[英]Swift GET request with parameters
I'm very new to swift, so I will probably have a lot of faults in my code but what I'm trying to achieve is send a GET
request to a localhost server with paramters.我对 swift 很陌生,所以我的代码中可能会有很多错误,但我想要实现的是向带有参数的本地主机服务器发送一个
GET
请求。 More so I'm trying to achieve it given my function take two parameters baseURL:string,params:NSDictionary
.更重要的是,鉴于我的函数采用两个参数
baseURL:string,params:NSDictionary
我正在尝试实现它。 I am not sure how to combine those two into the actual URLRequest ?我不确定如何将这两者结合到实际的 URLRequest 中? Here is what I have tried so far
这是我到目前为止尝试过的
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)
}
}
When building a GET
request, there is no body to the request, but rather everything goes on the URL.构建
GET
请求时,请求没有正文,而是所有内容都在 URL 上。 To build a URL (and properly percent escaping it), you can also use URLComponents
.要构建一个 URL(并正确地转义它),您还可以使用
URLComponents
。
var url = URLComponents(string: "https://www.google.com/search/")!
url.queryItems = [
URLQueryItem(name: "q", value: "War & Peace")
]
The only trick is that most web services need +
character percent escaped (because they'll interpret that as a space character as dictated by the application/x-www-form-urlencoded
specification ).唯一的技巧是大多数 Web 服务需要
+
字符百分比转义(因为它们会将其解释为由application/x-www-form-urlencoded
规范规定的空格字符)。 But URLComponents
will not percent escape it.但是
URLComponents
不会百分百逃避它。 Apple contends that +
is a valid character in a query and therefore shouldn't be escaped. Apple 认为
+
是查询中的有效字符,因此不应转义。 Technically, they are correct, that it is allowed in a query of a URI, but it has a special meaning in application/x-www-form-urlencoded
requests and really should not be passed unescaped.从技术上讲,它们是正确的,它在 URI 的查询中是允许的,但它在
application/x-www-form-urlencoded
请求中具有特殊含义,实际上不应该以非转义方式传递。
Apple acknowledges that we have to percent escaping the +
characters, but advises that we do it manually: Apple 承认我们必须对
+
字符进行百分比转义,但建议我们手动进行:
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")
This is an inelegant work-around, but it works, and is what Apple advises if your queries may include a +
character and you have a server that interprets them as spaces.这是一个不优雅的解决方法,但它有效,如果您的查询可能包含
+
字符并且您有一个将它们解释为空格的服务器,Apple 建议这样做。
So, combining that with your sendRequest
routine, you end up with something like:因此,将它与您的
sendRequest
例程结合起来,您最终会得到如下结果:
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 // was there no error
else {
completion(nil, error)
return
}
let responseObject = (try? JSONSerialization.jsonObject(with: data)) as? [String: Any]
completion(responseObject, nil)
}
task.resume()
}
And you'd call it like: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
}
Personally, I'd use JSONDecoder
nowadays and return a custom struct
rather than a dictionary, but that's not really relevant here.就个人而言,我现在会使用
JSONDecoder
并返回自定义struct
而不是字典,但这在这里并不重要。 Hopefully this illustrates the basic idea of how to percent encode the parameters into the URL of a GET request.希望这说明了如何将参数百分比编码到 GET 请求的 URL 中的基本思想。
See previous revision of this answer for Swift 2 and manual percent escaping renditions.有关 Swift 2 和手动百分比转义再现,请参阅此答案的先前版本。
Use NSURLComponents to build your NSURL like this像这样使用 NSURLComponents 构建你的 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
font: https://www.ralfebert.de/snippets/ios/encoding-nsurl-get-parameters/
字体: https ://www.ralfebert.de/snippets/ios/encoding-nsurl-get-parameters/
I am using this, try it in playground.我正在使用这个,在操场上试试。 Define the base urls as Struct in Constants
将基本 url 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
Swift 3 :斯威夫特 3 :
extension URL {
func getQueryItemValueForKey(key: String) -> String? {
guard let components = NSURLComponents(url: self, resolvingAgainstBaseURL: false) else {
return nil
}
guard let queryItems = components.queryItems else { return nil }
return queryItems.filter {
$0.name.lowercased() == key.lowercased()
}.first?.value
}
}
I used it to get the image name for UIImagePickerController
in func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any])
:我用它在
func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any])
中获取UIImagePickerController
的图像名称:
var originalFilename = ""
if let url = info[UIImagePickerControllerReferenceURL] as? URL, let imageIdentifier = url.getQueryItemValueForKey(key: "id") {
originalFilename = imageIdentifier + ".png"
print("file name : \(originalFilename)")
}
You can extend your Dictionary
to only provide stringFromHttpParameter
if both key and value conform to CustomStringConvertable
like this如果键和值都符合这样的
CustomStringConvertable
,您可以扩展您的Dictionary
以仅提供stringFromHttpParameter
extension Dictionary where Key : CustomStringConvertible, Value : CustomStringConvertible {
func stringFromHttpParameters() -> String {
var parametersString = ""
for (key, value) in self {
parametersString += key.description + "=" + value.description + "&"
}
return parametersString
}
}
this is much cleaner and prevents accidental calls to stringFromHttpParameters
on dictionaries that have no business calling that method这更干净,可以防止意外调用没有业务调用该方法的字典上的
stringFromHttpParameters
This extension that @Rob suggested works for Swift 3.0.1 @Rob 建议的这个扩展适用于 Swift 3.0.1
I wasn't able to compile the version he included in his post with Xcode 8.1 (8B62)我无法使用 Xcode 8.1 (8B62) 编译他在帖子中包含的版本
extension Dictionary {
/// Build string representation of HTTP parameter dictionary of keys and objects
///
/// :returns: String representation in the form of key1=value1&key2=value2 where the keys and values are percent escaped
func stringFromHttpParameters() -> String {
var parametersString = ""
for (key, value) in self {
if let key = key as? String,
let value = value as? String {
parametersString = parametersString + key + "=" + value + "&"
}
}
parametersString = parametersString.substring(to: parametersString.index(before: parametersString.endIndex))
return parametersString.addingPercentEncoding(withAllowedCharacters: .urlHostAllowed)!
}
}
I use:我用:
let dictionary = ["method":"login_user",
"cel":mobile.text!
"password":password.text!] as Dictionary<String,String>
for (key, value) in dictionary {
data=data+"&"+key+"="+value
}
request.HTTPBody = data.dataUsingEncoding(NSUTF8StringEncoding);
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