How to use RCurl to authenticate to spring security / grails app

Question

Today I tried to figure out how to use the R package RCurl to log onto my grails application, which uses the spring security plugin and not base authentication. I wanted to figure out how to log on to the website to download some data. On the console this seems to work easily like this:

curl -d j_username=user -d j_password=password -L http://localhost:8080/appName/j_spring_security_check

However, an RCurl equivalent like this fails:

require(RCurl)
authenticateUrl = paste(baseUrl, "j_spring_security_check", sep="")

cat(paste("trying to authenticate user", user))
agent="Mozilla/5.0"

#Set RCurl pars
curl = getCurlHandle()
curlSetOpt(ssl.verifypeer=FALSE, timeout=60, cookiefile="cookies.txt",   
cookiejar="cookies.txt", useragent = agent, 
followlocation = TRUE, curl=curl, verbose=verbose)

#Post login form
postForm(authenticateUrl, .params= list(j_username="user", j_password="password"),    
curl=curl, style="POST")

Instead of successfully logging in, I'm being redirected to the auth_fail page.

Answer 1

It turns out that one has to call the login page first. I'm guessing this has something to do with the JSESSIONID that is stored in the cookie. If I add this step before calling postForm everything works fine:

loginUrl = paste(baseUrl, "login/auth", sep="")
getURL(loginUrl, curl=curl)