Getting 404 error when request is made through Alamofire in swift3 - ios

Question

First of all, we are using below code so as the api's works only on mobile devices and not on browsers per say.
"
$iPod = stripos($_SERVER['HTTP_USER_AGENT'], "iPod");
$iPhone = stripos($_SERVER['HTTP_USER_AGENT'], "iPhone");
$iPad = stripos($_SERVER['HTTP_USER_AGENT'], "iPad");
$Android = stripos($_SERVER['HTTP_USER_AGENT'], "Android");
$json_data = json_decode(file_get_contents('php://input'));
if ($json_data) {
$username_1 = $json_data->username;
if ($Android || $iPad || $iPhone || $iPod) {}
Secondly, the api's are working on android(using volley) and in ios objective-c using AFNetworking. But, now i am porting the project to swift3 and i am using "Alamofire" for network calls.
Method:: (This is how i make POST request):
let headers : HTTPHeaders = [
"Accept" : "application/json"
]
Alamofire.request("API URL", method: .post, parameters: parameters, encoding: JSONEncoding.default, headers: headers)
.responseJSON{
response in
if let json = response.result.value{
}
But, i am getting error 404, which we usually get when we hit api in browser.
After that i removed that backend check and the request worked fine and got the proper response. But, we can't remove that check. So help me, if i am making any mistakes with headers of something else.
This is what i am getting in debugPrint(response)::
{ status code: 200, headers {
"Access-Control-Allow-Origin" = "*";
"Cache-Control" = "no-store, no-cache, must-revalidate, post-check=0, pre-check=0";
Connection = "Keep-Alive";
"Content-Encoding" = gzip;
"Content-Length" = 84;
"Content-Type" = "text/html; charset=UTF-8";
Date = "Thu, 14 Sep 2017 17:03:17 GMT";
Expires = "Thu, 19 Nov 1981 08:52:00 GMT";
"Keep-Alive" = "timeout=5";
Pragma = "no-cache";
Server = "Apache/2.4.25";
Vary = "Accept-Encoding,User-Agent";
"X-Powered-By" = "PHP/5.6.31";
} }
[Data]: 80 bytes
[Result]: SUCCESS: {
"is_valid" = 0;
status = 404;
"status_message" = "access denied";
success = 0;
}

Answer 1

Alomafire sends a default header parameter User-Agent alright but its value is something like this iOS Example/1.0 (com.alamofire.iOS-Example; build:1; iOS 10.0.0) Alamofire/4.0.0.
This is from their readme:
You can obviously provide your own custom headers:
let headers: HTTPHeaders = [
"User-Agent": "iPhone",
"Accept": "application/json"
]
Alamofire.request("<Ypur URL>", headers: headers)
.responseJSON { response in
debugPrint(response)
}
Or if you want to keep other default header parameters
var headers = Alamofire.SessionManager.defaultHTTPHeaders
headers["User-Agent"] = "iPhone"