Calcular frete dos correios com Laravel

example.php

<?php
$freightPostOffice = new FreightPostOfficeService();

$dataFreight = [
	'source-zip-code' => '18780-000',
	'destiny-zip-code' => '17025-060',
	'weight-product' => 1,
	'length-product' => 16,
	'height-product' => 5,
	'width-product' => 15,
	'diameter-product' => 0,
	'value-product' => '200.50',
	'code-service' => 40010
];

$freight = $freightPostOffice->setData($dataFreight)
  ->calcFreight());

FreightPostOfficeService.php

<?php
class FreightPostOfficeService {
	/**
	 * Source zip code to calculate the freight
	 *
	 * @var
	 */
	public $sourceZipCode;

	/**
	 * Destiny zip code to calculate the freight
	 *
	 * @var
	 */
	public $destinyZipCode;

	/**
	 * Weight of the product being shipped
	 *
	 * @var
	 */
	public $weightProduct;

	/**
	 * Format of the product being shipped (1 = box, 2 = package)
	 *
	 * @var int
	 */
	public $formatProduct = 1;

	/**
	 * Length of the product being shipped
	 *
	 * @var
	 */
	public $lengthProduct;

	/**
	 * Height of the product being shipped
	 *
	 * @var
	 */
	public $heightProduct;

	/**
	 * Width of the product being shipped
	 *
	 * @var
	 */
	public $widthProduct;

	/**
	 * Diameter of the product being shipped
	 *
	 * @var int
	 */
	public $diameterProduct = 0;

	/**
	 * Declared value of the product being shipped
	 *
	 * @var
	 */
	public $valueProduct;

	/**
	 * Only for a particular person
	 *
	 * @var bool
	 */
	public $onlyOwner = true;

	/**
	 * Receive delivery notifications
	 *
	 * @var bool
	 */
	public $receiveAlert = false;

	/**
	 * Type of data return
	 *
	 * @var string
	 */
	protected $typeReturn = 'xml';

	/**
	 * Post office service code
	 *
	 * @var
	 */
	public $codeService;

	/**
	 * Company code if have contract with the post office
	 *
	 * @var
	 */
	public $codeCompany;

	/**
	 * Company password if have contract with the post office
	 *
	 * @var
	 */
	public $passwordCompany;

	/**
	 * Calculate the freight
	 *
	 * @return array
	 */
	public function calcFreight(){
		$params = $this->buildQuery($this->createParams());

		$curl = curl_init('http://ws.correios.com.br/calculador/CalcPrecoPrazo.aspx?'.$params);
		curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
		$response = curl_exec($curl);

		$data = $this->loadXML($response);

		foreach($data->cServico as $service){
			return $this->formatService($service);
		}

		return ['type' => 'error', 'message' => 'Ocorreu um erro ao processar!'];
	}

	/**
	 * Format the received service information
	 *
	 * @param $service
	 *
	 * @return array
	 */
	private function formatService($service){
		if($service->Erro != 0)
			return ['type' => 'error', 'message' => $service->MsgErro];

		return [
			'type' => 'success',
			'response' => [
				'code' => $service->Codigo,
				'price' => $service->Valor,
				'deadline' => $service->PrazoEntrega
			]
		];
	}

	/**
	 * Create the parameters to make the requisition
	 *
	 * @return array
	 */
	private function createParams(){
		return [
			/*
			 * Company code and password, if you have a contract with the post office.
			 */
			'nCdEmpresa' => $this->codeCompany,
			'sDsSenha' => $this->passwordCompany,

			/*
			 * Zip codes
			 */
			'sCepOrigem' => $this->sourceZipCode,
			'sCepDestino' => $this->destinyZipCode,

			/*
			 * Product information to be sent
			 */
			'nVlPeso' => $this->weightProduct,
			'nCdFormato' => $this->formatProduct,
			'nVlComprimento' => $this->lengthProduct,
			'nVlAltura' => $this->heightProduct,
			'nVlLargura' => $this->widthProduct,
			'nVlDiametro' => $this->diameterProduct,
			'nVlValorDeclarado' => $this->valueProduct,

			/*
			 * If delivery is to be delivered only to a particular person
			 */
			'sCdMaoPropria' => $this->convertAnswersBoolean($this->onlyOwner),

			/*
			 * If you'd like to receive delivery notifications
			 */
			'sCdAvisoRecebimento' => $this->convertAnswersBoolean($this->receiveAlert),

			/*
			 * Type of information to be returned
			 */
			'StrRetorno' => $this->typeReturn,

			/*
			 * Post office service code
			 */
			'nCdServico' => $this->codeService
		];
	}

	/**
	 * Convert some bool values to Yes or No
	 *
	 * @param $value
	 *
	 * @return string
	 */
	private function convertAnswersBoolean($value){
		if(!is_bool($value))
			return $value;

		return ($value === true) ? 's' : 'n';
	}

	/**
	 * Build the query
	 *
	 * @param $params
	 *
	 * @return string
	 */
	private function buildQuery($params){
		return http_build_query($params);
	}

	/**
	 * Load the XML
	 *
	 * @param $response
	 *
	 * @return \SimpleXMLElement
	 */
	private function loadXML($response){
		return simplexml_load_string($response);
	}

	/**
	 * Define variables in class
	 *
	 * @param $data
	 *
	 * @return $this
	 */
	public function setData($data){
		foreach($data as $key => $val){
			$attr = camel_case($key);
			if(property_exists($this, $attr))
				$this->$attr = $val;
		}

		return $this;
	}
}