I work on an iPhone app (Swift 4), I do some updates on my database at few nodes at the same time.
Both following methods work but I'm wondering what's the most "clean" one ?
Way 1 :
let idNotification = BaseViewController.database.child("notifications").childByAutoId().key
BaseViewController.database.child("notifications").child(idNotification).updateChildValues(["content" : "some content"])
BaseViewController.database.child("users").child(userID).child("notifications").updateChildValues(["something" : true])
Way 2 :
let idNotification = BaseViewController.database.child("notifications").childByAutoId().key
let createNotif = ["content" : "some content"]
let notifToUser = ["something" : true]
BaseViewController.database.updateChildValues(["/notifications/\(idNotification)" : createNotif, "/users/\(userID)/notifications" : notifToUser])
And if that makes any difference in case of crash ? With the first one, if one of the two update request fail the other one will not be impacted. What happens with method 2 if there is a fail just for one of the two ?
Thanks !
The first snippet send multiple write operations to the database (one for each call to updateChildValues). The second snippet sends exactly one write operation.
Both are completely valid, and either could be what you want. For example, if there's no relation between the two updates, then it makes sense to send them separately. But if the updates are related, it makes more sense to send them in one go, since that allows the security rules of your database to allow/reject them as one write operation.
Related
Hi I am working on a Video Call Solution by using WebRTC directly. I have achieved 1-1 video call using firebase as Signaling service and using default google ICE Servers.
Core Req: Multiple users with in a Room using WebRTC at least 4 users using the default ice/stun servers available. I'm using pod 'GoogleWebRTC'
Issue comes when multiple users joins the same room ID.
So, I am maintaining Peerconnection reference as this
var peerConnection: RTCPeerConnection! = nil
When a new user i.e., remote user joins I set its description as below
self.peerConnection.setRemoteDescription(offer, completionHandler: {(error: Error?) in
if error == nil {
LOG("setRemoteDescription(offer) succsess")
self.makeAnswer() // Create Answer if setRemoteDescription succeeds
} else {
LOG("setRemoteDescription(offer) ERROR: " + error.debugDescription)
}
})
What I feel ? Issue is when third user joins again I set the remote Description with above mentioned code which makes my previous video stops to render sometimes or most of the times.
I looked for solutions and found need to maintain multiple peer connection references, but how? Any help with my requirement will be appreciated.
Just give me clue or sample code will be really great.
In case of multiple user call you should have multiple peerconnections, because it's isn't possible to set different sdps to one pc.
So you can use something like this
var peerConnectionMap = [String: RTCPeerConnection]()
Where String here is some constant user id.
When new user is joined to the room, then you create new pc and store it in this dictionary. Then you exchange with sdps as usual.
Don't forget that you should reuse local audio-video track created when first peerconnection is created.
I have a code fragment which I want to unit test , this code depends upon callback from network stack on event of receipt of data. The network calls are made through a library its basically amazon iOT library, thus I am not directly interacting with iOS network framework but this library. I want to unit test this code, not sure if its possible if yes how.
Attached is the code in question
static func subscribeForData(completionCallBack:((String,NSDictionary)->())?,errorCallBack:((NSError)->())?) {
let iotDataManager = AWSIoTDataManager.default()
let defaults = UserDefaults.standard
let login = .....
iotDataManager.subscribe(toTopic: "testNode/device/"+login, qoS: .messageDeliveryAttemptedAtLeastOnce, messageCallback: {
(payload) ->Void in
let stringValue = NSString(data: payload, encoding: String.Encoding.utf8.rawValue)!
})
}
The best way you can achieve this is through Dependency Injection (DI).
DI can be used as a mean to inject both the real networking code and the "mocked" one.
In order to deal with DI you need to modify your code. In particular an instance of AWSIoTDataManager should be passed to subscribeForData method instead of hardcoding it (why do you have a static method?).
There are different approaches in order to deal with this. One is described for example in The complete guide to Network Unit Testing in Swift. I think that if you read it, you will acquire something new useful for the feature.
Your "mocked" class (I put with "" since it could be defined as a stub or a spy) would have the same API provided by the real one.
As I stated previously, Unit Tests should be fast and should NOT depend on databases, real networks requests and so on.
How many maximum printings can UIPrintInteractionController (Swift) execute?
I'm currently doing AirPrint for a project.
Wondering how to do stress tests of printing in bulk in use of Printer Simulator.
Is there a delegate of something like printInteractionControllerIsPrintingJob?
How to debug a number of printing waiting in queue?
Is there any way to customise the alert view of printing?
Cheers,
From the documentation :
1- var printingItems: [Any]? { get set }
Takes an array of printing-ready objects ( NSURL, NSData, UIImage, or ALAsset). The documentation doesn't cite any limit so we assume the limit would be the value of unsigned int in your architecture.
2- There are 2 delegate methods for the beginning and end of printing :
Start and End of a Print Job
func printInteractionControllerWillStartJob(UIPrintInteractionController)
//Tells the delegate that the print job is about to start.
func printInteractionControllerDidFinishJob(UIPrintInteractionController)
//Tells the delegate that the print job has ended.
You can use those to get the IsPrinting status. (between first and second).
3- The documentation doesn't offer any delegate method to get the waiting in queue
4- You can customise the alert using :
printInfo UIPrintInfo: The aforementioned print job configuration.
printPaper UIPrintPaper: A simple type that describes the physical and printable size of a paper type; except for specialized applications, this will be handled for you by UIKit.
showsNumberOfCopies Bool: When true, lets the user choose the number of copies.
showsPageRange Bool: When true, lets the user choose a sub-range from the printed material. This only makes sense with multi-page content—it’s turned off by default for images.
showsPaperSelectionForLoadedPapers Bool: When this is true and the selected printer has multiple paper options, the UI will let the user choose which paper to print on.
For some detailed explanation about printing using Swift, please refer to the following link:
UIPrintInteractionController - Written by Nate Cook
If this response was helpful and has what you needed, please don't forget to validate it :).
Good luck with your app.
I have a iPhone app using Swift 2 and Parse as a back-end. In my app people can like everybody else pictures (the same way you will do it in Instagram). The notification system works well and everytime someone like a picture, I'm sending a Parse notification to the picture owner like this :
let pushQuery:PFQuery = PFInstallation.query()
pushQuery.whereKey("user", equalTo: receiver)
let push:PFPush = PFPush()
let data = [
"alert" : message,
"badge" : "Increment",
"sound" : "default"
]
push.setData(data)
push.setQuery(pushQuery)
push.sendPushInBackground()
I'm facing a problem when I have a lot of users liking a picture in a short amount of time. The problem is that the receiver is flooded by Notifications and I don't want the receiver to have his phone vibrating (or ringing) 100 times in 5 minutes.
As I'm a new user using parse I have no idea if I have to modify some parameters in the server (Parse) of I have to do it programmatically (and I have no idea how to do this).
Anyone has an idea ? Thank you !
A possible solution. create an extra column in your parse table called lastPush. In this store the date and time of the last push. So when you send a push first check to see if there is a lastPush value, if not send one and store the time. If there is a date then check if it's in your range, you can decide if you want to send a push or not. If you do remember to save the new time.
What I want to implement is as follow:
A-app (calling app) : request the return value of a-string sent as parameter : request(a-string) -> b-string.
B-app (plug-in installed separately by me or others, it plays the role of dictionary or database ) : search a-string from database and return the result (b-string).
With successful experiences of plug-in on android and with Apple's confident rhetoric of plug-in, I thought plug-in, of course, run on iOS. After a lot of hard work, however, I finally found out:
* Note : The creation and use of loadable bundles is not supported in iOS.*
Nonetheless, not giving up, I finally made it with custom URl and pasteboard:
A-app : write a-string and false state to pasteboard & call B-app via custom URL.
B-app : viewDidLoad runs following func and thereafter exit program ; func { read pasteboard and search from database & write the result(b-string) and true state to pasteboard }
A-app : while-loop detects whether state is false or true. if true, catch b-string from pasteboard.
Anyway it works but it's too long thus almost useless. Do you have any idea for better solutions? Why doesn't Apple allow plug-in for iOS? Any responses are welcome. Thank you.
I can't answer why Apple doesn't allow plug-ins, but I can offer some advice on what you're trying to achieve.
The common pattern for sending data back to your application is to implement a callback url, so the A-app would also implement a custom URI and add that to the uri sent to B-app.
B-app would then process the uri as you have already implemented, but then instead of exiting, it simply sends the data you requested in the uri passed to it.
See http://x-callback-url.com for more details and example implementations.