sdk.class.php

<?php
// … 
	/**
	 * Default, shared method for authenticating a connection to AWS.
	 *
	 * @param string $operation (Required) Indicates the operation to perform.
	 * @param array $payload (Required) An associative array of parameters for authenticating. See the individual methods for allowed keys.
	 * @return CFResponse Object containing a parsed HTTP response.
	 */
	public function authenticate($operation, $payload)
	{
		$original_payload = $payload;
		$method_arguments = func_get_args();
		$curlopts = array();
		$return_curl_handle = false;

		if (substr($operation, 0, strlen($this->operation_prefix)) !== $this->operation_prefix)
		{
			$operation = $this->operation_prefix . $operation;
		}

		// Extract the custom CURLOPT settings from the payload
		if (is_array($payload) && isset($payload['curlopts']))
		{
			$curlopts = $payload['curlopts'];
			unset($payload['curlopts']);
		}

		// Determine whether the response or curl handle should be returned
		if (is_array($payload) && isset($payload['returnCurlHandle']))
		{
			$return_curl_handle = isset($payload['returnCurlHandle']) ? $payload['returnCurlHandle'] : false;
			unset($payload['returnCurlHandle']);
		}

		// Use the caching flow to determine if we need to do a round-trip to the server.
		if ($this->use_cache_flow)
		{
			// Generate an identifier specific to this particular set of arguments.
			$cache_id = $this->key . '_' . get_class($this) . '_' . $operation . '_' . sha1(serialize($method_arguments));

			// Instantiate the appropriate caching object.
			$this->cache_object = new $this->cache_class($cache_id, $this->cache_location, $this->cache_expires, $this->cache_compress);

			if ($this->delete_cache)
			{
				$this->use_cache_flow = false;
				$this->delete_cache = false;
				return $this->cache_object->delete();
			}

			// Invoke the cache callback function to determine whether to pull data from the cache or make a fresh request.
			$data = $this->cache_object->response_manager(array($this, 'cache_callback'), $method_arguments);

			// Parse the XML body
			$data = $this->parse_callback($data);

			// End!
			return $data;
		}

		/*%******************************************************************************************%*/

		// Signer
		$signer = new $this->auth_class($this->hostname, $operation, $payload, $this->credentials);
		$signer->key = $this->key;
		$signer->secret_key = $this->secret_key;
		$signer->auth_token = $this->auth_token;
		$signer->api_version = $this->api_version;
		$signer->utilities_class = $this->utilities_class;
		$signer->request_class = $this->request_class;
		$signer->response_class = $this->response_class;
		$signer->use_ssl = $this->use_ssl;
		$signer->proxy = $this->proxy;
		$signer->util = $this->util;
		$signer->registered_streaming_read_callback = $this->registered_streaming_read_callback;
		$signer->registered_streaming_write_callback = $this->registered_streaming_write_callback;
		$request = $signer->authenticate();

		// Update RequestCore settings
		$request->request_class = $this->request_class;
		$request->response_class = $this->response_class;
		$request->ssl_verification = $this->ssl_verification;

		/*%******************************************************************************************%*/

		// Debug mode
		if ($this->debug_mode)
		{
			$request->debug_mode = $this->debug_mode;
		}

		// Set custom CURLOPT settings
		if (count($curlopts))
		{
			$request->set_curlopts($curlopts);
		}

		// Manage the (newer) batch request API or the (older) returnCurlHandle setting.
		if ($this->use_batch_flow)
		{
			$handle = $request->prep_request();
			$this->batch_object->add($handle);
			$this->use_batch_flow = false;

			return $handle;
		}
		elseif ($return_curl_handle)
		{
			return $request->prep_request();
		}

		// Send!
		$request->send_request();

		// Prepare the response.
		$headers = $request->get_response_header();
		$headers['x-aws-stringtosign'] = $signer->string_to_sign;

		if (isset($signer->canonical_request))
		{
			$headers['x-aws-canonicalrequest'] = $signer->canonical_request;
		}

		$headers['x-aws-request-headers'] = $request->request_headers;
		$headers['x-aws-body'] = $signer->querystring;

		$data = new $this->response_class($headers, ($this->parse_the_response === true) ? $this->parse_callback($request->get_response_body()) : $request->get_response_body(), $request->get_response_code());

		// Was it Amazon's fault the request failed? Retry the request until we reach $max_retries.
		if (
		    (integer) $request->get_response_code() === 500 || // Internal Error (presumably transient)
		    (integer) $request->get_response_code() === 503)   // Service Unavailable (presumably transient)
		{
			if ($this->redirects <= $this->max_retries)
			{
				// Exponential backoff
				$delay = (integer) (pow(4, $this->redirects) * 100000);
				usleep($delay);
				$this->redirects++;
				$data = $this->authenticate($operation, $original_payload);
			}
		}

		// DynamoDB has custom logic
		elseif (
			(integer) $request->get_response_code() === 400 &&
			 stripos((string) $request->get_response_body(), 'com.amazonaws.dynamodb.') !== false && (
				stripos((string) $request->get_response_body(), 'ProvisionedThroughputExceededException') !== false
			)
		)
		{
			if ($this->redirects === 0)
			{
				$this->redirects++;
				$data = $this->authenticate($operation, $original_payload);
			}
			elseif ($this->redirects <= max($this->max_retries, 10))
			{
				// Exponential backoff
				$delay = (integer) (pow(2, ($this->redirects - 1)) * 50000);
				usleep($delay);
				$this->redirects++;
				$data = $this->authenticate($operation, $original_payload);
			}
		}

		$this->redirects = 0;
		return $data;
	}