ios - 如何在 Swift 中转义 HTTP 参数

Question

我正在尝试向 HTTP 服务器发送消息

顺便说一句，这是我的代码:

  func sendPostToUrl(url:String, withParams params: [String: String?] ) {
    var request = NSMutableURLRequest(URL: NSURL(string: url)!)
    var session = NSURLSession.sharedSession()
    request.HTTPMethod = "POST"

    var err: NSError?
    var bodyData = ""
    for (key,value) in params{
        if (value==nil){ continue }
        let scapedKey = key.stringByAddingPercentEncodingWithAllowedCharacters(
                 .URLHostAllowedCharacterSet())!
        let scapedValue = value!.stringByAddingPercentEncodingWithAllowedCharacters(
                .URLHostAllowedCharacterSet())!
        bodyData += "\(scapedKey)=\(scapedValue)&"
    }
    request.HTTPBody = bodyData.dataUsingEncoding
               (NSUTF8StringEncoding, allowLossyConversion: true)

    var task = session.dataTaskWithRequest(request, 
    completionHandler: {data, response, error -> Void in
        println("Response: \(response)")
        let dataString = NSString(data: data, encoding: NSUTF8StringEncoding)
        println("Data: \(dataString)")

    })
    task.resume()
}

它有效但并不完美。如果我这样调用函数:

    client.sendPostToUrl("http://novagecko.com/tests/test.php", 
        withParams: ["hello":"world","inject":"param1=value1&param2=value2"]);

服务器检测到 3 个帖子字段(带有键 hello、inject 和 param2)而不是 2 个。

如何转义键和值？

我还能做些什么来改进该方法吗？

Answer 1

如果您可以针对 iOS 8(感谢@Rob)，请改用 NSURLComponents 来转义您的参数:

import Foundation

func encodeParameters(#params: [String: String]) -> String {
    var queryItems = map(params) { NSURLQueryItem(name:$0, value:$1)}
    var components = NSURLComponents()
    components.queryItems = queryItems
    return components.percentEncodedQuery ?? ""
}

现在 encodeParameters(params:["hello":"world","inject":"param1=value1&param2=value2"]) 返回 hello=world&inject=param1%3Dvalue1%26param2 %3Dvalue2 如您所料。

否则，创建可让您正确转义值的字符集的最佳方法是:

var safeCharacterSet = NSCharacterSet.URLQueryAllowedCharacterSet().mutableCopy()
safeCharacterSet.removeCharactersInString("&=")

并查看@rintaro 的回答以正确使用过滤器/映射以一种很好的方式执行编码。