R 语言 download.file 的 SSL connect error
异常信息：
> install.packages("rms")
--- Please select a CRAN mirror for use in this session ---
Warning: failed to download mirrors file (cannot open URL 'https://cran.r-project.org/CRAN_mirrors.csv'); using local file '/Bioinfo/Pipeline/SoftWare/R/R-3.6.1/lib64/R/doc/CRAN_mirrors.csv'
trying URL 'http://mirrors.tuna.tsinghua.edu.cn/CRAN/src/contrib/rms_6.0-0.tar.gz'
Content type 'application/x-gzip' length 623859 bytes (609 KB)
==================================================
downloaded 609 KB
......
* DONE (rms)
The downloaded source packages are in
‘/tmp/RtmpJF5nYY/downloaded_packages’
Updating HTML index of packages in '.Library'
Making 'packages.html' ... done
Warning message:
In download.file(url, destfile = f, quiet = TRUE) :
URL 'https://cran.r-project.org/CRAN_mirrors.csv': status was 'SSL connect error'
>
参考方法：
- 先设置镜像，再执行包安装。
# CRAN 镜像源配置文件之一是 .Rprofile (linux 下位于 ~/.Rprofile )，可以在文末添加如下语句:
options("repos" = c(CRAN="https://mirrors.tuna.tsinghua.edu.cn/CRAN/"))
- 也有可能是由于 CentOS 6.x 自带的 OpenSSL（最高版本是 openssl-1.0.1e-15.el6.x86_64）引发的一个 bug，如果是这种情况，请参考这篇文章解决。