Application Programming Interfaces

Chris Bail
Duke University

website: https://www.chrisbail.net
github: https://github.com/cbail
Twitter: https://www.twitter.com/chris_bail

What Is an Application Programming Interface (API)?

Growth of APIS

A List of APIs

There are now nearly 20,000 APIs and counting:

https://www.programmableweb.com/apis/directory

How Does an API Work?

Simple Example with Google Maps API

Anatomy of an API Call

Output of API call:

Designing your Own API Calls

API Credentials

Example: Facebook API

Navigate to:

https://developers.facebook.com/tools/explorer?classic=0

Rate Limiting

An Example with Twitter's API

Navigate to:

https://apps.twitter.com.

An Example with Twitter's API

Select Account Type and Describe Use

The Waiting Is the Hardest Part...

Your Developer Console

Callback URL

http://127.0.0.1:1410

Keys and Access Tokens

The rtweet Package

install.packages("rtweet")

Define Your Credentials

app_name<-"YOURAPPNAMEHERE"
consumer_key<-"YOURKEYHERE"
consumer_secret<-"YOURSECRETHERE"
access_token<-"YOURACCESSTOKENHERE"
access_token_secret<-"YOURACCESSTOKENSECRETHERE"

Authenticate Yourself with Twitter API

library(rtweet)
create_token(app=app_name, consumer_key=consumer_key, consumer_secret=consumer_secret, access_token=access_token,
access_secret=access_token_secret,
set_renv = TRUE)

Your First API Call

korea_tweets<-search_tweets("#Korea", n=3000, include_rts = FALSE)

Browse the Results

names(korea_tweets)

Browse the Results

head(korea_tweets$text)

Plot the Results

ts_plot(korea_tweets, "3 hours") +
  ggplot2::theme_minimal() +
  ggplot2::theme(plot.title = ggplot2::element_text(face = "bold")) +
  ggplot2::labs(
    x = NULL, y = NULL,
    title = "Frequency of Tweets about Korea from the Past Day",
    subtitle = "Twitter status (tweet) counts aggregated using three-hour intervals",
    caption = "\nSource: Data collected from Twitter's REST API via rtweet"
  )

Plot the Results

Next, Let's Search by Location

nk_tweets <- search_tweets("korea",
  "lang:en", geocode = lookup_coords("usa"), 
  n = 1000, type="recent", include_rts=FALSE
  )
geocoded <- lat_lng(nk_tweets)

Plot

par(mar = c(0, 0, 0, 0))
maps::map("state", lwd = .25)
with(geocoded, points(lng, lat, pch = 20, cex = .75, col = rgb(0, .3, .7, .75)))

Plot

Get Tweets from Individual Account

sanders_tweets <- get_timelines(c("sensanders"), n = 5)
head(sanders_tweets$text)

Get Tweets from Individual Account

Get General Information About a User

sanders_twitter_profile <- lookup_users("sensanders")

Browse Fields

sanders_twitter_profile$description

Browse Fields

sanders_twitter_profile$location

Browse Fields

sanders_twitter_profile$followers_count

Get Users' Favorites

sanders_favorites<-get_favorites("sensanders", n=5)
sanders_favorites$text

Get Users' Favorites

Get Networks

sanders_follows<-get_followers("sensanders")

Check Rate Limits

rate_limits<-rate_limit()
head(rate_limits[,1:4])