如何在Swift中转义HTTP参数

Question

我正在尝试向HTTP服务器发帖

顺便说一下这是我的代码:

  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.

我怎样才能逃脱关键和价值观？

我还能做些什么改进方法吗？

Answer 1

如果您可以定位iOS 8(感谢@Rob),请使用NSURLComponents以转义参数:

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 ?? ""
}

现在按照您的预期encodeParameters(params:["hello":"world","inject":"param1=value1&param2=value2"])返回hello=world&inject=param1%3Dvalue1%26param2%3Dvalue2.

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的答案,正确使用filter/map以很好的方式执行编码.