Estoy tratando de obtener el número de seguidores de una gran cantidad de usuarios de Twitter contwitteR. Mucho deotr preguntas publicado ha sido muy útil para llegar hasta aquí, pero ninguno parece ser directamente relevante para mi problema, por lo que puedo ver.

Puedo registrar mis credenciales de OAuth en una sesión de Twitter R, pero parece que no puedo hacer nada en absoluto, solo recibo este mensaje:

Error in function (type, msg, asError = TRUE) : SSL certificate problem, verify that the CA cert is OK. Details: error:14090086:SSL routines:SSL3_GET_SERVER_CERTIFICATE:certificate verify fail

Cuando uso latwitteR funciona sin usar OAuth, funcionan bien sin errores ni advertencias, pero me encuentro con límites y cuentas protegidas, que pensé que podría evitar con OAuth.

Aquí están los detalles

library(twitteR)
library(ROAuth)
library(RCurl)
#
# Here's how I register my credentials
#
requestURL <-  "https://api.twitter.com/oauth/request_token"
accessURL =    "https://api.twitter.com/oauth/access_token"
authURL =      "https://api.twitter.com/oauth/authorize"
consumerKey =   "------------"
consumerSecret = "-----------"
twitCred <- OAuthFactory$new(consumerKey=consumerKey,
                             consumerSecret=consumerSecret,
                             requestURL=requestURL,
                             accessURL=accessURL,
                             authURL=authURL)
download.file(url="http://curl.haxx.se/ca/cacert.pem",
              destfile="cacert.pem")
twitCred$handshake(cainfo="cacert.pem")
To enable the connection, please direct your web browser to: 
https://api.twitter.com/oauth/authorize?oauth_token=xxxx
When complete, record the PIN given to you and provide it here: xxxxxx
registerTwitterOAuth(twitCred)
[1] TRUE
# so the OAuth bit appears to be ok...
#
# save it for a future sessions...
save(list="twitCred", file="twitteR_credentials")
# works, in future I can just
load("twitteR_credentials")
registerTwitterOAuth(twitCred)
#
# try to get follower numbers, here's where it goes south
me <- getUser("Rbloggers")
me$followersCount
Error in function (type, msg, asError = TRUE)  :
SSL certificate problem, verify that the CA cert is OK. Details:
error:14090086:SSL routines:SSL3_GET_SERVER_CERTIFICATE:certificate verify failed
#
# another method, same problem
getUser("Rbloggers")$followersCount
Error in function (type, msg, asError = TRUE)  : 
SSL certificate problem, verify that the CA cert is OK. Details:
error:14090086:SSL routines:SSL3_GET_SERVER_CERTIFICATE:certificate verify failed
# 
# Here are the packages and versions I'm using
sessionInfo() 
R version 2.14.1 (2011-12-22)
Platform: i386-pc-mingw32/i386 (32-bit)

locale:
[1] LC_COLLATE=English_Australia.1252  LC_CTYPE=English_Australia.1252   
[3] LC_MONETARY=English_Australia.1252 LC_NUMERIC=C                      
[5] LC_TIME=English_Australia.1252    

attached base packages:
[1] stats4    stats     graphics  grDevices utils     datasets  methods   base     

other attached packages:
 [1] ROAuth_0.9.2      digest_0.5.1      twitteR_0.99.19   rjson_0.2.6       RCurl_1.91-1.1   
 [6] bitops_1.0-4.1    igraph_0.5.5-4    topicmodels_0.1-4 tm_0.5-7          slam_0.1-23      
[11] modeltools_0.2-18 lasso2_1.2-12    

loaded via a namespace (and not attached):
[1] tools_2.14.1

¿Cómo puedo obtener eltwitteR funciones que funcionan después de registrar mis credenciales?

ACTUALIZA: Probar la sugerencia de @ Btibert3 da el mismo error:

> ## Authenticate with Twitter = this is an important peice of code
> registerTwitterOAuth(cred)
[1] TRUE
> ##########################################################################
> ## lets test out what our session limits look like
> ##########################################################################
> rate.limit <- getCurRateLimitInfo()
Error in function (type, msg, asError = TRUE)  : 
  SSL certificate problem, verify that the CA cert is OK. Details:
error:14090086:SSL routines:SSL3_GET_SERVER_CERTIFICATE:certificate verify failed

ACTUALIZA siguiendo la sugerencia de @ flz para agregarcainfo="cacert.pem" en todas partes ha solucionado mi problema:

rate.limit <- getCurRateLimitInfo( cainfo="cacert.pem")
rate.limit
                             resource limit remaining               reset
1                  /lists/subscribers   180       180 2013-03-27 09:35:37
2                         /lists/list    15        15 2013-03-27 09:35:37
3                  /lists/memberships    15        15 2013-03-27 09:35:37
4                   /lists/ownerships    15        15 2013-03-27 09:35:37
5                /lists/subscriptions    15        15 2013-03-27 09:35:37
6                      /lists/members   180       180 2013-03-27 09:35:37
7             /lists/subscribers/show    15        15 2013-03-27 09:35:37
8                     /lists/statuses   180       180 2013-03-27 09:35:37
9                         /lists/show    15        15 2013-03-27 09:35:37
10                /lists/members/show    15        15 2013-03-27 09:35:37
11     /application/rate_limit_status   180       179 2013-03-27 09:35:37 (etc)

Información de la sesión:

sessionInfo()
R version 2.15.3 (2013-03-01)
Platform: x86_64-w64-mingw32/x64 (64-bit)

locale:
[1] LC_COLLATE=English_United States.1252  LC_CTYPE=English_United States.1252   
[3] LC_MONETARY=English_United States.1252 LC_NUMERIC=C                          
[5] LC_TIME=English_United States.1252    

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base     

other attached packages:
[1] ROAuth_0.9.2   digest_0.6.3   twitteR_1.1.0  rjson_0.2.12   RCurl_1.95-4.1 bitops_1.0-5  

loaded via a namespace (and not attached):
[1] tools_2.15.3