HTTP Requests and Email

📬 PHP HTTP Requests & Email: Your Digital Messenger!

Imagine you’re a delivery person. You pick up packages (data), travel to different houses (servers), drop off or pick up things, and sometimes send letters (emails). That’s exactly what PHP does when talking to the internet!

🎯 What We’ll Learn

Today we’re going to learn how PHP can:

• Talk to other websites (like asking a friend for information)
• Send and receive data (like passing notes in class)
• Send emails (like mailing a birthday card)

Let’s start our adventure! 🚀

🌀 cURL: Your Super Delivery Truck

cURL stands for “Client URL” - think of it as a super-powered delivery truck that can go anywhere on the internet!

🔧 cURL Initialization

Before our truck can go anywhere, we need to start the engine!

// Start the cURL truck engine!
$ch = curl_init();

// Or give it a destination right away
$ch = curl_init("https://api.example.com");

What’s happening?

• curl_init() = Turn on the truck
• $ch = Our truck’s “handle” (like a steering wheel)

💡 Simple Rule: Always start with curl_init() before doing anything else!

⚙️ cURL Options

Now let’s program our GPS (tell the truck where to go and how to behave)!

$ch = curl_init();

// Where are we going?
curl_setopt($ch, CURLOPT_URL,
  "https://api.example.com/data");

// Bring back what you find!
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);

// Wait max 30 seconds
curl_setopt($ch, CURLOPT_TIMEOUT, 30);

Common Options Explained:

🎯 Pro Tip: Always set CURLOPT_RETURNTRANSFER to true or you won’t get any data back!

🚗 cURL Execution

Time to send our truck on its journey!

$ch = curl_init();
curl_setopt($ch, CURLOPT_URL,
  "https://jsonplaceholder.typicode.com/posts/1");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);

// GO! Send the truck!
$response = curl_exec($ch);

// Park the truck (close connection)
curl_close($ch);

// See what we got!
echo $response;

The Journey:

graph TD
    A["🔧 curl_init"] --> B["⚙️ curl_setopt"]
    B --> C["🚗 curl_exec"]
    C --> D["📦 Get Response"]
    D --> E["🅿️ curl_close"]

⚠️ Important: Always call curl_close() when done - like turning off your car!

📥 cURL GET Requests

GET requests are like asking a question - “Hey, can you give me some information?”

function getData($url) {
    $ch = curl_init();

    curl_setopt_array($ch, [
        CURLOPT_URL => $url,
        CURLOPT_RETURNTRANSFER => true,
        CURLOPT_HTTPGET => true
    ]);

    $result = curl_exec($ch);
    curl_close($ch);

    return json_decode($result, true);
}

// Use it!
$users = getData("https://api.example.com/users");
print_r($users);

Real Example - Get Weather:

$city = "London";
$url = "https://api.weather.com/city=" .
  urlencode($city);

$weather = getData($url);
echo "Temperature: " . $weather['temp'];

💡 GET = “Give me info!” - You’re just looking, not changing anything.

📤 cURL POST Requests

POST requests are like sending a package - you’re giving information TO the server!

function postData($url, $data) {
    $ch = curl_init();

    curl_setopt_array($ch, [
        CURLOPT_URL => $url,
        CURLOPT_RETURNTRANSFER => true,
        CURLOPT_POST => true,
        CURLOPT_POSTFIELDS => json_encode($data),
        CURLOPT_HTTPHEADER => [
            'Content-Type: application/json'
        ]
    ]);

    $result = curl_exec($ch);
    curl_close($ch);

    return json_decode($result, true);
}

// Create a new user
$newUser = [
    'name' => 'Alice',
    'email' => 'alice@example.com'
];

$response = postData(
  "https://api.example.com/users",
  $newUser
);

GET vs POST:

🚨 cURL Error Handling

What if our truck gets lost or breaks down? We need to handle problems!

$ch = curl_init();

curl_setopt_array($ch, [
    CURLOPT_URL => "https://api.example.com/data",
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_TIMEOUT => 10
]);

$response = curl_exec($ch);

// Did something go wrong?
if ($response === false) {
    $errorNumber = curl_errno($ch);
    $errorMessage = curl_error($ch);

    echo "Oops! Error #$errorNumber: $errorMessage";
} else {
    // Check HTTP status
    $httpCode = curl_getinfo($ch, CURLINFO_HTTP_CODE);

    if ($httpCode >= 200 && $httpCode < 300) {
        echo "Success! Got: $response";
    } else {
        echo "Server said no! Code: $httpCode";
    }
}

curl_close($ch);

Common Error Codes:

🛡️ Always check for errors! Things can and will go wrong.

🌊 Stream Context: The Simple Alternative

Sometimes you don’t need a big truck - a bicycle will do! Stream context is simpler for basic requests.

// Create options (like packing a small bag)
$options = [
    'http' => [
        'method' => 'GET',
        'header' => "Accept: application/json\r\n",
        'timeout' => 10
    ]
];

// Create the context (get your bicycle ready)
$context = stream_context_create($options);

// Go fetch!
$response = file_get_contents(
    "https://api.example.com/data",
    false,
    $context
);

echo $response;

POST with Stream Context:

$data = json_encode(['name' => 'Bob']);

$options = [
    'http' => [
        'method' => 'POST',
        'header' => "Content-Type: application/json\r\n",
        'content' => $data
    ]
];

$context = stream_context_create($options);
$result = file_get_contents($url, false, $context);

When to use what?

📧 The mail() Function: Sending Letters

Finally, let’s send emails with PHP’s built-in mail() function!

Basic Email

$to = "friend@example.com";
$subject = "Hello from PHP!";
$message = "This is my first email from PHP!";
$headers = "From: me@example.com";

// Send it!
$sent = mail($to, $subject, $message, $headers);

if ($sent) {
    echo "Email sent! 📬";
} else {
    echo "Oops, couldn't send email 😢";
}

The 4 Parts of an Email:

graph TD
    A["📧 mail function"] --> B["To: Who gets it?"]
    A --> C[Subject: What's it about?]
    A --> D["Message: The letter itself"]
    A --> E["Headers: Extra info"]

HTML Email

$to = "friend@example.com";
$subject = "Pretty HTML Email!";

$message = "
<html>
<body>
    <h1>Hello!</h1>
    <p>This is a <b>fancy</b> email!</p>
</body>
</html>
";

$headers = "MIME-Version: 1.0\r\n";
$headers .= "Content-type: text/html; charset=UTF-8\r\n";
$headers .= "From: me@example.com\r\n";

mail($to, $subject, $message, $headers);

Multiple Recipients

// Send to many friends at once!
$to = "alice@example.com, bob@example.com";

// Or use CC/BCC
$headers = "From: me@example.com\r\n";
$headers .= "Cc: manager@example.com\r\n";
$headers .= "Bcc: secret@example.com\r\n";

mail($to, $subject, $message, $headers);

⚠️ Reality Check: The basic mail() function is good for learning, but for real apps, use libraries like PHPMailer or SwiftMailer - they’re much more reliable!

🎯 Quick Summary

🏆 You Did It!

Now you know how PHP can:

• ✅ Start and configure cURL
• ✅ Make GET and POST requests
• ✅ Handle errors like a pro
• ✅ Use stream context for simple stuff
• ✅ Send emails to anyone!

Think of it this way:

• cURL = Your super delivery truck 🚛
• Stream Context = Your quick bicycle 🚴
• mail() = Your postal service 📮

You’re now ready to make PHP talk to the whole internet! 🌐🎉