12.5. Using REST in PHP

Issuing GET Requests
Modern versions of PHP make it trivial to GET web pages: any file-access function (even include!) works seamlessly with URLs, too. Thus, you can use fopen, file_get_contents, and any other file-reading function to issue GET requests. For example:

$url = "http://www.acme.com/products/3322";
$response = file_get_contents($url);
echo $response;

Any parameters passed to GET requests must be encoded (e.g., a space is %20); you can encode strings using the urlencode function.

Issuing POST Requests
In stark contrast to the ease of doing a GET, there's no simple way to do a POST in PHP. You have to open a connection to the server and manually send all HTTP headers. Here's a simple function that will do the trick, for any HTTP method:

function httpRequest($host, $port, $method, $path, $params) {
  // Params are a map from names to values
  $paramStr = "";
  foreach ($params as $name, $val) {
    $paramStr .= $name . "=";
    $paramStr .= urlencode($val);
    $paramStr .= "&";
  }

  // Assign defaults to $method and $port, if needed
  if (empty($method)) {
    $method = 'GET';
  }
  $method = strtoupper($method);
  if (empty($port)) {
    $port = 80; // Default HTTP port
  }

  // Create the connection
  $sock = fsockopen($host, $port);
  if ($method == "GET") {
    $path .= "?" . $paramStr;
  }
  fputs($sock, "$method $path HTTP/1.1\r\n");
  fputs($sock, "Host: $host\r\n");
  fputs($sock, "Content-type: " .
               "application/x-www-form-urlencoded\r\n");
  if ($method == "POST") {
    fputs($sock, "Content-length: " . 
                 strlen($paramStr) . "\r\n");
  }
  fputs($sock, "Connection: close\r\n\r\n");
  if ($method == "POST") {
    fputs($sock, $paramStr);
  }

  // Buffer the result
  $result = "";
  while (!feof($sock)) {
    $result .= fgets($sock,1024);
  }

  fclose($sock);
  return $result;
}

Issuing a POST request using this function is as simple as:

$resp = httpRequest("www.acme.com",
    80, "POST", "/userDetails",
    array("firstName" => "John", "lastName" => "Doe"));

One alternative to this approach is using PHP's CURL support; however, I'm not sure if it's really easier.