+
+  IF (WIN32)
+    SET (_BOTAN_POSSIBLE_DIRS ${_BOTAN_POSSIBLE_DIRS} "C:\\usr\\local" "C:\\usr")
+  ENDIF (WIN32)
+
+  # Note: after 1.11.34, botan library moved to semantic versioning (a.k.a. 2.0)
+  SET (_BOTAN_POSSIBLE_INCLUDE_SUFFIXES include include/botan-1.10 include/botan-1.11 include/botan-2.0 include/botan-2)
+  SET (_BOTAN_POSSIBLE_LIB_SUFFIXES lib)
+
+  FIND_PATH (BOTAN_ROOT_DIR
+    NAMES botan/botan.h
+    PATHS ${_BOTAN_POSSIBLE_DIRS}
+    PATH_SUFFIXES ${_BOTAN_POSSIBLE_INCLUDE_SUFFIXES}
+    DOC "Botan root directory")
+
+  FIND_PATH (BOTAN_INCLUDE_DIR
+    NAMES botan/botan.h
+    PATHS ${BOTAN_ROOT_DIR}
+    PATH_SUFFIXES ${_BOTAN_POSSIBLE_INCLUDE_SUFFIXES}
+    DOC "Botan include directory")
+
+  FIND_LIBRARY (BOTAN_LIBRARY_DEBUG
+    NAMES botand botand-1.10 botand-1.11 botand-2
+    PATHS ${_BOTAN_POSSIBLE_DIRS}
+    PATH_SUFFIXES ${_BOTAN_POSSIBLE_LIB_SUFFIXES}
+    DOC "Botan debug library")
+
+  FIND_LIBRARY (BOTAN_LIBRARY_RELEASE
+    NAMES botan botan-1.10 botan-1.11 botan-2
+    PATHS ${_BOTAN_POSSIBLE_DIRS}
+    PATH_SUFFIXES ${_BOTAN_POSSIBLE_LIB_SUFFIXES}
+    DOC "Botan release library")
+
+  IF (NOT DEFINED BOTAN_LIBRARIES)
+    IF (BOTAN_LIBRARY_DEBUG AND BOTAN_LIBRARY_RELEASE)
+      SET (BOTAN_LIBRARIES
+        optimized ${BOTAN_LIBRARY_RELEASE}
+        debug ${BOTAN_LIBRARY_DEBUG})
+    ELSEIF (BOTAN_LIBRARY_RELEASE)
+      SET (BOTAN_LIBRARIES ${BOTAN_LIBRARY_RELEASE})
+    ENDIF (BOTAN_LIBRARY_DEBUG AND BOTAN_LIBRARY_RELEASE)
+  ENDIF (NOT DEFINED BOTAN_LIBRARIES)
+
+  IF (BOTAN_INCLUDE_DIR)
+    SET (BOTAN_INCLUDE_DIRS ${BOTAN_INCLUDE_DIR})
+
+    SET (_BOTAN_VERSION_HEADER ${BOTAN_INCLUDE_DIR}/botan/build.h)
+
+    IF (EXISTS ${_BOTAN_VERSION_HEADER})
+      FILE (STRINGS ${_BOTAN_VERSION_HEADER} _BOTAN_VERSION_TMP REGEX
+        "#define BOTAN_VERSION_(MAJOR|MINOR|PATCH)[ \t]+[0-9]+")
+
+      STRING (REGEX REPLACE
+        ".*#define BOTAN_VERSION_MAJOR[ \t]+([0-9]+).*" "\\1" BOTAN_VERSION_MAJOR
+        ${_BOTAN_VERSION_TMP})
+      STRING (REGEX REPLACE
+        ".*#define BOTAN_VERSION_MINOR[ \t]+([0-9]+).*" "\\1" BOTAN_VERSION_MINOR
+        ${_BOTAN_VERSION_TMP})
+      STRING (REGEX REPLACE
+        ".*#define BOTAN_VERSION_PATCH[ \t]+([0-9]+).*" "\\1" BOTAN_VERSION_PATCH
+        ${_BOTAN_VERSION_TMP})
+
+      SET (BOTAN_VERSION_COUNT 3)
+      SET (BOTAN_VERSION
+        ${BOTAN_VERSION_MAJOR}.${BOTAN_VERSION_MINOR}.${BOTAN_VERSION_PATCH})
+    ENDIF (EXISTS ${_BOTAN_VERSION_HEADER})
+  ENDIF (BOTAN_INCLUDE_DIR)
+
+  MARK_AS_ADVANCED (BOTAN_ROOT_DIR BOTAN_INCLUDE_DIR BOTAN_LIBRARY_DEBUG
+    BOTAN_LIBRARY_RELEASE)
+
+  FIND_PACKAGE_HANDLE_STANDARD_ARGS (Botan REQUIRED_VARS BOTAN_INCLUDE_DIRS
+    BOTAN_LIBRARIES VERSION_VAR BOTAN_VERSION)
+
+  add_library(Botan INTERFACE)
+  target_include_directories(Botan INTERFACE ${BOTAN_INCLUDE_DIR})
+  target_link_libraries(Botan INTERFACE ${BOTAN_LIBRARIES})
+
+  add_library(cpprestsdk_botan_internal INTERFACE)
+  target_link_libraries(cpprestsdk_botan_internal INTERFACE "$<BUILD_INTERFACE:${BOTAN_LIBRARY}>")
+  target_include_directories(cpprestsdk_botan_internal INTERFACE "$<BUILD_INTERFACE:${BOTAN_INCLUDE_DIR}>")
+endfunction()

Release/include/cpprest/http_client.h

@@ -61,6 +61,11 @@ typedef void* native_handle;
 #include "cpprest/oauth2.h"
 
 #if !defined(_WIN32) && !defined(__cplusplus_winrt) || defined(CPPREST_FORCE_HTTP_CLIENT_ASIO)
+
+#if defined(CPPREST_BOTAN_SSL)
+#include <botan/asio_context.h>
+#else  // CPPREST_BOTAN_SSL
+
 #if defined(__clang__)
 #pragma clang diagnostic push
 #pragma clang diagnostic ignored "-Wconversion"
@@ -69,6 +74,9 @@ typedef void* native_handle;
 #if defined(__clang__)
 #pragma clang diagnostic pop
 #endif
+
+#endif  // CPPREST_BOTAN_SSL
+
 #endif
 
 /// The web namespace contains functionality common to multiple protocols like HTTP and WebSockets.
@@ -86,6 +94,12 @@ namespace client
 using web::credentials;
 using web::web_proxy;
 
+#if defined(CPPREST_BOTAN_SSL)
+using ssl_context_t = Botan::TLS::Context;
+#else
+using ssl_context_t = boost::asio::ssl::context;
+#endif
+
 /// <summary>
 /// HTTP client configuration class, used to set the possible configuration options
 /// used to create an http_client instance.
@@ -334,15 +348,15 @@ class http_client_config
     /// </summary>
     /// <param name="callback">A user callback allowing for customization of the ssl context at construction
     /// time.</param>
-    void set_ssl_context_callback(const std::function<void(boost::asio::ssl::context&)>& callback)
+    void set_ssl_context_callback(const std::function<void(ssl_context_t&)>& callback)
     {
         m_ssl_context_callback = callback;
     }
 
     /// <summary>
     /// Gets the user's callback to allow for customization of the ssl context.
     /// </summary>
-    const std::function<void(boost::asio::ssl::context&)>& get_ssl_context_callback() const
+    const std::function<void(ssl_context_t&)>& get_ssl_context_callback() const
     {
         return m_ssl_context_callback;
     }
@@ -386,7 +400,7 @@ class http_client_config
     std::function<void(native_handle)> m_set_user_nativesessionhandle_options;
 
 #if !defined(_WIN32) && !defined(__cplusplus_winrt) || defined(CPPREST_FORCE_HTTP_CLIENT_ASIO)
-    std::function<void(boost::asio::ssl::context&)> m_ssl_context_callback;
+    std::function<void(ssl_context_t&)> m_ssl_context_callback;
     bool m_tlsext_sni_enabled;
 #endif
 #if defined(_WIN32) && !defined(__cplusplus_winrt)
@@ -402,6 +416,8 @@ class http_pipeline;
 class http_client
 {
 public:
+    using ssl_context = ssl_context_t;
+
     /// <summary>
     /// Creates a new http_client connected to specified uri.
     /// </summary>

Release/src/CMakeLists.txt

@@ -127,10 +127,18 @@ endif()
 # Http client component
 if(CPPREST_HTTP_CLIENT_IMPL STREQUAL "asio")
   cpprest_find_boost()
-  cpprest_find_openssl()
-  target_compile_definitions(cpprest PUBLIC -DCPPREST_FORCE_HTTP_CLIENT_ASIO)
+  if(CPPREST_NO_OPENSSL)
+    cpprest_find_botan()
+    set(CPPREST_BOTAN_SSL_FLAG "-DCPPREST_BOTAN_SSL")
+    set(CPPREST_SSL_LINK_LIB cpprestsdk_botan_internal)
+  else()
+    cpprest_find_openssl()
+    set(CPPREST_BOTAN_SSL_FLAG "")
+    set(CPPREST_SSL_LINK_LIB cpprestsdk_openssl_internal)
+  endif()
+  target_compile_definitions(cpprest PUBLIC ${CPPREST_BOTAN_SSL_FLAG} -DCPPREST_FORCE_HTTP_CLIENT_ASIO)
   target_sources(cpprest PRIVATE http/client/http_client_asio.cpp http/client/x509_cert_utilities.cpp)
-  target_link_libraries(cpprest PUBLIC cpprestsdk_boost_internal cpprestsdk_openssl_internal)
+  target_link_libraries(cpprest PUBLIC cpprestsdk_boost_internal ${CPPREST_SSL_LINK_LIB})
 elseif(CPPREST_HTTP_CLIENT_IMPL STREQUAL "winhttp")
   target_link_libraries(cpprest PRIVATE
     httpapi.lib
@@ -248,6 +256,7 @@ if(CPPREST_INSTALL)
   set(CPPREST_USES_ZLIB OFF)
   set(CPPREST_USES_BROTLI OFF)
   set(CPPREST_USES_OPENSSL OFF)
+  set(CPPREST_USES_BOTAN OFF)
 
   set(CPPREST_TARGETS cpprest)
   if(TARGET cpprestsdk_boost_internal)
@@ -266,6 +275,10 @@ if(CPPREST_INSTALL)
     list(APPEND CPPREST_TARGETS cpprestsdk_openssl_internal)
     set(CPPREST_USES_OPENSSL ON)
   endif()
+  if(TARGET cpprestsdk_botan_internal)
+    list(APPEND CPPREST_TARGETS cpprestsdk_botan_internal)
+    set(CPPREST_USES_BOTAN ON)
+  endif()
   if(TARGET cpprestsdk_websocketpp_internal)
     list(APPEND CPPREST_TARGETS cpprestsdk_websocketpp_internal)
   endif()