PHP cURL and HTTP Clients: Making API Requests

PHP cURL and HTTP Clients

cURL is PHP's primary tool for making HTTP requests to external APIs. Mastering it — along with modern alternatives like Guzzle — is essential for any backend PHP developer.

Basic GET Request

<?php
function httpGet(string $url, array $headers = []): array {
    $ch = curl_init();
    curl_setopt_array($ch, [
        CURLOPT_URL            => $url,
        CURLOPT_RETURNTRANSFER => true,      // return response as string
        CURLOPT_FOLLOWLOCATION => true,      // follow redirects
        CURLOPT_TIMEOUT        => 10,        // 10 second timeout
        CURLOPT_HTTPHEADER     => $headers,
        CURLOPT_SSL_VERIFYPEER => true,      // verify SSL certificate
    ]);
    $response = curl_exec($ch);
    $httpCode = curl_getinfo($ch, CURLINFO_HTTP_CODE);
    $error    = curl_error($ch);
    curl_close($ch);

    if ($error) throw new RuntimeException("cURL error: $error");

    return [
        'code' => $httpCode,
        'body' => $response,
        'data' => json_decode($response, true),
    ];
}

$result = httpGet('https://jsonplaceholder.typicode.com/users/1', [
    'Authorization: Bearer my-token',
    'Accept: application/json',
]);
echo $result['data']['name'];  // Leanne Graham

POST Request with JSON

<?php
function httpPost(string $url, array $data, array $headers = []): array {
    $json = json_encode($data);
    $ch   = curl_init();
    curl_setopt_array($ch, [
        CURLOPT_URL            => $url,
        CURLOPT_RETURNTRANSFER => true,
        CURLOPT_POST           => true,
        CURLOPT_POSTFIELDS     => $json,
        CURLOPT_HTTPHEADER     => array_merge([
            'Content-Type: application/json',
            'Content-Length: ' . strlen($json),
        ], $headers),
        CURLOPT_TIMEOUT        => 15,
    ]);
    $response = curl_exec($ch);
    $httpCode = curl_getinfo($ch, CURLINFO_HTTP_CODE);
    curl_close($ch);

    return ['code' => $httpCode, 'data' => json_decode($response, true)];
}

$res = httpPost('https://api.example.com/users', [
    'name'  => 'Rahul Sharma',
    'email' => 'rahul@ezycoders.in',
]);
echo $res['code'];            // 201
echo $res['data']['id'];      // new user ID

Guzzle — Modern HTTP Client

<?php
// composer require guzzlehttp/guzzle
use GuzzleHttp\Client;
use GuzzleHttp\Exception\RequestException;

$client = new Client([
    'base_uri' => 'https://api.ezycoders.in',
    'timeout'  => 10.0,
    'headers'  => ['Authorization' => 'Bearer ' . API_TOKEN],
]);

// GET
$response = $client->get('/posts', ['query' => ['page' => 1, 'limit' => 10]]);
$posts    = json_decode($response->getBody(), true);

// POST
$response = $client->post('/posts', [
    'json' => ['title' => 'PHP Guide', 'status' => 'published'],
]);

// Concurrent requests
use GuzzleHttp\Promise;
$promises = [
    'users'    => $client->getAsync('/users'),
    'posts'    => $client->getAsync('/posts'),
    'settings' => $client->getAsync('/settings'),
];
$results = Promise\Utils::settle($promises)->wait();
// All 3 run simultaneously — much faster than sequential!