github_connect.module

<?php

/**
 * @file
 * Gives site visitors the ability to log in with GitHub (http://github.com).
 */

/**
 * Implements hook_help().
 */
function github_connect_help($path, $arg) {
  switch ($path) {
    case 'admin/config/people/github':
      return t('Gives site visitors the ability to login to Drupal with their GitHub account.');
  }
}


/**
 * Implements hook_block_info().
 */
function github_connect_block_info() {
  $blocks['github_connect-login'] = array(
    'info' => t('Github connect'),
  );

  return $blocks;
}


/**
 * Implements hook_block_view().
 */
function github_connect_block_view($delta = '') {
  $block = array();

  switch ($delta) {
    case 'github_connect-login':
      return array(
        'subject' => '',
        'content' => github_connect_connect_block(),
      );
      break;

  }
  return $block;
}


/**
 * GitHub connect block.
 */
function github_connect_connect_block() {
  if (user_is_logged_in()) return FALSE;

  $client_id = variable_get('github_connect_client_id');
  $link = 'https://github.com/login/oauth/authorize?client_id=' . $client_id;
  $output = l(t('Login with GitHub'), $link);

  return $output;
}


/*
 * Implements hook_menu().
 */
function github_connect_menu() {
  // Admin settings page.
  $items['admin/config/people/github'] = array(
    'title' => 'Github settings',
    'description' => 'Settings for connecting with Github.',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('github_connect_admin_settings_form'),
    'access arguments' => array('administer github_connect'),
    'type' => MENU_NORMAL_ITEM,
    'file' => 'github_connect.admin.inc',
  );
  // Callback for oauth token request from Github API.
  $items['github/register/create'] = array(
    'type' => MENU_CALLBACK,
    'title' => 'Connected to Github',
    'page callback' => 'github_connect_get_access_token',
    'access callback' => 'user_is_anonymous',
    // 'file' => 'github_connect.pages.inc',
  );
  // Require password when merging accounts
  $items['github/verify/email/%/%'] = array(
    'type' => MENU_CALLBACK,
    'title' => 'Merge accounts',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('github_connect_verify_email_form', 3, 4),
    'access callback' => TRUE,
  );

  return $items;
}


/**
 * Implements hook_user_delete().
 */
function github_connect_user_delete($account) {
  // Delete the user from github_connect_users table.
  if (github_connect_get_user_token($account->uid)) {
    db_delete('github_connect_users')
      ->condition('uid', $account->uid)
      ->execute();
  }
}


/*
 * Custom access callback.
 */
function github_connect_get_access_token() {
  $client_id = variable_get('github_connect_client_id');
  $client_secret = variable_get('github_connect_client_secret');

  // The response code after first call to GitHub.
  $code = $_GET['code'];

  $url = 'https://github.com/login/oauth/access_token?';
  $options = array(
    'data' => 'client_id=' . $client_id . '&client_secret=' . $client_secret . '&code=' . $code,
    'method' => 'POST',
  );
  $response = drupal_http_request($url, $options);
  $token = $response->data;

  if ($token) {
    // Check if a user exists for the token.
    $uid = github_connect_get_token_user($token);

    if (!empty($uid)) {
      // If there is a user with the token log that user in.
      $form_state['uid'] = $uid;
      user_login_submit(array(), $form_state);
      drupal_goto();
      return;
    }
    else {
      // Collects the User information from GitHub.
      $options = array(
        'method' => 'GET',
        'timeout' => 7200,
      );
      $github_user = drupal_http_request('https://api.github.com/user?' . $token, $options);
      $ghuser = drupal_json_decode($github_user->data);

      if ($ghuser['email']) {
        $existing_user = user_load_by_mail($ghuser['email']);
        if ($existing_user) {
          drupal_goto('github/verify/email/' . $existing_user->uid . '/' . $token);
        }
        else {
          _github_connect_register($ghuser, $token);
        }
      }
      else {
        drupal_set_message(t('We could not log you in due to an error accessing your GitHub account.'), 'error');
        return;
      }
    }
  }
  else {
    drupal_set_message(t('Failed connecting to GitHub.'), 'error');
  }
}


/*
 * Save the new GitHub user in github_connect_users
 */
function _github_connect_save_github_user($account, $token) {
  // Store GitHub user with token.
  if ($account) {
    db_insert('github_connect_users')
      ->fields(array(
        'uid' => $account->uid,
        'access_token' => $token,
        'timestamp' => REQUEST_TIME,
      ))
      ->execute();

    // Log in the stored user.
    $form_state['uid'] = $account->uid;
    user_login_submit(array(), $form_state);
    drupal_set_message(t('You are now connected with your GitHub account.'));

    drupal_goto();
  }
}


/*
 * Register new user.
 */
function _github_connect_register($ghuser, $token) {
  $username = $ghuser['login'];

  // Check if username exists and assign a new username.
  // @TODO If username already exists the user should be able to pick a new one.
  // @TODO User should be notified that he has been assigned a new username.
  if (_github_connect_username_stored($username)) {
    $i = 1;
    do {
      if (_github_connect_username_stored($username . $i)) {
        $i++;
      }
      elseif ($i === 10) {
        drupal_set_message(t('Error connecting account. A username could not be generated.'), 'error');
        return;
      }
      else {
        // If availible the user will be given $username_[number].
        $username = $username . '_' . $i;
        break;
      }
    }
    // Limit to 10.
    while ($i <= 10);
  }

  $userinfo = array(
    'name' => $username,
    'mail' => $ghuser['email'],
    'pass' => user_password(),
    'status' => 1,
    'access' => REQUEST_TIME,
    'init' => $ghuser['email'],
  );

  $account = user_save('', $userinfo);

  if ($account) {
    _github_connect_save_github_user($account, $token);
  }
  else {
    drupal_set_message(t('Error saving new user.'), 'error');
    return;
  }
}


/**
 * Check to see if username is already stored
 */
function _github_connect_username_stored($name) {
  $query = db_select('users', 'u');
  $query->fields('u', array('uid'));
  $query->condition('name', $name, '=');
  return $query->execute()->fetchField();
}


/**
 * Require user to verify email address when merging accounts.
 */
function github_connect_verify_email_form($form, &$form_state, $uid, $token) {
  $account = user_load($uid);

  $form['message'] = array(
    '#type' => 'item',
    '#title' => t('Email address in use'),
    '#markup' => t('There is already an account associated with your GitHub email address. Type your !site account password to merge accounts.', array('!site' => variable_get('site_name'))),
  );
  $form['name'] = array('#type' => 'hidden', '#value' => $account->name);
  $form['pass'] = array('#type' => 'password',
    '#title' => t('Password'),
    '#description' => t('Enter your password.'),
    '#required' => TRUE,
  );
  $form['token'] = array('#type' => 'hidden', '#value' => $token);
  $form['actions'] = array('#type' => 'actions');
  $form['actions']['submit'] = array('#type' => 'submit', '#value' => t('Merge accounts'));
  $form['#validate'] = array('github_connect_verify_email_form_validate');
  $form['#submit'] = array('github_connect_verify_email_form_submit');

  return $form;
}


/**
 * Validation to check correct password when merging.
 */
function github_connect_verify_email_form_validate($form, &$form_state) {
  $name = $form_state['values']['name'];
  $password = $form_state['values']['pass'];

  if (user_authenticate($name, $password) == FALSE) {
    form_set_error('pass', t('Incorrect password.'));
  }
}


/**
 * Custom submit function to save user when merging.
 */
function github_connect_verify_email_form_submit($form, &$form_state) {
  $account = user_load_by_name($form_state['values']['name']);
  $token = $form_state['values']['token'];

  _github_connect_save_github_user($account, $token);
}


/**
 * Get User id from GitHub access token
 *
 * @param $token Access token from GitHub
 * @return $uid Drupal user id
 */
function github_connect_get_token_user($token) {
  if ($token) {
    $result = db_select('github_connect_users', 'g_u')
    ->fields('g_u', array('uid', 'access_token'))
    ->condition('access_token', $token, '=')
    ->execute()
    ->fetchAssoc();

    $uid = $result['uid'];
    return $uid;
  }
}


/**
 * Get GitHub access token for User
 *
 * @param $uid User user id
 * @return $token Access token from GitHub
 */
function github_connect_get_user_token($uid) {
  if ($uid) {
    $result = db_select('github_connect_users', 'g_u')
    ->fields('g_u', array('uid', 'access_token'))
    ->condition('uid', $uid, '=')
    ->execute()
    ->fetchAssoc();

    $token = $result['access_token'];
    return $token;
  }
}