send push notification to device directly from a device swift 3 - ios

Question

Is there any way to send push notification from a device to device directly using https://fcm.googleapis.com/fcm/send.
My code:
func sendPushNotification(toUser: String, message: String) {
let urlString = "https://fcm.googleapis.com/fcm/send"
let url = NSURL(string: urlString)!
let paramString = "to="
let request = NSMutableURLRequest(url: url as URL)
request.httpMethod = "POST"
request.httpBody = paramString.data(using: String.Encoding.utf8)!
request.setValue("application/json; charset=utf-8", forHTTPHeaderField: "Content-Type")
let task = URLSession.shared.dataTask(with: request as URLRequest) { (data, response, error) in
do {
if let jsonData = data {
if let jsonDataDict = try JSONSerialization.jsonObject(with: jsonData, options: JSONSerialization.ReadingOptions.allowFragments) as? [String: AnyObject] {
NSLog("Received data:\n\(jsonDataDict))")
}
}
} catch let err as NSError {
print(err.debugDescription)
}
}
task.resume()
}

Answer 1

let paramString = ["to" : FCM_ID/UDID, "notification" : ["title" : NOTIFICATION_TITLE, "body" : NOTIFICATION_BODY], "data" : ["user" : USER_ID, "image" : IMAGE_URL, "extrainfo" : ANY_STRING]]
just replace your line with this one and push notification should deliver.
Read more about it here... https://firebase.google.com/docs/cloud-messaging/server

Answer 2

Old post but it's worth to add to accepted solution as it can be helping others. You can check my post Push Notifications are delivered but didReceiveRemoteNotification is never called Swift or here didReceiveRemoteNotification function doesn't called with FCM notification server.
You must have "content_available": truein your notification definition or push notification service(with underscore) or your didReceiveRemoteNotification won't be called and you won't be able to use userInfo.