init.php

<?php
class mercury_fulltext extends Plugin
{
    private $host;
    
    public function about()
    {
        return array(
            2.0,
            "Try to get fulltext of the article using Self-hosted Mercury Parser API",
            "https://github.com/HenryQW/mercury_fulltext/"
        );
    }
    public function flags()
    {
        return array(
            "needs_curl" => true
        );
    }
    public function save()
    {
        $this
            ->host
            ->set($this, "mercury_API", $_POST["mercury_API"]);
        echo __("Your self-hosted Mercury Parser API Endpoint.");
    }
    public function init($host)
    {
        $this->host = $host;
        
        if (version_compare(PHP_VERSION, '5.6.0', '<')) {
            return;
        }

        $host->add_hook($host::HOOK_ARTICLE_FILTER, $this);
        $host->add_hook($host::HOOK_PREFS_TAB, $this);
        $host->add_hook($host::HOOK_PREFS_EDIT_FEED, $this);
        $host->add_hook($host::HOOK_PREFS_SAVE_FEED, $this);

        $host->add_hook($host::HOOK_ARTICLE_BUTTON, $this);
        
        $host->add_filter_action($this, "mercury_fulltext", __("Mercury Fulltext"));
    }

    public function get_js()
    {
        return file_get_contents(__DIR__ . "/init.js");
    }

    public function hook_article_button($line)
    {
        return "<i class='material-icons'
			style='cursor : pointer' onclick='Plugins.mercury_fulltext.extract(".$line["id"].")'
			title='".__('Extract fulltext via Mercury')."'>subject</i>";
    }


    public function hook_prefs_tab($args)
    {
        if ($args != "prefFeeds") {
            return;
        }

        print "<div dojoType='dijit.layout.AccordionPane' 
            title=\"<i class='material-icons'>extension</i> ".__('Mercury Fulltext settings (mercury_fulltext)')."\">";

        if (version_compare(PHP_VERSION, '7.0.0', '<')) {
            print_error("This plugin requires PHP 7.0.");
        } else {
            print "<h2>" . __("Per feed auto-extraction") . "</h2>";

            print_notice("Enable for specific feeds in the feed editor.");

            print "<form dojoType='dijit.form.Form'>";

            print "<script type='dojo/method' event='onSubmit' args='evt'>
                evt.preventDefault();
                if (this.validate()) {
                xhrPost(\"backend.php\", this.getValues(), (transport) => {
                            Notify.info(transport.responseText);
                        })
                }
                </script>";

            print \Controls\hidden_tag("op", "pluginhandler");
            print \Controls\hidden_tag("method", "save");
            print \Controls\hidden_tag("plugin", "mercury_fulltext");

            $mercury_API = $this
                ->host
                ->get($this, "mercury_API");

            print "<input dojoType='dijit.form.ValidationTextBox' required='1' name='mercury_API' value='$mercury_API'/>";

            print "&nbsp;<label for='mercury_API'>" . __("Your self-hosted Mercury Parser API address (including the port number), eg https://mercury.parser.com:3000.") . "</label>";

            print "<p>Read the <a href='http://ttrss.henry.wang/#mercury-fulltext-extraction'>documents</a>.</p>";
            print "<button dojoType=\"dijit.form.Button\" type=\"submit\" class=\"alt-primary\">".__('Save')."</button>";
            print "</form>";

            $enabled_feeds = $this
                ->host
                ->get($this, "enabled_feeds");

            if (!is_array($enabled_feeds)) {
                $enabled_feeds = array();
            }

            $enabled_feeds = $this->filter_unknown_feeds($enabled_feeds);

            $this
                ->host
                ->set($this, "enabled_feeds", $enabled_feeds);

            if (count($enabled_feeds) > 0) {
                print "<h3>" . __("Currently enabled for (click to edit):") . "</h3>";

                print "<ul class='panel panel-scrollable list list-unstyled'>";

                foreach ($enabled_feeds as $f) {
                    print "<li><i class='material-icons'>rss_feed</i> <a href='#'
                        onclick='CommonDialogs.editFeed($f)'>".
                        Feeds::_get_title($f) . "</a></li>";

                }

                print "</ul>";
            }
        }
        print "</div>";
    }

    public function hook_prefs_edit_feed($feed_id)
    {
        print "<header>".__("Mercury Fulltext")."</header>";
        print "<section>";
        
        $enabled_feeds = $this
            ->host
            ->get($this, "enabled_feeds");
        if (!is_array($enabled_feeds)) {
            $enabled_feeds = array();
        }
        
        $key = array_search($feed_id, $enabled_feeds);
        $checked = $key !== false ? "checked" : "";

        print "<fieldset>";
        
        print "<label class='checkbox'><input dojoType='dijit.form.CheckBox' type='checkbox' id='mercury_fulltext_enabled' name='mercury_fulltext_enabled' $checked>&nbsp;" . __('Get fulltext via Mercury Parser') . "</label>";

        print "</fieldset>";

        print "</section>";
    }

    public function hook_prefs_save_feed($feed_id)
    {
        $enabled_feeds = $this
            ->host
            ->get($this, "enabled_feeds");
            
        if (!is_array($enabled_feeds)) {
            $enabled_feeds = array();
        }
        
        $enable = checkbox_to_sql_bool($_POST["mercury_fulltext_enabled"]);
        
        $key = array_search($feed_id, $enabled_feeds);
        
        if ($enable) {
            if ($key === false) {
                array_push($enabled_feeds, $feed_id);
            }
        } else {
            if ($key !== false) {
                unset($enabled_feeds[$key]);
            }
        }

        $this
            ->host
            ->set($this, "enabled_feeds", $enabled_feeds);
    }

    /**
     * @SuppressWarnings(PHPMD.UnusedFormalParameter)
     */
    public function hook_article_filter_action($article, $action)
    {
        return $this->process_article($article);
    }

    public function send_request($link)
    {
        $ch = curl_init();
        
        $api_endpoint = $this
            ->host
            ->get($this, "mercury_API");
            
        curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
        curl_setopt($ch, CURLOPT_URL, rtrim($api_endpoint, '/') . '/parser?url=' . rawurlencode($link));
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
        curl_setopt($ch, CURLOPT_ENCODING, "UTF-8");
        
        $output = json_decode(curl_exec($ch));
        
        curl_close($ch);
        
        return $output;
    }
    
    public function process_article($article)
    {
        $output  = $this->send_request($article["link"]);

        if ($output->content) {
            $article["content"] = $output->content;
        }

        return $article;
    }

    public function hook_article_filter($article)
    {
        $enabled_feeds = $this
            ->host
            ->get($this, "enabled_feeds");
            
        if (!is_array($enabled_feeds)) {
            return $article;
        }
        
        $key = array_search($article["feed"]["id"], $enabled_feeds);
        
        if ($key === false) {
            return $article;
        }
        
        return $this->process_article($article);
    }

    public function api_version()
    {
        return 2;
    }

    private function filter_unknown_feeds($enabled_feeds)
    {
        $tmp = array();
        
        foreach ($enabled_feeds as $feed) {
            $sth = $this
                ->pdo
                ->prepare("SELECT id FROM ttrss_feeds WHERE id = ? AND owner_uid = ?");
            $sth->execute([$feed, $_SESSION['uid']]);
            
            if ($row = $sth->fetch()) {
                array_push($tmp, $feed);
            }
        }

        return $tmp;
    }

    public function extract()
    {
        $article_id = (int) $_REQUEST["param"];

        $sth = $this->pdo->prepare("SELECT link FROM ttrss_entries WHERE id = ?");
        $sth->execute([$article_id]);

        if ($row = $sth->fetch()) {
            $output = $this->send_request($row["link"]);
        }

        $result=[];

        if ($output->content) {
            $result["content"] = $output->content;
        }

        print json_encode($result);
    }
}