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04.

Saving Pets

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Saving Pets

Ok, let’s talk about saving pets. No, not like rescuing them, though that’s really cool too. I’m talking about being able to submit our new pet form and saving that pet information somewhere so that it shows up on our site. I want to make our pet list truly dynamic!

We haven’t talked about databases yet, and we’re not using one. But actually, the pet data our site needs is being stored in a simple pets.json file. And this file is something we can read from and even update. And hey, that’s basically all a database really does. So if we can figure out how to update the pets.json file each time we submit this form, we’re in business!

First, we can re-use our get_pets function to get an array of all of the existing pets from the file. Let’s add this right at the bottom of our form processing code:

if ($_SERVER['REQUEST_METHOD'] == 'POST') {

    // ...

    $pets = get_pets();
    var_dump($name, $breed, $weight, $bio);die;
}

Next, create an associative array that represents the new pet that’s being added. Make sure the keys you’re using match the existing pets from the file. We don’t have age or image fields yet, so just set those to be blank:

if ($_SERVER['REQUEST_METHOD'] == 'POST') {

    // ...

    $pets = get_pets();

    $newPet = array(
        'name' => $name,
        'breed' => $breed,
        'weight' => $weight,
        'bio' => $bio,
        'image' => '',
        'age' => '',
    );

    var_dump($name, $breed, $weight, $bio);die;
}

Ok! Now just add that new pet to the $pets array:

if ($_SERVER['REQUEST_METHOD'] == 'POST') {

    // ...

    $pets = get_pets();

    $newPet = array(
        'name' => $name,
        'breed' => $breed,
        'weight' => $weight,
        'bio' => $bio,
        'image' => '',
        'age' => '',
    );

    $pets[] = $newPet;

    var_dump($name, $breed, $weight, $bio);die;
}

Remember that the empty square brackets tells PHP we want to add something to the $pets array, but we don’t care what the items key is. It’ll choose a unique number for us.

Saving the Pets to pets.json

Now, $pets has all the existing little fur balls, and our new one. It basically represents what we want to save to pets.json.

Let’s do it! First, turn $pets back into JSON with PHP’s json_encode function. To actually save the file, use another PHP function: file_put_contents:

// ...
$pets[] = $newPet;

$json = json_encode($pets);
file_put_contents('data/pets.json', $json);

This is basically what the get_pets function does, only in reverse! json_encode turns the array into a string, and then we save it back to the file.

Let’s try it! Fill out the form and submit. An error!

Call to undefined function get_pets()

Ah, woops! That function lives in the functions.php file. If we want to use it, we need to require that file:

<?php
require 'lib/functions.php';

if ($_SERVER['REQUEST_METHOD'] == 'POST') {
    // ...
}

Ok, refresh and re-post the form. Hmm, it looks like it did nothing. But that’s not true! We submitted the form, our code detected this was a POST request, we saved the new stuff to pets.json, and then the page continued rendering the blank form. There weren’t any fireworks, but I think this worked!

Go to the homepage to find out for sure! We didn’t give it an image, but there’s our pet. We don’t even have a database, and we already have a dynamic app.

Readable JSON!

If you look at pets.json, it got flattened onto one line. That’s ok! Spaces and new lines aren’t important in JSON, and PHP saved without any extra whitespace. Again, that’s fine really.

But since I did like my file better when it was readable, give json_encode a second argument of JSON_PRETTY_PRINT:

$json = json_encode($pets, JSON_PRETTY_PRINT);

Fill out our form again. Hey, now pets.json looks awesome again. We are really good at training this digital pet :) JSON_PRETTY_PRINT is called a constant, which is kind of like a variable, exept that it’s magically available everywhere, doesn’t have a $, and its value can’t change. You won’t use them often, so don’t worry about them too much.