Building a Twitter Hashtag Contest – Registering the App

This entry is part 1 of 2 in the series Building a Twitter Hashtag Contest with Twitter's API

Building a Twitter Hashtag Contest with Twitter's API

Introduction

Social networking sites play a vital role in increasing the popularity of a website or application. The vast majority of web sites provide the ability to share their content on popular social media sites with the click of a button. Organizing a contest on these sites is another excellent way of promoting your application.

We are going to build a contest on Twitter to enhance user interaction with a web application. This will be a two part series where the first part focuses on introducing you to Twitter contests and configuring a Twitter application, while the second part will focus on the implementation of the contest. Let’s get started.

Introduction to Contests in Twitter

Twitter is a social networking and micro blogging service utilizing instant messaging, SMS or a web interface. Twitter is considered to be the SMS of web, so contests on Twitter will usually be different from contests on other popular social networking sites.

The main goal of a Twitter contest is to get people to create as many tweets as possible about a certain topic to improve awareness. Let’s take a look at some of the most popular types of contests using Twitter.

  • Sweepstakes – This is the simplest type of Twitter contests. Users can enter the contest by creating a tweet with a given #tag and their username. The winner will be picked through a lucky draw.

  • Creative Answer – In this contest, organizers ask a question by creating a tweet or publishing the question on their website. User have to create tweets with a given #tag to answer the question. The most creative answer will be chosen manually by the organizers.

  • Retweet to win – Organizers create a tweet and users have to retweet it. The winner will be picked randomly from all the retweeters.

  • Follow to win – Organizers provide a company profile or the profile they want to promote. Users have to be a follower of given profile. Picking the winners is usually done randomly at the end of the contest.

Instead of relying entirely on luck, we’ll create a hashtag contest that generates a winner based on the effort and performance of the users.

Planning a Twitter Hashtag Contest

Here are the steps of the contest:

  • Users need to authenticate their Twitter account – Usually, this is done by providing a Twitter login button where users can authorize access to the application through their Twitter account.

  • Create Tweets with Hashtags through our application – We are going to use two hashtags with each tweet. The first tag is used to promote the brand. If our brand is SitePoint, we will have a hashtag called #SitePoint to promote our brand. The second tag is used to identify the application amongst the other tweets with the first hashtag.

  • Select the winners – There are many ways of picking winners automatically in such contests. In this case, we are going to evaluate winners based on the number of retweets. The winner will be picked based on the total number of retweets for the tweets the users create.

Building

To begin, you need to register an application on Twitter. Visit the Twitter Developer site and create an application with write access. Once you have a Twitter application with consumer_key and consumer_secret, follow the instructions in the step by step guide to complete the implementation.

Step 1 – Configuring the OAuth Library

OAuth is the standard technique used by Twitter to authenticate access to their API. There are many existing libraries for automating the authentication process with Twitter. We are going to use a library called tmhOAuth. Download and extract the zip file from Github, or clone it.

Create the application folder with an index.php file inside it and copy the contents of tmhOAuth library into a folder called twitter. Then include the tmhOAuth.php file inside the index.php file (see below).

Step 2 – Authenticating Users with Twitter

First, users have to authorize the app using their Twitter account. We need a button or link that redirects the user to the authorization process. We are going to use a separate class for managing the logic of this application. Create a file called twitter_hashtag_contest.php inside the application folder. Now let’s take a look at the updated index.php file.

<?php
    require 'twitter/tmhOAuth.php';
    require 'twitter_hashtag_contest.php';

    session_start();

    $contest = new TwitterHashTagContest();

    if(isset($_GET['action']) && $_GET['action'] == 'twitter'){

      $contest->getRequestToken();

    } else {
      echo "<a href='?action=twitter'>LogIn with Twitter</a>";
    }

We can display the login link by default. Once the login link is clicked, we have to redirect the user to Twitter for app authorization and retrieving the request tokens. We have to set up the initial details of TwitterHashTagContest class, before we move into the implementation of getRequestToken function.

Step 3 – Initializing TwitterHashTagContest Class

We are using TwitterHashTagContest class to handle all the application specific details, so let’s look at the initialization and configuration for said class.

class TwitterHashTagContest{

    private $config;
    private $twitter_auth;
    private $app_details;
    private $result_tweets;

    public function __construct(){
        $this->config['consumer_key'] = 'consumer_key';
        $this->config['consumer_secret'] = 'consumer_secret';
        $this->config['OAUTH_CALLBACK']='URL to index.php file';

        $this->twitter_auth = new tmhOAuth($this->config);

        $this->result_tweets = array();
    }
}

We can start the configuration by defining consumer_key,consumer_secret and callback URL in an array. Then we can initialize the tmhOAuth library using the configuration array. Finally, we initialize an array for storing the results at the completion of the contest.

Having completed configuration details, now we can move into the Twitter authorization process.

Step 4 – Generate Request Tokens

First, we have to get request tokens to initialize the user authorization process. Twitter provides the API URL oauth/request_token for generating request tokens. Let’s take a look at the implementation of the getRequestToken function defined earlier.

public function getRequestToken() {
    $this->twitter_auth->request("POST", $this->twitter_auth->url("oauth/request_token", ""), array(
        'oauth_callback' => $this->config['OAUTH_CALLBACK']
    ));

    if ($this->twitter_auth->response["code"] == 200) {

        // get and store the request token
        $response = $this->twitter_auth->extract_params($this->twitter_auth->response["response"]);
        $_SESSION["authtoken"] = $response["oauth_token"];
        $_SESSION["authsecret"] = $response["oauth_token_secret"];

        // redirect the user to Twitter to authorize
        $url = $this->twitter_auth->url("oauth/authenticate", "") . '?oauth_token=' . $response["oauth_token"];
        header("Location: " . $url);
        exit;
    }
    return false;
}

We already have an instance of the tmhOAuth class, initialized within the constructor of TwitterHashTagContest. We have to use the request method of tmhOAuth to access Twitter’s API. This function takes 3 arguments where the first one defines the request type (POST or GET) and the next two arguments define the API endpoint URL and parameters respectively.

We are using the oauth/request_token API URL to generate the tokens. The response will contain the request tokens as well as the status of the request. Code 200 means a successful completion of the request and we proceed by using the extract_params function to extract all the parameters from the response into an array. Next, we store the oauth_token and oauth_token_secret in the current session.

Finally, we redirect the user for authorization using oauth/authenticate or oauth/authorize.

We can use either oauth/authenticate or oauth/authorize to handle the authorization process. oauth/authorize requires the user to authorize the application on each request, even if it’s already authorized for the user. oauth/authenticate differentiates from oauth/authorize by avoiding authorization on each request. We have to tick the Allow this application to be used to Sign in with Twitter checkbox on the Settings tab of our Twitter application to allow this.

Once redirected, users can log in and authorize the application, then Twitter will automatically redirect the request to the callback URL. Next, we have to generate user specific request credentials (access tokens) by validating the request tokens.

Step 5 – Generate Access Tokens

First, we have to filter the response retrieved after authorizing the app. Let’s look at the updated code.

if(isset($_GET['action']) && $_GET['action'] == 'twitter'){
    $contest->getRequestToken();
} else if(isset($_GET['oauth_token'])) {
    $oauth_token = isset($_GET['oauth_token']) ? $_GET['oauth_token'] : '';
    $oauth_verifier = isset($_GET['oauth_verifier']) ? $_GET['oauth_verifier'] : '';
    $response = $contest->getRequestCredentials($oauth_verifier,$oauth_token);
    $contest->createUserSession($response);
} else {
    echo "<a href='?action=twitter'>LogIn with Twitter</a>";
}

The response from Twitter contains oauth_token and oauth_verifier as URL parameters. We can filter the request using these parameters and call the getRequestCredentials function to generate the access tokens. The following code illustrates the implementation of getRequestCredentials.

    public function getRequestCredentials($oauth_verifier,$oauth_token){
        $this->twitter_auth->request("POST", $this->twitter_auth->url("oauth/access_token", ""), array(  
            // pass a variable to set the callback  
            'oauth_verifier'    => $oauth_verifier,
            'oauth_token' => $oauth_token  
        ));

        $response = array();

        if($this->twitter_auth->response["code"] == 200) {  
            $response = $this->twitter_auth->extract_params($this->twitter_auth->response["response"]);  

        }

        return $response;
    }

As we did earlier, the POST request is created on $this->twitter_auth object to access oauth/access_token API. Here, we are passing the oauth_verifier and oauth_token retrieved from previous request for generating the access tokens. Finally, we check the response code to match 200 and return the extracted components of the response object.

Please keep in mind that we are only implementing the success path considering the scope of this tutorial. In a real implementation, we will have to implement the error handling part to filter other response codes as well.

Afterwards, we can use the access tokens and enable tweeting capabilities for the users. We pass the response to a function called createUserSession, for adding the details to the browser session and initializing the tweeting screen.

In a real implementation, we need to keep the access tokens and the details of the logged in user in the database to retrieve the tokens. Here, we are using browser sessions instead to simplify the tutorial.

Conclusion

Promoting applications through social media contests is an excellent approach. Twitter is one of the easiest platforms to host a contest on, so we started with the goal of building a hashtag contest on Twitter.

So far, we implemented the initial steps to create a Twitter application and authenticate users into our system. In the next part, we will be completing the implementation of this contest by creating the tweet capabilities for the users and generating the results.

Until then, let us know your thoughts about this part!

Building a Twitter Hashtag Contest with Twitter's API

Building a Twitter Hashtag Contest – Creating and Counting Tweets >>

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