Merge pull request #7174 from piwik/seo-metrics

Refactored the SEO plugin to make it extensible and error-proof

14 files changed, 835 insertions, 480 deletions

diff --git a/plugins/SEO/API.php b/plugins/SEO/API.php
index c57aea2156..fdadbf518f 100644
--- a/plugins/SEO/API.php
+++ b/plugins/SEO/API.php
@@ -4,25 +4,28 @@
  *
  * @link http://piwik.org
  * @license http://www.gnu.org/licenses/gpl-3.0.html GPL v3 or later
- *
  */
+
 namespace Piwik\Plugins\SEO;
 
-use Piwik\Cache;
 use Piwik\DataTable;
 use Piwik\Piwik;
+use Piwik\Plugins\SEO\Metric\Aggregator;
+use Piwik\Plugins\SEO\Metric\Metric;
+use Piwik\Plugins\SEO\Metric\ProviderCache;
+use Piwik\Url;
 
 /**
  * @see plugins/Referrers/functions.php
- * @method static \Piwik\Plugins\SEO\API getInstance()
+ * @method static API getInstance()
  */
 require_once PIWIK_INCLUDE_PATH . '/plugins/Referrers/functions.php';
 
 /**
- * The SEO API lets you access a list of SEO metrics for the specified URL: Google Pagerank, Goolge/Bing indexed pages
+ * The SEO API lets you access a list of SEO metrics for the specified URL: Google PageRank, Google/Bing indexed pages
  * Alexa Rank, age of the Domain name and count of DMOZ entries.
  *
- * @method static \Piwik\Plugins\SEO\API getInstance()
+ * @method static API getInstance()
  */
 class API extends \Piwik\Plugin\API
 {
@@ -36,93 +39,37 @@ class API extends \Piwik\Plugin\API
     {
         Piwik::checkUserHasSomeViewAccess();
 
-        $data = $this->getCachedRanks($url);
-
-        $translated = array();
-        if (!empty($data)) {
-            foreach ($data as $title => $rank) {
-                $translated[Piwik::translate($title)] = $rank;
-            }
-        }
+        $metricProvider = new ProviderCache(new Aggregator());
+        $domain = Url::getHostFromUrl($url);
+        $metrics = $metricProvider->getMetrics($domain);
 
-        return DataTable::makeFromIndexedArray($translated);
+        return $this->toDataTable($metrics);
     }
 
-    private function getCachedRanks($url)
-    {
-        $cacheId = 'SEO_getRank_' . md5($url);
-
-        $cache = Cache::getLazyCache();
-        $data  = $cache->fetch($cacheId);
-
-        if (empty($data)) {
-            $data = $this->getRanks($url);
-
-            $cache->save($cacheId, $data, 60 * 60 * 6);
-        }
-
-        return $data;
-    }
-
-    private function getRanks($url)
+    /**
+     * @param Metric[] $metrics
+     * @return DataTable
+     */
+    private function toDataTable(array $metrics)
     {
-        $rank = new RankChecker($url);
-
-        $linkToMajestic = MajesticClient::getLinkForUrl($url);
-
-        $data = array(
-            'Google PageRank' => array(
-                'rank' => $rank->getPageRank(),
-                'logo' => \Piwik\Plugins\Referrers\getSearchEngineLogoFromUrl('http://google.com'),
-                'id'   => 'pagerank'
-            ),
-            'SEO_Google_IndexedPages' => array(
-                'rank' => $rank->getIndexedPagesGoogle(),
-                'logo' => \Piwik\Plugins\Referrers\getSearchEngineLogoFromUrl('http://google.com'),
-                'id'   => 'google-index',
-            ),
-            'SEO_Bing_IndexedPages' => array(
-                'rank' => $rank->getIndexedPagesBing(),
-                'logo' => \Piwik\Plugins\Referrers\getSearchEngineLogoFromUrl('http://bing.com'),
-                'id'   => 'bing-index',
-            ),
-            'SEO_AlexaRank' => array(
-                'rank' => $rank->getAlexaRank() . '',
-                'logo' => \Piwik\Plugins\Referrers\getSearchEngineLogoFromUrl('http://alexa.com'),
-                'id'   => 'alexa',
-            ),
-            'SEO_DomainAge' => array(
-                'rank' => $rank->getAge(),
-                'logo' => 'plugins/SEO/images/whois.png',
-                'id'   => 'domain-age',
-            ),
-            'SEO_ExternalBacklinks' => array(
-                'rank' => $rank->getExternalBacklinkCount(),
-                'logo' => 'plugins/SEO/images/majesticseo.png',
-                'logo_link' => $linkToMajestic,
-                'logo_tooltip' => Piwik::translate('SEO_ViewBacklinksOnMajesticSEO'),
-                'id' => 'external-backlinks',
-            ),
-            'SEO_ReferrerDomains' => array(
-                'rank' => $rank->getReferrerDomainCount(),
-                'logo' => 'plugins/SEO/images/majesticseo.png',
-                'logo_link' => $linkToMajestic,
-                'logo_tooltip' => Piwik::translate('SEO_ViewBacklinksOnMajesticSEO'),
-                'id' => 'referrer-domains',
-            ),
-        );
+        $translated = array();
 
-        // Add DMOZ only if > 0 entries found
-        $dmozRank = array(
-            'rank' => $rank->getDmoz(),
-            'logo' => \Piwik\Plugins\Referrers\getSearchEngineLogoFromUrl('http://dmoz.org'),
-            'id'   => 'dmoz',
-        );
+        foreach ($metrics as $metric) {
+            if (!$metric instanceof Metric) {
+                continue;
+            }
 
-        if ($dmozRank['rank'] > 0) {
-            $data['SEO_Dmoz'] = $dmozRank;
+            $label = Piwik::translate($metric->getName());
+            $translated[$label] = array(
+                'id'           => $metric->getId(),
+                'rank'         => $metric->getValue(),
+                'logo'         => $metric->getLogo(),
+                'logo_link'    => $metric->getLogoLink(),
+                'logo_tooltip' => Piwik::translate($metric->getLogoTooltip()),
+                'rank_suffix'  => Piwik::translate($metric->getValueSuffix()),
+            );
         }
 
-        return $data;
+        return DataTable::makeFromIndexedArray($translated);
     }
 }
diff --git a/plugins/SEO/Metric/Aggregator.php b/plugins/SEO/Metric/Aggregator.php
new file mode 100644
index 0000000000..69f9139d1e
--- /dev/null
+++ b/plugins/SEO/Metric/Aggregator.php
@@ -0,0 +1,63 @@
+<?php
+/**
+ * Piwik - free/libre analytics platform
+ *
+ * @link http://piwik.org
+ * @license http://www.gnu.org/licenses/gpl-3.0.html GPL v3 or later
+ */
+
+namespace Piwik\Plugins\SEO\Metric;
+
+use Piwik\Container\StaticContainer;
+use Piwik\Metrics\Formatter;
+use Piwik\Piwik;
+
+/**
+ * Aggregates metrics from several providers.
+ */
+class Aggregator implements MetricsProvider
+{
+    /**
+     * @var MetricsProvider[]
+     */
+    private $providers;
+
+    public function __construct()
+    {
+        $this->providers = $this->getProviders();
+    }
+
+    public function getMetrics($domain)
+    {
+        $metrics = array();
+
+        foreach ($this->providers as $provider) {
+            $metrics = array_merge($metrics, $provider->getMetrics($domain));
+        }
+
+        return $metrics;
+    }
+
+    private function getProviders()
+    {
+        $container = StaticContainer::getContainer();
+
+        $providers = array(
+            $container->get('Piwik\Plugins\SEO\Metric\Google'),
+            $container->get('Piwik\Plugins\SEO\Metric\Bing'),
+            $container->get('Piwik\Plugins\SEO\Metric\Alexa'),
+            $container->get('Piwik\Plugins\SEO\Metric\DomainAge'),
+            $container->get('Piwik\Plugins\SEO\Metric\Majestic'),
+            $container->get('Piwik\Plugins\SEO\Metric\Dmoz'),
+        );
+
+        /**
+         * Use this event to register new SEO metrics providers.
+         *
+         * @param array $providers Contains an array of Piwik\Plugins\SEO\Metric\MetricsProvider instances.
+         */
+        Piwik::postEvent('SEO.getMetricsProviders', array(&$providers));
+
+        return $providers;
+    }
+}
diff --git a/plugins/SEO/Metric/Alexa.php b/plugins/SEO/Metric/Alexa.php
new file mode 100644
index 0000000000..d9ec020954
--- /dev/null
+++ b/plugins/SEO/Metric/Alexa.php
@@ -0,0 +1,51 @@
+<?php
+/**
+ * Piwik - free/libre analytics platform
+ *
+ * @link http://piwik.org
+ * @license http://www.gnu.org/licenses/gpl-3.0.html GPL v3 or later
+ */
+
+namespace Piwik\Plugins\SEO\Metric;
+
+use Piwik\Http;
+use Psr\Log\LoggerInterface;
+
+/**
+ * Retrieves the Alexa rank.
+ */
+class Alexa implements MetricsProvider
+{
+    const URL = 'http://data.alexa.com/data?cli=10&url=';
+    const LINK = 'http://www.alexa.com/siteinfo/';
+
+    /**
+     * @var LoggerInterface
+     */
+    private $logger;
+
+    public function __construct(LoggerInterface $logger)
+    {
+        $this->logger = $logger;
+    }
+
+    public function getMetrics($domain)
+    {
+        try {
+            $response = Http::sendHttpRequest(self::URL . urlencode($domain), $timeout = 10, @$_SERVER['HTTP_USER_AGENT']);
+
+            $xml = @simplexml_load_string($response);
+            $value = $xml ? (string)$xml->SD->POPULARITY['TEXT'] : null;
+        } catch (\Exception $e) {
+            $this->logger->warning('Error while getting Alexa SEO stats: {message}', array('message' => $e->getMessage()));
+            $value = null;
+        }
+
+        $logo = \Piwik\Plugins\Referrers\getSearchEngineLogoFromUrl('http://alexa.com');
+        $link = self::LINK . urlencode($domain);
+
+        return array(
+            new Metric('alexa', 'SEO_AlexaRank', $value, $logo, $link)
+        );
+    }
+}
diff --git a/plugins/SEO/Metric/Bing.php b/plugins/SEO/Metric/Bing.php
new file mode 100644
index 0000000000..c01b23d576
--- /dev/null
+++ b/plugins/SEO/Metric/Bing.php
@@ -0,0 +1,54 @@
+<?php
+/**
+ * Piwik - free/libre analytics platform
+ *
+ * @link http://piwik.org
+ * @license http://www.gnu.org/licenses/gpl-3.0.html GPL v3 or later
+ */
+
+namespace Piwik\Plugins\SEO\Metric;
+
+use Piwik\Http;
+use Psr\Log\LoggerInterface;
+
+/**
+ * Fetches the number of pages indexed in Bing.
+ */
+class Bing implements MetricsProvider
+{
+    const URL = 'http://www.bing.com/search?mkt=en-US&q=site%3A';
+
+    /**
+     * @var LoggerInterface
+     */
+    private $logger;
+
+    public function __construct(LoggerInterface $logger)
+    {
+        $this->logger = $logger;
+    }
+
+    public function getMetrics($domain)
+    {
+        $url = self::URL . urlencode($domain);
+
+        try {
+            $response = str_replace('&nbsp;', ' ', Http::sendHttpRequest($url, $timeout = 10, @$_SERVER['HTTP_USER_AGENT']));
+
+            if (preg_match('#([0-9\,]+) results#i', $response, $p)) {
+                $pageCount = (int)str_replace(',', '', $p[1]);
+            } else {
+                $pageCount = 0;
+            }
+        } catch (\Exception $e) {
+            $this->logger->warning('Error while getting Bing SEO stats: {message}', array('message' => $e->getMessage()));
+            $pageCount = null;
+        }
+
+        $logo = \Piwik\Plugins\Referrers\getSearchEngineLogoFromUrl('http://bing.com');
+
+        return array(
+            new Metric('bing-index', 'SEO_Bing_IndexedPages', $pageCount, $logo, null, null, 'General_Pages')
+        );
+    }
+}
diff --git a/plugins/SEO/Metric/Dmoz.php b/plugins/SEO/Metric/Dmoz.php
new file mode 100644
index 0000000000..82ffd248ba
--- /dev/null
+++ b/plugins/SEO/Metric/Dmoz.php
@@ -0,0 +1,61 @@
+<?php
+/**
+ * Piwik - free/libre analytics platform
+ *
+ * @link http://piwik.org
+ * @license http://www.gnu.org/licenses/gpl-3.0.html GPL v3 or later
+ */
+
+namespace Piwik\Plugins\SEO\Metric;
+
+use Piwik\Http;
+use Psr\Log\LoggerInterface;
+
+/**
+ * Retrieves the number of Dmoz.org entries.
+ */
+class Dmoz implements MetricsProvider
+{
+    const URL = 'http://www.dmoz.org/search?q=';
+
+    /**
+     * @var LoggerInterface
+     */
+    private $logger;
+
+    /**
+     * @param LoggerInterface $logger
+     */
+    public function __construct(LoggerInterface $logger)
+    {
+        $this->logger = $logger;
+    }
+
+    public function getMetrics($domain)
+    {
+        try {
+            $response = Http::sendHttpRequest(self::URL . urlencode($domain), $timeout = 10, @$_SERVER['HTTP_USER_AGENT']);
+
+            preg_match('#Open Directory Sites[^\(]+\([0-9]-[0-9]+ of ([0-9]+)\)#', $response, $p);
+            if (!empty($p[1])) {
+                $value = (int)$p[1];
+            } else {
+                $value = 0;
+            }
+
+            // Add DMOZ only if > 0 entries found
+            if ($value == 0) {
+                return array();
+            }
+        } catch (\Exception $e) {
+            $this->logger->warning('Error while getting Dmoz SEO stats: {message}', array('message' => $e->getMessage()));
+            $value = null;
+        }
+
+        $logo = \Piwik\Plugins\Referrers\getSearchEngineLogoFromUrl('http://dmoz.org');
+
+        return array(
+            new Metric('dmoz', 'SEO_Dmoz', $value, $logo)
+        );
+    }
+}
diff --git a/plugins/SEO/Metric/DomainAge.php b/plugins/SEO/Metric/DomainAge.php
new file mode 100644
index 0000000000..a059b49572
--- /dev/null
+++ b/plugins/SEO/Metric/DomainAge.php
@@ -0,0 +1,141 @@
+<?php
+/**
+ * Piwik - free/libre analytics platform
+ *
+ * @link http://piwik.org
+ * @license http://www.gnu.org/licenses/gpl-3.0.html GPL v3 or later
+ */
+
+namespace Piwik\Plugins\SEO\Metric;
+
+use Piwik\Http;
+use Piwik\Metrics\Formatter;
+use Psr\Log\LoggerInterface;
+
+/**
+ * Fetches the domain age using archive.org, who.is and whois.com.
+ */
+class DomainAge implements MetricsProvider
+{
+    /**
+     * @var Formatter
+     */
+    private $formatter;
+
+    /**
+     * @var LoggerInterface
+     */
+    private $logger;
+
+    public function __construct(Formatter $formatter, LoggerInterface $logger)
+    {
+        $this->formatter = $formatter;
+        $this->logger = $logger;
+    }
+
+    public function getMetrics($domain)
+    {
+        $ages = array();
+
+        $age = $this->getAgeArchiveOrg($domain);
+        if ($age > 0) {
+            $ages[] = $age;
+        }
+
+        $age = $this->getAgeWhoIs($domain);
+        if ($age > 0) {
+            $ages[] = $age;
+        }
+
+        $age = $this->getAgeWhoisCom($domain);
+        if ($age > 0) {
+            $ages[] = $age;
+        }
+
+        if (count($ages) > 0) {
+            $value = min($ages);
+            $value = $this->formatter->getPrettyTimeFromSeconds(time() - $value, true);
+        } else {
+            $value = null;
+        }
+
+        return array(
+            new Metric('domain-age', 'SEO_DomainAge', $value, 'plugins/SEO/images/whois.png')
+        );
+    }
+
+    /**
+     * Returns the domain age archive.org lists for the current url
+     *
+     * @param string $domain
+     * @return int
+     */
+    private function getAgeArchiveOrg($domain)
+    {
+        $url = str_replace('www.', '', $domain);
+        $data = $this->getUrl('http://wayback.archive.org/web/*/' . urlencode($url));
+        preg_match('#<a href=\"([^>]*)' . preg_quote($url) . '/\">([^<]*)<\/a>#', $data, $p);
+        if (!empty($p[2])) {
+            $value = strtotime($p[2]);
+            if ($value === false) {
+                return 0;
+            }
+            return $value;
+        }
+        return 0;
+    }
+
+    /**
+     * Returns the domain age who.is lists for the current url
+     *
+     * @param string $domain
+     * @return int
+     */
+    private function getAgeWhoIs($domain)
+    {
+        $url = preg_replace('/^www\./', '', $domain);
+        $url = 'http://www.who.is/whois/' . urlencode($url);
+        $data = $this->getUrl($url);
+        preg_match('#(?:Creation Date|Created On|created|Registered on)\.*:\s*([ \ta-z0-9\/\-:\.]+)#si', $data, $p);
+        if (!empty($p[1])) {
+            $value = strtotime(trim($p[1]));
+            if ($value === false) {
+                return 0;
+            }
+            return $value;
+        }
+        return 0;
+    }
+
+    /**
+     * Returns the domain age whois.com lists for the current url
+     *
+     * @param string $domain
+     * @return int
+     */
+    private function getAgeWhoisCom($domain)
+    {
+        $url = preg_replace('/^www\./', '', $domain);
+        $url = 'http://www.whois.com/whois/' . urlencode($url);
+        $data = $this->getUrl($url);
+        preg_match('#(?:Creation Date|Created On|created):\s*([ \ta-z0-9\/\-:\.]+)#si', $data, $p);
+        if (!empty($p[1])) {
+            $value = strtotime(trim($p[1]));
+            if ($value === false) {
+                return 0;
+            }
+            return $value;
+        }
+        return 0;
+    }
+
+    private function getUrl($url)
+    {
+        try {
+            return str_replace('&nbsp;', ' ', Http::sendHttpRequest($url, $timeout = 10, @$_SERVER['HTTP_USER_AGENT']));
+        } catch (\Exception $e) {
+            $this->logger->warning('Error while getting SEO stats (domain age): {message}', array('message' => $e->getMessage()));
+            return '';
+        }
+    }
+}
diff --git a/plugins/SEO/Metric/Google.php b/plugins/SEO/Metric/Google.php
new file mode 100644
index 0000000000..84e021c2ea
--- /dev/null
+++ b/plugins/SEO/Metric/Google.php
@@ -0,0 +1,170 @@
+<?php
+/**
+ * Piwik - free/libre analytics platform
+ *
+ * @link http://piwik.org
+ * @license http://www.gnu.org/licenses/gpl-3.0.html GPL v3 or later
+ */
+
+namespace Piwik\Plugins\SEO\Metric;
+
+use Piwik\Http;
+use Psr\Log\LoggerInterface;
+
+/**
+ * Retrieves Google PageRank.
+ */
+class Google implements MetricsProvider
+{
+    const SEARCH_URL = 'http://www.google.com/search?hl=en&q=site%3A';
+
+    /**
+     * @var LoggerInterface
+     */
+    private $logger;
+
+    /**
+     * @param LoggerInterface $logger
+     */
+    public function __construct(LoggerInterface $logger)
+    {
+        $this->logger = $logger;
+    }
+
+    public function getMetrics($domain)
+    {
+        $pageCount = $this->fetchIndexedPagesCount($domain);
+        $pageRank = $this->fetchPageRank($domain);
+
+        $logo = \Piwik\Plugins\Referrers\getSearchEngineLogoFromUrl('http://google.com');
+
+        return array(
+            new Metric('google-index', 'SEO_Google_IndexedPages', $pageCount, $logo, null, null, 'General_Pages'),
+            new Metric('pagerank', 'Google PageRank', $pageRank, $logo, null, null, '/10'),
+        );
+    }
+
+    public function fetchIndexedPagesCount($domain)
+    {
+        $url = self::SEARCH_URL . urlencode($domain);
+
+        try {
+            $response = str_replace('&nbsp;', ' ', Http::sendHttpRequest($url, $timeout = 10, @$_SERVER['HTTP_USER_AGENT']));
+
+            if (preg_match('#([0-9\,]+) results#i', $response, $p)) {
+                return (int)str_replace(',', '', $p[1]);
+            } else {
+                return 0;
+            }
+        } catch (\Exception $e) {
+            $this->logger->warning('Error while getting Google search SEO stats: {message}', array('message' => $e->getMessage()));
+            return null;
+        }
+    }
+
+    public function fetchPageRank($domain)
+    {
+        $chwrite = $this->checkHash($this->hashURL($domain));
+
+        $url = "http://toolbarqueries.google.com/tbr?client=navclient-auto&ch=" . $chwrite . "&features=Rank&q=info:" . $domain . "&num=100&filter=0";
+
+        try {
+            $response = Http::sendHttpRequest($url, $timeout = 10, @$_SERVER['HTTP_USER_AGENT']);
+
+            preg_match('#Rank_[0-9]:[0-9]:([0-9]+){1,}#si', $response, $p);
+
+            return isset($p[1]) ? $p[1] : null;
+        } catch (\Exception $e) {
+            $this->logger->warning('Error while getting Google PageRank for SEO stats: {message}', array('message' => $e->getMessage()));
+            return null;
+        }
+    }
+
+    /**
+     * Generate a hash for a url
+     *
+     * @param string $string
+     * @return int
+     */
+    private function hashURL($string)
+    {
+        $Check1 = $this->strToNum($string, 0x1505, 0x21);
+        $Check2 = $this->strToNum($string, 0, 0x1003F);
+
+        $Check1 >>= 2;
+        $Check1 = (($Check1 >> 4) & 0x3FFFFC0) | ($Check1 & 0x3F);
+        $Check1 = (($Check1 >> 4) & 0x3FFC00) | ($Check1 & 0x3FF);
+        $Check1 = (($Check1 >> 4) & 0x3C000) | ($Check1 & 0x3FFF);
+
+        $T1 = (((($Check1 & 0x3C0) << 4) | ($Check1 & 0x3C)) << 2) | ($Check2 & 0xF0F);
+        $T2 = (((($Check1 & 0xFFFFC000) << 4) | ($Check1 & 0x3C00)) << 0xA) | ($Check2 & 0xF0F0000);
+
+        return ($T1 | $T2);
+    }
+
+    /**
+     * Generate a checksum for the hash string
+     *
+     * @param int $hashnum
+     * @return string
+     */
+    private function checkHash($hashnum)
+    {
+        $CheckByte = 0;
+        $Flag = 0;
+
+        $HashStr = sprintf('%u', $hashnum);
+        $length = strlen($HashStr);
+
+        for ($i = $length - 1; $i >= 0; $i--) {
+            $Re = $HashStr{$i};
+            if (1 === ($Flag % 2)) {
+                $Re += $Re;
+                $Re = (int)($Re / 10) + ($Re % 10);
+            }
+            $CheckByte += $Re;
+            $Flag++;
+        }
+
+        $CheckByte %= 10;
+        if (0 !== $CheckByte) {
+            $CheckByte = 10 - $CheckByte;
+            if (1 === ($Flag % 2)) {
+                if (1 === ($CheckByte % 2)) {
+                    $CheckByte += 9;
+                }
+                $CheckByte >>= 1;
+            }
+        }
+
+        return '7' . $CheckByte . $HashStr;
+    }
+
+    /**
+     * Convert numeric string to int
+     *
+     * @param string $Str
+     * @param int $Check
+     * @param int $Magic
+     * @return int
+     */
+    private function strToNum($Str, $Check, $Magic)
+    {
+        $Int32Unit = 4294967296; // 2^32
+
+        $length = strlen($Str);
+        for ($i = 0; $i < $length; $i++) {
+            $Check *= $Magic;
+            // If the float is beyond the boundaries of integer (usually +/- 2.15e+9 = 2^31),
+            // the result of converting to integer is undefined
+            // refer to http://www.php.net/manual/en/language.types.integer.php
+            if ($Check >= $Int32Unit) {
+                $Check = ($Check - $Int32Unit * (int)($Check / $Int32Unit));
+                //if the check less than -2^31
+                $Check = ($Check < -2147483648) ? ($Check + $Int32Unit) : $Check;
+            }
+            $Check += ord($Str{$i});
+        }
+        return $Check;
+    }
+}
diff --git a/plugins/SEO/MajesticClient.php b/plugins/SEO/Metric/Majestic.php
index b7a7eeddc8..f276232945 100644
--- a/plugins/SEO/MajesticClient.php
+++ b/plugins/SEO/Metric/Majestic.php
@@ -4,22 +4,54 @@
  *
  * @link http://piwik.org
  * @license http://www.gnu.org/licenses/gpl-3.0.html GPL v3 or later
- *
  */
-namespace Piwik\Plugins\SEO;
 
-use Piwik\Common;
+namespace Piwik\Plugins\SEO\Metric;
+
 use Piwik\Http;
+use Psr\Log\LoggerInterface;
 
 /**
  * Client for Majestic SEO's HTTP API.
- *
- * Hides the HTTP request sending logic.
  */
-class MajesticClient
+class Majestic implements MetricsProvider
 {
     const API_BASE = 'http://simpleapi.majesticseo.com/sapi/';
     const API_KEY = 'ETHPYY'; // please only use this key within Piwik
+    const LOGO = 'plugins/SEO/images/majesticseo.png';
+
+    /**
+     * @var LoggerInterface
+     */
+    private $logger;
+
+    /**
+     * @param LoggerInterface $logger
+     */
+    public function __construct(LoggerInterface $logger)
+    {
+        $this->logger = $logger;
+    }
+
+    public function getMetrics($domain)
+    {
+        try {
+            $stats = $this->getBacklinkStats($domain);
+            $backlinks = $stats['backlink_count'];
+            $referrers = $stats['referrer_domains_count'];
+        } catch (\Exception $e) {
+            $this->logger->warning('Error while getting Majestic SEO stats: {message}', array('message' => $e->getMessage()));
+            $backlinks = null;
+            $referrers = null;
+        }
+
+        $link = $this->getLinkForUrl($domain);
+
+        return array(
+            new Metric('external-backlinks', 'SEO_ExternalBacklinks', $backlinks, self::LOGO, $link, 'SEO_ViewBacklinksOnMajesticSEO'),
+            new Metric('referrer-domains', 'SEO_ReferrerDomains', $referrers, self::LOGO, $link, 'SEO_ViewBacklinksOnMajesticSEO'),
+        );
+    }
 
     /**
      * Returns a URL that can be used to view all SEO data for a particular website.
@@ -28,7 +60,7 @@ class MajesticClient
      *                              accessible for.
      * @return string
      */
-    public static function getLinkForUrl($targetSiteUrl)
+    private function getLinkForUrl($targetSiteUrl)
     {
         $domain = @parse_url($targetSiteUrl, PHP_URL_HOST);
         return "http://www.majesticseo.com/reports/site-explorer/summary/$domain?IndexDataSource=F";
@@ -52,7 +84,7 @@ class MajesticClient
      *               If either stat is false, either the API returned an
      *               error, or the IP was blocked for this request.
      */
-    public function getBacklinkStats($siteDomain, $timeout = 300)
+    private function getBacklinkStats($siteDomain, $timeout = 300)
     {
         $apiUrl = $this->getApiUrl($method = 'GetBacklinkStats', $args = array(
             'items' => '1',
diff --git a/plugins/SEO/Metric/Metric.php b/plugins/SEO/Metric/Metric.php
new file mode 100644
index 0000000000..ec28b55138
--- /dev/null
+++ b/plugins/SEO/Metric/Metric.php
@@ -0,0 +1,145 @@
+<?php
+/**
+ * Piwik - free/libre analytics platform
+ *
+ * @link http://piwik.org
+ * @license http://www.gnu.org/licenses/gpl-3.0.html GPL v3 or later
+ */
+
+namespace Piwik\Plugins\SEO\Metric;
+
+/**
+ * Describes a SEO metric.
+ */
+class Metric
+{
+    /**
+     * @var string
+     */
+    private $id;
+
+    /**
+     * @var string
+     */
+    private $name;
+
+    /**
+     * @var string
+     */
+    private $value;
+
+    /**
+     * @var string
+     */
+    private $logo;
+
+    /**
+     * @var string|null
+     */
+    private $logoLink;
+
+    /**
+     * @var string|null
+     */
+    private $logoTooltip;
+
+    /**
+     * @var string|null
+     */
+    private $valueSuffix;
+
+    /**
+     * @param string $id
+     * @param string $name Can be a string or a translation ID.
+     * @param string $value Rank value.
+     * @param string $logo URL to a logo.
+     * @param string|null $logoLink
+     * @param string|null $logoTooltip
+     * @param string|null $valueSuffix
+     */
+    public function __construct($id, $name, $value, $logo, $logoLink = null, $logoTooltip = null, $valueSuffix = null)
+    {
+        $this->id = $id;
+        $this->name = $name;
+        $this->value = $value;
+        $this->logo = $logo;
+        $this->logoLink = $logoLink;
+        $this->logoTooltip = $logoTooltip;
+        $this->valueSuffix = $valueSuffix;
+    }
+
+    /**
+     * @return string
+     */
+    public function getId()
+    {
+        return $this->id;
+    }
+
+    /**
+     * @return string
+     */
+    public function getName()
+    {
+        return $this->name;
+    }
+
+    /**
+     * @return string
+     */
+    public function getValue()
+    {
+        return $this->value;
+    }
+
+    /**
+     * @return string
+     */
+    public function getLogo()
+    {
+        return $this->logo;
+    }
+
+    /**
+     * @return string|null
+     */
+    public function getLogoLink()
+    {
+        return $this->logoLink;
+    }
+
+    /**
+     * @return string|null
+     */
+    public function getLogoTooltip()
+    {
+        return $this->logoTooltip;
+    }
+
+    /**
+     * @return null|string
+     */
+    public function getValueSuffix()
+    {
+        return $this->valueSuffix;
+    }
+
+    /**
+     * Allows the class to be serialized with var_export (in the cache).
+     *
+     * @param array $array
+     * @return Metric
+     */
+    public static function __set_state($array)
+    {
+        return new self(
+            $array['id'],
+            $array['name'],
+            $array['value'],
+            $array['logo'],
+            $array['logoLink'],
+            $array['logoTooltip'],
+            $array['valueSuffix']
+        );
+    }
+}
diff --git a/plugins/SEO/Metric/MetricsProvider.php b/plugins/SEO/Metric/MetricsProvider.php
new file mode 100644
index 0000000000..c737efb928
--- /dev/null
+++ b/plugins/SEO/Metric/MetricsProvider.php
@@ -0,0 +1,21 @@
+<?php
+/**
+ * Piwik - free/libre analytics platform
+ *
+ * @link http://piwik.org
+ * @license http://www.gnu.org/licenses/gpl-3.0.html GPL v3 or later
+ */
+
+namespace Piwik\Plugins\SEO\Metric;
+
+/**
+ * Provides SEO metrics for a domain.
+ */
+interface MetricsProvider
+{
+    /**
+     * @param string $domain
+     * @return Metric[]
+     */
+    public function getMetrics($domain);
+}
diff --git a/plugins/SEO/Metric/ProviderCache.php b/plugins/SEO/Metric/ProviderCache.php
new file mode 100644
index 0000000000..cb03063281
--- /dev/null
+++ b/plugins/SEO/Metric/ProviderCache.php
@@ -0,0 +1,48 @@
+<?php
+/**
+ * Piwik - free/libre analytics platform
+ *
+ * @link http://piwik.org
+ * @license http://www.gnu.org/licenses/gpl-3.0.html GPL v3 or later
+ */
+
+namespace Piwik\Plugins\SEO\Metric;
+
+use Piwik\Cache;
+
+/**
+ * Caches another provider.
+ */
+class ProviderCache implements MetricsProvider
+{
+    /**
+     * @var MetricsProvider
+     */
+    private $provider;
+
+    /**
+     * @var Cache\Lazy
+     */
+    private $cache;
+
+    public function __construct(MetricsProvider $provider)
+    {
+        $this->provider = $provider;
+        $this->cache = Cache::getLazyCache();
+    }
+
+    public function getMetrics($domain)
+    {
+        $cacheId = 'SEO_getRank_' . md5($domain);
+
+        $metrics = $this->cache->fetch($cacheId);
+
+        if (! is_array($metrics)) {
+            $metrics = $this->provider->getMetrics($domain);
+
+            $this->cache->save($cacheId, $metrics, 60 * 60 * 6);
+        }
+
+        return $metrics;
+    }
+}
diff --git a/plugins/SEO/RankChecker.php b/plugins/SEO/RankChecker.php
deleted file mode 100644
index 655c434fc9..0000000000
--- a/plugins/SEO/RankChecker.php
+++ /dev/null
@@ -1,378 +0,0 @@
-<?php
-/**
- * Piwik - free/libre analytics platform
- *
- * @link http://piwik.org
- * @license http://www.gnu.org/licenses/gpl-3.0.html GPL v3 or later
- *
- */
-namespace Piwik\Plugins\SEO;
-
-use Exception;
-use Piwik\Http;
-use Piwik\Log;
-use Piwik\Metrics\Formatter;
-
-/**
- * The functions below are derived/adapted from GetRank.org's
- * Free PageRank Script v2.0, released under GPL.
- *
- * @copyright Copyright (C) 2007 - 2010 GetRank.Org  All rights reserved.
- * @link http://www.getrank.org/free-pagerank-script/
- * @license GPL
- */
-class RankChecker
-{
-    private $url;
-    private $majesticInfo = null;
-    private $formatter = null;
-
-    public function __construct($url)
-    {
-        $this->url = self::extractDomainFromUrl($url);
-        $this->formatter = new Formatter();
-    }
-
-    /**
-     * Extract domain from URL as the web services generally
-     * expect only a domain name (i.e., no protocol, port, path, query, etc).
-     *
-     * @param string $url
-     * @return string
-     */
-    public static function extractDomainFromUrl($url)
-    {
-        return preg_replace(
-            array(
-                 '~^https?\://~si', // strip protocol
-                 '~[/:#?;%&].*~', // strip port, path, query, anchor, etc
-                 '~\.$~', // trailing period
-            ),
-            '', $url);
-    }
-
-    /**
-     * Web service proxy that retrieves the content at the specified URL
-     *
-     * @param string $url
-     * @return string
-     */
-    private function getPage($url)
-    {
-        try {
-            return str_replace('&nbsp;', ' ', Http::sendHttpRequest($url, $timeout = 10, @$_SERVER['HTTP_USER_AGENT']));
-        } catch (Exception $e) {
-            return '';
-        }
-    }
-
-    /**
-     * Returns the google page rank for the current url
-     *
-     * @return int
-     */
-    public function getPageRank()
-    {
-        $chwrite = $this->CheckHash($this->HashURL($this->url));
-
-        $url = "http://toolbarqueries.google.com/tbr?client=navclient-auto&ch=" . $chwrite . "&features=Rank&q=info:" . $this->url . "&num=100&filter=0";
-        $data = $this->getPage($url);
-        preg_match('#Rank_[0-9]:[0-9]:([0-9]+){1,}#si', $data, $p);
-        $value = isset($p[1]) ? $p[1] : 0;
-
-        return $value;
-    }
-
-    /**
-     * Returns the alexa traffic rank for the current url
-     *
-     * @return int
-     */
-    public function getAlexaRank()
-    {
-        $xml = @simplexml_load_string($this->getPage('http://data.alexa.com/data?cli=10&url=' . urlencode($this->url)));
-        return $xml ? $xml->SD->POPULARITY['TEXT'] : '';
-    }
-
-    /**
-     * Returns the number of Dmoz.org entries for the current url
-     *
-     * @return int
-     */
-    public function getDmoz()
-    {
-        $url = 'http://www.dmoz.org/search?q=' . urlencode($this->url);
-        $data = $this->getPage($url);
-        preg_match('#Open Directory Sites[^\(]+\([0-9]-[0-9]+ of ([0-9]+)\)#', $data, $p);
-        if (!empty($p[1])) {
-            return (int)$p[1];
-        }
-        return 0;
-    }
-
-    /**
-     * Returns the number of pages google holds in it's index for the current url
-     *
-     * @return int
-     */
-    public function getIndexedPagesGoogle()
-    {
-        $url = 'http://www.google.com/search?hl=en&q=site%3A' . urlencode($this->url);
-        $data = $this->getPage($url);
-        if (preg_match('#([0-9\,]+) results#i', $data, $p)) {
-            $indexedPages = (int)str_replace(',', '', $p[1]);
-            return $indexedPages;
-        }
-        return 0;
-    }
-
-    /**
-     * Returns the number of pages bing holds in it's index for the current url
-     *
-     * @return int
-     */
-    public function getIndexedPagesBing()
-    {
-        $url = 'http://www.bing.com/search?mkt=en-US&q=site%3A' . urlencode($this->url);
-        $data = $this->getPage($url);
-        if (preg_match('#([0-9\,]+) results#i', $data, $p)) {
-            return (int)str_replace(',', '', $p[1]);
-        }
-        return 0;
-    }
-
-    /**
-     * Returns the domain age for the current url
-     *
-     * @return int
-     */
-    public function getAge()
-    {
-        $ageArchiveOrg = $this->_getAgeArchiveOrg();
-        $ageWhoIs = $this->_getAgeWhoIs();
-        $ageWhoisCom = $this->_getAgeWhoisCom();
-
-        $ages = array();
-
-        if ($ageArchiveOrg > 0) {
-            $ages[] = $ageArchiveOrg;
-        }
-
-        if ($ageWhoIs > 0) {
-            $ages[] = $ageWhoIs;
-        }
-
-        if ($ageWhoisCom > 0) {
-            $ages[] = $ageWhoisCom;
-        }
-
-        if (count($ages) > 1) {
-            $maxAge = min($ages);
-        } else {
-            $maxAge = array_shift($ages);
-        }
-
-        if ($maxAge) {
-            return $this->formatter->getPrettyTimeFromSeconds(time() - $maxAge, true);
-        }
-        return false;
-    }
-
-    /**
-     * Returns the number backlinks that link to the current site.
-     *
-     * @return int
-     */
-    public function getExternalBacklinkCount()
-    {
-        try {
-            $majesticInfo = $this->getMajesticInfo();
-            return $majesticInfo['backlink_count'];
-        } catch (Exception $e) {
-            Log::info($e);
-            return 0;
-        }
-    }
-
-    /**
-     * Returns the number of referrer domains that link to the current site.
-     *
-     * @return int
-     */
-    public function getReferrerDomainCount()
-    {
-        try {
-            $majesticInfo = $this->getMajesticInfo();
-            return $majesticInfo['referrer_domains_count'];
-        } catch (Exception $e) {
-            Log::info($e);
-            return 0;
-        }
-    }
-
-    /**
-     * Returns the domain age archive.org lists for the current url
-     *
-     * @return int
-     */
-    protected function _getAgeArchiveOrg()
-    {
-        $url = str_replace('www.', '', $this->url);
-        $data = @$this->getPage('http://wayback.archive.org/web/*/' . urlencode($url));
-        preg_match('#<a href=\"([^>]*)' . preg_quote($url) . '/\">([^<]*)<\/a>#', $data, $p);
-        if (!empty($p[2])) {
-            $value = strtotime($p[2]);
-            if ($value === false) {
-                return 0;
-            }
-            return $value;
-        }
-        return 0;
-    }
-
-    /**
-     * Returns the domain age who.is lists for the current url
-     *
-     * @return int
-     */
-    protected function _getAgeWhoIs()
-    {
-        $url = preg_replace('/^www\./', '', $this->url);
-        $url = 'http://www.who.is/whois/' . urlencode($url);
-        $data = $this->getPage($url);
-        preg_match('#(?:Creation Date|Created On|created|Registered on)\.*:\s*([ \ta-z0-9\/\-:\.]+)#si', $data, $p);
-        if (!empty($p[1])) {
-            $value = strtotime(trim($p[1]));
-            if ($value === false) {
-                return 0;
-            }
-            return $value;
-        }
-        return 0;
-    }
-
-    /**
-     * Returns the domain age whois.com lists for the current url
-     *
-     * @return int
-     */
-    protected function _getAgeWhoisCom()
-    {
-        $url = preg_replace('/^www\./', '', $this->url);
-        $url = 'http://www.whois.com/whois/' . urlencode($url);
-        $data = $this->getPage($url);
-        preg_match('#(?:Creation Date|Created On|created):\s*([ \ta-z0-9\/\-:\.]+)#si', $data, $p);
-        if (!empty($p[1])) {
-            $value = strtotime(trim($p[1]));
-            if ($value === false) {
-                return 0;
-            }
-            return $value;
-        }
-        return 0;
-    }
-
-    /**
-     * Convert numeric string to int
-     *
-     * @see getPageRank()
-     *
-     * @param string $Str
-     * @param int $Check
-     * @param int $Magic
-     * @return int
-     */
-    private function StrToNum($Str, $Check, $Magic)
-    {
-        $Int32Unit = 4294967296; // 2^32
-
-        $length = strlen($Str);
-        for ($i = 0; $i < $length; $i++) {
-            $Check *= $Magic;
-            // If the float is beyond the boundaries of integer (usually +/- 2.15e+9 = 2^31),
-            // the result of converting to integer is undefined
-            // refer to http://www.php.net/manual/en/language.types.integer.php
-            if ($Check >= $Int32Unit) {
-                $Check = ($Check - $Int32Unit * (int)($Check / $Int32Unit));
-                //if the check less than -2^31
-                $Check = ($Check < -2147483648) ? ($Check + $Int32Unit) : $Check;
-            }
-            $Check += ord($Str{$i});
-        }
-        return $Check;
-    }
-
-    /**
-     * Generate a hash for a url
-     *
-     * @see getPageRank()
-     *
-     * @param string $String
-     * @return int
-     */
-    private function HashURL($String)
-    {
-        $Check1 = $this->StrToNum($String, 0x1505, 0x21);
-        $Check2 = $this->StrToNum($String, 0, 0x1003F);
-
-        $Check1 >>= 2;
-        $Check1 = (($Check1 >> 4) & 0x3FFFFC0) | ($Check1 & 0x3F);
-        $Check1 = (($Check1 >> 4) & 0x3FFC00) | ($Check1 & 0x3FF);
-        $Check1 = (($Check1 >> 4) & 0x3C000) | ($Check1 & 0x3FFF);
-
-        $T1 = (((($Check1 & 0x3C0) << 4) | ($Check1 & 0x3C)) << 2) | ($Check2 & 0xF0F);
-        $T2 = (((($Check1 & 0xFFFFC000) << 4) | ($Check1 & 0x3C00)) << 0xA) | ($Check2 & 0xF0F0000);
-
-        return ($T1 | $T2);
-    }
-
-    /**
-     * Generate a checksum for the hash string
-     *
-     * @see getPageRank()
-     *
-     * @param int $Hashnum
-     * @return string
-     */
-    private function CheckHash($Hashnum)
-    {
-        $CheckByte = 0;
-        $Flag = 0;
-
-        $HashStr = sprintf('%u', $Hashnum);
-        $length = strlen($HashStr);
-
-        for ($i = $length - 1; $i >= 0; $i--) {
-            $Re = $HashStr{$i};
-            if (1 === ($Flag % 2)) {
-                $Re += $Re;
-                $Re = (int)($Re / 10) + ($Re % 10);
-            }
-            $CheckByte += $Re;
-            $Flag++;
-        }
-
-        $CheckByte %= 10;
-        if (0 !== $CheckByte) {
-            $CheckByte = 10 - $CheckByte;
-            if (1 === ($Flag % 2)) {
-                if (1 === ($CheckByte % 2)) {
-                    $CheckByte += 9;
-                }
-                $CheckByte >>= 1;
-            }
-        }
-
-        return '7' . $CheckByte . $HashStr;
-    }
-
-    private function getMajesticInfo()
-    {
-        if ($this->majesticInfo === null) {
-            $client = new MajesticClient();
-            $this->majesticInfo = $client->getBacklinkStats($this->url);
-        }
-
-        return $this->majesticInfo;
-    }
-}
diff --git a/plugins/SEO/Widgets.php b/plugins/SEO/Widgets.php
index bf2e95e0a7..1f06c2ec8b 100644
--- a/plugins/SEO/Widgets.php
+++ b/plugins/SEO/Widgets.php
@@ -11,6 +11,7 @@ namespace Piwik\Plugins\SEO;
 use Piwik\Common;
 use Piwik\DataTable\Renderer;
 use Piwik\Site;
+use Piwik\Url;
 use Piwik\UrlHelper;
 use Piwik\View;
 
@@ -41,7 +42,7 @@ class Widgets extends \Piwik\Plugin\Widgets
         $dataTable = API::getInstance()->getRank($url);
 
         $view = new View('@SEO/getRank');
-        $view->urlToRank = RankChecker::extractDomainFromUrl($url);
+        $view->urlToRank = Url::getHostFromUrl($url);
 
         /** @var \Piwik\DataTable\Renderer\Php $renderer */
         $renderer = Renderer::factory('php');
diff --git a/plugins/SEO/templates/getRank.twig b/plugins/SEO/templates/getRank.twig
index 5233fc82ea..80bf40ef7b 100644
--- a/plugins/SEO/templates/getRank.twig
+++ b/plugins/SEO/templates/getRank.twig
@@ -22,25 +22,24 @@
                 {% endset %}
                 {{ 'SEO_SEORankingsFor'|translate(cleanUrl)|raw }}
                 <table cellspacing="2" style="margin:auto;line-height:1.5em;padding-top:10px;">
+
                     {% for rank in ranks %}
                         <tr>
-{% set seoLink %}{% if rank.logo_link is defined %}<a class="linkContent" href="?module=Proxy&action=redirect&url={{ rank.logo_link|url_encode }}"
+{% set seoLink %}{% if rank.logo_link is not empty %}<a class="linkContent" href="?module=Proxy&action=redirect&url={{ rank.logo_link|url_encode }}"
                                                     target="_blank"
                          {% if rank.logo_tooltip is not empty %}title="{{ rank.logo_tooltip }}"{% endif %}>{% endif %}{% endset %}
                             {% set majesticLink %}{{ seoLink }}Majestic</a>{% endset %}
-                            <td>{% if rank.logo_link is defined %}{{ seoLink|raw }}{% endif %}<img
+                            <td>{% if rank.logo_link is not empty %}{{ seoLink|raw }}{% endif %}<img
                                             style='vertical-align:middle;margin-right:6px;' src='{{ rank.logo }}' border='0'
-                                            alt="{{ rank.label }}">{% if rank.logo_link is defined %}</a>{% endif %} {{ rank.label|replace({"Majestic":
+                                            alt="{{ rank.label }}">{% if rank.logo_link is not empty %}</a>{% endif %} {{ rank.label|replace({"Majestic":
                                 majesticLink})|raw }}
                             </td>
                             <td>
                                 <div style="margin-left:15px;">
-                                {% if rank.logo_link is defined %}{{ seoLink|raw }}{% endif %}
+                                {% if rank.logo_link is not empty %}{{ seoLink|raw }}{% endif %}
                                     {% if rank.rank %}{{ rank.rank|raw }}{% else %}-{% endif %}
-                                    {% if rank.id=='pagerank' %} /10
-                                    {% elseif rank.id=='google-index' or rank.id=='bing-index' %} {{ 'General_Pages'|translate }}
-                                    {% endif %}
-                                {% if rank.logo_link is defined %}</a>{% endif %}
+                                    {{ rank.rank_suffix }}
+                                {% if rank.logo_link is not empty %}</a>{% endif %}
                                 </div>
                             </td>
                         </tr>