swift 升級到5，更新了三方庫，支持的系統也從ios 8 升到了 ios 10 。
發現有很多方法過期了。
1.編碼

func urlencode(_ string: String) -> String {
        let mstring = string.replacingOccurrences(of: " ", with: "+")
        let legalURLCharactersToBeEscaped: CFString = "!*'\"();:@&=+$,/?%#[]% " as CFString
        return CFURLCreateStringByAddingPercentEscapes(nil, mstring as CFString?, nil, legalURLCharactersToBeEscaped, CFStringBuiltInEncodings.UTF8.rawValue) as String
}

告警如下：
'CFURLCreateStringByAddingPercentEscapes' was deprecated in iOS 9.0: Use [NSString stringByAddingPercentEncodingWithAllowedCharacters:] instead, which always uses the recommended UTF-8 encoding, and which encodes for a specific URL component or subcomponent (since each URL component or subcomponent has different rules for what characters are valid).

修改方法：

func urlencode(_ string: String) -> String {
    let mstring = string.replacingOccurrences(of: " ", with: "+")
    let set = CharacterSet(charactersIn: "!*'\"();:@&=+$,/?%#[]% ")
    return mstring.addingPercentEncoding(withAllowedCharacters: set) ?? ""
}

charactersIn的內容和服務器溝通好，但在網上也找到了通用的封裝

extension String {
     
    //將原始的url編碼為合法的url
    func urlEncoded() -> String {
        let encodeUrlString = self.addingPercentEncoding(withAllowedCharacters:
            .urlQueryAllowed)
        return encodeUrlString ?? ""
    }
     
    //將編碼后的url轉換回原始的url
    func urlDecoded() -> String {
        return self.removingPercentEncoding ?? ""
    }
}

app內一頓測試，發現以上修改方法不行，很多特殊符號沒有編譯。
最終找到了目前經過很多特殊字符測試都通過的90%完美寫法。

func urlencode(_ string: String) -> String {
    var allowedQueryParamAndKey = NSCharacterSet.urlQueryAllowed
    allowedQueryParamAndKey.remove(charactersIn: "!*'\"();:@&=+$,/?%#[]% ")
    return string.addingPercentEncoding(withAllowedCharacters: allowedQueryParamAndKey) ?? string
}

如果按你的理解認為這個上面代碼是胡扯八道，其實你不防嘗試一下。

最開始我搜索信息看到相關的代碼的時候，我直接pass他，都是要加一些未被收錄的字符，在這里刪除那肯定是錯誤的，沒想到讓一個不會swift的安卓開發同事讓嘗試一下，為了讓他死心，我一嘗試，結果竟然是正確的，我目前也給不了一個合理的解析，這段代碼就是能解決這個問題。

我們對應的后臺用的是go技術，對應的解碼是url.go中如下方法：

// QueryUnescape does the inverse transformation of QueryEscape,
// converting each 3-byte encoded substring of the form "%AB" into the
// hex-decoded byte 0xAB.
// It returns an error if any % is not followed by two hexadecimal
// digits.
func QueryUnescape(s string) (string, error) {
    return unescape(s, encodeQueryComponent)
}