PHP MYSQL Like Dislike System

0-PHP-LIKE-DISLIKE.MD

PHP MYSQL LIKE DISLIKE

https://code-boxx.com/php-like-dislike-system/

NOTES

1. Create a database and import 1-database.sql.
2. Change the database settings in 2-lidi-lib.php to your own.
3. Launch 4-demo.php in your browser.

IMAGES

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) REACTIONS TABLE
CREATE TABLE `reactions` (
  `id` bigint(20) NOT NULL,
  `user_id` bigint(20) NOT NULL,
  `reaction` tinyint(1) NOT NULL DEFAULT 1
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;

ALTER TABLE `reactions`
  ADD PRIMARY KEY (`id`,`user_id`),
  ADD KEY `reaction` (`reaction`);

-- (B) DUMMY DATA
INSERT INTO `reactions` (`id`, `user_id`, `reaction`) VALUES
(900, 1, -1),
(900, 2, 1),
(900, 3, 1),
(900, 4, -1);

2-lidi-lib.php

<?php
class Reactions {
  // (A) CONSTRUCTOR - CONNECT TO DATABASE
  private $pdo;
  private $stmt;
  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_NAMED
    ]);
  }

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

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

  // (D) GET REACTIONS FOR ID
  function get ($id, $uid=null) {
    // (D1) GET TOTAL REACTIONS
    $reacts = ["react" => [0, 0]]; // [likes, dislikes]
    $this->query(
      "SELECT `reaction`, COUNT(`reaction`) `total`
       FROM `reactions` WHERE `id`=?
       GROUP BY `reaction`", [$id]
    );
    while ($r = $this->stmt->fetch()) {
      if ($r["reaction"]==1) { $reacts["react"][0] = $r["total"]; }
      else { $reacts["react"][1] = $r["total"]; }
    }

    // (D2) GET REACTION BY USER (IF SPECIFIED)
    if ($uid != null) {
      $this->query(
        "SELECT `reaction` FROM `reactions` WHERE `id`=? AND `user_id`=?",
        [$id, $uid]
      );
      $reacts["user"] = $this->stmt->fetchColumn();
    }

    // (D3) DONE - RETURN RESULTS
    return $reacts;
  }

  // (E) SAVE REACTION
  function save ($id, $uid, $react) {
    // (E1) FORMULATE SQL
    if ($react == 0) {
      $sql = "DELETE FROM `reactions` WHERE `id`=? AND `user_id`=?";
      $data = [$id, $uid];
    } else {
      $sql = "REPLACE INTO `reactions` (`id`, `user_id`, `reaction`) VALUES (?,?,?)";
      $data = [$id, $uid, $react];
    }

    // (E2) EXECUTE SQL
    $this->query($sql, $data);
    return true;
  }
}

// (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 REACTIONS OBJECT
$_REACT = new Reactions();

3-lidi-ajax.php

<?php
if (isset($_POST["req"])) {
  // (A) LOAD LIKE DISLIKE LIBRARY
  require "2-lidi-lib.php";

  // (B) FIXED DUMMY USER ID
  $uid = 1;

  // (C) HANDLE REQUESTS
  switch ($_POST["req"]) {
    // (C1) GET REACTIONS
    case "get":
      echo json_encode($_REACT->get($_POST["pid"], $uid));
      break;

    // (C2) SAVE REACTION
    case "save":
      if ($_REACT->save($_POST["pid"], $uid, $_POST["react"])) {
        echo json_encode($_REACT->get($_POST["pid"], $uid));
      } else { echo $_REACT->error ; }
      break;
}}

4-demo.js

var demo = {
  // (A) SUPPORT FUNCTION - AJAX FETCH
  fetch : (data, load) => {
    // (A1) FORM DATA
    var form = new FormData();
    for (let [k,v] of Object.entries(data)) { form.append(k, v); }

    // (A2) AJAX FETCH
    fetch("3-lidi-ajax.php", { method: "post", body : form })
    .then(res => res.json())
    .then(res => load(res))
    .catch(err => console.error(err));
  },

  // (B) INIT
  lidi : null, // like dislike instance
  init : () => demo.fetch(
    // (B1) GET LIKES COUNT FROM SERVER
    {
      req : "get",
      pid : 900 // fixed dummy product id
    },

    // (B2) DRAW HTML LIKE/DISLIKE BUTTON
    data => {
      demo.lidi = lidi({
        hWrap : document.getElementById("demo"),
        status : data.user ? data.user : 0,
        count : data.react,
        change : demo.save
      });
    }
  ),

  // (C) SAVE LIKE/DISLIKE REACTION
  save : status => demo.fetch(
    // (C1) SEND NEW STATUS TO SERVER
    {
      req : "save",
      react : status,
      pid : 900 // fixed dummy product id
    },

    // (C2) UPDATE HTML COUNT
    res => demo.lidi.recount(res.react)
  )
};
window.onload = demo.init;

4-demo.php

<!DOCTYPE html>
<html>
  <head>
    <title>PHP MYSQL Like Dislike</title>
    <meta charset="utf-8">

    <!-- (X) NOT IMPORTANT -->
    <style>
    * {
      font-family: Arial, Helvetica, sans-serif;
      box-sizing: border-box;
    }
    #demowrap {
      width: 300px; padding: 15px;
      background: #b31212;
      display: flex; flex-direction: column; align-items: center;
    }
    #demowrap h1 { color: #fff; }
    #img {
      border-radius: 50%;
      width: 256px;
    }
    #demo {
      margin-top: 20px;
      background: #000;
    }
    </style>

    <!-- (A) LOAD LIKE/DISLIKE "WIDGET" -->
    <link rel="stylesheet" href="lidi.css">
    <script src="lidi.js"></script>
    <script src="4-demo.js"></script>
  </head>
  <body>
    <!-- (B) DUMMY PRODUCT -->
    <div id="demowrap">
      <h1>PRODUCT</h1>
      <img id="img" src="demo.png">
      <div id="demo"></div>
    </div>
  </body>
</html>

lidi.css

/* (A) WRAPPER */
.lidiWrap {
  display: flex;
  justify-content: space-around;
  align-items: center;
  width: 120px;
  padding: 15px;
  background: #f3f3f3;
}
.lidiWrap.count { width: 250px; }

/* (B) LIKE-DISLIKE BUTTONS */
.lidiUp, .lidiDown {
  width: 24px; height: 24px;
  background-image: url("lidi.png");
  cursor: pointer;
}
.lidiDown { background-position: -48px; }
.lidiUp.set { background-position: -24px; }
.lidiDown.set { background-position: -72px; }

/* (C) LIKE-DISLIKE COUNT */
.lidiUpCount, .lidiDownCount {
  font-size: 18px;
  color: #858585;
}

lidi.js

function lidi (inst) {
//  hWrap : html like/dislike container
//  change : function to handle like/dislike toggle change
//  status : -1 dislike, 0 neutral, 1 like (optional, default 0)
//  count : [likes, dislikes] (optional)

  // (A) DEFAULT STATUS + CSS WRAPPER CLASS
  if (!inst.status) { inst.status = 0; }
  inst.hWrap.classList.add("lidiWrap");

  // (B) ATTACH LIKE & DISLIKE BUTTON
  inst.hUp = document.createElement("div");
  inst.hDown = document.createElement("div");
  inst.hUp.className = "lidiUp";
  inst.hDown.className = "lidiDown";
  if (inst.status==1) { inst.hUp.classList.add("set"); }
  if (inst.status==-1) { inst.hDown.classList.add("set"); }
  inst.hWrap.appendChild(inst.hUp);
  inst.hWrap.appendChild(inst.hDown);

  // (C) ATTACH LIKE & DISLIKE COUNT
  if (inst.count) {
    // (C1) LIKE & DISLIKE COUNT HTML
    inst.hUpCount = document.createElement("div");
    inst.hDownCount = document.createElement("div");
    inst.hUpCount.className = "lidiUpCount";
    inst.hDownCount.className = "lidiDownCount";
    inst.hUpCount.innerHTML = inst.count[0];
    inst.hDownCount.innerHTML = inst.count[1];
    inst.hWrap.classList.add("count");
    inst.hWrap.insertBefore(inst.hUpCount, inst.hDown);
    inst.hWrap.insertBefore(inst.hDownCount, inst.hDown.nextSibling);

    // (C2) UPDATE LIKE & DISLIKE COUNT
    inst.recount = count => {
      inst.count = count;
      inst.hUpCount.innerHTML = count[0];
      inst.hDownCount.innerHTML = count[1];
    };
  }

  // (D) TOGGLE LIKE/DISLIKE
  inst.updown = up => {
    // (D1) UPDATE STATUS FLAG
    if (up) { inst.status = inst.status == 1 ? 0 : 1; }
    else { inst.status = inst.status == -1 ? 0 : -1; }

    // (D2) UPDATE LIKE/DISLIKE CSS
    if (inst.status==1) {
      inst.hUp.classList.add("set");
      inst.hDown.classList.remove("set");
    } else if (inst.status==-1) {
      inst.hUp.classList.remove("set");
      inst.hDown.classList.add("set");
    } else {
      inst.hUp.classList.remove("set");
      inst.hDown.classList.remove("set");
    }

    // (D3) TRIGGER CHANGE
    inst.change(inst.status);
  };

  // (E) ENABLE/DISABLE
  inst.enable = () => {
    inst.hUp.onclick = () => inst.updown(true);
    inst.hDown.onclick = () => inst.updown(false);
  };
  inst.disable = () => {
    inst.hUp.onclick = "";
    inst.hDown.onclick = "";
  };
  inst.enable();

  // (F) DONE
  return inst;
}