Display a list of past MailChimp campaigns

mailchimp-archive.php

<?php
class NH_MailChimp_Archive {
    private $_args, $max_page,

    public function __construct($args = array()) {
        global $paged;
        $defaults = array(
            'apikey'     => false,
            'start'      => 0,
            'limit'      => 12,
            'sort_field' => 'send_time',
            'filters'    => array(
                'template_id' => false,
                'list_id'     => false,
                'status'      => 'sent',
            )
        );
        $request = array_replace_recursive( $defaults, $args );
        // Cleanup the filters array
        $request['filters'] = array_filter($request['filters']);
        $this->_args = $request;

        add_shortcode( 'mailchimp_archive', array($this, 'archive_shortcode') );
    }

    /**
     * Fetch a list of campaigns using MailChimp's API
     * @return    array/bool    An array of campaigns or false on failure
     */
    public function fetch_campaigns() {
        if(!$this->apikey) return;

        // echo '<pre>'.print_r($this->_args, true).'</pre>'; die();
        $return = false;
        $mc_url = 'https://us1.api.mailchimp.com/2.0/campaigns/list.json/';

        $ch = curl_init();
        curl_setopt($ch, CURLOPT_URL, $mc_url);
        curl_setopt($ch, CURLOPT_POST, 1);
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
        curl_setopt($ch, CURLOPT_POSTFIELDS, json_encode( $this->_args ));
        $result = curl_exec($ch);
        if(!curl_errno($ch)) {
            $numpages = ceil($result->total / $this->limit);
            $this->start++;
            $result = json_decode($result);
            if(is_null($this->max_page)) $this->max_page = ceil($result->total / $this->limit);

            $return = $result->data;

        }
        curl_close($ch);
        return $return;
    }

    /**
     * Helper function to add pagination to the bottom of the shortcode
     * @return    string    HTML output for pagination
     */
    public function archive_pagination() {
        global $post;
        $link = get_permalink($post->ID);
        $output  = '<ul class="wp_page_numbers">';
        $output .= sprintf('<li class="page_info">Page %s of %s</li>', $this->start, $this->max_page);

        for($i = 1; $i <= $this->max_page; $i++):
            $output .= sprintf('<li%s><a href="%s">%s</a></li>',
                ($this->start === $i ? ' class="active_page"' : ''),
                ($i === 1 ? $link : $link .$i.'/'),
                $i
            );
        endfor;
        $output .= '</ul>';
        return $output;
    }

    /**
     * Shortcode for listing out past MailChimp campaigns
     * @param     array    $atts    Shortcode atts
     * @return    string            HTML output for shortcode
     */
    public function archive_shortcode($atts) {
        // extract(shortcode_atts( array(

        // ), $atts ));
        $page = get_query_var('page') ? get_query_var('page') : 1;
        $this->start = $page - 1;

        $output = '';

        $before = '<ul class="mailchimp-archive">';
        $after = '</ul>';

        $list = '';
        if($campaigns = $this->fetch_campaigns()):
            $pagination = $this->archive_pagination();
            foreach($campaigns as $c):
                $list .= sprintf('<li><a href="%s" title="%s" target="_blank"><strong>%s</strong> <span class="campaign-date">%s</span></a></li>',
                    $c->archive_url,
                    esc_attr($c->subject),
                    $c->subject,
                    date('F jS, Y', strtotime($c->send_time))
                );
            endforeach;

            $output = $before . $list . $after . $pagination;

            $ouput = apply_filters( 'mailchimp_archive_output', $output, $list, $before, $after, $pagination, $campaigns );
        endif;
        return $output;
    }

    /**
     * Function for retrieving list names and IDs
     * Useful for finding the correct list_id for fetch_campaigns function
     */
    public function fetch_lists() {
        $mc_url = 'https://us1.api.mailchimp.com/2.0/lists/list.json/';
        $request = array(
            'apikey' => $this->apikey
        );
        $ch = curl_init();
        curl_setopt($ch, CURLOPT_URL, $mc_url);
        curl_setopt($ch, CURLOPT_POST, 1);
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
        curl_setopt($ch, CURLOPT_POSTFIELDS, json_encode( $request ));
        $result = curl_exec($ch);
        if(!curl_errno($ch)) {
            echo '<pre>'.print_r(json_decode($result), true).'</pre>'; die();
        }
        curl_close($ch);
    }

    // Magic Functions
    public function __set($property, $value) {
        return $this->_args[$property] = $value;
    }

    public function __get($property){
        return array_key_exists($property, $this->_args) ? $this->_args[$property] : null;
    }
}

$mc_archive = new MailChimp_Archive_401(array(
    'apikey'  => 'API KEY',
    'filters' => array(
        'template_id' => 00000000,
        'list_id'     => 'LIST ID'
    )
));
// $mc_archive->fetch_lists();