Where is the actual API call within this RxAlamofire source code?

Question

I'm trying to figure out where data in an API call is coming from. Specifically, I want to know where req.user is coming from as from what I can tell there's no paramters being passed into the API call.

Here's the server-side code (in JS):

let APIHandler = (req, res) = > {
    if (req.user) {
       latitude = req.user.location.latitude
       longitude = req.user.location.longitude
    }
}

And here's the client-side code (in Swift):

 let strURLTo = SERVICE.BASE_URL + apiName + limit
 let headers = AuthorizationHeader.getAuthHeader(staticToken: false)

 var urlComponents = URLComponents(string: strURLTo)
 urlComponents?.queryItems = [URLQueryItem(name: "offset", value: String(offset)),
                             URLQueryItem(name: "limit", value: String(limit))]

 let strURL  = urlComponents?.url

 RxAlamofire.requestJSON(.get,strURL!,parameters:[:],headers:headers) 

            .debug()

            .subscribe(onNext: {(HeaderResponse, bodyResponse) in

                if let dict = bodyResponse as? [String: AnyObject] {
                    if let respDict: [String: Any] = JSON(dict).dictionaryObject {
                        let response = ResponseModel.init(statusCode: HeaderResponse.statusCode, response:respDict)
                        self.subject_response.onNext(response)
                    }
                }

            }, onError: { (error) in
                self.subject_response.onError(error)
            })

            .disposed(by: disposeBag)

And finally here's the RxAlamofire.requestJson definition:

public func requestJSON(_ method: Alamofire.HTTPMethod,
    _ url: URLConvertible,
    parameters: [String: Any]? = nil,
    encoding: ParameterEncoding = URLEncoding.default,
    headers: [String: String]? = nil)
    -> Observable<(HTTPURLResponse, Any)>
{
    return SessionManager.default.rx.responseJSON(
        method,
        url,
        parameters: parameters,
        encoding: encoding,
        headers: headers
    )
}

What I tried was tracing through the RxAlamofire.requestJSON function step-by-step but I don't see anywhere where the actual API call happens (to me it seems like it's just outlining the types it's expecting/returning). Additionally there's no parameters in the RxAlamofire.requestJSON(.get,strURL!,parameters:[:],headers:headers) call.

Answer 1

The actual call is being made in this line (which has been spread out over multiple lines for clarity):

return SessionManager.default.rx.responseJSON(
    method,
    url,
    parameters: parameters,
    encoding: encoding,
    headers: headers
    )

The parameters are being set here:

var urlComponents = URLComponents(string: strURLTo)
urlComponents?.queryItems = [URLQueryItem(name: "offset", value: String(offset)),
                             URLQueryItem(name: "limit", value: String(limit))]

However, I also do not see user being set, so maybe it is happening in the API function at the top of this answer?