建立GET
请求时,请求的主体没有,但是所有内容都放在URL上。要构建网址(并正确地将其转义), 您还可以使用URLComponents
.
var url = URLComponents(string: "https://www.google.com/search/")!
url.queryItems = [
URLQueryItem(name: "q", value: "War & Peace")
]
唯一的窍门是,大多数Web服务都需要+转义字符百分比 (因为它们会将其解释为application/x-www-form-urlencoded
规范规定的空格字符)。但是URLComponents不会百分百逃脱它。Apple认为这+是查询中的有效字符,因此不应 转义。从技术上讲,它们是正确的,它可以在URI查询中使用,但它在application/x-www-form-urlencoded
请求中具有特殊含义,实际上不应未经转义地传递。
苹果公司承认我们必须对+字符进行转义,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")
这是一个不太好的解决方法,但是它可以工作,这是Apple建议您的查询是否可以包含+字符并且您拥有将其解释为空格的服务器的建议。
因此,将其与sendRequest
例行程序结合在一起,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 else { // was there no error, otherwise ...
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:
sendRequest("someurl", parameters: ["foo": "bar"]) { responSEObject, error in
guard let responSEObject = responSEObject, error == nil else {
print(error ?? "UnkNown error")
return
}
// use `responSEObject` here
}
就我个人而言,JSONDecoder如今我会使用它并返回一个自定义struct而不是字典,但这在这里并不重要。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。