PHP Class for Yii PHP Framework to Send E-mails using Curl. It's uses MailGun API to send emails.

Yii-MailGun.php

<?php

/**
 * MailGun PHP Curl Client
 * 
 * @version 1.1b
 * @copyright &copy; 2015, VINAY KUMAR SHARMA <vinaykrsharma@live.in>
 * @author VINAY KUMAR SHARMA
 */
class MailGun extends CApplicationComponent {
    /*     * *************************************************************************
      PUBLIC Properties
     * ************************************************************************* */

    /**
     * PHP Curl Options, use PHP Curl constant variable to pass.
     * e.g:
     *   CURLOPT_HEADER => TRUE
     *   CURLOPT_USERAGENT => 'Bond/0.0.7'
     * @var array PHP Curl extension options
     */
    public $options = array();

    /**
     * Default Sender Address
     * if don't found in send() method parameters
     * 
     * @var string Sender email
     */
    public $defaultFromEmail;

    /**
     * Domain listed in MailGun Control Panel
     * @var string Mail will be used to sent using
     */
    public $domain;

    /**
     * You can find your API Key in your 
     * <a href="https://mailgun.com/cp">Control Panel</a>
     * @var string MailGun Api Key
     */
    public $apiKey;


    /*     * *************************************************************************
      PRIVATE and PROTECTED Properties
     * ************************************************************************* */

    /**
     * MailGun Api URL Address
     * 
     * @var string Api URL
     */
    protected $mailGunApiURL = 'https://api.mailgun.net/v2/';

    /**
     * The path to the directory where the view for getView is stored. Must not
     * have ending dot.
     *
     * @var string
     */
    protected $pathViews = 'application.views.email';

    /**
     * The path to the directory where the layout for getView is stored. Must
     * not have ending dot.
     *
     * @var string
     */
    protected $pathLayouts = 'application.views.email.layouts';

    /**
     * NOT IMPLEMENT YET
     * 
     * HTTP Request Headers
     * @var array request with headers
     */
    protected $httpHeaders = array(
        CURLOPT_HTTPHEADER => array(
            'Accept: application/json',
            'Accept-Language: en-us;q=0.5,en;q=0.3',
            'Accept-Charset: utf-8;q=0.7,*;q=0.7',
            'Keep-Alive: 300'
        ),
    );

    /**
     * @var object curl_init() return value
     */
    private $_ch;

    /**
     * CURL Options, see PHP curl options for more
     * 
     * @var array options
     */
    private $_curlOptions = array(
        CURLOPT_HEADER => false,
        CURLOPT_RETURNTRANSFER => true,
        CURLOPT_TIMEOUT => 30,
        CURLOPT_CUSTOMREQUEST => 'POST',
        CURLOPT_POST => true,
        CURLOPT_USERAGENT => 'MailGun-PHP-Curl-Client/1.1b'
    );

    public function __construct() {
        
    }

    public function init() {
        parent::init();
        if (empty($this->domain)) {
            throw new CException('MailGun: Domain can not be empty.');
        }
        if (empty($this->apiKey)) {
            throw new CException('MailGun: API Key is not found in option');
        }
        // Unset `CURLOPT_URL` is found in options,
        // This will be created later using `$domain` and API end point call
        if (isset($this->options[CURLOPT_URL])) {
            unset($this->options[CURLOPT_URL]);
        }
        if (isset($this->options[CURLOPT_USERPWD])) {
            unset($this->options[CURLOPT_USERPWD]);
        }
        foreach ($this->options as $key => $value) {
            $this->_curlOptions[$key] = $value;
        }
        $this->_curlOptions[CURLOPT_USERPWD] = "api:$this->apiKey";
    }

    /*     * *************************************************************************
      GETTERS and SETTERS
     * ************************************************************************* */

    /**
     * Setter
     *
     * @param string $value pathLayouts
     */
    public function setPathLayouts($value) {
        if (!is_string($value) && !preg_match("/[a-z0-9\.]/i", $value)) {
            throw new CException('MailGun: pathLayouts must be a Yii alias path');
        }
        $this->pathLayouts = $value;
    }

    /**
     * Getter
     *
     * @return string pathLayouts
     */
    public function getPathLayouts() {
        return $this->pathLayouts;
    }

    /**
     * Setter
     *
     * @param string $value pathViews
     */
    public function setPathViews($value) {
        if (!is_string($value) && !preg_match("/[a-z0-9\.]/i", $value)) {
            throw new CException('MailGun: pathViews must be a Yii alias path');
        }
        $this->pathViews = $value;
    }

    /**
     * Getter
     *
     * @return string pathViews
     */
    public function getPathViews() {
        return $this->pathViews;
    }

    /**
     * Displays an e-mail in preview mode. 
     *
     * @param string $view the class
     * @param array $vars Controller->renderPartial() options
     * @param string $layout
     */
    public function getView($view, $vars = array(), $layout = null) {
        $controller = Yii::app()->controller;
        $body = $controller->renderPartial($this->pathViews . '.' . $view, $vars, true);
        if ($layout === null) {
            return $body;
        }
        return $controller->renderPartial($this->pathLayouts . '.' . $layout, array('content' => $body), true);
    }

    /*     * *************************************************************************
      MailGun API call methods
     * ************************************************************************* */

    /**
     * Send Email
     * 
     * @param string $to Send emails to. comma seperate email address for multiple
     * receipients
     * @param string $subject Subject of the Email
     * @param string $html_body HTML Body of the email
     * @param array $extras options
     *  <ul>
     *      <li><strong>from:</strong> Sender Email ID</li>
     *      <li><strong>text:</strong> Alternate email in simple text format</li>
     *      <li><strong>tags:</strong> Tag the email with comma seperated value</li>
     *  </ul>
     * for more options please check MailGun API Reference:
     *  <a href="https://documentation.mailgun.com/api-sending.html#sending">
     *      https://documentation.mailgun.com/api-sending.html#sending
     *  </a>
     */
    public function send($to, $subject, $html_body, $extras = array()) {
        try {
            $this->_curlOptions[CURLOPT_URL] = $this->getApiUrl('messages');
            $this->_ch = curl_init($this->_curlOptions[CURLOPT_URL]);

            $fields = array(
                "from" => $this->defaultFromEmail,
            );
            if (isset($extras['from']) && !empty($extras['from'])) {
                $fields['from'] = & $extras['from'];
            }
            if (empty($fields['from'])) {
                throw new CException('MailGun: Send Email address can not be null');
            }
            if (empty($to) || strlen($to) < 5) {
                throw new CException('MailGun: Receipients can not be empty');
            }
            $fields['to'] = & $to;
            $fields['subject'] = & $subject;
            if (!empty($html_body) && strlen($html_body) >= 5) {
                $fields['html'] = & $html_body;
            }
            if (isset($extras['text']) && !empty($extras['text'])) {
                $fields['text'] = & $extras['text'];
            } elseif (isset($fields['html'])) {
                $fields['text'] = strip_tags($fields['html']);
            }
            if (isset($extras['tags']) && !empty($extras['tags'])) {
                $fields['o:tag'] = & $extras['tags'];
            }
            if (isset($extras['attachment']) && !empty($extras['attachment'])) {
                $attachment = $extras['attachment'];
                // For older version of PHP, which does not supports PHPFILE for upload
                $fields['attachment'] = "@{$attachment['file']};filename={$attachment['name']};type={$attachment['mime_type']}";
                // PHP 5.5 introduced a CurlFile object that deprecates the old @filename syntax
                // See: https://wiki.php.net/rfc/curl-file-upload
                if (function_exists('curl_file_create')) {
                    $fields['attachment'] = curl_file_create($attachment['file'], $attachment['mime_type'], $attachment['name']);
                }
                unset($extras['attachment']);
            }
            $fields = CMap::mergeArray($fields, $extras);
            $this->_curlOptions[CURLOPT_POSTFIELDS] = $fields;
            curl_setopt_array($this->_ch, $this->_curlOptions);

            $response_with_headers = curl_exec($this->_ch);
            curl_close($this->_ch);
            return $response_with_headers;
        } catch (Exception $e) {
            
        }
        return NULL;
    }

    private function getApiUrl($action) {
        return $this->mailGunApiURL . $this->domain . "/$action";
    }

    /**
     * This action allows you to create, access, and validate domains
     * programmatically.
     */
    public function domains() {
        $this->_curlOptions[CURLOPT_URL] = $this->getApiUrl('domains');
    }

    /**
     * Mailgun allows you to quickly add “Unsubscribe me” feature to your
     * outgoing emails without any programming on your end. You can enable
     * this in your Control Panel under your domain settings.
     */
    public function unsubscribes() {
        $this->_curlOptions[CURLOPT_URL] = $this->getApiUrl('unsubscribes');
    }

    /**
     * This API allows you to programmatically download the list of users
     * who have complained, add a complaint, or delete a complaint.
     */
    public function complaints() {
        $this->_curlOptions[CURLOPT_URL] = $this->getApiUrl('complaints');
    }

    /**
     * The list of bounced addresses can be accessed programmatically:
     */
    public function bounces() {
        $this->_curlOptions[CURLOPT_URL] = $this->getApiUrl('bounces');
    }

    /**
     * Mailgun collects many different events and generates event statistics
     * which are available in your Control Panel.
     */
    public function stats() {
        $this->_curlOptions[CURLOPT_URL] = $this->getApiUrl('stats');
    }

    /**
     * Mailgun tracks every event that happens to your emails and makes this
     * data available to you through the Events API.
     */
    public function events() {
        $this->_curlOptions[CURLOPT_URL] = $this->getApiUrl('events');
    }

    /**
     * Mailgun Routes are a powerful way to handle the incoming traffic.
     */
    public function routes() {
        $this->_curlOptions[CURLOPT_URL] = $this->getApiUrl('routes');
    }

    /**
     * Unlike other email platforms Mailgun analytics is not limited to
     * campaigns sent to the mailing lists. You can generate powerful reports
     * and analytize data for any subset of your email traffic: just create an
     * email campaign and specify that campaign’s ID when sending a message.
     */
    public function campaigns() {
        $this->_curlOptions[CURLOPT_URL] = $this->getApiUrl('campaigns');
    }

    /**
     * This API allows you to create, access, and delete webhooks programmatically.
     */
    public function webhooks() {
        $this->_curlOptions[CURLOPT_URL] = $this->getApiUrl('webhooks');
    }

    /**
     * You can programmatically create mailing lists using Mailgun Mailing
     * List API. A mailing list is a group of members (recipients) which itself
     * has an email address, like developers@mailgun.net. This address becomes
     * an ID for this mailing list.
     */
    public function lists() {
        $this->_curlOptions[CURLOPT_URL] = $this->getApiUrl('lists');
    }

    /**
     * This API endpoint is an email address validation service.
     * Given an arbitrary address, we will validate the address based on:
     */
    public function address_validate() {
        $this->_curlOptions[CURLOPT_URL] = $this->getApiUrl('address/validate');
    }

}

Configure MailGun to Yii PHP Framework:

Create a mailgun component to config/main.php as below:

return array(
    // ...
    'components' => array(
        // ...
        'mailgun' => array(
            'class' => 'application.components.MailGun',
            'domain' => 'example.com',
            'apiKey' => 'key-xxxxxxxxxxxxxxxxxxxxx-xxxxxxx',
            'defaultFromEmail' => 'Sender Name <no-reply@example.com>',
            'pathLayouts' => 'application.views.layouts.emailer',
            'pathViews' => 'application.views.partials',
        ),
        // ...
    )
);

And Use:

// Get MailGun component object
$mg = Yii::app()->mailgun;
// Generate Email body HTML from template
$body = $mg->getView('__emailer_your_email_template', $array_data_to_pass_in_template);
// [OPTIONAL] Extra data to pass to MailGun
$extras = array(
    'attachment' => array(
        'file' => $attachment,
        'name' => $file_name,
        'mime_type' => $file_mime_type,
    )
);

$to = 'sendto@example.com'
$subject = 'Testing some awesomeness!'

// Now trigger send, and capture json response
$response = $mg->send($to, $subject, $body, $extras);