How to make HTTP Requests in PHP with cURL: GET, POST, PUT, DELETE, HEAD, OPTIONS

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When developing web applications, interacting with external APIs or services is a common requirement. Whether you’re retrieving data, sending data, updating resources, or deleting them, understanding how to make HTTP requests is essential. PHP’s cURL (Client URL Library) is a powerful tool that allows you to perform all these tasks with ease. In this blog post, we’ll explore how to use cURL in PHP to send HTTP requests using various methods like GET, POST, PUT, DELETE, and more.

What is cURL?

cURL is a library that allows you to connect and communicate with different servers using various protocols, most commonly HTTP and HTTPS. It supports a wide range of HTTP methods and provides detailed error handling, making it a preferred choice for interacting with APIs.

Why Use cURL?

• Flexibility: cURL allows you to customize your HTTP requests extensively, including setting headers, sending data, and handling responses.
• Error Handling: It offers detailed error messages, making it easier to debug issues with requests.
• Broad Protocol Support: cURL can handle multiple protocols, including HTTP, HTTPS, FTP, and more, making it versatile for various applications.

cURL Basics: Setting Up Requests

Before diving into the various HTTP methods, let’s look at how cURL works in PHP. The basic steps for making a cURL request are:

1. Initialize a cURL session with curl_init().
2. Set options for the request using curl_setopt() or curl_setopt_array().
3. Execute the request with curl_exec() and capture the response.
4. Close the cURL session with curl_close() to free up resources.

Now, let’s explore how to use cURL for different HTTP methods.

1. GET Request

The GET method is used to retrieve data from a specified resource. It’s the most common HTTP method and is often used to fetch data from APIs.

Example: Sending a GET Request

function sendGetRequest($url, $headers = []) {
    $ch = curl_init();

    $options = [
        CURLOPT_URL => $url, // The URL to send the GET request to
        CURLOPT_RETURNTRANSFER => true, // Return the response as a string
    ];

    if (!empty($headers)) {
        $options[CURLOPT_HTTPHEADER] = $headers;
    }

    curl_setopt_array($ch, $options);

    $response = curl_exec($ch);

    if ($response === false) {
        $error = curl_error($ch);
        curl_close($ch);
        return "cURL Error: " . $error;
    }

    curl_close($ch);

    return $response;
}

// Example Usage
$url = "https://jsonplaceholder.typicode.com/posts/1";
$response = sendGetRequest($url);
echo $response;

Explanation

• CURLOPT_URL: Sets the URL for the GET request.
• CURLOPT_RETURNTRANSFER: Ensures that the response is returned as a string rather than being output directly.

2. POST Request

The POST method is used to send data to a server, often to create a new resource. It is commonly used in form submissions, where the data needs to be processed by the server.

Example: Sending a POST Request

function sendPostRequest($url, $postFields = [], $headers = []) {
    $ch = curl_init();

    $options = [
        CURLOPT_URL => $url,
        CURLOPT_RETURNTRANSFER => true,
        CURLOPT_POST => true,
        CURLOPT_POSTFIELDS => http_build_query($postFields),
    ];

    if (!empty($headers)) {
        $options[CURLOPT_HTTPHEADER] = $headers;
    }

    curl_setopt_array($ch, $options);

    $response = curl_exec($ch);

    if ($response === false) {
        $error = curl_error($ch);
        curl_close($ch);
        return "cURL Error: " . $error;
    }

    curl_close($ch);

    return $response;
}

// Example Usage
$url = "https://jsonplaceholder.typicode.com/posts";
$postFields = [
    'title' => 'foo',
    'body' => 'bar',
    'userId' => 1
];
$response = sendPostRequest($url, $postFields);
echo $response;

Explanation

• CURLOPT_POST: Tells cURL to send a POST request.
• CURLOPT_POSTFIELDS: Sets the data to be sent in the POST request, which is encoded using http_build_query to ensure proper format.

3. PUT Request

The PUT method is used to update an existing resource on the server. Unlike POST, which creates new resources, PUT is idempotent, meaning that multiple identical requests should have the same effect as a single request.

Example: Sending a PUT Request

function sendPutRequest($url, $putFields = [], $headers = []) {
    $ch = curl_init();

    $options = [
        CURLOPT_URL => $url,
        CURLOPT_RETURNTRANSFER => true,
        CURLOPT_CUSTOMREQUEST => "PUT",
        CURLOPT_POSTFIELDS => http_build_query($putFields),
    ];

    if (!empty($headers)) {
        $options[CURLOPT_HTTPHEADER] = $headers;
    }

    curl_setopt_array($ch, $options);

    $response = curl_exec($ch);

    if ($response === false) {
        $error = curl_error($ch);
        curl_close($ch);
        return "cURL Error: " . $error;
    }

    curl_close($ch);

    return $response;
}

// Example Usage
$url = "https://jsonplaceholder.typicode.com/posts/1";
$putFields = [
    'id' => 1,
    'title' => 'foo',
    'body' => 'bar',
    'userId' => 1
];
$response = sendPutRequest($url, $putFields);
echo $response;

Explanation

• CURLOPT_CUSTOMREQUEST: Specifies the HTTP method to use (in this case, PUT).
• CURLOPT_POSTFIELDS: Sends the updated data to the server.

4. DELETE Request

The DELETE method is used to delete a specific resource from the server.

Example: Sending a DELETE Request

function sendDeleteRequest($url, $headers = []) {
    $ch = curl_init();

    $options = [
        CURLOPT_URL => $url,
        CURLOPT_RETURNTRANSFER => true,
        CURLOPT_CUSTOMREQUEST => "DELETE",
    ];

    if (!empty($headers)) {
        $options[CURLOPT_HTTPHEADER] = $headers;
    }

    curl_setopt_array($ch, $options);

    $response = curl_exec($ch);

    if ($response === false) {
        $error = curl_error($ch);
        curl_close($ch);
        return "cURL Error: " . $error;
    }

    curl_close($ch);

    return $response;
}

// Example Usage
$url = "https://jsonplaceholder.typicode.com/posts/1";
$response = sendDeleteRequest($url);
echo $response;

Explanation

• CURLOPT_CUSTOMREQUEST: Sets the HTTP method to DELETE.
• No Body: Typically, a DELETE request does not require a body.

5. PATCH Request

The PATCH method is used to apply partial modifications to a resource. It’s useful when you need to update only certain fields of a resource without sending the entire data set.

Example: Sending a PATCH Request

function sendPatchRequest($url, $patchFields = [], $headers = []) {
    $ch = curl_init();

    $options = [
        CURLOPT_URL => $url,
        CURLOPT_RETURNTRANSFER => true,
        CURLOPT_CUSTOMREQUEST => "PATCH",
        CURLOPT_POSTFIELDS => http_build_query($patchFields),
    ];

    if (!empty($headers)) {
        $options[CURLOPT_HTTPHEADER] = $headers;
    }

    curl_setopt_array($ch, $options);

    $response = curl_exec($ch);

    if ($response === false) {
        $error = curl_error($ch);
        curl_close($ch);
        return "cURL Error: " . $error;
    }

    curl_close($ch);

    return $response;
}

// Example Usage
$url = "https://jsonplaceholder.typicode.com/posts/1";
$patchFields = [
    'title' => 'foo',
];
$response = sendPatchRequest($url, $patchFields);
echo $response;

Explanation

• CURLOPT_CUSTOMREQUEST: Specifies PATCH as the HTTP method.
• CURLOPT_POSTFIELDS: Contains the fields to be partially updated.

6. HEAD Request

The HEAD method is similar to GET, but it only retrieves the headers from the server, not the body of the response. This is useful for checking what a GET request would return without actually fetching the data.

Example: Sending a HEAD Request

function sendHeadRequest($url, $headers = []) {
    $ch = curl_init();

    $options = [
        CURLOPT_URL => $url,
        CURLOPT_RETURNTRANSFER => true,
        CURLOPT_NOBODY => true, // No body, only headers
    ];

    if (!empty($headers)) {
        $options[CURLOPT_HTTPHEADER] = $headers;
    }

    curl_setopt_array($ch, $options);

    $response = curl_exec($ch);

    if ($response === false) {
        $error = curl_error($ch);
        curl_close($ch);
        return "cURL Error

: " . $error;
    }

    curl_close($ch);

    return $response;
}

// Example Usage
$url = "https://jsonplaceholder.typicode.com/posts/1";
$response = sendHeadRequest($url);
echo $response;

Explanation

• CURLOPT_NOBODY: Ensures that the response body is not included, only the headers.

7. OPTIONS Request

The OPTIONS method is used to describe the communication options available for the target resource. It’s often used to check which HTTP methods are supported by a server.

Example: Sending an OPTIONS Request

function sendOptionsRequest($url, $headers = []) {
    $ch = curl_init();

    $options = [
        CURLOPT_URL => $url,
        CURLOPT_RETURNTRANSFER => true,
        CURLOPT_CUSTOMREQUEST => "OPTIONS",
    ];

    if (!empty($headers)) {
        $options[CURLOPT_HTTPHEADER] = $headers;
    }

    curl_setopt_array($ch, $options);

    $response = curl_exec($ch);

    if ($response === false) {
        $error = curl_error($ch);
        curl_close($ch);
        return "cURL Error: " . $error;
    }

    curl_close($ch);

    return $response;
}

// Example Usage
$url = "https://jsonplaceholder.typicode.com/posts/1";
$response = sendOptionsRequest($url);
echo $response;

Explanation

• CURLOPT_CUSTOMREQUEST: Specifies OPTIONS as the HTTP method.
• No Body: The response typically contains information about the supported methods and no body.

Conclusion

PHP’s cURL library is a powerful and flexible tool for making HTTP requests. Whether you need to retrieve, send, update, or delete data, cURL provides the necessary functionality to interact with web servers and APIs using various HTTP methods. By understanding and using these methods, you can enhance your PHP applications’ ability to communicate with external services effectively.

Understanding how to use cURL with different HTTP methods is crucial for modern web development. Each method serves a specific purpose, and by mastering them, you can build robust, scalable, and efficient web applications that interact seamlessly with external APIs and services.