Posted onDec 13, 2022 • Edited onMay 5, 2023

Creating a Twitter Bot with Phoenix

#elixir #phoenix #uruguay #movies

I started this blog in order to learn how to use Twitter API and also because i love going to the cinema 🙌. Im from Uruguay 🇺🇾, and here we have a cinema called "Movie Center". After checking their request, I started to investigate what we can get from them

Investigation 🕵️

After checking their request I found out that I can use that information for the Twitter bot.

Creating the app 👨‍💻

Let’s start by creating our Phoenix app

mix phx.new movies_uycdmovies_uymix ecto.createiex-S mix phx.server

Now Im going to add the following dependencies that are needed for the bot:

# mix.exsdefpdepsdo[{:finch,"~> 0.13"},{:oauther,"~> 1.1"},{:extwitter,"~> 0.12"},{:oban,"~> 2.13"}]end

Finch for doing request to the "Movie Center" API.
ExTwitter it's a Twitter Client for using Twitter API
Oban for creating jobs that run whenever we want (in our case once a day)

After adding this don't forget to runmix deps.get.

Config Finch

Let’s configure Finch by adding this, note that you can follow this from the Finch repo too.

# lib/movies_uy/application.exdefstart(_type,_args)dochildren=[...{Finch,name:MoviesUyFinch}]end

Config ExTwitter 🧵

# config/config.exsconfig:extwitter,:oauth,[consumer_key:System.get_env("TWITTER_CONSUMER_KEY"),consumer_secret:System.get_env("TWITTER_CONSUMER_SECRET"),access_token:System.get_env("TWITTER_ACCESS_TOKEN"),access_token_secret:System.get_env("TWITTER_ACCESS_TOKEN_SECRET")]

Getting Movies 🎬

Let's add the following code that will search for all the movies from the Movie Center API.

# lib/movies_uy/movie_center.exdefmoduleMoviesUy.MovieCenterdorequireLoggerdeffetch_moviesdomovie_url="https://api.movie.com.uy/api/billboard/cinema/weekly?nextReleases=false"request=Finch.build(:get,movie_url)|>Finch.request(MoviesUyFinch)with{:ok,%Finch.Response{body:data}}<-request,%{"items"=>movies}<-Jason.decode!(data)domovies|>Enum.map(fn%{"content"=>%{"title"=>title,"id"=>id,"urlSlug"=>slug}}}->"#{title} - https://www.movie.com.uy/movie/#{id}/#{slug}"end)else_->Logger.error"Error!"endendend

You can also check if this is working correctly by running the following line on your iex
$iex> MoviesUy.MovieCenter.fetch_movies# this should show all the movies from Movie center API

Using ExTwitter 🧵

Now is time to build the messages and post them on Twitter using ExTwitter.

What Im going to do is create a tweet that contains the current date, and the comments of this twitter will be the movies with their current url on Movie Center.

# lib/movies_uy/movie_center.exdefmoduleMoviesUy.MovieCenterdorequireLoggerdeffetch_moviesdomovie_url="https://api.movie.com.uy/api/billboard/cinema/weekly?nextReleases=false"request=Finch.build(:get,movie_url)|>Finch.request(MoviesUyFinch)with{:ok,%Finch.Response{body:data}}<-request,%{"items"=>movies}<-Jason.decode!(data),%ExTwitter.Model.Tweet{id:tweet_id}<-post_message()domovies|>Enum.map(&post_thread_message(&1,tweet_id))elseerror->Logger.errorerrorendenddefppost_thread_message(%{"content"=>%{"title"=>title,"id"=>id,"urlSlug"=>slug}},tweet_id)do"#{title} - https://www.movie.com.uy/movie/#{id}/#{slug}"|>ExTwitter.update(in_reply_to_status_id:tweet_id)enddefppost_messagedo%Date{day:day,month:month,year:year}=Date.utc_today"Cartelera de Movie Center del#{day}/#{month}/#{year}"|>ExTwitter.updateendend

We can run this using the same function as before and we should be able to see that is posting correctly on Twitter.

Config Oban 📅

It’s time to use Oban, this will allow us to create a worker that runs our code whenever we want, in our case once a day! Lets config Oban (you can also read the docs).

$mix ecto.gen.migration add_oban_jobs_table

Then open the generated migration and update it:

defmoduleMoviesUy.Repo.Migrations.AddObanJobsTabledouseEcto.MigrationdefupdoOban.Migrations.up(version:11)end# We specify `version: 1` in `down`, ensuring that we'll roll all the way back down if# necessary, regardless of which version we've migrated `up` to.defdowndoOban.Migrations.down(version:1)endend

And finally lets run this

$mix ecto.migrate

Lets add this

#config/config.exsconfig:movies_uy,Oban,repo:MoviesUy.Repo,plugins:[Oban.Plugins.Pruner,{Oban.Plugins.Cron,crontab:[{"@daily",MoviesUy.DailyWorker,max_attempts:1},]}],queues:[default:10]

# lib/my_app/application.exdefstart(_type,_args)dochildren=[...{Oban,Application.fetch_env!(:movies_uy,Oban)}]end

# lib/movies_uy/workers/daily_worker.exdefmoduleMoviesUy.DailyWorkerdouseOban.Worker,queue::default@implOban.Workerdefperform(_)doMoviesUy.MovieCenter.fetch_movies()endend