LiveQuery Support

[cbaker6]

Minimum requirements to use LiveQuery are: macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0

Was able to reuse some of the ParseLiveQuery-iOS SDK.

This is a work in progress...

• LiveQuerySocket - Uses URLSessionWebSocket hence the minimum requirements above... Uses a dedicated session URLSession.liveQuery. Supports multiple connections to different servers
• Delegate authentication challenges to the developer. They can do their own cert pinning and auth if they want. If no authentication provided, will default to OS auth.
• (Parse) All parse network calls now have a dedicated session, URLSession.parse which delegates authentication challenges also. LiveQuery will default to the parse authentication challenge if one isn't specified in the LiveQuery delegate.
• (Parse) Use POST instead of GET for user login
• LiveQuery Subscribe/Unsubscribe/Update
• LiveQuery Events
• Documentation
• Playground examples
• Testcases for encoding/decoding, states

[codecov]

Codecov Report

Merging #45 (b58fb67) into main (f124d0a) will increase coverage by 0.12%.
The diff coverage is 71.35%.

@@            Coverage Diff             @@
##             main      #45      +/-   ##
==========================================
+ Coverage   76.53%   76.65%   +0.12%     
==========================================
  Files          35       42       +7     
  Lines        3239     3757     +518     
==========================================
+ Hits         2479     2880     +401     
- Misses        760      877     +117     

Impacted Files	Coverage Δ
Sources/ParseSwift/Storage/KeychainStore.swift	97.75% <ø> (ø)
...rces/ParseSwift/Storage/PrimitiveObjectStore.swift	88.00% <ø> (ø)
...t/LiveQuery/Protocols/ParseLiveQueryDelegate.swift	20.00% <20.00%> (ø)
...urces/ParseSwift/API/ParseURLSessionDelegate.swift	24.13% <24.13%> (ø)
Sources/ParseSwift/Types/Query.swift	91.54% <50.00%> (+4.49%)	⬆️
Sources/ParseSwift/LiveQuery/LiveQuerySocket.swift	61.40% <61.40%> (ø)
Sources/ParseSwift/LiveQuery/Subscription.swift	63.26% <63.26%> (ø)
Sources/ParseSwift/LiveQuery/ParseLiveQuery.swift	74.73% <74.73%> (ø)
Sources/ParseSwift/API/URLSession+extensions.swift	78.04% <75.00%> (+16.75%)	⬆️
Sources/ParseSwift/API/API+Commands.swift	80.75% <100.00%> (+3.32%)	⬆️
... and 14 more

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[cbaker6]

@TomWFox can you review the docs? This PR is moving into testing.

[cbaker6]

@pmmlo Can you test this locally?

I have a server setup via docker that will work out-of-the box with the Playgrounds files if you need it. It also gives you dashboard so you can add/remove/edit fields in there. Clone, and type docker-compose up. I usually select the "Mac OS" framework when testing in Playgrounds, the iOS one messes up sometimes and asks for entitlements.

The Playgrounds file with how to use LiveQuery is here:

Parse-Swift/ParseSwift.playground/Pages/11 - LiveQuery.xcplaygroundpage/Contents.swift

Lines 33 to 82 in c2c7e14

	//: Create a query just as you normally would.
	var query = GameScore.query("score" > 9)
	//: This is how you subscribe your created query
	let subscription = query.subscribe!
	//: This is how you receive notifications about the success
	//: of your subscription.
	subscription.handleSubscribe { subscribedQuery, isNew in
	//: You can check this subscription is for this query\
	if isNew {
	print("Successfully subscribed to new query \(subscribedQuery)")
	} else {
	print("Successfully updated subscription to new query \(subscribedQuery)")
	}
	}
	//: This is how you register to receive notificaitons of events related to your LiveQuery.
	subscription.handleEvent { _, event in
	switch event {
	case .entered(let object):
	print("Entered: \(object)")
	case .left(let object):
	print("Left: \(object)")
	case .created(let object):
	print("Created: \(object)")
	case .updated(let object):
	print("Updated: \(object)")
	case .deleted(let object):
	print("Deleted: \(object)")
	}
	}
	//: Now go to your dashboard, goto the GameScore table and add, update, remove rows.
	//: You should receive notifications for each.
	//: This is how you register to receive notificaitons about being unsubscribed.
	subscription.handleUnsubscribe { query in
	print("Unsubscribed from \(query)")
	}
	//: To unsubscribe from your query.
	do {
	try query.unsubscribe()
	} catch {
	print(error)
	}

From what I've seen Subscribe and all of the Events seem to work fine.

I broke something in unsubscribe and update, but it's probably an easy fix I'l get to later.

[cbaker6]

@pranjalsatija can you review?

[TomWFox]

Only being picky really...

[pmmlo]

@cbaker6 I had a little time to test this with a HTTPS server and .subscribe and .handleSubscribe return expected callbacks. However, after about ~29s (timed twice, but seems consistent), I get these two errors:

2021-01-15 16:12:45.010269-0800 Member[60224:14126091] [tcp] tcp_input [C1.1:3] flags=[R] seq=3454113186, ack=0, win=0 state=LAST_ACK rcv_nxt=3454113186, snd_una=1642147939
2021-01-15 16:12:45.011230-0800 Member[60224:14126091] [tcp] tcp_input [C1.1:3] flags=[R] seq=3454113186, ack=0, win=0 state=CLOSED rcv_nxt=3454113186, snd_una=1642147939
2021-01-15 16:12:45.012326-0800 Member[60224:14126091] [tcp] tcp_input [C1.1:3] flags=[R] seq=3454113186, ack=0, win=0 state=CLOSED rcv_nxt=3454113186, snd_una=1642147939

It seems like the Subscription is timing out or crashing. I have guesses on what may be going on but thought you may know immediately.

Here's the code:

query = Team.query("member" == User.current?.objectId)
guard let subscription = query.limit(1).subscribe else { return }

subscription.handleSubscribe { subscribedQuery, isNew in
    if isNew {
        print("Successfully subscribed to new query \(subscribedQuery)")
    } else {
        print("Successfully updated subscription to new query \(subscribedQuery)")
    }
}

subscription.handleEvent { _, event in
    print("\(event)")
    switch event {
    case .entered(let object):
        print("Entered: \(object)")
    case .left(let object):
        print("Left: \(object)")
    case .created(let object):
        print("Created: \(object)")
    case .updated(let object):
        print("Updated: \(object)")
    case .deleted(let object):
        print("Deleted: \(object)")
    }
}

 subscription.handleUnsubscribe { query in
    print("Unsubscribed from \(query)")
}

I never receive any events, despite editing in dashboard. I can unsubscribe with the expected response before the two errors fire.

Any ideas?

[cbaker6]

Did you register your Team class for LiveQuery in your index file of your Parse Server? The subscription should go through immediately.

liveQuery: {
    classNames: ["GameScore", "Book", "Author"] // List of classes to support for query subscriptions
  },

I tested this LiveQuery by leaving a subscriptions on over night in the simulator for an iPhone and Apple Watch and it didn't disconnect and sent events the next day.

[cbaker6]

You can see how I setup the server for playgrounds here: https://github.com/netreconlab/parse-hipaa/blob/parse-swift/parse/index.js

Also, for your server, are you behind a proxy? If you are using Nginx be sure to setup https://www.nginx.com/blog/websocket-nginx/

[pmmlo]

You can see how I setup the server for playgrounds here: https://github.com/netreconlab/parse-hipaa/blob/parse-swift/parse/index.js

I have something similar with Express as well. I also ensured livequery server was initialized and the Team class name was listed.

I guess not as straight forward as I thought it would be. I will dig into this then. Must be an implementation issue.

[pmmlo]

Also, for your server, are you behind a proxy? If you are using Nginx be sure to setup https://www.nginx.com/blog/websocket-nginx/

I'm actually running it in a k8s cluster with an ingress. No Nginx proxy.

[cbaker6]

But your http/localhost works when you use playgrounds and docker?

[pmmlo]

Yup. The remote works as well, even graphql.

[pmmlo]

I ran playgrounds using your docker and playgrounds. Worked well there.

[cbaker6]

Maybe it's configuration, can you check if

Parse-Swift/Sources/ParseSwift/LiveQuery/ParseLiveQuery.swift

Line 192 in 84f9231

components.scheme = (components.scheme == "https" || components.scheme == "wss") ? "wss" : "ws"

is converting your url to wss since you are tls?

[pmmlo]

Maybe it's configuration, can you check if

Parse-Swift/Sources/ParseSwift/LiveQuery/ParseLiveQuery.swift

Line 192 in 84f9231

components.scheme = (components.scheme == "https" || components.scheme == "wss") ? "wss" : "ws"

is converting your url to wss since you are tls?

This looks promising. I think it may be...let me try to test this.

[pmmlo]

It's wss. Will need to checkout the ingress. Thanks!

[cbaker6]

Are you able to connect using a site like https://www.websocket.org/echo.html

[pmmlo]

There was an undocumented backend timeout of 30 seconds in AWS that seems to have been the issue. Would have guessed 30 seconds was enough... Just raised it to 5 minutes, which should be more than enough. No error, but I'm still not getting anything from .handleEvent(). I'll play around with this and post, if I figure out my issue. ;)

[pmmlo]

Just started working after I put in breakpoints. Changed nothing, and I have an empty console. Maybe I should have cleaned the project first...

Sorry!