带参数的Swift GET请求

Question

我对swift非常新,所以我的代码中可能会有很多错误,但我想要实现的是向GET带有参数的localhost服务器发送请求.更多,所以我试图实现它,因为我的函数有两个参数baseURL:string,params:NSDictionary.我不确定如何将这两者合并到实际的URLRequest中？这是我到目前为止所尝试的

    func sendRequest(url:String,params:NSDictionary){
       let urls: NSURL! = NSURL(string:url)
       var request = NSMutableURLRequest(URL:urls)
       request.HTTPMethod = "GET"
       var data:NSData! =  NSKeyedArchiver.archivedDataWithRootObject(params)
       request.HTTPBody = data
       println(request)
       var session = NSURLSession.sharedSession()
       var task = session.dataTaskWithRequest(request, completionHandler:loadedData)
       task.resume()

    }

}

func loadedData(data:NSData!,response:NSURLResponse!,err:NSError!){
    if(err != nil){
        println(err?.description)
    }else{
        var jsonResult: NSDictionary = NSJSONSerialization.JSONObjectWithData(data, options: NSJSONReadingOptions.MutableContainers, error: nil) as NSDictionary
        println(jsonResult)

    }

}

Answer 1

在构建GET请求时,请求没有正文,而是URL上的所有内容.要构建URL(并正确地转义它),您也可以使用URLComponents.

var url = URLComponents(string: "https://www.google.com/search/")!

url.queryItems = [
    URLQueryItem(name: "q", value: "War & Peace")
]

唯一的技巧是大多数Web服务需要+转义字符百分比(因为它们会将其解释为application/x-www-form-urlencoded规范所指示的空格字符).但URLComponents不会百分之百逃脱它.Apple认为这+是查询中的有效字符,因此不应进行转义.从技术上讲,它们是正确的,它允许在URI的查询中,但它在application/x-www-form-urlencoded请求中具有特殊含义,实际上不应该传递未转义.

Apple承认我们必须百分之百逃避+角色,但建议我们手动完成:

var url = URLComponents(string: "https://www.wolframalpha.com/input/")!

url.queryItems = [
    URLQueryItem(name: "i", value: "1+2")
]

url.percentEncodedQuery = url.percentEncodedQuery?.replacingOccurrences(of: "+", with: "%2B")

这是一个不优雅的解决方案,但是它有效,并且如果您的查询可能包含一个+字符并且您有一个服务器将它们解释为空格,那么它就是Apple建议的.

因此,将它与您的sendRequest日常工作相结合,您最终得到的结果如下:

func sendRequest(_ url: String, parameters: [String: String], completion: @escaping ([String: Any]?, Error?) -> Void) {
    var components = URLComponents(string: url)!
    components.queryItems = parameters.map { (key, value) in 
        URLQueryItem(name: key, value: value) 
    }
    components.percentEncodedQuery = components.percentEncodedQuery?.replacingOccurrences(of: "+", with: "%2B")
    let request = URLRequest(url: components.url!)

    let task = URLSession.shared.dataTask(with: request) { data, response, error in
        guard let data = data,                            // is there data
            let response = response as? HTTPURLResponse,  // is there HTTP response
            (200 ..< 300) ~= response.statusCode,         // is statusCode 2XX
            error == nil else {                           // was there no error, otherwise ...
                completion(nil, error)
                return
        }

        let responseObject = (try? JSONSerialization.jsonObject(with: data)) as? [String: Any]
        completion(responseObject, nil)
    }
    task.resume()
}

你会这样称呼它:

sendRequest("someurl", parameters: ["foo": "bar"]) { responseObject, error in
    guard let responseObject = responseObject, error == nil else {
        print(error ?? "Unknown error")
        return
    }

    // use `responseObject` here
}

就个人而言,我JSONDecoder现在使用并返回自定义struct而不是字典,但这并不重要.希望这说明了如何将参数百分比编码为GET请求的URL的基本思路.

请参阅Swift 2 的此答案的前一版本以及手动转义的百分比再现.

Answer 2

使用NSURLComponents来构建这样的NSURL

var urlComponents = NSURLComponents(string: "https://www.google.de/maps/")!

urlComponents.queryItems = [
  NSURLQueryItem(name: "q", value: String(51.500833)+","+String(-0.141944)),
  NSURLQueryItem(name: "z", value: String(6))
]
urlComponents.URL // returns https://www.google.de/maps/?q=51.500833,-0.141944&z=6

字体:https://www.ralfebert.de/snippets/ios/encoding-nsurl-get-parameters/

Answer 3

我正在使用这个，在操场上试试。将基本网址定义为常量中的结构

struct Constants {

    struct APIDetails {
        static let APIScheme = "https"
        static let APIHost = "restcountries.eu"
        static let APIPath = "/rest/v1/alpha/"
    }
}

private func createURLFromParameters(parameters: [String:Any], pathparam: String?) -> URL {

    var components = URLComponents()
    components.scheme = Constants.APIDetails.APIScheme
    components.host   = Constants.APIDetails.APIHost
    components.path   = Constants.APIDetails.APIPath
    if let paramPath = pathparam {
        components.path = Constants.APIDetails.APIPath + "\(paramPath)"
    }
    if !parameters.isEmpty {
        components.queryItems = [URLQueryItem]()
        for (key, value) in parameters {
            let queryItem = URLQueryItem(name: key, value: "\(value)")
            components.queryItems!.append(queryItem)
        }
    }

    return components.url!
}

let url = createURLFromParameters(parameters: ["fullText" : "true"], pathparam: "IN")

//Result url= https://restcountries.eu/rest/v1/alpha/IN?fullText=true