remove pubsubhubbub: dead

12 files changed, 4 insertions, 567 deletions

diff --git a/classes/api.php b/classes/api.php
index 220d37981..0176e1672 100644
--- a/classes/api.php
+++ b/classes/api.php
@@ -301,17 +301,6 @@ class API extends Handler {
 				}
 			}
 
-			if ($num_updated > 0 && $field == "published") {
-				if (PUBSUBHUBBUB_HUB) {
-					$rss_link = get_self_url_prefix() .
-						"/public.php?op=rss&id=-2&key=" .
-						get_feed_access_key(-2, false);
-
-					$p = new pubsubhubbub\publisher\Publisher(PUBSUBHUBBUB_HUB);
-					$p->publish_update($rss_link);
-				}
-			}
-
 			$this->wrap(self::STATUS_OK, array("status" => "OK",
 				"updated" => $num_updated));
 
diff --git a/classes/handler/public.php b/classes/handler/public.php
index d525bc54c..403e20ca5 100644
--- a/classes/handler/public.php
+++ b/classes/handler/public.php
@@ -105,11 +105,6 @@ class Handler_Public extends Handler {
 			$tpl->setVariable('VERSION', VERSION, true);
 			$tpl->setVariable('FEED_URL', htmlspecialchars($feed_self_url), true);
 
-			if (PUBSUBHUBBUB_HUB && $feed == -2) {
-				$tpl->setVariable('HUB_URL', htmlspecialchars(PUBSUBHUBBUB_HUB), true);
-				$tpl->addBlock('feed_hub');
-			}
-
 			$tpl->setVariable('SELF_URL', htmlspecialchars(get_self_url_prefix()), true);
 			while ($line = $this->dbh->fetch_assoc($result)) {
 
@@ -195,10 +190,6 @@ class Handler_Public extends Handler {
 			$feed['version'] = VERSION;
 			$feed['feed_url'] = $feed_self_url;
 
-			if (PUBSUBHUBBUB_HUB && $feed == -2) {
-				$feed['hub_url'] = PUBSUBHUBBUB_HUB;
-			}
-
 			$feed['self_url'] = get_self_url_prefix();
 
 			$feed['articles'] = array();
@@ -305,71 +296,6 @@ class Handler_Public extends Handler {
 		print "</select>";
 	}
 
-	function pubsub() {
-		$mode = $this->dbh->escape_string($_REQUEST['hub_mode']);
-		if (!$mode) $mode = $this->dbh->escape_string($_REQUEST['hub.mode']);
-
-		$feed_id = (int) $this->dbh->escape_string($_REQUEST['id']);
-		$feed_url = $this->dbh->escape_string($_REQUEST['hub_topic']);
-
-		if (!$feed_url) $feed_url = $this->dbh->escape_string($_REQUEST['hub.topic']);
-
-		if (!PUBSUBHUBBUB_ENABLED) {
-			header('HTTP/1.0 404 Not Found');
-			echo "404 Not found (Disabled by server)";
-			return;
-		}
-
-		// TODO: implement hub_verifytoken checking
-		// TODO: store requested rel=self or whatever for verification
-		// (may be different from stored feed url) e.g. http://url/ or http://url
-
-		$result = $this->dbh->query("SELECT feed_url FROM ttrss_feeds
-			WHERE id = '$feed_id'");
-
-		if ($this->dbh->num_rows($result) != 0) {
-
-			$check_feed_url = $this->dbh->fetch_result($result, 0, "feed_url");
-
-			// ignore url checking for the time being
-			if ($check_feed_url && (true || $check_feed_url == $feed_url || !$feed_url)) {
-				if ($mode == "subscribe") {
-
-					$this->dbh->query("UPDATE ttrss_feeds SET pubsub_state = 2
-						WHERE id = '$feed_id'");
-
-					print $_REQUEST['hub_challenge'];
-					return;
-
-				} else if ($mode == "unsubscribe") {
-
-					$this->dbh->query("UPDATE ttrss_feeds SET pubsub_state = 0
-						WHERE id = '$feed_id'");
-
-					print $_REQUEST['hub_challenge'];
-					return;
-
-				} else if (!$mode) {
-
-					// Received update ping, schedule feed update.
-					//update_rss_feed($feed_id, true, true);
-
-					$this->dbh->query("UPDATE ttrss_feeds SET
-						last_update_started = '1970-01-01',
-						last_updated = '1970-01-01' WHERE id = '$feed_id'");
-
-				}
-			} else {
-				header('HTTP/1.0 404 Not Found');
-				echo "404 Not found (URL check failed)";
-			}
-		} else {
-			header('HTTP/1.0 404 Not Found');
-			echo "404 Not found (Feed not found)";
-		}
-
-	}
-
 	function logout() {
 		logout_user();
 		header("Location: index.php");
diff --git a/classes/pref/feeds.php b/classes/pref/feeds.php
index 002d56aeb..785451707 100755
--- a/classes/pref/feeds.php
+++ b/classes/pref/feeds.php
@@ -784,20 +784,8 @@ class Pref_Feeds extends Handler_Protected {
 			<button class=\"danger\" dojoType=\"dijit.form.Button\" onclick='return unsubscribeFeed($feed_id, \"$title\")'>".
 				__('Unsubscribe')."</button>";
 
-		if (PUBSUBHUBBUB_ENABLED) {
-			$pubsub_state = $this->dbh->fetch_result($result, 0, "pubsub_state");
-			$pubsub_btn_disabled = ($pubsub_state == 2) ? "" : "disabled=\"1\"";
-
-			print "<button dojoType=\"dijit.form.Button\" id=\"pubsubReset_Btn\" $pubsub_btn_disabled
-					onclick='return resetPubSub($feed_id, \"$title\")'>".__('Resubscribe to push updates').
-					"</button>";
-		}
-
 		print "</div>";
 
-		print "<div dojoType=\"dijit.Tooltip\" connectId=\"pubsubReset_Btn\" position=\"below\">".
-			__('Resets PubSubHubbub subscription status for push-enabled feeds.')."</div>";
-
 		print "<button dojoType=\"dijit.form.Button\" onclick=\"return dijit.byId('feedEditDlg').execute()\">".__('Save')."</button>
 			<button dojoType=\"dijit.form.Button\" onclick=\"return dijit.byId('feedEditDlg').hide()\">".__('Cancel')."</button>
 		</div>";
@@ -1118,16 +1106,6 @@ class Pref_Feeds extends Handler_Protected {
 		return;
 	}
 
-	function resetPubSub() {
-
-		$ids = $this->dbh->escape_string($_REQUEST["ids"]);
-
-		$this->dbh->query("UPDATE ttrss_feeds SET pubsub_state = 0 WHERE id IN ($ids)
-			AND owner_uid = " . $_SESSION["uid"]);
-
-		return;
-	}
-
 	function remove() {
 
 		$ids = explode(",", $this->dbh->escape_string($_REQUEST["ids"]));
diff --git a/classes/rpc.php b/classes/rpc.php
index 70ee423af..7d39261b1 100755
--- a/classes/rpc.php
+++ b/classes/rpc.php
@@ -274,20 +274,7 @@ class RPC extends Handler_Protected {
 			published = $pub, last_published = NOW()
 			WHERE ref_id = '$id' AND owner_uid = " . $_SESSION["uid"]);
 
-		$pubsub_result = false;
-
-		if (PUBSUBHUBBUB_HUB) {
-			$rss_link = get_self_url_prefix() .
-				"/public.php?op=rss&id=-2&key=" .
-				get_feed_access_key(-2, false);
-
-			$p = new pubsubhubbub\publisher\Publisher(PUBSUBHUBBUB_HUB);
-
-			$pubsub_result = $p->publish_update($rss_link);
-		}
-
-		print json_encode(array("message" => "UPDATE_COUNTERS",
-			"pubsub_result" => $pubsub_result));
+		print json_encode(array("message" => "UPDATE_COUNTERS"));
 	}
 
 	function getAllCounters() {
@@ -618,16 +605,6 @@ class RPC extends Handler_Protected {
 			published = NOT published,last_published = NOW()
 			WHERE ($ids_qpart) AND owner_uid = " . $_SESSION["uid"]);
 		}
-
-		if (PUBSUBHUBBUB_HUB) {
-			$rss_link = get_self_url_prefix() .
-				"/public.php?op=rss&id=-2&key=" .
-				get_feed_access_key(-2, false);
-
-			$p = new pubsubhubbub\publisher\Publisher(PUBSUBHUBBUB_HUB);
-
-			/* $pubsub_result = */ $p->publish_update($rss_link);
-		}
 	}
 
 	function getlinktitlebyid() {
diff --git a/classes/rssutils.php b/classes/rssutils.php
index 1c8846e4e..e6fe39592 100644
--- a/classes/rssutils.php
+++ b/classes/rssutils.php
@@ -310,14 +310,12 @@ class RSSUtils {
 		$result = db_query("SELECT id,update_interval,auth_login,
 			feed_url,auth_pass,cache_images,
 			mark_unread_on_update, owner_uid,
-			pubsub_state, auth_pass_encrypted,
-			feed_language
+			auth_pass_encrypted, feed_language
 			FROM ttrss_feeds WHERE id = '$feed'");
 
 		$owner_uid = db_fetch_result($result, 0, "owner_uid");
 		$mark_unread_on_update = sql_bool_to_bool(db_fetch_result($result,
 			0, "mark_unread_on_update"));
-		$pubsub_state = db_fetch_result($result, 0, "pubsub_state");
 		$auth_pass_encrypted = sql_bool_to_bool(db_fetch_result($result,
 			0, "auth_pass_encrypted"));
 
@@ -530,55 +528,6 @@ class RSSUtils {
 				return; // no articles
 			}
 
-			if ($pubsub_state != 2 && PUBSUBHUBBUB_ENABLED) {
-
-				_debug("checking for PUSH hub...", $debug_enabled);
-
-				$feed_hub_url = false;
-
-				$links = $rss->get_links('hub');
-
-				if ($links && is_array($links)) {
-					foreach ($links as $l) {
-						$feed_hub_url = $l;
-						break;
-					}
-				}
-
-				_debug("feed hub url: $feed_hub_url", $debug_enabled);
-
-				$feed_self_url = $fetch_url;
-
-				$links = $rss->get_links('self');
-
-				if ($links && is_array($links)) {
-					foreach ($links as $l) {
-						$feed_self_url = $l;
-						break;
-					}
-				}
-
-				_debug("feed self url = $feed_self_url");
-
-				if ($feed_hub_url && $feed_self_url && function_exists('curl_init') &&
-					!ini_get("open_basedir")) {
-
-					require_once 'lib/pubsubhubbub/Subscriber.php';
-
-					$callback_url = get_self_url_prefix() .
-						"/public.php?op=pubsub&id=$feed";
-
-					$s = new Pubsubhubbub\Subscriber\Subscriber($feed_hub_url, $callback_url);
-
-					$rc = $s->subscribe($feed_self_url);
-
-					_debug("feed hub url found, subscribe request sent. [rc=$rc]", $debug_enabled);
-
-					db_query("UPDATE ttrss_feeds SET pubsub_state = 1
-						WHERE id = '$feed'");
-				}
-			}
-
 			_debug("processing articles...", $debug_enabled);
 
 			$tstart = time();
@@ -960,16 +909,6 @@ class RSSUtils {
 								$last_read_qpart, $marked, $published, '$score', '', '',
 								'', $last_marked, $last_published)");
 
-						if (PUBSUBHUBBUB_HUB && $published == 'true') {
-							$rss_link = get_self_url_prefix() .
-								"/public.php?op=rss&id=-2&key=" .
-								get_feed_access_key(-2, false, $owner_uid);
-
-							$p = new pubsubhubbub\publisher\Publisher(PUBSUBHUBBUB_HUB);
-
-							/* $pubsub_result = */ $p->publish_update($rss_link);
-						}
-
 						$result = db_query(
 							"SELECT int_id FROM ttrss_user_entries WHERE
 								ref_id = '$ref_id' AND owner_uid = '$owner_uid' AND
diff --git a/config.php-dist b/config.php-dist
index c86af943b..38a56f115 100644
--- a/config.php-dist
+++ b/config.php-dist
@@ -99,16 +99,6 @@
 	// intervals is disabled and all articles (which are not starred) 
 	// older than this amount of days are purged.
 
-	// *** PubSubHubbub settings ***
-
-	define('PUBSUBHUBBUB_HUB', '');
-	// URL to a PubSubHubbub-compatible hub server. If defined, "Published
-	// articles" generated feed would automatically become PUSH-enabled.
-
-	define('PUBSUBHUBBUB_ENABLED', false);
-	// Enable client PubSubHubbub support in tt-rss. When disabled, tt-rss
-	// won't try to subscribe to PUSH feed updates.
-
 	// ****************************
 	// *** Sphinx search plugin ***
 	// ****************************
diff --git a/include/functions.php b/include/functions.php
index 3ea1035cb..a664212b2 100644
--- a/include/functions.php
+++ b/include/functions.php
@@ -145,8 +145,6 @@
 	define('SELF_USER_AGENT', 'Tiny Tiny RSS/' . VERSION . ' (http://tt-rss.org/)');
 	ini_set('user_agent', SELF_USER_AGENT);
 
-	require_once 'lib/pubsubhubbub/Publisher.php';
-
 	$schema_version = false;
 
 	function _debug_suppress($suppress) {
diff --git a/include/sanity_check.php b/include/sanity_check.php
index 12cc5579d..83ff36737 100755
--- a/include/sanity_check.php
+++ b/include/sanity_check.php
@@ -140,10 +140,6 @@
 				array_push($errors, "PHP safe mode setting is obsolete and not supported by tt-rss.");
 			}
 
-			if ((PUBSUBHUBBUB_HUB || PUBSUBHUBBUB_ENABLED) && !function_exists("curl_init")) {
-				array_push($errors, "PHP support for CURL is required for PubSubHubbub.");
-			}
-
 			if (!class_exists("DOMDocument")) {
 				array_push($errors, "PHP support for DOMDocument is required, but was not found.");
 			}
diff --git a/include/sanity_config.php b/include/sanity_config.php
index 797b74eda..0e9944361 100644
--- a/include/sanity_config.php
+++ b/include/sanity_config.php
@@ -1,3 +1,3 @@
-<?php # This file has been generated at:  Tue, Dec 1, 2015 10:11:18 AM
+<?php # This file has been generated at:  Tue, May 16, 2017 10:37:57 AM
 define('GENERATED_CONFIG_CHECK', 26);
-$requred_defines = array( 'DB_TYPE', 'DB_HOST', 'DB_USER', 'DB_NAME', 'DB_PASS', 'MYSQL_CHARSET', 'SELF_URL_PATH', 'FEED_CRYPT_KEY', 'SINGLE_USER_MODE', 'SIMPLE_UPDATE_MODE', 'PHP_EXECUTABLE', 'LOCK_DIRECTORY', 'CACHE_DIR', 'ICONS_DIR', 'ICONS_URL', 'AUTH_AUTO_CREATE', 'AUTH_AUTO_LOGIN', 'FORCE_ARTICLE_PURGE', 'PUBSUBHUBBUB_HUB', 'PUBSUBHUBBUB_ENABLED', 'SPHINX_SERVER', 'SPHINX_INDEX', 'ENABLE_REGISTRATION', 'REG_NOTIFY_ADDRESS', 'REG_MAX_USERS', 'SESSION_COOKIE_LIFETIME', 'SMTP_FROM_NAME', 'SMTP_FROM_ADDRESS', 'DIGEST_SUBJECT', 'SMTP_SERVER', 'SMTP_LOGIN', 'SMTP_PASSWORD', 'SMTP_SECURE', 'CHECK_FOR_UPDATES', 'ENABLE_GZIP_OUTPUT', 'PLUGINS', 'LOG_DESTINATION', 'CONFIG_VERSION'); ?>
+$requred_defines = array( 'DB_TYPE', 'DB_HOST', 'DB_USER', 'DB_NAME', 'DB_PASS', 'MYSQL_CHARSET', 'SELF_URL_PATH', 'FEED_CRYPT_KEY', 'SINGLE_USER_MODE', 'SIMPLE_UPDATE_MODE', 'PHP_EXECUTABLE', 'LOCK_DIRECTORY', 'CACHE_DIR', 'ICONS_DIR', 'ICONS_URL', 'AUTH_AUTO_CREATE', 'AUTH_AUTO_LOGIN', 'FORCE_ARTICLE_PURGE', 'SPHINX_SERVER', 'SPHINX_INDEX', 'ENABLE_REGISTRATION', 'REG_NOTIFY_ADDRESS', 'REG_MAX_USERS', 'SESSION_COOKIE_LIFETIME', 'SMTP_FROM_NAME', 'SMTP_FROM_ADDRESS', 'DIGEST_SUBJECT', 'SMTP_SERVER', 'SMTP_LOGIN', 'SMTP_PASSWORD', 'SMTP_SECURE', 'CHECK_FOR_UPDATES', 'ENABLE_GZIP_OUTPUT', 'PLUGINS', 'LOG_DESTINATION', 'CONFIG_VERSION'); ?>
diff --git a/js/functions.js b/js/functions.js
index b33c23dc1..934f69e96 100755
--- a/js/functions.js
+++ b/js/functions.js
@@ -1123,27 +1123,6 @@ function quickAddFilter() {
 
 }
 
-function resetPubSub(feed_id, title) {
-
-	var msg = __("Reset subscription? Tiny Tiny RSS will try to subscribe to the notification hub again on next feed update.").replace("%s", title);
-
-	if (title == undefined || confirm(msg)) {
-		notify_progress("Loading, please wait...");
-
-		var query = "?op=pref-feeds&quiet=1&method=resetPubSub&ids=" + feed_id;
-
-		new Ajax.Request("backend.php", {
-			parameters: query,
-			onComplete: function(transport) {
-				dijit.byId("pubsubReset_Btn").attr('disabled', true);
-				notify_info("Subscription reset.");
-			} });
-	}
-
-	return false;
-}
-
-
 function unsubscribeFeed(feed_id, title) {
 
 	var msg = __("Unsubscribe from %s?").replace("%s", title);
diff --git a/lib/pubsubhubbub/Publisher.php b/lib/pubsubhubbub/Publisher.php
deleted file mode 100644
index df7c1920e..000000000
--- a/lib/pubsubhubbub/Publisher.php
+++ /dev/null
@@ -1,125 +0,0 @@
-<?php
-/**
- * a PHP client library for pubsubhubbub.
- *
- * @link    https://github.com/pubsubhubbub/
- *
- * @author  Josh Fraser | joshfraser.com | [email protected]
- * @license Apache License 2.0
- */
-namespace pubsubhubbub\publisher;
-
-use InvalidArgumentException;
-
-class Publisher
-{
-    /**
-     * @var string
-     */
-    protected $hub_url;
-
-    /**
-     * @var string
-     */
-    protected $last_response;
-
-    /**
-     * Create a new Publisher.
-     *
-     * @param string $hub_url
-     */
-    public function __construct($hub_url)
-    {
-        if (! isset($hub_url)) {
-            throw new InvalidArgumentException('Please specify a hub url');
-        }
-
-        if (! preg_match('|^https?://|i', $hub_url)) {
-            throw new InvalidArgumentException('The specified hub url does not appear to be valid: ' . $hub_url);
-        }
-
-        $this->hub_url = $hub_url;
-    }
-
-    /**
-     * Accepts either a single url or an array of urls.
-     *
-     * @param string|array $topic_urls
-     * @param callable     $http_function
-     *
-     * @return mixed
-     */
-    public function publish_update($topic_urls, $http_function = false)
-    {
-        if (! isset($topic_urls)) {
-            throw new InvalidArgumentException('Please specify a topic url');
-        }
-
-        // check that we're working with an array
-        if (! is_array($topic_urls)) {
-            $topic_urls = [$topic_urls];
-        }
-
-        // set the mode to publish
-        $post_string = 'hub.mode=publish';
-        // loop through each topic url
-        foreach ($topic_urls as $topic_url) {
-
-            // lightweight check that we're actually working w/ a valid url
-            if (! preg_match('|^https?://|i', $topic_url)) {
-                throw new InvalidArgumentException('The specified topic url does not appear to be valid: ' . $topic_url);
-            }
-
-            // append the topic url parameters
-            $post_string .= '&hub.url=' . urlencode($topic_url);
-        }
-
-        // make the http post request and return true/false
-        // easy to over-write to use your own http function
-        if ($http_function) {
-            return $http_function($this->hub_url, $post_string);
-        }
-
-        return $this->http_post($this->hub_url, $post_string);
-    }
-
-    /**
-     * Returns any error message from the latest request.
-     *
-     * @return string
-     */
-    public function last_response()
-    {
-        return $this->last_response;
-    }
-
-    /**
-     * Default http function that uses curl to post to the hub endpoint.
-     *
-     * @param string $url
-     * @param string $post_string
-     *
-     * @return bool
-     */
-    private function http_post($url, $post_string)
-    {
-        // add any additional curl options here
-        $options = [
-            CURLOPT_URL        => $url,
-            CURLOPT_POST       => true,
-            CURLOPT_POSTFIELDS => $post_string,
-            CURLOPT_USERAGENT  => 'PubSubHubbub-Publisher-PHP/1.0',
-        ];
-
-        $ch = curl_init();
-        curl_setopt_array($ch, $options);
-
-        $response = curl_exec($ch);
-        $this->last_response = $response;
-        $info = curl_getinfo($ch);
-
-        curl_close($ch);
-
-        return $info['http_code'] == 204;
-    }
-}
diff --git a/lib/pubsubhubbub/Subscriber.php b/lib/pubsubhubbub/Subscriber.php
deleted file mode 100644
index 5b980a111..000000000
--- a/lib/pubsubhubbub/Subscriber.php
+++ /dev/null
@@ -1,210 +0,0 @@
-<?php
-/**
- * A PHP client library for pubsubhubbub.
- *
- * @link    http://code.google.com/p/pubsubhubbub/
- *
- * @author  Josh Fraser | joshfraser.com | [email protected]
- * @license Apache License 2.0
- */
-namespace Pubsubhubbub\Subscriber;
-
-use InvalidArgumentException;
-
-class Subscriber
-{
-    /**
-     * Put your google key here.
-     * Required if you want to use the google feed API to lookup RSS feeds.
-     *
-     * @var string
-     */
-    protected $google_key = '';
-
-    /**
-     * @var string
-     */
-    protected $hub_url;
-
-    /**
-     * @var string
-     */
-    protected $callback_url;
-
-    /**
-     * @var string
-     */
-    protected $credentials;
-
-    /**
-     * @var string accepted values are "async" and "sync"
-     */
-    protected $verify = 'async';
-
-    /**
-     * @var string
-     */
-    protected $verify_token;
-
-    /**
-     * @var string
-     */
-    protected $lease_seconds;
-
-    /**
-     * Create a new Subscriber (credentials added for SuperFeedr support).
-     *
-     * @param string $hub_url
-     * @param string $callback_url
-     * @param string $credentials
-     */
-    public function __construct($hub_url, $callback_url, $credentials = false)
-    {
-        if (! isset($hub_url)) {
-            throw new InvalidArgumentException('Please specify a hub url');
-        }
-
-        if (! preg_match('|^https?://|i', $hub_url)) {
-            throw new InvalidArgumentException('The specified hub url does not appear to be valid: ' . $hub_url);
-        }
-
-        if (! isset($callback_url)) {
-            throw new InvalidArgumentException('Please specify a callback');
-        }
-
-        $this->hub_url = $hub_url;
-        $this->callback_url = $callback_url;
-        $this->credentials = $credentials;
-    }
-
-    /**
-     * $use_regexp lets you choose whether to use google AJAX feed api (faster, but cached) or a regexp to read from site.
-     *
-     * @param string   $url
-     * @param callable $http_function
-     *
-     * @return string
-     */
-    public function find_feed($url, $http_function = false)
-    {
-        // using google feed API
-        $url = "http://ajax.googleapis.com/ajax/services/feed/lookup?key={$this->google_key}&v=1.0&q=" . urlencode($url);
-        // fetch the content
-        if ($http_function) {
-            $response = $http_function($url);
-        } else {
-            $response = $this->http($url);
-        }
-
-        $result = json_decode($response, true);
-        $rss_url = $result['responseData']['url'];
-
-        return $rss_url;
-    }
-
-    /**
-     * Subscribe to a topic.
-     *
-     * @param string   $topic_url
-     * @param callable $http_function
-     *
-     * @return mixed
-     */
-    public function subscribe($topic_url, $http_function = false)
-    {
-        return $this->change_subscription('subscribe', $topic_url, $http_function);
-    }
-
-    /**
-     * Unsubscribe from a topic.
-     *
-     * @param string   $topic_url
-     * @param callable $http_function
-     *
-     * @return mixed
-     */
-    public function unsubscribe($topic_url, $http_function = false)
-    {
-        return $this->change_subscription('unsubscribe', $topic_url, $http_function);
-    }
-
-    /**
-     * Helper function since sub/unsub are handled the same way.
-     *
-     * @param string   $mode
-     * @param string   $topic_url
-     * @param callable $http_function
-     *
-     * @return mixed
-     */
-    private function change_subscription($mode, $topic_url, $http_function = false)
-    {
-        if (! isset($topic_url)) {
-            throw new InvalidArgumentException('Please specify a topic url');
-        }
-
-        // lightweight check that we're actually working w/ a valid url
-        if (! preg_match('|^https?://|i', $topic_url)) {
-            throw new InvalidArgumentException('The specified topic url does not appear to be valid: ' . $topic_url);
-        }
-
-        // set the mode subscribe/unsubscribe
-        $post_string = 'hub.mode=' . $mode;
-        $post_string .= '&hub.callback=' . urlencode($this->callback_url);
-        $post_string .= '&hub.verify=' . $this->verify;
-        $post_string .= '&hub.verify_token=' . $this->verify_token;
-        $post_string .= '&hub.lease_seconds=' . $this->lease_seconds;
-
-        // append the topic url parameters
-        $post_string .= '&hub.topic=' . urlencode($topic_url);
-
-        // make the http post request and return true/false
-        // easy to over-write to use your own http function
-        if ($http_function) {
-            return call_user_func_array($http_function, [$this->hub_url, $post_string]);
-        }
-
-        return $this->http($this->hub_url, $post_string);
-    }
-
-    /**
-     * Default http function that uses curl to post to the hub endpoint.
-     *
-     * @param string $url
-     * @param string $post_string
-     *
-     * @return mixed
-     */
-    private function http($url, $post_string)
-    {
-
-        // add any additional curl options here
-        $options = [
-            CURLOPT_URL            => $url,
-            CURLOPT_USERAGENT      => 'PubSubHubbub-Subscriber-PHP/1.0',
-            CURLOPT_RETURNTRANSFER => true,
-        ];
-
-        if ($post_string) {
-            $options[CURLOPT_POST] = true;
-            $options[CURLOPT_POSTFIELDS] = $post_string;
-        }
-
-        if ($this->credentials) {
-            $options[CURLOPT_USERPWD] = $this->credentials;
-        }
-
-        $ch = curl_init();
-        curl_setopt_array($ch, $options);
-
-        $response = curl_exec($ch);
-        $info = curl_getinfo($ch);
-
-        // all good -- anything in the 200 range
-        if (substr($info['http_code'], 0, 1) == '2') {
-            return $response;
-        }
-
-        return false;
-    }
-}