demonstration of HTTP GET requests in swift

http_get.swift

//
//  main.swift
//  HTTPGet
//
//  Created by david on 9/30/20.
//

import Foundation

func async_req() -> Void {
    let url = URL(string: "http://example.com")!

    let task = URLSession.shared.dataTask(with: url) {(data, response, error) in
        guard let data = data else { return }
        print(String(data: data, encoding: .utf8)!)
    }

    task.resume()
    
    //wait for task to complete
    RunLoop.main.run()
}


extension URLSession {
    func synchronousDataTask(urlrequest: URLRequest) -> (data: Data?, response: URLResponse?, error: Error?) {
        var data: Data?
        var response: URLResponse?
        var error: Error?

        let semaphore = DispatchSemaphore(value: 0)

        let dataTask = self.dataTask(with: urlrequest) {
            data = $0
            response = $1
            error = $2

            semaphore.signal()
        }
        dataTask.resume()

        _ = semaphore.wait(timeout: .distantFuture)

        return (data, response, error)
    }
}

func sync_req() -> Void {
    
    let url = URL(string: "http://example.com")!
    var request = URLRequest(url: url)
    request.httpMethod = "GET"
    let (data, response, error) = URLSession.shared.synchronousDataTask(urlrequest: request)
    if let error = error {
        print("Synchronous task ended with error: \(error)")
    }
    else {
        print("Synchronous task ended without errors.")
        print("response: \(response)")
        
        if let data = data,
            let urlContent = NSString(data: data, encoding: String.Encoding.ascii.rawValue) {
            print(urlContent)
        } else {
            print("Error: \(error)")
        }
        
        if let data = data,
            let urlContent = NSString(data: data, encoding: String.Encoding.ascii.rawValue) {
            print(urlContent)
        } else {
            print("Error: \(error)")
        }
        
        //print("data: \(data)")
    }

}

sync_req()
async_req()