如何使用 R 发送/接收 (SMTP/POP3) 电子邮件？

Question

我强烈怀疑最受好评的答案将是“那是工作的错误工具”。我承认 R 可能不是特别适合发送和接收电子邮件，但它是我最了解的脚本语言。我希望找到一种在 R 中发送和接收短电子邮件的方法。有人知道在 Windows 平台上执行此操作的既定方法吗？我或许可以结合使用 BLAT 和 GetMail，但首选 R 原生解决方案。

编辑：可接受的解决方案应该能够与需要 SSL 的服务器交互。

编辑 2： 我提供了 80% 的答案。遗憾的是，没有展示 R 原生方式。相反，我使用了可能无法跨平台兼容的系统调用和命令行程序的邪恶组合。 R 本机调用将需要深入研究 POP3 服务器喜欢与连接的客户端通信的方式，以及我目前没有的对 SSL 的理解。仍然鼓励其他答案。

##Note: Other programs are wrapped in R functions and system calls.
#They each have their own licenses which may or may not allow the use suggested here
#Programs used here:
#STunnel: http://www.stunnel.org/; Provides an SSL tunnel but requires OpenSSL 
#OpenSSL: http://www.openssl.org/; OpenSSL to actually provide SSL
#   Note that these .dlls should be placed with the stunnel exe.
#   Also note that libssl32.dll may need to be renamed from ssleay32.dll
#Microsoft Visual C++ 2008 Redistributable (may be required for the SSL .dlls to work correctly)
#Blat: http://www.blat.net; a public domain SMTP sending program
#Getmail is free for non-commercial use. If you use it in a business environment, then a fee of $50 USD is payable to Tim Charron. 

#Stunnel is a TSR, so it will need to be killed from the task manager if there is an issue.  If you are willing to install it as a service you may be able to tweak my code to start and stop the service.  
#My current code does not create .conf file for stunnel the way a full version ought.  Check http://spampal.sanesecurity.com/manual_eng/servers/stunnel/stunnel.htm#sconfig21 to create the appropriate configuration file.

#Set the config values as appropriate
##Config##
BLAT.loc <- "c:/Programming/R/Rmail/blat262/full/blat.exe"
GetMail.loc <- "C:/Programming/R/RMail/getmail133/getmail.exe"
stunnel.loc <- "C:/Programming/R/RMail/stunnel/stunnel-4.11.exe"

#The set mail function assigns the username and password to be used as well as the smtp and pop3 servers it starts stunnel (and assumes that the stunnel.conf file is present and set correctly).
setMail <- function(user,pw,SSL=FALSE,smtp="127.0.0.1:259",pop3="127.0.0.1:1109")
{
    if (SSL==TRUE)
    {
        print("Starting stunnel; you will need to kill this from the task-manager")
        system(stunnel.loc,wait=FALSE)
        Sys.sleep(2) #Give it time to start 
    }
    return(list(user=user,pw=pw,smtp=smtp,pop3=pop3,SSL=SSL))
}

#function to send mail, myMail is the resulting list from setMail
sendmail <- function(myMail, to, subject, msg,VERBOSE=FALSE)
{
    writeLines(msg, "out.txt", sep = "\n", useBytes = FALSE)
      targ <- paste(getwd(),"/out.txt",sep="")
    call <- paste(BLAT.loc, ' "',targ,'" -subject "',subject,'" -to ',to," -u ",myMail$user," -pw ",myMail$pw, " -f ",myMail$user, " -debug -server ",myMail$smtp,sep="")
    res <- system(call,intern=TRUE)
    if (VERBOSE) {return(res)}
}

#function to get mail, myMail is the resulting list from setMail; it returns a list with one element that contains everything unparsed, another list provides the number of messages remaining on the server.
getmail <- function(myMail,VERBOSE=FALSE)
{      
    unlink("MSG1.txt") #drop previous get
    #download next message
    call <- paste(GetMail.loc," -u ",myMail$user," -pw ",myMail$pw," -s ",strsplit(myMail$pop3,":")[[1]][1],
        " -port ",strsplit(myMail$pop3,":")[[1]][2]," -n 1",sep="")
    res <- system(call,intern=TRUE)
    if (VERBOSE) {print(res)}
    nmsgtxt <- res[grep("messages on the server.",res)]
    nstart <- regexpr("There are",nmsgtxt)
    nend <- regexpr("messages on the server.",nmsgtxt)
    nmess <- as.numeric(substr(nmsgtxt,10,nend-1))-1
      x <- readLines("MSG1.txt",-1)
    return(list(message=x,remaining=nmess))
}

使用案例：简单地说，我需要让 R 能够将其内容在 R 脚本的其他位置确定的消息发送到 SMTP 服务器。参与者将收到电子邮件并回复。我需要从我的 POP3 服务器检索他们的响应并将其存储在 R 数据结构中，以便我可以对其执行后期处理。在实践中，我正在建立一种通过 R 进行体验采样的方法。也就是说，R 可以向参与者发送电子邮件“你今天好吗（1 = 糟糕；7 = 很好）？”参与者可以回答“4”，我可以在数据库中匹配提出的问题、回答等进行统计分析。

Answer 1

从 Pop 服务器拉取消息

为了尝试实现@JorisMeys 利用其他语言的想法，我尝试使用 Python 和 rJython 包从 Gmail（通过 ssl）提取邮件。 Jython 是在 Java 虚拟机上实现的 Python，所以使用 rJython 对我来说有点像用 R 调用 Java，然后伪装成 Python。

我发现 rJython 对于简单的事情非常容易，但由于我不精通 S4 对象和 (r)Java，我有时很难正确操作来自 rJython 的返回对象。但是，它有效。下面是一个从 Gmail 帐户中提取单条消息的基本结构：

library(rJython)

rJython <- rJython( modules = "poplib")

rJython$exec("import poplib")
rJython$exec("M = poplib.POP3_SSL('pop.gmail.com', 995)")
rJython$exec("M.user(\'yourGmailAddy@gmail.com\')")
rJython$exec("M.pass_(\'yourGmailPassword\')")
rJython$exec("numMessages = len(M.list()[1])")
numMessages <- rJython$get("numMessages")$getValue()

# grab message number one. Loop here if you
# want more messages
rJython$exec("msg = M.retr(1)[1]")
emailContent <- rJython$get("msg")

# turn the message into a list
contentList <- as.list(emailContent)
# so we have an R list... of Java objects
# To get a more native R list we have to
# yank the string from each Java item

messageToList <- function(contentList){
  outList <- list()
  for (i in 1:length(contentList)){
    outList[i] <- contentList[[i]]$toString()
  }
  outList
}

messageAsList <- messageToList(contentList)
messageAsList

Answer 2

查看 CRAN 上的 sendmailR 包。

Answer 3

使用 mailR 包 (http://rpremraj.github.io/mailR/)，您可以使用 SSL 发送电子邮件：

send.mail(from = "sender@gmail.com",
          to = c("recipient1@gmail.com", "recipient2@gmail.com"),
          subject = "Subject of the email",
          body = "<html>The apache logo - <img src=\"http://www.apache.org/images/asf_logo_wide.gif\"></html>",
          html = TRUE,
          smtp = list(host.name = "smtp.gmail.com", port = 465, user.name = "gmail_username", passwd = "password", ssl = TRUE),
          attach.files = c("./download.log", "upload.log"),
          authenticate = TRUE,
          send = TRUE)