In my last blog I’m following you in Twitter…are you following me back? I show you how to use the Twitter APIs to get a list of the people that you follow but doesn’t follow you back.

This time, I want to extend the tool as I installed the Rook library on my RStudio -:)

So..what is Rook? Nothing more that just a nice Web Server for R…something that I was really missing in R when compared to Ruby (Sinatra, Camping) or Python (Bottle, Flask).

The idea here is that we request a Twitter username and then provide the list with the “Bad People”. Here’s the source code…

require("Rook")

Get_Twitter_Info<-function(p_source){
  web_page<-readLines(p_source)
  mypattern = '<id>([^<]*)</id>'
  datalines = grep(mypattern,web_page,value=TRUE)
  getexpr = function(s,g)substring(s,g,g+attr(g,'match.length')-1)
  g_list = gregexpr(mypattern,datalines)
  matches = mapply(getexpr,datalines,g_list)
  result = gsub(mypattern,'\\1',matches) 
  names(result) = NULL
  return(result)
}

Get_Screen_Name<-function(p_userid){
  user_url<-paste("https://api.twitter.com/1/users/lookup.xml?user_id=",
                      p_userid,"&include_entities=false")
  web_page<-readLines(user_url)
  mypattern = '<screen_name>([^<]*)</screen_name>'
  datalines = grep(mypattern,web_page,value=TRUE)
  getexpr = function(s,g)substring(s,g,g+attr(g,'match.length')-1)
  g_list = gregexpr(mypattern,datalines)
  matches = mapply(getexpr,datalines,g_list)
  screen_name = gsub(mypattern,'\\1',matches)
  names(screen_name) = NULL
  return(screen_name)
}

trim <- function(x){
  x<-gsub(' ','',x)
  return(x)
} 

newapp<-function(env){
  req<-Rook::Request$new(env)
  res<-Rook::Response$new()
  res$write('<form method="POST">\n')
  res$write('Enter your Twitter username: <input type="text" name="UserName">\n')
  res$write('<input type="submit" name="Get Bad People!">')
  res$write('</form>')

  People_Id<-""
  Bad_People<-c()
  Bad_Names<-c()
  j<-0  
  
  if (!is.null(req$POST())) {
    UserName = req$POST()[["UserName"]]
    
    followers_link<-paste("https://api.twitter.com/1/followers/ids.xml?cursor=-1&screen_name=",UserName)
    following_link<-paste("https://api.twitter.com/1/friends/ids.xml?cursor=-1&screen_name=",UserName)
    followers_link<-trim(followers_link)
    following_link<-trim(following_link)    
    followers<-Get_Twitter_Info(followers_link)
    following<-Get_Twitter_Info(following_link)
        
    for(i in 1:length(following)) {
      j<-j+1
      if(j>=100){
        j<-0
        People_Id<-substring(People_Id,2)
        Bad_People<-Get_Screen_Name(People_Id)
        Bad_Names<-append(Bad_Names,Bad_People)
        People_Id<-""
      }
      Match<-following[i] %in% followers
      if(Match == TRUE){
      }
      else{
        following[i]<-trim(following[i])
        People_Id<-paste(People_Id,following[i],sep=",")
      }
    }    
  }
  for(i in 1:length(Bad_Names)) {
    res$write(paste(' ',Bad_Names[i],sep=' '))
    res$write('<BR>')
  }
  res$finish()
}

server = Rhttpd$new()
server$add(app = newapp, name = "Twitter_Rook")
server$start()
server$browse("Twitter_Rook")

When we run the code, the browser will open automatically showing us the application.