verify_cmake_check_for_bad_ssl_cert.cmake

#
# slicer_check_cmake_https
#
# Check if CMake supports downloading files using the HTTPS protocol. Fail if
# HTTPS is unsupported.
#
# CMake should support HTTPS when compiled with CMAKE_USE_OPENSSL enabled.
#
# Based on the script created by Jean-Christophe Fillion-Robin:
# https://gist.github.com/jcfr/e88a2a7cbc4ddd235186
#


set(GOOD_SSL "https://google.com")
set(BAD_SSL "https://self-signed.badssl.com")

#-------------------------------------------------------------------------------
message(STATUS "Trying to download from ${GOOD_SSL}")

file(DOWNLOAD ${GOOD_SSL} ${CMAKE_CURRENT_BINARY_DIR}/good_ssl TLS_VERIFY ON STATUS status)

if(NOT status MATCHES "^0.*")
  message(FATAL_ERROR "Failed to download from ${GOOD_SSL}: ${status}")
endif()

message(STATUS "Trying to download from ${GOOD_SSL} - ok")


#-------------------------------------------------------------------------------
message(STATUS "Trying to download from ${BAD_SSL}")

file(DOWNLOAD ${BAD_SSL} ${CMAKE_CURRENT_BINARY_DIR}/bad_ssl TLS_VERIFY ON STATUS status)

if(status MATCHES "^0.*")
  message(FATAL_ERROR "Download is expected to fail because of bad certs: ${status}")
endif()

message(STATUS "Trying to download from ${BAD_SSL} - failed as expected")