Cert Support URL

[jlacko]

repost from rodazuero#60

---

Hello, everyone. In reviewing my usage of this particular package, I have a question. I am not familiar with R coding and have been handed this process. My tech team has discovered that the URL process to call Google Maps API does not allow the use of certificates. We need to figure out how to use RCurl to pass the URL through to the Google Maps API. I am going to cut and paste the information from my tech team for additional context.

Thanks.

The opensource code (gmapsdistance/R/gmapsdistance.R) maintainer should provide option to use certs for getURL.
For example:
https://github.com/rodazuero/gmapsdistance/blob/master/R/gmapsdistance.R#L378 should have logic as below:

library ("RCurl")
webpageXML = xmlParse(getURL(url,cainfo=system.file("CurlSSL","ZscalerRootCertificate-2048-SHA256.pem",package="RCurl")));