ios - Twitter 仅应用程序身份验证始终返回 401

Question

我正在尝试仅使用 App auth 进行身份验证，并且成功获得了不记名 token ，但是当我尝试调用 REST API 时，我总是收到 401 错误，这是我的代码:

private var accessToken: String?
private let consumerKey = "*********"
private let consumerSecret = "*********"
private let baseUrlString = "https://api.twitter.com/1.1/"
private let pageSize = 20

private func authenticate(completionBlock: Void -> ()) {

    if accessToken != nil {
        completionBlock()
    }

    let credentials = "\(consumerKey):\(consumerSecret)"
    let headers = ["Authorization": "Basic \(credentials.getBase64())"]
    let params: [String : AnyObject] = ["grant_type": "client_credentials"]

    Alamofire.request(.POST, "https://api.twitter.com/oauth2/token", headers: headers, parameters: params)
        .responseJSON { response in
            if let JSON = response.result.value {
                self.accessToken = JSON.objectForKey("access_token") as? String
                completionBlock()
            }
    }
}

func getTimelineForScreenName(screenName: String) {

    authenticate {

        guard let token = self.accessToken else {
            // TODO: Show authentication error
            return
        }

        let headers = ["Authorization": "Bearer \(token.getBase64())"]
        let params: [String : AnyObject] = [
            "screen_name" : screenName,
            "count": self.pageSize
        ]
        Alamofire.request(.GET, self.baseUrlString + "statuses/user_timeline.json", headers: headers, parameters: params)
            .responseJSON { response in
                print(response.response)

                if let JSON = response.result.value {
                    print(JSON)
                }
        }
    }
}

...

private extension String {
    func getBase64() -> String {
        let credentialData = self.dataUsingEncoding(NSUTF8StringEncoding)!
        return credentialData.base64EncodedStringWithOptions([])
    }
}

我已经尝试生成新 key ，但什么也没有，还尝试了在 iOS 9 中发现的这个错误中的建议，不让 Authorization header 在重定向上传递，但这个请求没有使用任何重定向。

任何想法将不胜感激。

Answer 1

经过几个小时的调查，我偶然发现带有 Bearer Token 的 header 不应编码为 base64，因此 header 应如下所示:
let headers = ["Authorization": "Bearer \(token)"] .

我希望这能帮助任何尝试类似事情的人，因为 documentation说你必须使用 base64 编码的 token 。

Step 3: Authenticate API requests with the bearer token
The bearer token may be used to issue requests to API endpoints which support application-only auth. To use the bearer token, construct a normal HTTPS request and include an Authorization header with the value of Bearer <base64 bearer token value from step 2>. Signing is not required.