Combine Frameworkcan be used to build robust and reusable Network Services in an iOS app. In this post I will demonstrate how to create a Network Service with Combine and Alamofire.

First let’s add Alamofire to the Podfile.

platform :ios, '11.0'

	target 'Project' do
	  # Comment the next line if you don't want to use dynamic frameworks
	  use_frameworks!

	  # Pods for Project
	  pod 'Alamofire', '~> 5.2'

	end

Now Let’s check the **CoreService **struct.

import Combine
	import Alamofire

	struct CoreService {

	    static func request<T: Decodable, E: Error>(
	        url: String,
	        method: HTTPMethod,
	        parameters: Parameters?,
	        decoder: JSONDecoder = JSONDecoder(),
	        headers: HTTPHeaders? = nil
	    ) -> Future<T, E> {
	        return Future({ promise in
	            AF.request(
	                url,
	                method: method,
	                parameters: parameters,
	                headers: headers
	            ).responseDecodable(decoder: decoder, completionHandler: { (response: DataResponse<T, AFError>) in
	                switch response.result {
	                    case .success(let value):
	                        promise(.success(value))
	                    case .failure(let error):
	                        promise(.failure(
	                            NSError(domain: error.destinationURL?.absoluteString ?? "", code: error.responseCode ?? 0) as! E
	                            )
	                    )
	                }
	            })
	        })
	    }
	}

The **request **method defines type **T **which conforms to **Codable **(Encodable or Decodable protocols) and type E which conforms to **Error **protocol as type parameters. It returns a Futurewhich takes in type **T **as Output and type **E **as Failure.

Here is the **ExampleService **struct.

import Combine
	import Alamofire

	struct ExampleService {

	    static func getData(_ parameters: [String: String]) -> Future<EditionResponse, Error> {
	        let url = Constants.baseUrl + Constants.versionUrl + Constants.editionUrl
	        return CoreService.request(
	            url: url,
	            method: HTTPMethod.get,
	            parameters: parameters
	        )
	    }
	}

ExampleService defines a getData method that has parametersdictionary as its parameter and returns a Future<EditionResponse, Error>. It calls **CoreService.request **passing **HTTPMethod.get **which makes this request an **HTTP GET **request.

#ios #swift #programming