#NRW - Tweets aus Nordrhein-Westfalen in #R saugen

In diesem Post zeige ich ein kurzes Beispiel, wie man das streamR-Package nutzen kann, um Tweets aus NRW zu speichern.
Voraussetzung ist, dass man ein consumer secret und einen consumerkey von Twitter hat.
Das Beispiel aus der streamR-Doku ist im Prinzip richtig. Nur muss man inzwischen https anstelle von http verwenden.
Hier also "stuff that works", wie Guy Clark sagen würde.
Wichtig ist, dass man eine gültige cacert.pem Datei im Arbeitsverzeichnis hat. Eine entsprechende Datei findet sich hier. 

#load libraries
library(streamR)
library(ROAuth)
library(twitteR)

requestURL <- "https://api.twitter.com/oauth/request_token"
accessURL <- "https://api.twitter.com/oauth/access_token"
authURL <- "https://api.twitter.com/oauth/authorize"
#own consumerKey and Secret is needed!
consumerKey <- "xxxxxyyyyyzzzzzz"
consumerSecret <- "xxxxxxyyyyyzzzzzzz111111222222"
Cred <- OAuthFactory$new(consumerKey=consumerKey,
                         consumerSecret=consumerSecret,
                         requestURL=requestURL,
                         accessURL=accessURL,
                         authURL=authURL)
Cred$handshake(cainfo = system.file("CurlSSL", "cacert.pem", package = "RCurl") )
#to validate the handshake, it is necessary to go to the webpage and get a pin...
registerTwitterOAuth(Cred)
#If everything has worked, this should be "TRUE"

#and now you can save the "Cred"
save(list="Cred", file="twitteR_credentials")
#next time, you can start the script here!!!

#(But don't forget to load the libraries...)
load("twitteR_credentials")
registerTwitterOAuth(Cred)
#The following parameters can be modified to fit to your search interest.
#Now, all tweets from NRW (and a little beyond) are captured.
#Full information on the parameters can be found here:
#https://dev.twitter.com/docs/streaming-apis/parameters

file = "tweets.json"
track = NULL
follow = NULL
loc = c(50.33, 6.1, 52.36, 9.4)
lang = NULL
time = 60*1
tweets = NULL
filterStream(file.name = file, track = track,
             follow = follow, locations = loc, language = lang,
             timeout = time, tweets = tweets, oauth = Cred,
             verbose = TRUE)
tweets.df <- parseTweets(file, verbose = FALSE)
View(tweets.df)