使用 Alamofire Swift 分块的 JSON 流式传输

Question

如何使用 Alamofire 请求获取 JSON 流。我正在使用以下函数来获取响应

self.sessionManager?.request(url, method: methodType!, parameters: params, encoding: JSONEncoding.default, headers: headers)
            .validate()
            .responseJSON { (response) in
                if (response.result.error == nil) {
                    completion(response.result.value as AnyObject?, nil , response.response?.statusCode )
                } else {
                    // debugPrint("HTTP Request failed: \(String(describing: response.result.error))")
                    completion(nil, response.result.error, response.response?.statusCode)
                }
        }

我的 API Url 类似于

http://{server Url}/services/data/{number of chunks}/{items in per chunk}

如果块数为 3 且每个块的项目数为 3，我从 API 得到的响应

data: [
    {
        "invalidDraft": false,
        "bulkReserve": false,
        "srNo": 0,
        "returned": false,
        "status": "ACTIVE",
        "timestamp": 1580186026419,

    },
    {
        "invalidDraft": false,
        "bulkReserve": false,
        "srNo": 0,
        "returned": false,
        "status": "ACTIVE",
        "timestamp": 1580186026417,
    },
    {
        "invalidDraft": false,
        "bulkReserve": false,
        "srNo": 0,
        "returned": false,
        "status": "ACTIVE",
        "timestamp": 1580186026417,
    }
]

data: [
    {
        "invalidDraft": false,
        "bulkReserve": false,
        "srNo": 0,
        "returned": false,
        "status": "ACTIVE",
        "timestamp": 1580186026417,
    },
    {
        "invalidDraft": false,
        "bulkReserve": false,
        "srNo": 0,
        "returned": false,
        "status": "ACTIVE",
        "timestamp": 1580186026417,
    },
    {
        "invalidDraft": false,
        "bulkReserve": false,
        "srNo": 0,
        "returned": false,
        "status": "ACTIVE",
        "timestamp": 1580186026417,
    }
]

data: [
    {
        "invalidDraft": false,
        "bulkReserve": false,
        "srNo": 0,
        "returned": false,
        "status": "ACTIVE",
        "timestamp": 1580186026417,
    },
    {
        "invalidDraft": false,
        "bulkReserve": false,
        "srNo": 0,
        "returned": false,
        "status": "ACTIVE",
        "timestamp": 1580186026417,
    },
    {
        "invalidDraft": false,
        "bulkReserve": false,
        "srNo": 0,
        "returned": false,
        "status": "ACTIVE",
        "timestamp": 1580186026417,
    }
]

data:done

我没有从服务器得到任何响应，但在 Postman 中它工作正常。

Answer 1

要接收流数据，可以尝试添加

request.stream(closure: { data in ... })

在闭包内部，您应该在调用响应后从服务器收集数据块并在最近解析它们。 在这种情况下，响应将为零。

所以应该是这样的：

let mData = NSMutableData()

self.sessionManager?
    .request(url, method: methodType!, parameters: params, encoding: JSONEncoding.default, headers: headers)
    .validate()       
    .stream(closure: { data in mData.append(data) })
    .response { response in
       //parse mData
    }

Answer 2

您的请求失败的原因可能是您使用responseJSON 来解析响应，而响应似乎不是有效的json。

返回的数据由三个名为data 的单独数组组成，它们都位于顶层。这应该如何转换为字典或数组？

是否可以更改服务器格式化响应的方式，例如 - 让它返回一个顶级数组，其中包含多个 data 子数组（每个块一个）？有点像这样：

[
    [
        {
            "invalidDraft": false,
            "bulkReserve": false,
            "srNo": 0,
            "returned": false,
            "status": "ACTIVE",
            "timestamp": 1580186026419
        },
        {
            "invalidDraft": false,
            "bulkReserve": false,
            "srNo": 0,
            "returned": false,
            "status": "ACTIVE",
            "timestamp": 1580186026417
        },
        {
            "invalidDraft": false,
            "bulkReserve": false,
            "srNo": 0,
            "returned": false,
            "status": "ACTIVE",
            "timestamp": 1580186026417
        }
    ],
    [
        {
            "invalidDraft": false,
            "bulkReserve": false,
            "srNo": 0,
            "returned": false,
            "status": "ACTIVE",
            "timestamp": 1580186026417
        },
        {
            "invalidDraft": false,
            "bulkReserve": false,
            "srNo": 0,
            "returned": false,
            "status": "ACTIVE",
            "timestamp": 1580186026417
        },
        {
            "invalidDraft": false,
            "bulkReserve": false,
            "srNo": 0,
            "returned": false,
            "status": "ACTIVE",
            "timestamp": 1580186026417
        }
    ],
    [
         {
            "invalidDraft": false,
            "bulkReserve": false,
            "srNo": 0,
            "returned": false,
            "status": "ACTIVE",
            "timestamp": 1580186026417
        },
        {
            "invalidDraft": false,
            "bulkReserve": false,
            "srNo": 0,
            "returned": false,
            "status": "ACTIVE",
            "timestamp": 1580186026417
        },
        {
            "invalidDraft": false,
            "bulkReserve": false,
            "srNo": 0,
            "returned": false,
            "status": "ACTIVE",
            "timestamp": 1580186026417
        }
    ]
]

如果无法做到这一点，请将响应解析为字符串，然后使用正则表达式查找字符串中的每个“数据”数组，然后将其解析为 JSON。

Answer 3

详细阐述 Alex 最有帮助的答案：

fileprivate lazy var alamoSession: Session = {
    let configuration = URLSessionConfiguration.default
    configuration.timeoutIntervalForRequest = 20
    configuration.urlCache?.removeAllCachedResponses()
    return Alamofire.Session(configuration: configuration /*, interceptor: interceptor*/)
}()

fileprivate func alamofireChunked () {

    guard let url = URL(string: "http://A_Steaming_Source.com")    // Put your datasource here
    else {
        return
    }
    let urlRequest = URLRequest(url: url)

    alamoSession.streamRequest(urlRequest).validate().responseStream { response in
        if let data = response.value {
            print("received \(data.count) bytes")
            if data.count > 0 {
                // process received data here
            }
        } else {
            switch response.event {
            case .complete( _):
                // perform any post processing here
                print("stream is finished")
                break;
            default:
                break;
            }
        }
    }
}