PHP MYSQL Hashtag System

0-PHP-HASHTAG.MD

PHP MYSQL HASHTAG SYSTEM

https://code-boxx.com/hashtag-system-php-mysql/

NOTES

1. Create a test database and import 1-database.sql.
2. Change the database settings in 2-lib-tag.php to your own.
3. Access 4a-tag.html in the browser - Enter a few test messages with hashtags, then do a search by hashtag.

LICENSE

Copyright by Code Boxx

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

1-database.sql

-- (A) POSTS
CREATE TABLE `posts` (
  `post_id` bigint(20) NOT NULL,
  `post_txt` text NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;

ALTER TABLE `posts`
  ADD PRIMARY KEY (`post_id`),
  ADD FULLTEXT KEY `post_txt` (`post_txt`);

ALTER TABLE `posts`
  MODIFY `post_id` bigint(20) NOT NULL AUTO_INCREMENT;

-- (B) TAGS
CREATE TABLE `tags` (
  `post_id` bigint(20) NOT NULL,
  `tag` varchar(255) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;

ALTER TABLE `tags`
  ADD PRIMARY KEY (`post_id`,`tag`);

2-lib-tag.php

<?php
class Tag {
  // (A) CONSTRUCTOR - CONNECT TO DATABASE
  private $pdo = null;
  private $stmt = null;
  public $error = "";
  function __construct () {
    $this->pdo = new PDO(
      "mysql:host=".DB_HOST.";dbname=".DB_NAME.";charset=".DB_CHARSET,
      DB_USER, DB_PASSWORD, [
      PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
      PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC
    ]);
  }

  // (B) DESTRUCTOR - CLOSE DATABASE CONNECTION
  function __destruct () {
    if ($this->stmt!==null) { $this->stmt = null; }
    if ($this->pdo!==null) { $this->pdo = null; }
  }

  // (C) HELPER FUNCTION - EXECUTE SQL QUERY
  function query ($sql, $data=null) : void {
    $this->stmt = $this->pdo->prepare($sql);
    $this->stmt->execute($data);
  }

  // (D) SAVE POST + TAGS
  function save ($txt, $tags=null, $id=null) {
    // (D1) ADD/UPDATE POST
    if ($id==null) {
      $this->query("INSERT INTO `posts` (`post_txt`) VALUES (?)", [$txt]);
    } else {
      $this->query("UPDATE `posts` SET `post_txt`=? WHERE `post_id`=?", [$txt, $id]);
    }

    // (D2) DELETE OLD TAGS
    if ($id==null) { $id = $this->pdo->lastInsertId(); }
    else { $this->query("DELETE FROM `tags` WHERE `post_id`=?", [$id]); }

    // (D3) INSERT NEW TAGS
    if ($tags != null) {
      $tags = json_decode($tags, true);
      $sql = "INSERT INTO `tags` (`post_id`, `tag`) VALUES ";
      $data = [];
      foreach ($tags as $t) {
        $sql .= "(?,?),";
        $data[] = $id; $data[] = $t;
      }
      $this->query(substr($sql, 0, -1).";", $data);
    }

    // (D4) DONE
    return true;
  }

  // (E) GET POSTS
  function get ($tag=null) {
    // (E1) GET ALL
    if ($tag==null) { $this->query("SELECT * FROM `posts`"); }

    // (E2) SEARCH BY TAG
    else {
      $sql = "SELECT p.* FROM `tags` `t`
              JOIN `posts` `p` USING (`post_id`)
              WHERE `tag`=?";
      $this->query($sql, [$tag]);
    }

    // (E3) FETCH!
    return $this->stmt->fetchAll();
  }
}

// (F) DATABASE SETTINGS - CHANGE TO YOUR OWN!
define("DB_HOST", "localhost");
define("DB_NAME", "test");
define("DB_CHARSET", "utf8mb4");
define("DB_USER", "root");
define("DB_PASSWORD", "");

// (G) NEW HASH TAG OBJECT
$_TAG = new Tag();

3-ajax-tag.php

<?php
if (isset($_POST["req"])) {
  require "2-lib-tag.php";
  switch ($_POST["req"]) {
  // (A) GET POSTS
  case "get":
    echo json_encode($_TAG->get(
      isset($_POST["tag"]) ? $_POST["tag"] : null
    ));
    break;

  // (B) SAVE POST
  case "save":
    echo $_TAG->save(
      $_POST["txt"],
      isset($_POST["tags"]) ? $_POST["tags"] : null,
      isset($_POST["id"]) ? $_POST["id"] : null
    ) ? "OK" : $_TAG->error;
    break;
}}

4a-tag.html

<!DOCTYPE html>
<html>
  <head>
    <title>PHP MySQL Hashtag</title>
    <meta charset="utf-8">
    <script src="4b-tag.js"></script>
    <link rel="stylesheet" href="4c-tag.css">
  </head>
  <body>
    <!-- (A) ADD POST -->
    <form onsubmit="return htag.save()">
      <input type="text" required id="add"
             placeholder="Post some dummy messages with #hashtags">
      <input type="submit" value="Post">
    </form>

    <!-- (B) SEARCH BY TAG -->
    <form onsubmit="return htag.get(true)">
      <input type="text" id="search"
             placeholder="Then search by hashtag">
      <input type="submit" value="Search">
    </form>

    <!-- (C) POSTS -->
    <div id="posts"></div>
  </body>
</html>

4b-tag.js

var htag = {
  // (A) INITIALIZE
  hAdd : null,    // html add post field
  hSearch : null, // html search field
  hPosts : null,   // html posts <div>
  init : () => {
    // (A1) GET HTML ELEMENTS
    htag.hAdd = document.getElementById("add");
    htag.hSearch = document.getElementById("search");
    htag.hPosts = document.getElementById("posts");

    // (A2) LOAD POSTS
    htag.get();
  },

  // (B) GET/SEARCH POSTS
  get : search => {
    // (B1) FORM DATA
    let data = new FormData();
    data.append("req", "get");
    if (search == true) {
      data.append("tag", htag.hSearch.value);
    }

    // (B2) FETCH & DRAW HTML
    fetch("3-ajax-tag.php", { method : "post", body : data })
    .then(res => res.json())
    .then(data => {
      htag.hPosts.innerHTML = "";
      data.forEach(post => {
        let row = document.createElement("div");
        row.className = "row";
        row.innerHTML = post["post_txt"];
        htag.hPosts.append(row);
      });
    });
    return false;
  },

  // (C) SAVE POST
  save : () => {
    // (C1) GET TAGS
    let matches = htag.hAdd.value.match(/(^|\s)(#[a-z\d-]+)/g),
        tags = matches === null ? null : [...new Set(matches)];
    if (tags!=null) {
      tags.forEach((t, i) => { tags[i] = t.substring(2); });
    }

    // (C2) FORM DATA
    let data = new FormData();
    data.append("req", "save");
    data.append("txt", htag.hAdd.value);
    if (tags!=null) { data.append("tags", JSON.stringify(tags)); }

    // (C3) POST + UPDATE HTML LIST
    fetch("3-ajax-tag.php", { method : "post", body : data })
    .then(res => res.text())
    .then(txt => {
      if (txt == "OK") {
        htag.hAdd.value = "";
        htag.get();
      } else { alert(txt); }
    });

    // (C4) DONE
    return false;
  }
};
window.onload = htag.init;

4c-tag.css

/* (A) WHOLE PAGE */
* {
  font-family: Arial, Helvetica, sans-serif;
  box-sizing: border-box;
}
body {
  max-width: 500px;
  margin: 0 auto;
  background: #f5f5f5;
}

/* (B) ADD & SEARCH FORMS */
form {
  display: flex;
  padding: 15px;
  background: #505050;
}
input[type=text], input[type=submit] { padding: 10px; }
input[type=text], input[type=submit] { border: 0; }
input[type=text] { flex-grow: 1; }
input[type=submit] {
  width: 80px;
  font-weight: 700;
  color: #fff;
  background: #b73b3b;
  cursor: pointer;
}

/* (C) POSTS LIST */
#posts {
  padding: 15px;
  background: #ebebeb;
}
#posts .row {
  padding: 15px;
  background: #fff;
  border: 1px solid #ddd;
  margin: 15px;
}