Curl extension in PHP installation & initialization with sample code

A current cURL request pattern

Use cURL with explicit timeouts, return-transfer mode, and an error check. In PHP 8+, cURL handles are objects, so focus on request options and response/error handling rather than older resource-specific assumptions.

<?php
$ch = curl_init('https://example.com/');
curl_setopt_array($ch, [
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_CONNECTTIMEOUT => 5,
    CURLOPT_TIMEOUT => 10,
    CURLOPT_FOLLOWLOCATION => false,
]);

$response = curl_exec($ch);
if ($response === false) {
    throw new RuntimeException(curl_error($ch));
}

$status = curl_getinfo($ch, CURLINFO_RESPONSE_CODE);
echo "HTTP status: $status";
curl_close($ch);
?>

The examples below build on this pattern and show common cURL request types.

In PHP, cURL (Client URL) is a library and set of functions that allow you to make HTTP requests to remote servers and retrieve data. cURL provides a way to interact with web services, APIs, and other web resources programmatically.

These are four steps involved in working with cURL.

Initialization and create handler
Setting the options
Execution with curl_exec()
Close the cURL handle

DEMO scripts to post data using cURL
This is not only to collect data but we can also submit form data by POST or GET method to a remote URL or server. Curl function supports many other protocols.

Curl support.

We have to first ensure that curl support is available in our server, for this PHP installation is to be checked. The best way is to check is our phpinfo function. Here is a screenshot of phpinfo.
php info curl extension support

If curl support is not available then process is same as adding any other features to PHP. Here is one example. Same can be followed to add curl extensions in PHP. Once the curl support is available then we will start with a simple code by getting google.com url. The first line will initialize a curl instance and then we will use

<?php
$my_curl = curl_init(); // cURL handle

// WE will add options to our curl 
curl_setopt($my_curl, CURLOPT_URL, "https://www.google.com/");
curl_setopt($my_curl, CURLOPT_HEADER, 0);

curl_setopt($my_curl, CURLOPT_RETURNTRANSFER, true);
curl_setopt($my_curl, CURLOPT_CONNECTTIMEOUT, 5);
curl_setopt($my_curl, CURLOPT_TIMEOUT, 10);
$response = curl_exec($my_curl);
if ($response === false) {
    throw new RuntimeException(curl_error($my_curl));
}
echo $response;
curl_close($my_curl); // close the curl connection
?>

Example: Verifying cURL Installation

if (function_exists('curl_version')) {
    echo "cURL is installed.";
} else {
    echo "cURL is not installed.";
}

Example: cURL Installation in Linux

sudo apt-get install php-curl
sudo service apache2 restart

Example: Handling cURL Error

$ch = curl_init('https://example.com');
if (!$ch) {
    die('cURL not available!');
}

These examples cover extension checks, a typical Linux installation command, and basic request error handling. Keep TLS certificate verification enabled; fix the CA/certificate configuration instead of disabling verification.
Reading external url by curl Webpage Auditor using cURL
PHP Scripts

Subhendu Mohapatra

Author & Instructor at plus2net

I write and maintain practical tutorials on Python, PHP, SQL, JavaScript, HTML, jQuery, and web development at plus2net. The tutorials focus on clear explanations, working examples, and code that readers can test and adapt while learning.

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Curl functions in PHP