Data to AWS Eventbridge without external AWS dependency

AmazonEventbridge.php

<?php

/*
   POST / HTTP/1.1
   Host: events.<region>.<domain>
   x-amz-Date: <Date>
   Authorization: AWS4-HMAC-SHA256 Credential=<Credential>, SignedHeaders=content-type;date;host;user-agent;x-amz-date;x-amz-target;x-amzn-requestid, Signature=<Signature>
   User-Agent: <UserAgentString>
   Content-Type: application/x-amz-json-1.1
   Content-Length: <PayloadSizeBytes>
   Connection: Keep-Alive 
   X-Amz-Target: AWSEvents.PutEvents

   {
   "Entries":[
   {
   "Source":"com.mycompany.myapp",
   "Detail":"{ \"key1\": \"value1\", \"key2\": \"value2\" }",
   "Resources":[
   "resource1",
   "resource2"
   ],
   "DetailType":"myDetailType"
   },
   {
   "Source":"com.mycompany.myapp",
   "Detail":"{ \"key1\": \"value3\", \"key2\": \"value4\" }",
   "Resources":[
   "resource1",
   "resource2"
   ],
   "DetailType":"myDetailType"
   }
   ]
   }
 */

class AmazonEventbridge
{

	static  $utc_tz;

	/** @var string $access_key */
	private $ACCESS_KEY;
	/** @var string $secret_key */
	private $SECRET_KEY;
	private $REGION = 'eu-west-1';

	public function __construct($access_key, $secret_key, $region = 'eu-west-1')
	{
		$this->ACCESS_KEY = $access_key;
		$this->SECRET_KEY = $secret_key;

		if (empty($this->ACCESS_KEY) || empty($this->SECRET_KEY)) {
			throw new InvalidArgumentException('Must define Amazon access key and secret key');
		}

		$this->REGION = $region;
	}

	// Minimum number of 1 item. Maximum number of 10 items.
	function eventbridge($eventBus, $source, $detailType, $entries)
	{

		if (!is_array($entries)) throw new Exception("Argument entries must be an array");
		if (count($entries) == 0 || count($entries) > 10) throw new Exception("Argument must minimum of 1 and maximum 10 entries");

		if (!self::$utc_tz)
			self::$utc_tz = new \DateTimeZone('UTC');

		$APIVERSION = '20131202';
		$datestamp  = new \DateTime("now", self::$utc_tz);
		$longdate   = $datestamp->format("Ymd\\THis\\Z");
		$shortdate  = $datestamp->format("Ymd");


		$out = array();
		foreach ($entries as $entry) {
			$arr = array(
					"EventBusName" => $eventBus,
					"Source" => $source, // The source of the event.
					"Detail" => json_encode($entry), // A valid JSON string
					"DetailType" => $detailType, // Free-form string used to decide what fields to expect in the event detail,
					// "TraceHeader" => 
					);
			array_push($out, $arr);
		}

		$payload = json_encode(array("Entries" => $out));

		// establish the signing key
		{
			$ksecret    = 'AWS4' . $this->SECRET_KEY;
			$kdate      = hash_hmac('sha256', $shortdate, $ksecret, true);
			$kregion    = hash_hmac('sha256', $this->REGION, $kdate, true);
			$kservice   = hash_hmac('sha256', 'events', $kregion, true);
			$ksigning   = hash_hmac('sha256', 'aws4_request', $kservice, true);
		}

		// command parameters
		$params     = array(
				'host'          => 'events.' . $this->REGION . '.amazonaws.com',
				'content-type'  => 'application/x-amz-json-1.1',
				'x-amz-date'    => $longdate,
				'x-amz-target'  => 'AWSEvents.PutEvents',
				'content-length' => strlen($payload),
				'user-agent'    => 'PHPEventbridgeLib',
				'connection'    => 'keep-alive',
				);

		$canonical_request  = $this->createCanonicalRequest($params, $payload);
		$signed_request     = hash('sha256', $canonical_request);
		$sign_string        = "AWS4-HMAC-SHA256\n{$longdate}\n$shortdate/" . $this->REGION . "/events/aws4_request\n" . $signed_request;
		$signature          = hash_hmac('sha256', $sign_string, $ksigning);

		$params['authorization'] = "AWS4-HMAC-SHA256 Credential=" . $this->ACCESS_KEY . "/$shortdate/" . $this->REGION . "/events/aws4_request, " .
			"SignedHeaders=" . implode(";", array_keys($params))  . ", " .
			"Signature=$signature";


		/*
		 * Execute Crafted Request
		 */

		$url    = "https://events." . $this->REGION . ".amazonaws.com";
		$ch     = curl_init();

		$curl_headers = array();
		foreach ($params as $p => $k)
			$curl_headers[] = $p . ": " . $k;

		curl_setopt($ch, CURLOPT_URL, $url);
		curl_setopt($ch, CURLOPT_POST, 1);
		curl_setopt($ch, CURLOPT_POSTFIELDS, $payload);
		curl_setopt($ch, CURLOPT_HTTPHEADER, $curl_headers);
		curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
		curl_setopt($ch, CURLOPT_TCP_NODELAY, true);
		curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, false);
		curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);

		// debug opts
		{
			curl_setopt($ch, CURLOPT_VERBOSE, true);
			$verbose = fopen('php://temp', 'rw+');
			curl_setopt($ch, CURLOPT_STDERR, $verbose);
			$result = curl_exec($ch); // raw result
			rewind($verbose);
			$verboseLog = stream_get_contents($verbose);
		}
		$rescode = curl_getinfo($ch, CURLINFO_HTTP_CODE);

		if ($rescode == '200') {
			return true;
		} else {
			throw new EventbridgeException("Invalid server response " . $rescode .  $result);
		}
	}

	private function createCanonicalRequest(array $params, $payload)
	{
		$canonical_request      = array();
		$canonical_request[]    = 'POST';
		$canonical_request[]    = '/';
		$canonical_request[]    = '';

		$can_headers            = array(
				'host' => 'events.' . $this->REGION . '.amazonaws.com'
				);

		foreach ($params as $k => $v)
			$can_headers[strtolower($k)] = trim($v);

		uksort($can_headers, 'strcmp');

		foreach ($can_headers as $k => $v)
			$canonical_request[] = $k . ':' . $v;

		$canonical_request[] = '';
		$canonical_request[] = implode(';', array_keys($can_headers));
		$canonical_request[] = hash('sha256', $payload);

		$canonical_request = implode("\n", $canonical_request);

		return $canonical_request;
	}
}

class EventbridgeException extends Exception
{
}

// $eb = new AmazonEventbridge("xxx", "xxx");
// $eb->eventbridge("test-bus", "aaa.test.event", "Some testing", array(array("action" => "test", "somethng" => "else")));