JSON Streaming in chunks using Alamofire Swift

Question

How to request using Alamofire to get stream JSON. I am using the below function to get the response

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)
                }
        }

And my API Url something like

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

and the response I get from API if the number of chunks is 3 and items per chunk is 3

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

I did not get any response from the server but in Postman it works fine.

Answer 1

To receive streaming data, you can try adding

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

Inside closure you should collect data chunks from server and parse them lately, after response is called. In that case response will be nil.

So it would be something like:

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
    }