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CRUD With PHP

Lesson Objectives

By the end of this lesson, developers will be able to:

  1. Route URLs to php files
  2. Connect to MySQL
  3. Build CRUD functionality with PHP

Route URLs to php files

Routing can be accomplished with a .htaccess file placed in your root directory for the app. It will look like this:

RewriteEngine On
RewriteRule ^users/[0-9]+$ server.php

It uses regular expressions to map urls to files.

Before we can use our .htaccess file, we will need to change a security setting. Go into your httpd.conf file in /Applications/MAMP/conf/apache and change the following

<FilesMatch "^\.ht">
    Order allow,deny
    Deny from all
    Satisfy All
</FilesMatch>

to Allow your .htaccess file.

<FilesMatch "^\.ht">
    Order allow,deny
    Allow from all
    Satisfy All
</FilesMatch>

Once this change is made, you will need to Stop Servers and Start Servers in your MAMP console.

Connect to MySQL

Simple database connection and querying looks like this:

$servername = "localhost";
$username = "root";
$password = "root";
$dbname = "phpexample";

// Create connection
 $conn = new mysqli($servername, $username, $password, $dbname);

// Check connection
 if ($conn->connect_error) {
  die("Connection failed: " . $conn->connect_error);
}
$sql = "SELECT * FROM cars";
$this->results = $conn->query($sql);
$conn->close();

Looping through the results would go like this:

<?php while($row = $this->cars->fetch_object()): ?>
 <!-- print_r($row); -->
 <li>
  <?= $row->brand ?>:
  <?= $row->num_wheels ?>
 </li>
<?php endwhile; ?>

The Task

We need an app to keep track of all the cool cars we have. How are we going to do this? With a CRUD app! If we were building this in Javascript, this would be old hat. Since PHP is new to us, though, we'll go a little slower.

Setup

  1. Create a new directory inside your MAMP Web Server root called php_cars.

  2. Before we build our CRUD app, go into your Sequel Pro program, open the Query tab, and create the phpcrud database. We will use this database for all our data manipulation.

  3. Once this is done, we need to create a table for all the cars we are going to add. Run the following query in Sequel Pro:

    CREATE TABLE cars (
	id INT(6) UNSIGNED AUTO_INCREMENT PRIMARY KEY,
	car VARCHAR(50) NOT NULL,
	owner VARCHAR(50) NOT NULL
);

  4. INSERT a car into your table with a car and owner field.

  5. Make sure your car is in the table before moving on.

Hello PHP

  1. Create a views directory inside your php_cars directory.

  2. Create a cars directory inside your views directory.

  3. Create an index.php file inside your cars directory. Give it an HTML boilerplate, and an <h1> tag that says "Cars Index Page".

  4. Go to http://localhost:8888/php_cars/views/cars/, and see your beautiful work!

Getting our car from the DB

Hard-coded text is great and all, but as with any CRUD route, we need to do two more things before we are really "full-stack": we need routes, and we need to talk to the DB. That's where our notes from earlier come in. We need to create an .htaccess file, and we need to connect to MySQL. Here we go...

  1. Create an .htaccess file at the root of php_cars. Put the following lines inside:

    RewriteEngine On
RewriteRule ^cars/$ controllers/cars.php?action=index

  2. You can probably guess what's coming next. That controller folder and file we just referenced in .htaccess? We need to create that.

  3. Since this is a PHP file, we need to create a <?php tag. Also, notice that we have a View and a Controller. Are we missing something? Yes we are. And we'll get there soon enough. For now, start your cars.php file this way:

    <?php

require('../models/car.php');

?>

  4. We'll get to the model file in just a bit. For now, though, we need build out that action=index we put in query params earlier.

    if($_GET['action'] == 'index') {
	$new_car_controller->indexPage();
}

  5. Wait, $new_car_controller? We never created one of those. Hold your horses, we're getting there:

    Class CarController {

	public function indexPage(){
		$cars = Car::find();
		require('../views/cars/index.php');
	}
}

  6. Alright, there's our indexPage(), but what about the $new_car_controller? Well, take a look at that first word and think for a second what we want to do...think back to our OOP classes, and you'll get:

    $new_car_controller = new CarController();

  7. Noice! Make sure all of this code is in the proper order (PHP, like JS, reads top-down, so you can't use any variables above where they are created), then our controller is good to go.

  8. Now it's time for our (America's Next Top) model. Create a models folder and put a car.php file inside it.

  9. Start out the model with another class:

    <?php

Class Car {

}

?>

  10. Now we need to give it that Car::find() function we are using in the controller. Put this inside the Class:

    static public function find() {
	$servername = 'localhost';
	$username = 'root';
	$password = 'root';
	$dbname = 'phpcrud';
}

  11. Make sure this matches your DB name and login parameters for MySQL, then add in the meat of the function below the setup variables:

    $mysql_connection = new mysqli($servername, $username, $password, $dbname);

  12. Since we want to escalate any issues we see, we need to make sure this connection actually worked. So we need this conditional:

    if($mysql_connection->connect_error){
	$mysql_connection->close();
	die('Connection Failed: ' . $mysql_connection->connect_error);
}

  13. Home stretch now. We have a MySQL connection, much like our earlier Mongo and PostgreSQL connections. But just like with those tools, the connection is only the first step. Now we need to get our data. Enter the SQL query:

    } else {
	$sql = "SELECT * FROM cars;";
	$results = $mysql_connection->query($sql);
	return $results;
}

  14. Last piece. Our index.php for cars is still a blank template. Let's get some cars in there. Add this to the file below your h1:

      <section>
      <ul>
	  <?php while($row = $cars->fetch_object()): ?>
	      <li>
		  Here is a <?php echo $row->car ?> for <?php echo $row->owner?>
	      </li>
	  <?php endwhile; ?>
      </ul>
  </section>

  15. If you restart your MAMP server, and go to http://localhost:8888/php_cars/cars/, you should see the car you created during setup!

The "C" in CRUD

OK, so now we can see our cars. Now we need to be able to save new ones. For this, we will have to make a create and new route. We'll start the same place we did last time, in .htaccess.

  1. Add these two lines to your .htaccess file:

    RewriteRule ^cars/new$ controllers/cars.php?action=new
RewriteRule ^cars/create$ controllers/cars.php?action=create

  2. Now we need to create those two actions in cars.php. Use the pattern we used for index to make two more conditionals for new and create.

    Try writing out a skeleton before checking here ``` if($_GET['action'] == 'index') { $new_car_controller->indexPage(); } else if($_GET['action']=='new') { $new_car_controller->newPage(); } else if($_GET['action']=='create') { $new_car_controller->createAction(); } ```

  3. And we need to create those two functions. Try creating newPage() on your own (it's very similar to index()).

    Try writing out a skeleton for `createAction()` before checking here ``` public function newPage(){ require('../views/cars/new.php'); }

    public function createAction() { Car::create($_POST['car'], $_POST['owner']); header('Location: ./'); }

    </details>

  4. Now we need to head over to models/car.php to make the Car::create() method. This is almost identical to the Car::find() method except for two crucial details: your SQL query will be different, and you need to pass in parameters. Those lines will look like this, respectively:

    } else {
	$sql = "INSERT INTO cars (car, owner) VALUES ('".$car."','".$owner."');";
	$mysql_connection->query($sql);
}
    static public function create($car, $owner) {

  5. Once you've combined the lines above with your find() method to make a full create() method, we're ready to circle back to our views. Create a new view in views/cars called new.php. All you need on this page is some HTML boilerplate, a heading, and a form. The form will have two <input>s, one with a name of "car", and the other with a name of "owner". What should the submit action and method be?

  6. Add a link to your index.php that takes you to your new.php. (What should it route to, based on your .htaccess file?)

  7. Now go back to http://localhost:8888/php_cars/cars/, and add a new car. Yee haw!

Challenge Yourself

OK, now we can Read and Create cars. Wouldn't it be cool if we could Update and Delete them? Think about a few things and then Google your way to a solution.

  • What would the SQL query look like for Delete or Update?
  • What would the route look like in .htaccess?
  • How can you re-use the code we already have?

If you get stuck, remember to:

  • Check all the logs in /Applications/MAMP/logs
  • Ask your neighbors

Another challenge

Connecting to MySQL with every DB request? That's silly, and it's not DRY. Create a connection.php file and require it wherever you need it, rather than repeating the connection all over the place.