[bhldev]

I notice this a lot on apps in the subway (who doesn't) and the app just dies

A lot of problems in life can be simply avoided this is no different... If you're getting that tiny last bit of differentiation because you're 90% market share and you can afford to hire people to solve that exact specific problem then great. But that isn't most places. Most apps would do better to 100% avoid the problem and just say "No Internet Connection" if there's no WiFi or 3g. On top of that you get mobile developers who swore to God they solved this problem but guess what they actually have no idea what they are doing. They think it works but it doesn't because it's actually a database concurrency control problem. This https://www.postgresql.org/docs/current/mvcc-intro.html and what I expect for someone who claims to "solve the problem" not some "algorithm" they invented.

So I don't buy it, and I don't buy the business need for it unless it's an app specifically made for disconnected use. Unfortunately it sounds like one of those things people do to make themselves feel important or smart (no nice way to put it; I see it as bad as someone who invents their own encryption "algorithm" without realizing how ridiculous that is).

In short I would say don't do it. And if someone does it better be a real business requirement.

[scarface74]

And you’re kind of demonstrating my point - the difference between people who think it’s an easy problem and the proportion who have experience.

Enterprise mobile apps aren’t about the apps you download from the App Store. Usually they are distributed using an on-site mobile device management system.

1st use case: I worked for s company that wrote field service applications for ruggedized Windows mobile devices. Some had cellular, some had WiFi, and some had neither. You had to actually dock the device. The field service techs had to have all of the information they needed on the device to do service calls including routes whether or not they had connectivity. They would record the information and it would sync back to the server whenever they had a connection.

2nd use case: worked for a company that wrote software for railroad car repair billing. Repairs are governed by Raillinc (https://www.railinc.com/rportal/documents/18/260737/CRB_Proc...) all of the rules and audits had to be on the device and the record of the repair had to be available whether or not they had connectivity. It had to sync back with the server whenever a connection was available.

3rd case: software for doctors. Hospitals are notorious for having poor connections.

4th case: home health care nurses had to record lots of information for Medicare billing. Again you can’t count on having mobile connections.

[bhldev]

It's not an easy problem. It's a database concurrency issue and well beyond the skillset of most mobile devs. Database isn't even a required course for a compsci degree it's usually an elective.

My point is the problem you think you solved, you didn't and it will break under dozens of scenarios. Maybe the clients are happy and they think it works but you just haven't encountered the case where data goes missing or overwritten.

In other words what I am saying is it is wrong and hard to know it is wrong unless you directly attack it. The word "enterprise" is an euphemism for low cost and potentially low quality. It's a buzzword. I wouldn't take an Enterprise mobile developer over a B2C mobile developer just because of the word enterprise.

Not everything in the world should exist that leads to 737 Max. The word "sync" has implications way beyond the concerns of a mobile developer.

So I call bullshit; the fact the industry does it, that everyone does it, that you consider "real" mobile devs to require it, that customers want it doesn't mean it is a good idea or that it's mathematically or scientifically sound. It may cover most cases and nobody may notice the problems except once in a blue moon but that doesn't make it right because operational systems need full data integrity.

The correct way to handle such a request is not to "sync" but to collect data push it to the backend and let the backend sort out the mess. Not "sync" by whatever stretch of the imagination no matter what cottage industry or cult beliefs have been born of it.

[scarface74]

So you’re saying “it’s not a good idea” to have software that actually fulfills the need? The mobile app that doesn’t work in the majority of use cases to solve the problem that it was meant to solve is useless.

And yes “the problem” we solved, a mobile app that could route field technicians dynamically at a level of quality we needed we did solve.

The word "enterprise" is an euphemism for low cost and potentially low quality. It's a buzzword. I wouldn't take an Enterprise mobile developer over a B2C mobile developer just because of the word enterprise.

Again this comes from someone who thinks they have experience versus someone who does have experience. Did you read the link I posted about the industry required rules for repairing railway cars? That isn’t even the entire regulation. If the typical B2C app doesn’t work, oh well. For the railroad industry, if you don’t submit your railcar repair just right - it gets rejected either by the interchange or the customer and you can only submit your invoices and rebuttals once per month.

The correct way to handle such a request is not to "sync" but to collect data push it to the backend and let the backend sort out the mess. Not "sync" by whatever stretch of the imagination no matter what cottage industry or cult beliefs have been born of it.

How well does “one way server syncing” when you’re a field tech doing routes and the customer calls customer service and cancels one of your routes while you’re in the truck? How well does it work when your back end system needs to calculate where each truck is on the road and needs to re-assign routes on the fly? How well does it work when one tech needs a part and they need to know where the parts are based on what other techs have already been at the warehouse and now they have the part? But wait, they went to the customer’s house and found that they don’t need the part at all and it’s available on the truck a mile away? All of this involves dynamic two way syncing...

Again, the difference between someone who has real world experience and someone who thinks that because their Twitter app doesn’t need to work in the subway nothing does.

[bhldev]

I value experience a lot, over almost anything.

What you mention is very dangerous to the data. Take the medical app example. Suppose there's an app to update a chart that doctors carry around. Suppose there's five doctors and/or nurses working on the patient. Whose prescription or orders do you take? On top of that it gets worse -- there might be dependencies between the orders, orders might be to countermand other orders or in response to others which may or may not exist. It is not a problem that any algorithm or programming can solve, because the whole point is to take the experience and skill of the doctors which is being blindly ignored for some process that the doctors may or may not be aware of who submit the information. Similar problems could appear for any of the examples you mentioned if you dug hard enough.

As for the submission you can simply ban submission unless you have an active Internet connection. 737 Max is also "real world experience" Boeing panicked at Airbus and instead of going through a 10 year design and 10 billion dollar process for a plane they surrendered to market realities at the cost of lives. The fact that "enterprise" has onerous business requirements or even legal requirements demanding technical sacrifice doesn't make it any less technically wrong. If asked to make a sync on the client side I would make it as simple and straightforward as possible and assume nothing.

I suppose so long as it doesn't cost lives or ruins people I don't particularly care if you value handling data on the client in this way as a qualification for "enterprise" mobile developer. As long as it's "good enough" to meet the requirement, great. But it doesn't mean I like it, and it doesn't mean one should ignore technical flaws. Unless it's ACID you don't guarantee anything it's just a feel good (and possibly done in a much simpler way). For all the scenarios you mentioned I can mention another half dozen scenarios or even a very simple one, one person with same seniority making exactly the same change to the same record. Then your system tosses one or the other or even merges them -- in other words you dive into expert systems, NOT anything to do with "syncing".

Experience is important but there's a theoretical foundation to everything and it's wrong to expect an offline node in a distributed network to act as a source of truth for any period of time. Sorry.

[username90]

> And yes “the problem” we solved, a mobile app that could route field technicians dynamically at a level of quality we needed we did solve.

Just look for people good at handling split data updates and ownership, there are a lot of people working on that kind issues on the backend, I really doubt you find more mobile devs with those skills than backend devs with it.

[scarface74]

What makes you think that the two are distinct?

[username90]

What two are distinct? Yes you sometimes have conflicting data on two machines when you work on mobile apps, but that is the core of a lot of distributed computing problems. So if you only look for those skills in mobile devs you will miss out on a lot of people with relevant experience.

[braindeath]

> Most apps would do better to 100% avoid the problem and just say "No Internet Connection" if there's no WiFi or 3g.

Lol we are in such a bubble.

[coldtea]

If the bubble is large enough, it's the others who are in a bubble, and we're just "in the world"...

[codetrotter]

I recently came across a company similar to Udemy offering cheap “on sale” video courses like Udemy does.

This company has an app and in it you can download the videos and watch them offline, just like Udemy.

That’s great, I have a limited amount of data on my plan.

And better yet, I can watch these videos when I am completely offline, for example on the 30 hour connecting series of flights I went on recently. Except... whereas the Udemy app actually works completely offline, this other app needs internet access in order for the “my courses” tab to work.

You still have access to the videos through the “downloads” tab. But there they are not organized neatly. So I decided to do other things than to look at any of the videos.

Also, a lot of apps are bad at properly syncing data. For example I think neither Udemy nor this other one properly syncs the course progress data. Even when they do have a connection.