Swift Sample

| Swift | SwiftUI |Xcode | Mac |

Network

データ取得

---

        let url = URL(string: "https://www.typea.info/blog/")!
        let task = URLSession.shared.dataTask(with: url) { data, response, error in
            if let error = error {
                print("\(error)\n")
                return
            }
            guard let data = data, let response = response as? HTTPURLResponse else {
                print("no data or no response.")
                return
            }
            if response.statusCode == 200 {
                if let text = String(bytes: data, encoding: .utf8) {
                    print(text)
                }
            }
        }
        task.resume()

MacOSでエラーの場合

Error Domain=NSURLErrorDomain Code=-1003

• https://www.poly-rhythm.com/hostname-could-not-be-found/
• https://developer.apple.com/documentation/xcode/adding_capabilities_to_your_app

UI

バックグラウンドからUIを操作する

---

• observableobj が、ObservableObject の派生クラス
• contentフィールドに、@Published アノテーション
• Viewで、@ObservedObjectを付与しインスタンスを生成
• 上記で、バックグラウンドから、observableobj.contentを操作すると、UIはメインスレッドから触るように怒られる。

Publishing changes from background threads is not allowed; make sure to publish values from the main thread (via operators like receive(on:)) on model updates.

• DispatchQueue.main.syncで囲む

DispatchQueue.main.sync {
    observableobj.content = text
}

処理

サブプロセスを起動

• プロセスを起動し、arp -a を呼び出し、出力

    func arp() {
        let outputPipe = Pipe()

        func shell(path:String ,args: String...) -> Int32 {
            let task = Process()
            task.launchPath = path
            task.arguments = args
            task.standardOutput = outputPipe
            task.standardError = outputPipe
            
            task.launch()
            task.waitUntilExit()
            
            return task.terminationStatus
        }
        let _ = shell(path:"/usr/sbin/arp",args: "-a")
        let theTaskData = outputPipe.fileHandleForReading.readDataToEndOfFile()
        let stringResult = String(data: theTaskData, encoding: .utf8)
        
        print(stringResult!)
    }

正規表現

    func parseArp(arpResult: String?) {
        if let input = arpResult {
            do {
                let pattern = #"[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}"#
                let regex = try NSRegularExpression(pattern: pattern, options:[])
                
                for subinput in input.split(separator: "\r\n") {
                    let line = String(subinput)
                    let maches = regex.matches(in: line, options: [], range: _NSRange(0..<line.count))
                    
                    print(line)
                    
                    for mach in maches {
                        for i in 0 ..< mach.numberOfRanges {
                            let start = line.index(line.startIndex, offsetBy: mach.range(at: i).location)
                            let end = line.index(start, offsetBy: mach.range(at: i).length)
                            let text = String(line[start..<end])
                            print(text)
                        }
                    }
                }
            } catch {
                print("RegEx fail.")
            }
        } else {
            print("arp -a result : error")
    }