I've been reading about and trying to use the CKSubscription feature for weeks, but I can't find info about some general questions. I've read Apple docs, online tutorials, books I bought, and questions here on SO, but I still don't understand the fundamentals I think. Any help is very much appreciated.
Here are questions I cannot find answers to:
1). What is the purpose of the subscriptionID? The convenience init does not include it, so why is it needed in the designated init? If you use it, is it the same for all users of the app?
2). I saw someone mention here that you can unregister a subscriptionID. Why or how would you do this?
3). Can subscriptions be setup in both public or the user's private database?
4). If I have a query based subscription that is the same for all users, will there only ever be 1 subscription listed in the database?
For instance, I'm having trouble getting notifications to work with my
specific use case. It's not a problem in my setup, as I can get a True predicate to work and the notification comes. So I must not understand the fundamentals of how subscriptions work still.
I'm trying to setup a subscription that fires whenever a new record is created when a different user makes a comment on a post. This new record will then contain a reference to the user who created the post. The only subscription I see in the database for both users is - Notifications.user (equals reference). So, I'm assuming I'll only ever see this one subscription.(?) But how does the server keep track of every user's recordID or know when to send it to a specific device?
The problem is I can't get the notification to work. I manually add a record in the dashboard, and I put the other user's recordID as the CKReference. While I'm adding the record, I have the app running in the background on a device under the user's account whom I added as the CKReference in the field. I'd expect the query to trigger and send a push notification since someone commented on this user's post.
Here's my code to setup the subscription:
func subscribe(userID: CKRecordID) {
let options = CKSubscriptionOptions.FiresOnRecordCreation
let userRef = CKReference(recordID: userID, action: .DeleteSelf)
let predicate = NSPredicate(format: "userRef == %#", userRef)
let predicateTwo = NSPredicate(format: "read = %#", "")
let compoundPred = NSCompoundPredicate(type: .AndPredicateType, subpredicates: [predicate, predicateTwo])
let subscription = CKSubscription(recordType: "Notifications", predicate: compoundPred, subscriptionID: subscriptionID,
options: options)
subscription.notificationInfo = CKNotificationInfo()
subscription.notificationInfo.desiredKeys = ["userPost"]
subscription.notificationInfo.alertBody = "Someone replied to your Pod post"
publicDB.saveSubscription(subscription, completionHandler: {
subscription, error in
if (error != nil) {
println("error subscribing: \(error)")
} else {
println("subscribed!")
}
})
}
Let me try and answer:
SubscriptionId allows you to identify later a subscription for example to delete it using the CKDatabase method deleteSubscriptionWithID
For how see answer 1. As to why, well maybe you do not want to get notifications on this subscription any more. This depends on what you are trying to achieve with your app.
Yes
Yes, if you register only one subscription it should work for all users of your app
Regarding your issues, please note that a user recordIDs are special, so you may have issues specifically related to that due to the privacy issues around them. I would suggest to try a simple case that does not involve users and see if subscriptions are working for you. Then think again about how you use user record IDs
Related
When i terminate app MUC group chat members are getting removed, i have to join them again while coming back to app from bookmarks? We do not want to rejoin again and again. Can someone please suggest way how to avoid rejoining.
In Android smack there is provision for auto-rejoin.
Even from Openfire back end we have managed code to do not remove.
So Android is working fine, iOS is removing users.
Please do suggest.
Instead of rejoining the room every time, do set the presence of the group when the user relaunches the app.
Set presence with below code function iterate through all your groups name and set presence:
for group in chatListModel ?? []{
if(group.opponent_type == "2"){
print("Group Name: \(group.opponent_uuid ?? "")")
XMPPGlobal.sharedIntanceXMPP.xmppController.updatePresence(roomJID: XMPPJID(string: "\(group.opponent_uuid ?? "")#\(groupServerName)"))
}
}
Define below function in your XMPPController class:
func updatePresence(roomJID : XMPPJID?) {
let presence = XMPPPresence(type: "presence")
presence.addAttribute(withName: "from", stringValue: self.xmppStream.myJID?.user ?? "")
presence.addAttribute(withName: "to", stringValue: "\(roomJID?.full ?? "")/\(self.xmppStream.myJID?.user ?? "")")
let element = DDXMLElement.init(name: "x", xmlns: XMPPMUCNamespace)
presence.addChild(element)
self.xmppStream.send(presence)
}
Hope it will works for you.
In spite of the fact that there is the answer.
I would like to elaborate a little bit :)
In case of MUC rooms: there is an affiliation, i.e. long-lasting role (admin, owner, etc) and "subscription" role (visitor, member etc).
What you are asking is per se described in XMPP MUC. 7.1 Order of Events
You send your presence to join the room, and receive presence from other other participants, you can also get some cached messages if your XMPP backend was configured properly.
For instance for ejabberd (process-one): mod_muc: history_size settings defines in-memory cache.
You might don't want to get set of room events, as described in 7.1 above.
There might be some server's extensions. In case of ejabberd there is MUCPubSub you send your subscription (not presence) and get the following messages, plus you can get list of members or track its changes, and etc:
<subscribe xmlns='urn:xmpp:mucsub:0'
nick='mynick'
password='roompassword'>
<event node='urn:xmpp:mucsub:nodes:messages' />
Just FYI I posted this question originally in the AWS AppSync forum (in case in the future AWS answers it).
I have been trying to make a simple Posts app like the one in the docs but I have found no documentation or guides that handle multiple subscriptions in one view controller.
Three mutations: onCreatePost, onUpdatePost, onDeletePost
(and of course three subscriptions to those mutations)
In Xcode, I have three functions called during viewDidLoad(): subscribeToNewPosts(), subscribeToUpdatedPosts(), subscribeToDeletedPosts()
Each subscription function works and creates a subscription with the correct functionality and updates the table view accordingly if used alone. But, if called one after the other, only the last subscription will actually receive data and update the table view. I put a breakpoint to check out topicSubscribersDictionary in AppSyncMQTTClient.swift after subscribing to all three mutations
func startNewSubscription(subscriptionInfo: AWSSubscriptionInfo) {
var topicQueue = [String]()
let mqttClient = MQTTClient<AnyObject, AnyObject>()
mqttClient.clientDelegate = self
for topic in subscriptionInfo.topics {
if topicSubscribersDictionary[topic] != nil {
// if the client wants subscriptions and is allowed we add it to list of subscribe
topicQueue.append(topic)
}
}
mqttClients.append(mqttClient)
mqttClientsWithTopics[mqttClient] = topicQueue
mqttClient.connect(withClientId: subscriptionInfo.clientId, toHost: subscriptionInfo.url, statusCallback: nil)
}
and all three subscriptions are in fact in the dictionary...
Do I need multiple instances of appSyncClient, one for each subscription? Is it a problem with the schema design?
schema.graphql
schema.json
mutations.graphql
queries.graphql
subscriptions.graphql
Example use case: simple chat app. New conversation started = OnCreatePostSubscription; new incoming message in that conversation = OnUpdatePostSubscription
Are you using API Key for authorization in AppSync? If you are using API Key only one subscription is supported by the SDK at this point. Could you switch to IAM (Cognito Identity) or Cognito UserPools based auth and see if multiple subscriptions work for you?
I managed to have several subscriptions working with API Key by replacing the call startSubscriptions to startNewSubscription inside AWSAppSyncSubscriptionWatcher
if let subscriptionInfo = subscriptionResult.subscrptionInfo {
self.subscriptionTopic = subscriptionResult.newTopics
self.client?.addWatcher(watcher: self, topics: subscriptionResult.newTopics!, identifier: self.uniqueIdentifier)
//self.client?.startSubscriptions(subscriptionInfo: subscriptionInfo)
subscriptionInfo.forEach { self.client?.startNewSubscription(subscriptionInfo: $0) }
}
Couldn't find any side effect with this approach yet, apart from requiring to fork the iOS SKD
I have made a following system where users can follow each other but it is not very useful at the moment. I cannot seem to get my head around how to only show the posts of the users you follow - so I am here to ask you how you would do it.
Let me just show you how the database is set up:
As you can see I have a tap called Users - in there all the users ID are stored. Whenever a user wants to follow another user, the tap Following is made and under there the user that the current user pressed follow - his/her ID is store under Following. And then the current users ID is added to the user he/she follows under Followers. Pretty simple but complicated to explain :D I hope you get where I'm going.
So now I want only to show posts of the users I am following. How would you do that? Would you do it like this: When a user is making a post it is added to his own name under a tap called Posts AND added to all the users names under PostsToFollow? I just think it would take up a lot of space in the database? Isn't there a better way to do this?
Well here is a part of my code that is getting me all of the current users followers. How can I use that code to, whenever I am creating a new post, add that to their postsToFollow?
func startObersvingDB() {
FIRDatabase.database().reference().child("Users").child(IDgotten).child("Followers").observeEventType(.Value, withBlock: { (snapshot: FIRDataSnapshot) in
var newUpdates = [FollowersStruct]()
for update in snapshot.children {
print(update)
let updateObject = FollowersStruct(snapshot: update as! FIRDataSnapshot)
newUpdates.append(updateObject)
}
self.updates = newUpdates.reverse()
self.tableView.reloadData()
}) { (error: NSError) in
print(error.description)
}
}
To Frank:
I've made this for adding the entire post to all the users that are following my user. I cannot do that because I have a like and comment button on the posts so the likes on one users posts will not be the same as other users posts and that is why I think the idea of adding the key to the post in the followers walls is great. But how do I do that?
I have made this so far, trying to accomplish what you said :-) :
let feed = Sweet(content: update, addedByUser: name!, profilePhoto: uid, likesForPost: ["user id": false], date: timePosted, category: 1, workoutComment: "", workoutTime: "")
let feedRef = FIRDatabase.database().reference().child("feed-items").childByAutoId()
feedRef.setValue(feed.toAnyObject())
FIRDatabase.database().reference().child("Users").child(uid).child("Followers").observeEventType(.Value, withBlock: { (snapshot: FIRDataSnapshot) in
var newFollowers = [FollowersStruct]()
for updateFollowers in snapshot.children {
let updateObjectFollowers = FollowersStruct(snapshot: updateFollowers as! FIRDataSnapshot)
newFollowers.append(updateObjectFollowers)
}
self.followings = newFollowers
print(self.followings.count)
for i in 0..<self.followings.count {
let followers = self.followings[i]
let feedRefFollowers = FIRDatabase.database().reference().child("Users").child(followers.Id).child("Wall").childByAutoId()
feedRefFollowers.setValue(feed.toAnyObject())
}
}) { (error: NSError) in
print(error.description)
}
Writing the post under the user's own name and all his follower's names is a typical example of fanning out the data. This indeed duplicates the data, but the benefit is that your read operations will be much faster and have significantly simpler code.
If you don't want to duplicate the entire post, you can also just write the key of the new post under each follower's "wall". Then when you need to show a list of posts for a user, you read their "wall" and client-side join each post. This is the approach taken by in our classic Firefeed example app.
Either of these approaches is a form of denormalization: duplicating part of your data to get better read performance.
I highly recommend reading this article on NoSQL data modeling and checking out our video series on Firebase for SQL developers. Oh... and this blog post on client-side fan-out also won't hurt.
I am trying to develop a simple messaging app to learn the basics of CloudKit.
I've got it almost figured out, except I am not able to receive notifications for record update events.
To test the app, I am running it simultaneously on the device and on a simulator.
Both instances are logged into the same iCloud account (haven't gotten around to create a dedicated account for testing...); however the app distinguishes the local user from the remote one using UUIds, so that is not a problem.
When one instance of the app wants to send a message, it creates a record and saves it to CloudKit.
I am aware that APNs is not supported on the Simulator, but if I send a message from the Simulator I can get notified on the device.
This works.
Next, I want to mark the messages as "read": That is, flag them when they are first displayed on a device that is not the one that authored them.
I do this by fetching the corresponding record, modifying it, and saving it. So, the message I sent from the device is displayed on the simulator, and flagged there as 'read'. I sync that change with cloudKit and expect the device to receive a notification:
publicDatabase.perform(query, inZoneWith: nil, completionHandler: {(records, error) in
guard let records = records, records.count > 0 else {
return print("Error - Message: \(message.text) by \(message.userName) NOT found on the cloud!")
}
let record = records[0]
// HERE THE RECORD IS MODIFIED LOCALLY:
record["readTimestamp"] = (message.readTimestamp! as NSDate)
// Now, save it:
self.publicDatabase.save(record, completionHandler: {record, error in
guard error == nil else {
return print("Error - Message: \(message.text) by \(message.userName) could NOT be saved as read!")
}
print("Message: \(message.text) by \(message.userName) SAVED as read at \(message.readTimestamp!)")
})
})
However, on the other end, the 'Update' notification is never received.
Is it because both instances are logged into iCloud as the same user? I find this hard to believe, since the "Create" notifications are delivered without problems.
Subscriptions for both notifications ("Message Create" and "Message Update") are registered successfully and appear listed on the CloudKit Dashboard (triggers INSERT and UPDATE).
Update: After a long time thinking what can possibly be different between my "create" subscription and my "update" subscription that could cause only one of them to fire a notification, I realized that only the "create" subscription had a notification body:
let subscription = CKQuerySubscription(recordType: "Message",
predicate: NSPredicate(value: true),
subscriptionID: Bundle.main.bundleIdentifier! + ".subscription.message.create",
options: .firesOnRecordCreation
)
let notificationInfo = CKNotificationInfo()
// THIS LINE MAKES ALL THE DIFFERENCE:
notificationInfo.alertBody = "You've Got Mail!"
subscription.notificationInfo = notificationInfo
publicDatabase.save(subscription, completionHandler: {savedSubscription, error in
...whereas the "update" subscription did not:
let notificationInfo = CKNotificationInfo()
subscription.notificationInfo = notificationInfo
Once I added an alert body, the "update" notifications started arriving.
However, this is just a workaround: I need silent notifications for my read updates. It doesn't make sense to display a banner just to alert the user that his message has been read on the other end.
Also, the CloudKit programming Guide does not mention this limitation.
Is there a way to subscribe with silent (i.e., empty) push notifications?
Update 2: Actually, I found this bit on the API Reference for CKNotificationInfo:
Note
If you don’t set any of the alertBody, soundName, or shouldBadge
properties, the push notification is sent at a lower priority that
doesn’t cause the system to alert the user.
(emphasis mine)
I still fail to see how this "lower priority that doesn’t cause the system to alert the user" is equivalent to "application(:didReceiveRemoteNotification:fetchCompletionHandler:) not being called at all".
The solution appears to be to use an info object with shouldSendContentAvailable = true, like this:
let info = CKNotificationInfo()
info.shouldSendContentAvailable = true
subscription.notificationInfo = info
That has solved it for me. It causes didReceiveRemoteNotification: to fire, without any user visible notification appearing. So it's a silent notification, as desired, and it's actually arriving, as desired.
If I leave subscription.notificationInfo nil the app is never notified of changes. But with an [effectively silent] info object I get the desired results.
Hopefully the title is self-explanatory. I'm trying to do something like this:
checkIfUserIsSubscribedToProduct(productID, transactionID: "some-unique-transaction-string", completion: { error, status in
if error == nil {
if status == .Subscribed {
// do something fun
}
}
}
does anything like the hypothetical code I've provided exist? I feel like I'm taking crazy pills
Edit
In similar questions I keep seeing a generic answer of "oh you gotta validate the receipt" but no explanation on how, or even what a receipt is. Could someone provide me with how to "validate the receipt"? I tried this tutorial but didn't seem to work.
Edit - For Bounty
Please address the following situation: A user subscribes to my auto-renewable subscription and gets more digital content because of it - cool, implemented. But how do I check whether that subscription is still valid (i.e. they did not cancel their subscription) each time they open the app? What is the simplest solution to check this? Is there something like the hypothetical code I provided in my question? Please walk me through this and provide any further details on the subject that may be helpful.
I know everyone was very concerned about me and how I was doing on this - fear not, solved my problem. Main problem was that I tried Apple's example code from the documentation, but it wasn't working so I gave up on it. Then I came back to it and implemented it with Alamofire and it works great. Here's the code solution:
Swift 3:
let receiptURL = Bundle.main.appStoreReceiptURL
let receipt = NSData(contentsOf: receiptURL!)
let requestContents: [String: Any] = [
"receipt-data": receipt!.base64EncodedString(options: []),
"password": "your iTunes Connect shared secret"
]
let appleServer = receiptURL?.lastPathComponent == "sandboxReceipt" ? "sandbox" : "buy"
let stringURL = "https://\(appleServer).itunes.apple.com/verifyReceipt"
print("Loading user receipt: \(stringURL)...")
Alamofire.request(stringURL, method: .post, parameters: requestContents, encoding: JSONEncoding.default)
.responseJSON { response in
if let value = response.result.value as? NSDictionary {
print(value)
} else {
print("Receiving receipt from App Store failed: \(response.result)")
}
}
As some comments pointed out there's a couple flaws with these answers.
Calling /verifyReceipt from the client isn't secure.
Comparing expiration dates against the device clock can be spoofed by changing the time (always a fun hack to try after cancelling a free trial :) )
There are some other tutorials of how to set up a server to handle the receipt verification, but this is only part of the problem. Making a network request to unpack and validate a receipt on every app launch can lead to issues, so there should be some caching too to keep things running smoothly.
The RevenueCat SDK provides a good out-of-the box solution for this.
A couple reasons why I like this approach:
Validates receipt server side (without requiring me to set up a server)
Checks for an "active" subscription with a server timestamp so can't be spoofed by changing the device clock
Caches the result so it's super fast and works offline
There's some more details in this question: https://stackoverflow.com/a/55404121/3166209
What it works down to is a simple function that you can call as often as needed and will return synchronously in most cases (since it's cached).
subscriptionStatus { (subscribed) in
if subscribed {
// Show that great pro content
}
}
What are you trying to achieve in particular? Do you want to check for a specific Apple ID?
I highly doubt that this is possible through the SDK. Referring to Is it possible to get the user's apple ID through the SDK? you can see that you can't even ask for the ID directly but rather services attached to it.
What would work is caching all transactions on your own server and search its database locally but that would require the app to ask for the user's Apple ID so the app could update the subscription state whenever it launches as it can check for IAP of the ID associated with the device.
However, the user could just type whatever he wanted - and it's unlikely to get this through Apple's app review process.
I am using MKSoreKit https://github.com/MugunthKumar/MKStoreKit for auto-renew subscriptions.but it is in objective c you can check the library code for solution.I am using it in my code and it is working fine.
using below method you can easily check subscription status..
if([MKStoreManager isProductPurchased:productIdentifier]) {
//unlock it
}
It gets the apple id from device and I think that is user specific