Swift 使用 Alamofire 框架上传文件

Alamofire 是一个在GitHub上star数已超过24k的网络库。

先贴出一段代码，这是我在StravaKit中增加的上传fit文件功能：

extension Requestor {

    public func uploadFitFile(url: String, params: [String : String]?, file: URL, completionHandler: ((_ response: Any?, _ error: NSError?) -> ())?) {

        guard let accessToken = Strava.sharedInstance.accessToken
            else {
                let error = Strava.error(.noAccessToken, reason: "No Access Token")
                completionHandler?(nil, error)
                return
        }
        debugPrint(accessToken)
        let au = "Bearer \(accessToken)"
        let headers = ["Authorization": au]


        Alamofire.upload(multipartFormData: { (multipartFormData) in
            if let params = params {
                for (key, value) in params {
                    multipartFormData.append(value.data(using: .utf8)!, withName: key)
                }
            }
            multipartFormData.append(file, withName: "file", fileName: file.lastPathComponent, mimeType: "multipart/form-data")
        }, usingThreshold: SessionManager.multipartFormDataEncodingMemoryThreshold, to: baseUrl + url, method: .post, headers: headers) { (encodingResult) in
            switch encodingResult {
            case .success(let upload, _, _):
                upload.responseJSON(completionHandler: { (response) in

                    if let value = response.result.value {
                        let dict = value as! Dictionary<String, Any>;
                        var error = response.result.error as NSError?
                        if let err = dict["error"] {
                            if (err as AnyObject).isKind(of: NSNull.self) {
                                // 成功
                                debugPrint("成功")

                            } else {
                                // 失败
                                debugPrint("失败",err)
                                error = NSError.init(domain: "strava", code: 0, userInfo: [NSLocalizedDescriptionKey:err])

                            }

                        }

                        if let completionHandler = completionHandler {
                            completionHandler(response.result,error)
                        }
                    } else {
                        if let completionHandler = completionHandler {
                            if let error = response.result.error {
                                completionHandler(response.result,error as NSError)
                            }

                        }

                    }

                })
            case .failure(let error):
                print(error)
            }

        }

    }


}