How to use PHP to implement RSS subscription function

With the development of the Internet, RSS has become a popular way to subscribe to information. RSS subscription function can be easily implemented using PHP, allowing users to obtain the latest information more easily.

1. Establish a database table

Before implementing the RSS subscription function, you need to create a table in the database to store the RSS source information subscribed by the user. The form contains four fields: ID, URL, title and description. The specific structure is as follows:

CREATE TABLE `feed` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `url` varchar(255) NOT NULL,
  `title` varchar(255) NOT NULL,
  `description` varchar(255) NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

2. Write subscription code

Next, we need to write PHP code to implement user subscription and display RSS Content functions. First, we define an RSS class to obtain and parse XML files:

class RSS {
    private $url;
    public function __construct($url) {
        $this->url = $url;
    }
    public function get_feed() {
        $xml = simplexml_load_file($this->url);
        $feed = array(
            'title' => (string) $xml->channel->title,
            'description' => (string) $xml->channel->description,
            'items' => array(),
        );
        foreach($xml->channel->item as $item) {
            $feed['items'][] = array(
                'title' => (string) $item->title,
                'description' => (string) $item->description,
                'link' => (string) $item->link,
                'date' => (string) $item->pubDate,
            );
        }
        return $feed;
    }
}

In this class, we use the simplexml_load_file function to load the XML file and parse out the title, description and article list. On the subscription page, we can instantiate this class based on the subscription URL and call the get_feed method to obtain RSS content.

require_once('RSS.class.php');

// 获取订阅的 ID
$id = $_GET['id'];

// 连接数据库
$mysqli = new mysqli('localhost', 'user', 'password', 'dbname');

// 获取订阅的 URL
$res = $mysqli->query("SELECT url FROM feed WHERE id = $id");
$url = $res->fetch_assoc()['url'];

// 实例化 RSS 类
$rss = new RSS($url);

// 获取 RSS 内容
$feed = $rss->get_feed();

// 显示 RSS 内容
foreach($feed['items'] as $item) {
    echo '<p>';
    echo '<a href="' . $item['link'] . '">' . $item['title'] . '</a><br>';
    echo $item['description'] . '<br>';
    echo $item['date'];
    echo '</p>';
}

In this code, we first get the subscription ID value from the URL parameter, then connect to the database and query the corresponding URL. Next, we instantiate the RSS class based on the URL and call the get_feed method to obtain the RSS content. Finally, we loop through and print out the title, description, link, and publication time of each article.

3. Add feeds

In order to allow users to add feeds, we also need to write a page to add new RSS feeds. The page contains a form that allows users to enter the URL, title and description of the subscription, and then inserts this information into the database:

if(isset($_POST['url'])) {
    $url = $_POST['url'];
    $title = $_POST['title'];
    $description = $_POST['description'];

    // 连接数据库
    $mysqli = new mysqli('localhost', 'user', 'password', 'dbname');

    // 插入订阅信息
    $mysqli->query("INSERT INTO feed (url, title, description) VALUES ('$url', '$title', '$description')");
    echo '添加成功！';
}

4. Summary

Through the implementation of the above PHP code, We successfully implemented basic RSS subscription functionality. Users can add multiple RSS feeds and get the latest article content through the subscription page. At the same time, through a simple database design, we can simply query, add and delete feeds to better meet user needs.

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