Using Twitter4j with Scala to perform user actions

Topics: twitter,twitter4j,word clouds

Introduction

My previous post showed how to use Twitter4j in Scala to access Twitter streams. This post shows how to control a Twitter user’s actions using Twitter4j. The primary purpose of this functionality is perhaps to create interfaces for Twitter like TweetDeck, but it can also be used to create bots that take automated actions on Twitter (one bot I’m playing around with is @tshrdlu, using the code in this tutorial and the code in the tshrdlu repository).

This post will only cover a small portion of the things you can do, but they are some of the more common things and I include a couple of simple but interesting use cases. Once you have these things in place, it is straightforward to figure out how to use the Twitter4j API docs (and Stack Overflow) to do the rest.

Getting set up: code and authorization

Rather than having the reader build the code up while going through the tutorial, I’ve set up the code in the repository twitter4j-tutorial. The version needed for this tutorial as v0.2.0. You can download a tarball of that version, which may be easier to work with if there have been further developments to the repository since the writing of this tutorial. Checkout or download that code now. The main file of interest is:

  • src/main/scala/TwitterUser.scala

This tutorial is mainly a walk through for that file in blog form, with some additional pointers and explanations here and there.

You also need to set up the authorization details. See “Setting up authorization” section of the previous post to do this if you haven’t already.

READ THE FOLLOWING

IMPORTANT: for this tutorial you must set the permissions for your application to be “Read and Write“. This does NOT mean to use ‘chmod’. It means going to the Twitter developers application site, signing in with your Twitter account, clicking on “Settings” and setting the permissions to read and write.

OKAY, THANKS FOR PAYING ATTENTION

In the previous tutorial, authorization details were put into code. This time, we’ll use a twitter4j.properties file. This is easy: just add a file with that name to the twitter4j-tutorial directory with the following contents, substituting your details as appropriate.

[sourcecode language=”bash”]
oauth.consumerKey=[your consumer key here]
oauth.consumerSecret=[your consumer secret here]
oauth.accessToken=[your access token here]
oauth.accessTokenSecret=[your access token secret here]
[/sourcecode]

Rate limits and a note of caution

Unlike streaming access to Twitter, performing user actions via the API is subject to rate limits. Once you hit your limit, Twitter will throw an exception and refuse to comply with your requests until a period of time has passed (usually 15 minutes). Twitter does this to limit bad bots and also preserve their computational resources. For more information on rate limits, see Twitter’s page about rate limiting.

I’ll discuss how to manage rate limits later in the post, but I mention them up front in case you exceed them while messing around with things early on.

A word of caution is also in order: since you are going to be able to take actions automatically, like following users, posting a status, and retweeting, you could end up doing many of these actions in rapid succession. This will (a) use up your rate limit very quickly, (b) probably not be interesting behavior, and (c) could get your account suspended. Make sure to follow the rules, especially those on following users.

If you are going to mess around quite a bit with actual posting, you may also want to consider creating an account that is not your primary Twitter account so that you don’t annoy your actual followers. (Suggestion: see the paragraph on “Create account” in part one of project phase one of my Applied NLP course for tips on how to add multiple accounts with the same gmail address.)

Basic interactions: searching, timelines, posting

All of the examples belowe are implemented as objects with main methods that do something using a twitter4j.Twitter object. To make it so we don’t have to call the TwitterFactory repeatedly, we first define a trait that gets a Twitter instance set up and ready to use.

[sourcecode language=”scala”]
trait TwitterInstance {
val twitter = new TwitterFactory().getInstance
}
[/sourcecode]

By extending this trait, our objects can access the twitter object conveniently.

As a first simple example, we can search for tweets that match a query by using the search method. The following object takes a query string given on the command line query, searches for tweets using that query, and prints them.

[sourcecode language=”scala”]
object QuerySearch extends TwitterInstance {

def main(args: Array[String]) {
val statuses = twitter.search(new Query(args(0))).getTweets
statuses.foreach(status => println(status.getText + "n"))
}

}
[/sourcecode]

Note that this uses a Query object, whereas with using a TwitterStream, a FilterQuery was needed. Also, for this to work, we must have the following import available:

[sourcecode language=”scala”]
import collection.JavaConversions._
[/sourcecode]

This ensures that we can use the java.util.List returned by the getTweets method (of twitter4j.QueryResult) as if it were a Scala collection with the method foreach (and map, filter, etc). This is done via implicit conversions that make working with Java libraries far nicer than it would be otherwise.

To run this, go to the twitter4j-tutorial directory, and do the following (some example output shown):

[sourcecode]
$ ./build
> run-main bcomposes.twitter.QuerySearch scala
[info] Running bcomposes.twitter.QuerySearch scala
E’ avvilente non sentirsi all’altezza di qualcosa o qualcuno, se non si possiede quella scala interiore sulla quale l’autostima pu? issarsi

Scala workshop will run with ECOOP, July 2nd in Montpellier, South of France. Call for papers is out. http://t.co/3WS6tHQyiF

#scala http://t.co/JwNrzXTwm8 Even two of them in #cologne #germany . #thumbsup

RT @MILLIB2DAL: @djcameo Birthday bash 30th march @ Scala nightclub 100 artists including myself make sur u reach its gonna be #Legendary

@kot_2010 I think it’s the same case with Scala: with macros it will tend to "outsource" things to macro libs, keeping a small lang core.

RT @waxzce: #scala hiring or job ? go there : http://t.co/NeEjoqwqwT

@esten That’s not only a front-end problem. Scala devs should use scalaz.Equal and === for type safe equality. /cc @sharonw

<…more…>

[success] Total time: 1 s, completed Feb 26, 2013 1:54:44 PM
[/sourcecode]

You might see some extra communications from SBT, which will probably need to download dependencies and compile the code. For the rest of the examples below, you can run them in a similar manner, substituting the right object name and providing any necessary arguments.

There are various timelines available for each user, including the home timeline, mentions timeline, and user timeline. They are accessible as twitter4j.api.TimelineResources. For example, the following object shows the most recent statuses on the authenticating user’s home timeline (which are the tweets by people the user follows).

[sourcecode language=”scala”]
object GetHomeTimeline extends TwitterInstance {

def main(args: Array[String]) {
val num = if (args.length == 1) args(0).toInt else 10
val statuses = twitter.getHomeTimeline.take(num)
statuses.foreach(status => println(status.getText + "n"))
}

}
[/sourcecode]

The number of tweets to show is given as the command-line argument.

You can also update the status of the authenticating user from the command line using the following object. Calling it will post to the authenticating user’s account (so only do it if you are comfortable with the command-line argument you give it going onto your timeline).

[sourcecode language=”scala”]
object UpdateStatus extends TwitterInstance {
def main(args: Array[String]) {
twitter.updateStatus(new StatusUpdate(args(0)))
}
}
[/sourcecode]

There are plenty of other useful methods that you can use to interact with Twitter, and if you have successfully run the above three, you should be able to look at the Twitter4j javadocs and start using them. Some examples doing more interesting things are given below.

Replying to tweets written to you

The following object goes through the most recent tweets that have mentioned the authenticating user, and replies “OK.” to them. It includes the author of the original tweet and any other entities that were mentioned in it.

[sourcecode language=”scala”]
object ReplyOK extends TwitterInstance {

def main(args: Array[String]) {
val num = if (args.length == 1) args(0).toInt else 10
val userName = twitter.getScreenName
val statuses = twitter.getMentionsTimeline.take(num)
statuses.foreach { status => {
val statusAuthor = status.getUser.getScreenName
val mentionedEntities = status.getUserMentionEntities.map(_.getScreenName).toList
val participants = (statusAuthor :: mentionedEntities).toSet – userName
val text = participants.map(p=>"@"+p).mkString(" ") + " OK."
val reply = new StatusUpdate(text).inReplyToStatusId(status.getId)
println("Replying: " + text)
twitter.updateStatus(reply)
}}
}

}
[/sourcecode]

This should be mostly self-explanatory, but there are a couple of things to note. First, you can find all the entities that have been mentioned (via @-mentions) in the tweet via the method getUserMentionEntities of the twitter4j.Status class. The code ensures that the author of the original tweet (who isn’t necessarily mentioned in it) is included as a participant for the response, and also we take out the authenticating user. So, if the message “@tshrdlu What do you think of @tshrdlc?” is sent from @jasonbaldridge, the response will be “@jasonbaldridge @tshrdlc OK.” Note how the screen names do not have the @ symbol, so that must be added in the tweet text of the reply.

Second, notice that StatusUpdate objects can be created by chaining methods that add more information to them, e.g. setInReplyToStatusId and setLocation, which incrementally build up the StatusUpdate object that gets actually posted. (This is a common Java strategy that basically helps get around the fact that parameters to classes can neither be specified by name in Java nor have defaults, the way Scala does.)

Checking and managing rate limit information

None of the above code makes many requests from Twitter, so there was little danger of exceeding rate limits. These limits are a mixture of both time and number of requests: you basically get a certain number of requests every hour (currently 350) per authenticating user. Because of these limits, you should consider accessing tweets, timelines, and such using the streaming methods when you can.

Every response you get from Twitter comes back as a sub-class of twitter4j.TwitterResponse, which not only gives you what you want (like a QueryResult) but also gives you information about your connection to Twitter. For rate limit information, you can use the getRateLimitStatus method, which can then inform you about the number of requests you can still make and the time until your limit resets.

The trait RateChecker below has a function checkAndWait that, when given a TwitterResponse object, checks whether the rate limit has been exceeded and wait if it has. When the rate is exceeded, it finds out how much time remains until the rate limit is reset and makes the thread sleep until that time (plus 10 seconds) has passed.

[sourcecode language=”scala”]
trait RateChecker {

def checkAndWait(response: TwitterResponse, verbose: Boolean = false) {
val rateLimitStatus = response.getRateLimitStatus
if (verbose) println("RLS: " + rateLimitStatus)

if (rateLimitStatus != null && rateLimitStatus.getRemaining == 0) {
println("*** You hit your rate limit. ***")
val waitTime = rateLimitStatus.getSecondsUntilReset + 10
println("Waiting " + waitTime + " seconds ( " + waitTime/60.0 + " minutes) for rate limit reset.")
Thread.sleep(waitTime*1000)
}
}

}
[/sourcecode]

Using rate limits is actually more complex than this. For example, this strategy ignores the fact that different request types have different limits, but it keeps things simple. This is surely not an optimal solution, but it does the trick for present purposes.

Note also that you can directly ask for rate limit information from the twitter4j.Twitter instance itself, using the getRateLimitStatus method. Unlike the results for the same method on a TwitterResponse, this gives a Map from various request types to the current rate limit statuses for each one. In a real application, you’d want to control each of these different limits at a more fine-grained level using this information.

Not all of the methods of Twitter4j classes actually hit the Twitter API. To see whether a given method does, look at its Javadoc: if it’s description says “This method calls http://api.twitter.com/1.1/some/method.json“, then it does hit the API. Otherwise, it doesn’t and you don’t need to guard it.

Examples using the checkAndWait function are given below.

Creating a word cloud from followers’ descriptions

Here’s a more interesting task: given a Twitter user, compute the counts of the words in the descriptions given in the bios of their followers and build a word cloud from them. The following code does this, outputing the resulting counts in a file, the contents of which can be pasted into Wordle’s advanced word cloud input.

[sourcecode language=”scala”]
object DescribeFollowers extends TwitterInstance with RateChecker {

def main(args: Array[String]) {
val screenName = args(0)
val maxUsers = if (args.length==2) args(1).toInt else 500
val followerIds = twitter.getFollowersIDs(screenName,-1).getIDs

val descriptions = followerIds.take(maxUsers).flatMap { id => {
val user = twitter.showUser(id)
checkAndWait(user)
if (user.isProtected) None else Some(user.getDescription)
}}

val tword = """(?i)[a-z#@]+""".r.pattern
val words = descriptions.flatMap(_.toLowerCase.split("\s+"))
val filtered = words.filter(_.length > 3).filter(tword.matcher(_).matches)
val counts = filtered.groupBy(x=>x).mapValues(_.length)
val rankedCounts = counts.toSeq.sortBy(- _._2)

import java.io._
val wordcountFile = "/tmp/follower_wordcount.txt"
val writer = new BufferedWriter(new FileWriter(wordcountFile))
for ((w,c) <- rankedCounts)
writer.write(w+":"+c+"n")
writer.flush
writer.close
}

}
[/sourcecode]

The thing to consider is that if you are pointing this at a person with several hundred followers, you will exceed the rate limit. The call to getFollowersIDs is a single hit, and then each call to showUser is a hit. Because the showUser calls come in rapid succession, we check the rate limit status after each one using checkAndWait (which is available because we mixed in the RateChecker trait) and it waits for the limit to reset as previously discussed, keeping us from exceeding the rate limit and getting an exception from Twitter.

The number of users returned by getFollowersIDs is at most 5000. If you run this on a user who has more followers, followers beyond 5000 won’t be considered. If you want to tackle such a user, you’ll need to use the cursor, which is the integer provided as the argument to getFollowersIDs, and make multiple calls while incrementing that cursor to get more.

Most of the rest of the code is just standard Scala stuff for getting the word counts and outputting them to a file. Note that a small effort is done to reduce the non-alphabetic characters (but allowing # and @) and filtering out short words.

As an example of the output, when put into Wordle, here is the word cloud for my followers.

jasonbaldridge_wordcloud

This looks about right for me—completely expected in fact—but it is still cool that it comes out of my followers’ self descriptions. One could start thinking of some fun algorithms for exploiting this kind of representation of a user to look into how well different users align or don’t align with their followers, or to look for clusters of different types of followers, etc.

Retweeting automatically

Tired of actually reading those tweets in your timeline and retweeting some of them? The following code gets some of the accounts the authenticating user follows, grabs twenty of those users, filters them to get interesting ones, and then takes up to 10 of the remaining ones and retweets their most recent statuses (provided they aren’t replies to someone else).

[sourcecode language=”scala”]
object RetweetFriends extends TwitterInstance with RateChecker {

def main(args: Array[String]) {
val friendIds = twitter.getFriendsIDs(-1).getIDs
val friends = friendIds.take(20).map { id => {
val user = twitter.showUser(id)
checkAndWait(user)
user
}}

val filtered = friends.filter(admissable)
val ranked = filtered.map(f => (f.getFollowersCount, f)).sortBy(- _._1).map(_._2)

ranked.take(10).foreach { friend => {
val status = friend.getStatus
if (status!=null && status.getInReplyToStatusId == -1) {
println("nRetweeting " + friend.getName + ":n" + status.getText)
twitter.retweetStatus(status.getId)
Thread.sleep(30000)
}
}}
}

def admissable(user: User) = {
val ratio = user.getFollowersCount.toDouble/user.getFriendsCount
user.getFriendsCount < 1000 && ratio > 0.5
}

}
[/sourcecode]

The getFriendsIDs method is used to get the users that the authenticating user is following (but who do not necessarily follow the authenticating user, despite the use of the word “friend”). We again take care with the rate limiting on gathering the users. We filter these users, looking for those who follow fewer than 1000 users and those who have a follower/friend ratio of greater than .5, in a simple attempt to filter out some less interesting (or spammy) accounts. The remaining users are then ranked according to their number of followers (most first). Finally, we take (up to) 10 of these (the take method returns 3 things if you ask for 10 but there are just 3), look at their most recent status, and if it is not null and isn’t a reply to someone, we retweet it. Between each of these, we wait for 30 seconds so that anyone following our account doesn’t get an avalanche of retweets.

Conclusion

This post and the related code should provide enough to get a decent feel for working with Twitter4j, including necessary setup and using some of the methods to start creating applications with it in Scala. See project phase three of my Applied NLP course to see exercises and code that takes this further to do interesting things for automated bots, including mixing streaming access and user access to get more complex behaviors.

Using twitter4j with Scala to access streaming tweets

Topics: twitter, twitter4j, sbt

Introduction

My previous post provided a walk-through for using the Twitter streaming API from the command line, but tweets can be more flexibly obtained and processed using an API for accessing Twitter using your programming language of choice. In this tutorial, I walk-through basic setup and some simple uses of the twitter4j library with Scala. Much of what I show here should be useful for those using other JVM languages like Clojure and Java. If you haven’t gone through the previous tutorial, have a look now before going on as this tutorial covers much of the same material but using twitter4j rather than HTTP requests.

I’ll introduce code, bit by bit, for accessing the Twitter data in different ways. If you get lost with what should go where, all of the code necessary to run the commands is available in this github gist, so you can compare to that as you move through the tutorial.

Update: The tutorial is set up to take you from nothing to being able to obtain tweets in various ways, but you can also get all the relevant code by looking at the twitter4j-tutorial repository. For this tutorial, the tag is v0.1.0, and you can also download a tarball of that version.

Getting set up

An easy way to use the twitter4j library in the context of a tutorial like this is for the reader to set up a new SBT project, declare it as a dependency, and then compile and run code within SBT. (See my tutorial on using Jerkson for processing JSON with Scala for another example of this.) This sorts out the process of obtaining external libraries and setting up the classpath so that they are available. Follow the instructions in this section to do so.

[sourcecode language=”bash”]
$ mkdir ~/twitter4j-tutorial
$ cd ~/twitter4j-tutorial/
$ wget http://repo.typesafe.com/typesafe/ivy-releases/org.scala-sbt/sbt-launch/0.12.2/sbt-launch.jar
[/sourcecode]

Now, save the following as the file ~/twitter4j-tutorial/build.sbt. Be aware that it is important to keep the empty lines between each of the declarations.

[sourcecode language=”scala”]
name := "twitter4j-tutorial"

version := "0.1.0 "

scalaVersion := "2.10.0"

libraryDependencies += "org.twitter4j" % "twitter4j-stream" % "3.0.3"
[/sourcecode]

Then save the following as the file ~/twitter4j-tutorial/build.

[sourcecode language=”bash”]
java -Xms512M -Xmx1536M -Xss1M -XX:+CMSClassUnloadingEnabled -XX:MaxPermSize=384M -jar `dirname $0`/sbt-launch.jar "$@"
[/sourcecode]

Make that file executable and run it, which will show SBT doing a bunch of work and then leave you with the SBT prompt. At the SBT prompt, invoke the update command.

[sourcecode language=”bash”]
$ cd ~/twitter4j-tutorial
$ chmod a+x build
$ ./build
[info] Set current project to twitter4j-tutorial (in build file:/Users/jbaldrid/twitter4j-tutorial/)
> update
[info] Updating {file:/Users/jbaldrid/twitter4j-tutorial/}default-570731…
[info] Resolving org.twitter4j#twitter4j-core;3.0.3 …
[info] Done updating.
[success] Total time: 1 s, completed Feb 8, 2013 12:55:41 PM
[/sourcecode]

To test whether you have access to twitter4j now, go to the SBT console and import the classes from the main twitter4j package.

[sourcecode language=”scala”]
> console
[info] Starting scala interpreter…
[info]
Welcome to Scala version 2.10.0 (Java HotSpot(TM) 64-Bit Server VM, Java 1.6.0_37).
Type in expressions to have them evaluated.
Type :help for more information.

scala> import twitter4j._
import twitter4j._
[/sourcecode]

If nothing further is output, then you are all set (exit the console using CTRL-D). If things are amiss (or if you are running in the default Scala REPL), you’ll instead see something like the following.

[sourcecode language=”scala”]
scala> import twitter4j._
<console>:7: error: not found: value twitter4j
import twitter4j._
^
[/sourcecode]

If this is what you got, try to follow the instructions above again to make sure that your setup is exactly as above (check the versions, etc).

If you just want to see some examples of using twitter4j as an API and are happy adding its jars by hand to your classpath or are using an IDE like Eclipse, then it is unnecessary to do the SBT setup — just read on and adapt the examples as necessary.

Write, compile and run a simple main method

To set the stage for how we’ll run programs in this tutorial, let’s create a simple main method and ensure it can be run in SBT. Do the following:

[sourcecode language=”bash”]
$ mkdir -p ~/twitter4j-tutorial/src/main/scala/
[/sourcecode]

Next, save the following code as ~/twitter4j-tutorial/src/main/scala/TwitterStream.scala.

[sourcecode language=”scala”]
package bcomposes.twitter

import twitter4j._

object StatusStreamer {
def main(args: Array[String]) {
println("hi")
}
}
[/sourcecode]

Next, at the SBT prompt for the twitter4j-tutorial project, use the run-main command as follows.

[sourcecode language=”scala”]
> run-main bcomposes.twitter.StatusStreamer
[info] Compiling 1 Scala source to /Users/jbaldrid/twitter4j-tutorial/target/scala-2.10/classes…
[info] Running bcomposes.twitter.StatusStreamer
hi
[success] Total time: 2 s, completed Feb 8, 2013 1:36:32 PM
[/sourcecode]

SBT compiles the code, and then runs it. This is a generally handy way of running code with all the dependencies available without having to worry about explicitly handling the classpath.

In what comes below, we’ll flesh out that main method so that it does more interesting work.

Setting up authorization

When using the Twitter streaming API to access tweets via HTTP requests, you must supply your Twitter username and password. To use twitter4j, you also must provide authentication details; however, for this you need to set up OAuth authentication. This is straightforward:

  1. Go to https://dev.twitter.com/apps and click on the button that says “Create a new application” (of course, you’ll need to log in with your Twitter username and password in order to do this)
  2. Fill in the name, description and website fields. Don’t worry too much about this: put in whatever you like for the name and description (e.g. “My example application” and “Tutorial app for me”). For the website, give the URL of your Twitter account if you don’t have anything better to use.
  3. A new screen will come up for your application. Click on the button at the bottom that says “Create my access token”.
  4. Click on the “OAuth tool” tab and you’ll see four fields for authentication which you need in order to use twitter4j to access tweets and other information from Twitter: Consumer key, Consumer secret, Access token, and Access token secret.

Based on these authorization details, you now need to create a twitter4j.conf.Configuration object that will allow twitter4j to access the Twitter API on your behalf. This can be done in a number of different ways, including environment variables, properties files, and in code. To keep it as simple as possible for this tutorial, we’ll go with the latter option.

Add the following object after the definition of StatusStreamer, providing your details rather than the descriptions given below.

[sourcecode language=”scala”]
object Util {
val config = new twitter4j.conf.ConfigurationBuilder()
.setOAuthConsumerKey("[your consumer key here]")
.setOAuthConsumerSecret("[your consumer secret here]")
.setOAuthAccessToken("[your access token here]")
.setOAuthAccessTokenSecret("[your access token secret here]")
.build
}
[/sourcecode]

You should of course be careful not to let your details be known to others, so make sure that this code stays on your machine. When you start developing for real, you’ll use other means to get the authorization information injected into your application.

Pulling tweets from the sample stream

In the previous tutorial, the most basic sort of access was to get a random sample of tweets from https://stream.twitter.com/1/statuses/sample.json, so let’s use twitter4j to do the same.

To do this, we are going to create a TwitterStream instance that gives us an authorized connection to the Twitter API. To see all the methods associated with the TwitterStream class, see the API documentation for TwitterStream.  A TwitterStream instance is able to get tweets (and other information) and then provide them to any listeners that have registered with it. So, in order to do something useful with the tweets, you need to implement the StatusListener interface and connect it to the TwitterStream.

Before showing the code for creating and using the stream, let’s create a StatusListener that will perform a simple action based on tweets streaming in. Add the following code to the Util object created earlier.

[sourcecode language=”scala”]
def simpleStatusListener = new StatusListener() {
def onStatus(status: Status) { println(status.getText) }
def onDeletionNotice(statusDeletionNotice: StatusDeletionNotice) {}
def onTrackLimitationNotice(numberOfLimitedStatuses: Int) {}
def onException(ex: Exception) { ex.printStackTrace }
def onScrubGeo(arg0: Long, arg1: Long) {}
def onStallWarning(warning: StallWarning) {}
}
[/sourcecode]

This method creates objects that implement StatusListener (though it only does something useful for the onStatus method and otherwise ignores all other events sent to it). Clearly, what it is going to do is take a Twitter status (which is all of the information associated with a tweet, including author, retweets, geographic coordinates, etc) and output the text of the status—i.e., what we usually think of as a “tweet”.

The following code puts it all together. We create a TwitterStream object by using the TwitterStreamFactory and the configuration, add a simpleStatusListener to the stream, and then call the sample method of TwitterStream to start receiving tweets. If that were the last line of the program, it would just keep receiving tweets until the process was killed. Here, I’ve added a 2 second sleep so that we can see some tweets, then clean up the connection and shut it down cleanly. (We could let it run indefinitely, but then to kill the process, we would need to use CTRL-C, which will kill not only that process, but also the process that is running SBT.)

[sourcecode language=”scala”]
object StatusStreamer {
def main(args: Array[String]) {
val twitterStream = new TwitterStreamFactory(Util.config).getInstance
twitterStream.addListener(Util.simpleStatusListener)
twitterStream.sample
Thread.sleep(2000)
twitterStream.cleanUp
twitterStream.shutdown
}
}
[/sourcecode]

To run this code, simply put in the same run-main command in SBT as before.

[sourcecode language=”scala”]
> run-main bcomposes.twitter.StatusStreamer
[/sourcecode]

You should see tweets stream by for a couple of seconds and then you’ll be returned to the SBT prompt.

Pulling tweets with specific properties

As with the HTTP streaming, it’s easy to use twitter4j to follow a particular set of users, particular search terms, or tweets produced within certain geographic regions. All that is required is creating appropriate FilterQuery objects and then using the filter method of TwitterStream rather than the sample method.

FilterQuery has several constructors, one of which allows an Array of Long values to be provided, each of which is the id of a Twitter user who is to be followed by the stream. (See the previous tutorial to see one easy way to get the id of a user based on their username.)

[sourcecode language=”scala”]
object FollowIdsStreamer {
def main(args: Array[String]) {
val twitterStream = new TwitterStreamFactory(Util.config).getInstance
twitterStream.addListener(Util.simpleStatusListener)
twitterStream.filter(new FilterQuery(Array(1344951,5988062,807095,3108351)))
Thread.sleep(10000)
twitterStream.cleanUp
twitterStream.shutdown
}
}
[/sourcecode]

These are the IDs for Wired Magazine (@wired), The Economist (@theeconomist), the New York Times (@nytimes), and the Wall Street Journal (@wsj). Add the code to TwitterStream.scala and then run it in SBT. Note that I’ve made the program sleep for 10 seconds in order to give more time for tweets to arrive (since these are just four accounts and will have varying activity). If you are not seeing anything show up, increase the sleep time.

[sourcecode language=”scala”]
> run-main bcomposes.twitter.FollowIdsStreamer
[/sourcecode]

To track tweets that contain particular terms, create a FilterQuery with the default constructor and then call the track method with an Array of strings that contains the query terms you are interested in. The object below does this, and uses the args Array as the container for the query terms.

[sourcecode language=”scala”]
object SearchStreamer {
def main(args: Array[String]) {
val twitterStream = new TwitterStreamFactory(Util.config).getInstance
twitterStream.addListener(Util.simpleStatusListener)
twitterStream.filter(new FilterQuery().track(args))
Thread.sleep(10000)
twitterStream.cleanUp
twitterStream.shutdown
}
}
[/sourcecode]

With things set up this way, you can track arbitrary queries by specifying them on the command line.

[sourcecode language=”scala”]
> run-main bcomposes.twitter.SearchStreamer scala
> run-main bcomposes.twitter.SearchStreamer scala python java
> run-main bcomposes.twitter.SearchStreamer "sentiment analysis" "machine learning" "text analytics"
[/sourcecode]

If the search terms are not particularly common, you’ll need to increase the sleep time.

To filter by location, again create a FilterQuery with the default constructor, but then use the locations method, with an Array[Array[Double]] argument — basically an Array of two-element Arrays, each of which contains the latitude and longitude of a corner of a bounding box. Here’s an example that creates bounding box for Austin and uses it.

[sourcecode language=”scala”]
object AustinStreamer {
def main(args: Array[String]) {
val twitterStream = new TwitterStreamFactory(Util.config).getInstance
twitterStream.addListener(Util.simpleStatusListener)
val austinBox = Array(Array(-97.8,30.25),Array(-97.65,30.35))
twitterStream.filter(new FilterQuery().locations(austinBox))
Thread.sleep(10000)
twitterStream.cleanUp
twitterStream.shutdown
}
}
[/sourcecode]

To make things more flexible, we can take the bounding box information on the command line, convert the Strings into Doubles and pair them up.

[sourcecode language=”scala”]
object LocationStreamer {
def main(args: Array[String]) {
val boundingBoxes = args.map(_.toDouble).grouped(2).toArray
val twitterStream = new TwitterStreamFactory(Util.config).getInstance
twitterStream.addListener(Util.simpleStatusListener)
twitterStream.filter(new FilterQuery().locations(boundingBoxes))
Thread.sleep(10000)
twitterStream.cleanUp
twitterStream.shutdown
}
}
[/sourcecode]

We can call LocationStreamer with multiple bounding boxes, e.g. as follows for Austin, San Francisco, and New York City.

[sourcecode language=”scala”]
> run-main bcomposes.twitter.LocationStreamer -97.8 30.25 -97.65 30.35 -122.75 36.8 -121.75 37.8 -74 40 -73 41
[/sourcecode]

Conclusion

This shows the start of how you can use twitter4j with Scala for streaming. It also supports programmatic access to the actions that any Twitter user can take, including posting messages, retweeting, following, and more. I’ll cover that in a later tutorial. Also, some examples of using twitter4j will start showing up soon in the tshrldu project.

A walk-through for the Twitter streaming API

Topics: Twitter, streaming API

Introduction

Analyzing tweets is all the rage, and if you are new to the game you want to know how to get them programmatically. There are many ways to do this, but a great start is to use the Twitter streaming API, a RESTful service that allows you to pull tweets in real time based on criteria you specify. For most people, this will mean having access to the spritzer, which provides only a very small percentage of all the tweets going through Twitter at any given moment. For access to more, you need to have a special relationship with Twitter or pay Twitter or an affiliate like Gnip.

This post provides a basic walk-through for using the Twitter streaming API. You can get all of this based on the documentation provided by Twitter, but this will be slightly easier going for those new to such services. (This post is mainly geared for the first phase of the course project for students in my Applied Natural Language Processing class this semester.)

You need to have a Twitter account to do this walk-through, so obtain one now if you don’t have one already.

Accessing a random sample of tweets

First, trying pulling a random sample of tweets using your browser by going to the following link.

  • https://stream.twitter.com/1/statuses/sample.json

You should see a growing, unwieldy list of raw tweets flowing by. It should look something like the following image.

tweets_sample

Here’s an example of a “raw” tweet (which comes in JSON, or JavaScript Object Notation):

[sourcecode language=”json”]
{"text":"#LetsGoMavs til the end RT @dallasmavs: Are You ALL IN?","truncated":false,"retweeted":false,"geo":null,"retweet_count":0,"source":"web","in_reply_to_status_id_str":null,"created_at":"Wed Apr 25 15:47:39 +0000 2012","in_reply_to_user_id_str":null,"id_str":"195177260792299521","coordinates":null,"in_reply_to_user_id":null,"favorited":false,"entities":{"hashtags":[{"text":"LetsGoMavs","indices":[0,11]}],"urls":[],"user_mentions":[{"indices":[27,38],"screen_name":"dallasmavs","id_str":"22185437","name":"Dallas Mavericks","id":22185437}]},"contributors":null,"user":{"show_all_inline_media":true,"statuses_count":3101,"following":null,"profile_background_image_url_https":"https://si0.twimg.com/profile_background_images/285480449/AAC_med500.jpg","profile_sidebar_border_color":"eeeeee","screen_name":"flyingcape","follow_request_sent":null,"verified":false,"listed_count":2,"profile_use_background_image":true,"time_zone":"Mountain Time (US &amp; Canada)","description":"HUGE ROCKETS &amp; MAVS fan. Lets take down the Lakers &amp; beat up on the East. Inaugural member of the FC Dallas – Fort Worth fan club.","profile_text_color":"333333","default_profile":false,"profile_background_image_url":"http://a0.twimg.com/profile_background_images/285480449/AAC_med500.jpg","created_at":"Thu Oct 21 15:40:21 +0000 2010","is_translator":false,"profile_link_color":"1212cc","followers_count":35,"url":null,"profile_image_url_https":"https://si0.twimg.com/profile_images/1658982184/204970_10100514487859080_7909803_68807593_5366704_o_normal.jpg","profile_image_url":"http://a0.twimg.com/profile_images/1658982184/204970_10100514487859080_7909803_68807593_5366704_o_normal.jpg","id_str":"205774740","protected":false,"contributors_enabled":false,"geo_enabled":true,"notifications":null,"profile_background_color":"0a2afa","name":"Mandy","default_profile_image":false,"lang":"en","profile_background_tile":true,"friends_count":48,"location":"ATX / FDub. From Galveston !","id":205774740,"utc_offset":-25200,"favourites_count":231,"profile_sidebar_fill_color":"efefef"},"id":195177260792299521,"place":{"bounding_box":{"type":"Polygon","coordinates":[[[-97.938383,30.098659],[-97.56842,30.098659],[-97.56842,30.49685],[-97.938383,30.49685]]]},"country":"United States","url":"http://api.twitter.com/1/geo/id/c3f37afa9efcf94b.json","attributes":{},"full_name":"Austin, TX","country_code":"US","name":"Austin","place_type":"city","id":"c3f37afa9efcf94b"},"in_reply_to_screen_name":null,"in_reply_to_status_id":null}
[/sourcecode]

There is a lot of information in there beyond the tweet text itself, which is simply “#LetsGoMavs til the end RT @dallasmavs: Are You ALL IN?” It is basically a map from attributes to values (and values may themselves be such a map, e.g. for the “user” attribute above). You can see whether the tweet has been retweeted (which will be zero when the tweet is first published), what time it was created, the unique tweet id, the geo-coordinates (if available), and more. If an attribute does not have a value for the tweet, it is ‘null’.

I will return to JSON processing of tweets in a later tutorial, but you can get a head start by seeing my tutorial on using Scala to process JSON in general.

Command line access to tweets

Assuming you were successful in being able to view tweets in the browser, we can now proceed to using the command line. For this, it will be convenient to first set environment variables for your Twitter username and password.

[sourcecode language=”bash”]
$ export TWUSER=foo
$ export TWPWD=bar
[/sourcecode]

Obviously, you need to provide your Twitter account details instead of foo and bar…

Next, we’ll use the program curl to interact with the API. Try it out by downloading this blog post.

[sourcecode language=”bash”]
$ curl http://bcomposes.wordpress.com/2013/01/25/a-walk-through-for-the-twitter-streaming-api/ > bcomposes-twitter-api.html
$ less bcomposes-twitter-api.html
[/sourcecode]

Given that you pulled tweets from the API using your web browser, and that curl can access web pages in this way, it is simple to use curl to get tweets and direct them straight to a file.

[sourcecode language=”bash”]
$ curl https://stream.twitter.com/1/statuses/sample.json -u$TWUSER:$TWPWD > tweets.json
[/sourcecode]

That’s it: you now have an ever-growing file with randomly sampled tweets. Have a look and try not to lose your faith in humanity. 😉

Pulling tweets with specific properties

You might want to get the tweets from specific users rather than a random sample. This requires user ids rather than the user names we usually see. The id for a user can be obtained from the Twitter API by looking at the /users/show endpoint. For example, the following gives my information:

  • https://api.twitter.com/1/users/show.xml?screen_name=jasonbaldridge

Which gives:

[sourcecode language=”xml”]

<user>
<id>119837224</id>
<name>Jason Baldridge</name>
<screen_name>jasonbaldridge</screen_name>
<location>Austin, Texas</location>
<description>
Assoc. Prof., Computational Linguistics, UT Austin. Senior Data Scientist, Converseon. OpenNLP developer. Scala, Java, R, and Python programmer.
</description>
…MORE…

[/sourcecode]

So, to follow @jasonbaldridge via the Twitter API, you need user id 119837224. You can pull my tweets via the API using the “follow” query parameter.

[sourcecode language=”bash”]
$ curl -d follow=119837224 https://stream.twitter.com/1/statuses/filter.json -u$TWUSER:$TWPWD
[/sourcecode]

There is a good chance I’m not tweeting right now, so you’ll probably not see anything. Let’s follow more users, which we can do by adding more id’s separated by commas.

[sourcecode language=”bash”]
$ curl -d follow=1344951,5988062,807095,3108351 https://stream.twitter.com/1/statuses/filter.json -u$TWUSER:$TWPWD
[/sourcecode]

This will follow Wired Magazine (@wired), The Economist (@theeconomist), the New York Times (@nytimes), and the Wall Street Journal (@wsj).

You can also write those ids to a file and read them from the file. For example:

[sourcecode language=”bash”]
$ echo "follow=1344951,5988062,807095,3108351" > following
$ curl -d @following https://stream.twitter.com/1/statuses/filter.json -u$TWUSER:$TWPWD
[/sourcecode]

You can of course edit the file “following” rather than using echo to create it. Also, the file name can be named whatever you like (“following” as the name is not important here).

You can search for a particular term in tweets, such as “Scala”, using the “track” query parameter.

[sourcecode language=”bash”]
$ curl -d track=scala https://stream.twitter.com/1/statuses/filter.json -u$TWUSER:$TWPWD
[/sourcecode]

And, no surprise, you can search for multiple items by using commas to separate them.

[sourcecode language=”bash”]
$ curl -d track=scala,python,java https://stream.twitter.com/1/statuses/filter.json -u$TWUSER:$TWPWD
[/sourcecode]

However, this only requires that a tweet match at least one of these terms. If you want to ensure that multiple terms match, you’ll need to write them to a file and then refer to that file. For example, to get tweets that have both “sentiment” and “analysis” OR both “machine” and “learning” OR both “text” and “analytics”, you could do the following:

[sourcecode language=”bash”]
$ echo "track=sentiment analysis,machine learning,text analytics" > tracking
$ curl -d @tracking https://stream.twitter.com/1/statuses/filter.json -u$TWUSER:$TWPWD
[/sourcecode]

You can pull tweets from a specific rectangular area (bounding box) on the Earth’s surface. For example, the following pulls geotagged tweets from Austin, Texas.

[sourcecode language=”bash”]
$ curl -d locations=-97.8,30.25,-97.65,30.35 https://stream.twitter.com/1/statuses/filter.json -u$TWUSER:$TWPWD
[/sourcecode]

The bounding box is given as latitude (bottom left), longitude (bottom left), latitude (top right), longitude (top right). You can add further bounding boxes to capture more locations. For example, the following captures tweets from Austin, San Francisco, and New York City.

[sourcecode language=”bash”]
$ curl -d locations=-97.8,30.25,-97.65,30.35,-122.75,36.8,-121.75,37.8,-74,40,-73,41 https://stream.twitter.com/1/statuses/filter.json -u$TWUSER:$TWPWD
[/sourcecode]

Conclusion

It’s all pretty straightforward, and quite handy for many kinds of tweet-gathering needs. One of the problems is that Twitter will drop the connection at times, and you’ll end up missing tweets until you start a new process. If you need constant monitoring,  see UT Austin’s Twools (Twitter tools) for obtaining a steady stream of tweets that picks up whenever Twitter drops your connection.

In a later post, I’ll detail how to use an API like twitter4j to pull tweets and interact with Twitter at a more fundamental level.