mac中自带的curl和PHP版本可能不兼容,或者其他原因,在未安装curl时总是无法调用https,提示SSL certificate problem: Couldn’t understand the server certificate format.
使用以下命令重装php调用外部curl搞定！
xcode-select --install brew uninstall --ignore-dependencies php71 brew install php71 --with-homebrew-curl