ios - 在 Swift 中的 WebService 中传递参数

Question

我正在学习 Swift，但我不知道如何使用 Swift 将参数发送到服务器。在 Objective-C 中，我们可以通过使用 "%@" 作为占位符来做到这一点。但是在 Swift 的情况下应该做什么，假设我有一个需要电子邮件和密码的登录网络服务。

现在我想知道的是如何将logintextfield 和passwordtextfield 文本发送到服务器，例如，

var bodyData = "email=logintextfield.text&password=passwordtextfield.text"

Answer 1

当创建包含用户输入的 HTTP 请求时，通常应该对它进行百分号转义，以防用户输入中有任何保留字符，因此:

let login    = logintextfield.text?.addingPercentEncodingForURLQueryValue() ?? ""
let password = passwordtextfield.text?.addingPercentEncodingForURLQueryValue() ?? ""
let bodyData = "email=\(login)&password=\(password)"

请注意，您确实需要检查 login 和 password 是否为 nil。无论如何，百分比转义是按如下方式完成的:

extension String {

    /// Percent escapes values to be added to a URL query as specified in RFC 3986
    ///
    /// This percent-escapes all characters besides the alphanumeric character set and "-", ".", "_", and "~".
    ///
    /// http://www.ietf.org/rfc/rfc3986.txt
    ///
    /// :returns: Returns percent-escaped string.

    func addingPercentEncodingForURLQueryValue() -> String? {
        let allowedCharacters = CharacterSet(charactersIn: "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-._~")

        return self.addingPercentEncoding(withAllowedCharacters: allowedCharacters)
    }

}

有关此扩展的另一个版本，请参阅 this answer。

---

如果您想观看上述内容的使用演示，请想象以下请求:

let keyData = "AIzaSyCRLa4LQZWNQBcjCYcIVYA45i9i8zfClqc"
let sensorInformation = false
let types = "building"
let radius = 1000000
let locationCoordinate = CLLocationCoordinate2D(latitude:40.748716, longitude: -73.985643)
let name = "Empire State Building, New York, NY"
let floors = 102
let now = Date()

let params:[String: Any] = [
    "key" : keyData,
    "sensor" : sensorInformation,
    "typesData" : types,
    "radius" : radius,
    "location" : locationCoordinate,
    "name" : name,
    "floors" : floors,
    "when" : now,
    "pi" : M_PI]

let url = URL(string: "http://some.web.site.com/inquiry")!
var request = URLRequest(url: url)
request.setValue("application/x-www-form-urlencoded", forHTTPHeaderField: "Content-Type")
request.httpBody = params.dataFromHttpParameters()

let task = URLSession.shared.dataTask(with: request) { data, response, error in
    guard data != nil && error == nil else {
        print("error submitting request: \(error)")
        return
    }

    if let httpResponse = response as? HTTPURLResponse where httpResponse.statusCode != 200 {
        print("response was not 200: \(response)")
        return
    }

    // handle the data of the successful response here
}
task.resume()

我包含了很多您的示例中未包含的参数，但只是为了说明例程对各种参数类型数组的处理方式。

顺便说一下，上面使用了我的 datafromHttpParameters 函数:

extension Dictionary {

    /// This creates a String representation of the supplied value.
    ///
    /// This converts NSDate objects to a RFC3339 formatted string, booleans to "true" or "false",
    /// and otherwise returns the default string representation.
    ///
    /// - parameter value: The value to be converted to a string
    ///
    /// - returns:         String representation

    private func httpStringRepresentation(_ value: Any) -> String {
        switch value {
        case let date as Date:
            return date.rfc3339String()
        case let coordinate as CLLocationCoordinate2D:
            return "\(coordinate.latitude),\(coordinate.longitude)"
        case let boolean as Bool:
            return boolean ? "true" : "false"
        default:
            return "\(value)"
        }
    }

    /// Build `Data` representation of HTTP parameter dictionary of keys and objects
    ///
    /// This percent escapes in compliance with RFC 3986
    ///
    /// http://www.ietf.org/rfc/rfc3986.txt
    ///
    /// :returns: String representation in the form of key1=value1&key2=value2 where the keys and values are percent escaped

    func dataFromHttpParameters() -> Data {
        let parameterArray = self.map { (key, value) -> String in
            let percentEscapedKey = (key as! String).addingPercentEncodingForURLQueryValue()!
            let percentEscapedValue = httpStringRepresentation(value).addingPercentEncodingForURLQueryValue()!
            return "\(percentEscapedKey)=\(percentEscapedValue)"
        }

        return parameterArray.joined(separator: "&").data(using: .utf8)!
    }

}

这里，因为我处理的是一个参数字符串数组，所以我使用join函数将它们连接起来，用&分隔，但思路是一样的。

随意自定义该函数以处理您可能传递给它的任何数据类型(例如，我通常没有 CLLocationCoordinate2D ，但您的示例包含一个，所以我想展示它可能看起来像什么)。但关键是，如果您提供任何包含用户输入的字段，请确保对其进行百分比转义。

仅供引用，这是我在上面使用的 rfc3339String 函数。 (显然，如果您不需要传输日期，则不需要这个，但为了更通用的解决方案的完整性，我将其包括在内。)

extension Date {

    /// Get RFC 3339/ISO 8601 string representation of the date.
    ///
    /// For more information, see:
    ///
    /// https://developer.apple.com/library/ios/qa/qa1480/_index.html
    ///
    /// - returns: Return RFC 3339 representation of date string

    func rfc3339String() -> String {
        let formatter = DateFormatter()

        formatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ss.SSSX"
        formatter.timeZone = TimeZone(secondsFromGMT: 0)
        formatter.locale = Locale(identifier: "en_US_POSIX")

        return formatter.string(from: self)
    }
}

要查看 Swift 2 版本，请参阅此答案的 previous rendition。