Application-only authentication on Twitter API using R

app-only-auth-twitter.R

# In order to use application-only authentification, one will need a consumer key and consumer secret.
# For more information regarding this mode of authentification : https://dev.twitter.com/oauth/application-only 
library(httr)
library(base64enc)

# 1. Encode consumer key and secret
consumer_key <- ""
consumer_secret <- ""
enc_consumer_key <- URLencode(URL = consumer_key)
enc_consumer_secret <- URLencode(URL = consumer_secret)

key_secret <- sprintf(fmt = "%s:%s", enc_consumer_key, enc_consumer_secret)

# Encoding consumer key and secret using Base64 encoding. key_secret must be convert to raw vector
enc_key_secret <- base64enc::base64encode(what = charToRaw(key_secret))

# 2. Obtaining bearer token using HTTP POST request

headers_connect <- c("Host"            = "api.twitter.com",
                     "Authorization"   = sprintf("Basic %s", enc_key_secret),
                     "Content-Type"    = "application/x-www-form-urlencoded;charset=UTF-8",
                     "Content-Length"  = "29",
                     "Accept-Encoding" = "gzip")

connect_app <- httr::POST(url    = "https://api.twitter.com/oauth2/token",
                          config = httr::add_headers(headers_connect),
                          body   = "grant_type=client_credentials")

bearer_token <- httr::content(connect_app)$access_token

# 3. Authentificate API requests using the bearer token. Example of GET request : Timeline of twitterapi
# Defining headers for GET
headers_get <- c(Host = "api.twitter.com",
                 "User-agent"= "",
                 "Authorization" = paste0("Bearer ", bearer_token))

# Defining request name. Available requests can be found on : https://dev.twitter.com/rest/reference
request_name <- "statuses/user_timeline"

# Defining parameters
parameters <- list(screen_name = "twitterapi", count = 100)
query <- lapply(parameters, function(x) URLencode(as.character(x)))


results <- httr::GET(url    = paste0("https://api.twitter.com/1.1/", request_name, ".json"),
                     query  = query, 
                     config = httr::add_headers(headers_get))

# Displaying status code. 200 means successful request
httr::status_code(results)
                
# Displaying the results, in list format.
httr::content(results)