在R studio中为Mac设置证书位置时出错

我在尝试使用R获取推文时遇到了一个证书错误。我环顾四周，发现对于windows，需要安装rCurl库。我找不到mac的任何信息。我尝试了windows的建议，但什么也找不到。非常感谢您的帮助

    install.packages('twitteR')
    install.packages('plyr')
    install.packages('stringr')
    install.packages('ggplot2')

    library(plyr)
    library(stringr)  
    library(ggplot2)
    library(twitteR)

    requestURL <- "https://api.twitter.com/oauth/request_token"
    accessURL = "http://api.twitter.com/oauth/access_token"
    authURL = "http://api.twitter.com/oauth/authorize"
    consumerKey = "xxxxxxxx"
    consumerSecret = "xxxxxxxx"
    Cred <- OAuthFactory$new(consumerKey=consumerKey,
                     consumerSecret=consumerSecret,
                     requestURL=requestURL,
                     accessURL=accessURL, 
                     authURL=authURL)

    Cred$handshake(cainfo = system.file("CurlSSL", "cacert.pem", package = "RCurl") )
    7699317
    registerTwitterOAuth(Cred)

    save(Cred, file="twitter authentication.Rdata")

是因为我在mac电脑上工作吗？还是我的代码有问题

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谢谢

我不得不再次下载证书。可能是R的安装版本更早。通过添加下面的代码，它工作得很好

download.file(url="http://curl.haxx.se/ca/cacert.pem", destfile="cacert.pem")

    library(RCurl)
    options(RCurlOptions = list(cainfo = system.file("CurlSSL", "cacert.pem", package = "RCurl")))

download.file(url="http://curl.haxx.se/ca/cacert.pem", destfile="cacert.pem")