I am writing android application which will request the data from the server after every 5 minutes and will load it into the sqlite. Later on, the data from the sqlite will be displayed to the user whenever he wants to view the data. Database will contain only the data up to last 2 days and will keep deleting the older data.
I want to achieve all this functionality using Firebase JobScheduler. But before writing, I want to know if it is the right tool to go for? Is there a better way to achieve this functionality? Or any recommended way?
Thanks in advance.
Your implementation plan sounds OK to me. But I think synchronizing every 5 minutes is excessive and will cause problems for your users from constant battery drain and network usage.
You implementation is right but there is a huge drawback in this mechanism i.e. battery drainage. I think the best mechanism would be if you implement that functionality on server end.
Server checks that if there is any change in the database
If it finds any change then you just need to push the specific updated data to your mobile agent.
Advantage:
1. You dont need to worry about the battery on mobile agent
2. All the hard work and calculation is done on server end.
Enjoy !!
Related
I want to use the forge viewer as a preview tool in my web app for generated data.
The problem I have is that the model derivative API is sometimes slow sometimes fast.
I read that this happens because the files are placed in a queue and being processed subsequentially.
In my opinion, this can be solved by:
Having the extraction.update webhook also tell me where I am in the queue. So I can inform my users with better progress information. Or when the queue is too long I can not stop the process.
Being able to have a private queue. I have no problem paying more credits if necessary.
Being able to generate svf2 files on my own server.
But I don't know if any of these options are possible. Or if there is another workaround.
Yes, that could be useful. I logged that request in our system: DERI-7940
Might be considered later on, but no plans currently
I'm not aware of any plans for that
We're always working on making the translation service better, but unfortunately, I cannot tell when it will meet your requirements - including the implementation of the webhook feature you mentioned.
SVF2 is specifically for very large models - is that what you are working with? If not, then I'm quite certain that translating to SVF would be faster.
I want to write an SMS bulk app. using .net core webapi app and rabbitMQ.
now, the end user want to send a message to huge number of cellphones.
I guess can do it using two flow.
is it correct? has another solution? or bether solution?
I guess the green flow is better because the user waiting is less than red flow?
maybe you say this two flow totally wrong. and I need another solution. can any one help me!
You need to break your problem down, without getting to your selected technology first.
Question:How much traffic you are required to terminate per second
Question:How much traffic sms-api(SMS Provider) can handle per second
Question:How much traceability you need per message, is the log enough or you need a permanent storage
I believe after answering these questions you would be able to have a rough idea about the design of application
I'm planning on creating a browser based RTS game using ASP.NET and MySQL.
I was wondering if there is a way to do this without having a central server running all the time - i.e. if all commands can be completed client side when a player logs on and performs an action, and then the database keeps a record of this.
Thanks
Simply put, no, it's a bad idea. Mostly for one of the main rules of creating an online game: Never trust the client.
Now, there's nothing technical to prevent you from doing this, but plenty of limitations you'd have to work around, and because of the aforementioned rule, it wouldn't be worth it.
I've written a ASP.NET app that I hope to sell to businesses, I could host the trial but it's designed to connect to the customers data so customers will certainly want to install it to do a successful evaluation.
I've never produced anything commercial before so I'm looking for advice on how best to limit the trial, a 30 day trial seems most common, do you simply rely on the clock of the PC/Server they install it on? Any other suggestions welcome, please keep in mind this is ASP.NET app so will be installed on their web server.
Thanks
Craig
I would just do it via the PC's clock. At the end of the day, they could just change the clock and continue to use your software, though it's probably not going to work in practice (i.e. most software actually uses the date/time for other things as well and changing it going to screw that up).
Generally, you can usually trust business more than you trust the general public. The liability of a business is much higher than that of an individual, so if it came to it, you could potentially sue them for quite a bit. That alone means most businesses will purchase licenses for all of their software: a few hundred (or even thousand) dollars for a software license is much better than risk getting sued.
When they sign up for the demo, make sure you get all of their contact details and so on.
I would setup a web service on your server to authenticate the demo application. The web service should get called periodically and if it fails, then shut down the application. That way you have complete control over the trial (you can extend it or shut it down remotely).
You should give them some sort of key which they will place in your web.config that will identify them as a customer.
Make sure you take the usual precautions of encrypting / using hashes with both the key and the web service so it's not bypassed.
This sort of thing has been well covered on SO in the past.
You cannot make it unbreakable, but you can make it very difficult for the client to break your trial period.
One way to do it is to take the first run time and encrypt that info and store it either in your web.config or database. This has a weakness though: what do you do if the value is not present where you expect it to be?
Another option is to ping a webservice that you host. If the webservice says their trial is over then you can render the appropriate page to tell them that. This has the advantage that the webservice is beyond their control and cannot be messed with. It has the disadvantage that not every client will want to be allowing their web app to phone home, and there may be connectivity issues which would interfere with the functioning of your app.
So you might want to come up with a variety of options, and then implement a licencing module using the Provider pattern, so that you can swap in the licencing module most suitable for that client.
Put a counter in the web.config, of course give the counter a non-related name so the customer does not know what it is for. Every time they access the application you can increment the counter. Give them x number of log-in's.
If you want you can encrypt the counter if you do not want the customer to figure out that the counter is incrementing.
In an Adobe flex applicaiton using BlazeDS AMF remoting, what is the best stategy for keeping the local data fresh and in synch with the backend database?
In a typical web application, web pages refresh the view each time they are loaded, so the data in the view is never too old.
In a Flex application, there is the tempation to load more data up-front to be shared across tabs, panels, etc. This data is typically refreshed from the backend less often, so there is a greater chance of it being stale - leading to problems when saving, etc.
So, what's the best way to overcome this problem?
a. build the Flex application as if it was a web app - reload the backend data on every possible view change
b. ignore the problem and just deal with stale data issues when they occur (at the risk of annoying users who are more likely to be working with stale data)
c. something else
In my case, keeping the data channel open via LiveCycle RTMP is not an option.
a. Consider optimizing back-end changes through a proxy that does its own notification or poling: it knows if any of the data is dirty, and will quick-return (a la a 304) if not.
b. Often, users look more than they touch. Consider one level of refresh for looking and another when they start and continue to edit.
Look at BuzzWord: it locks on edit, but also automatically saves and unlocks frequently.
Cheers
If you can't use the messaging protocol in BlazeDS, then I would have to agree that you should do RTMP polling over HTTP. The data is compressed when using RTMP in AMF which helps speed things up so the client is waiting long between updates. This would also allow you to later scale up to the push methods if the product's customer decides to pay up for the extra hardware and licenses.
You don't need Livecycle and RTMP in order to have a notification mechanism, you can do it with the channels from BlazeDS and use a streaming/long polling strategy
In the past I have gone with choice "a". If you were using Remote Objects you could setup some cache-style logic to keep them in sync on the remote end.
Sam
Can't you use RTMP over HTTP (HTTP Polling)?
That way you can still use RTMP, and although it is much slower than real RTMP you can still braodcast updates this way.
We have an app that uses RTMP to signal inserts, updates and deletes by simply broadcasting RTMP messages containing the Table/PrimaryKey pair, leaving the app to automatically update it's data. We do this over Http using RTMP.
I found this article about synchronization:
http://www.databasejournal.com/features/sybase/article.php/3769756/The-Missing-Sync.htm
It doesn't go into technical details but you can guess what kind of coding will implement this strategies.
I also don't have fancy notifications from my server so I need synchronization strategies.
For instance I have a list of companies in my modelLocator. It doesn't change really often, it's not big enough to consider pagination, I don't want to reload it all (removeAll()) on each user action but yet I don't want my application to crash or UPDATE corrupt data in case it has been UPDATED or DELETED from another instance of the application.
What I do now is saving in a SESSION the SELECT datetime. When I come back for refreshing the data I SELECT WHERE last_modified>$SESSION['lastLoad']
This way I get only rows modified after I loaded the data (most of the time 0 rows).
Obviously you need to UPDATE last_modified on each INSERT and UPDATE.
For DELETE it's more tricky. As the guy point out in his article:
"How can we send up a record that no longer exists"
You need to tell flex which item it should delete (say by ID) so you cannot really DELETE on DELETE :)
When a user delete a company you do an UPDATE instead: deleted=1
Then on refresh companies, for row where deleted=1 you just send back the ID to flex so that it makes sure this company isn't in the model anymore.
Last but not the least, you need to write a function that clean rows where deleted=1 and last_modified is older than ... 3days or whatever you think suits your needs.
The good thing is that if a user delete a row by mistake it's still in the database and you can save it from real delete within 3days.
Rather than caching on flex client, why not do caching on server side? Some reasons,
1) When you cache data on server side, its centralized and you can make sure all clients have the same state of data
2) There are much better options available on server side for caching rather than on flex. Also you can have a cron job which refreshes data based on some frequency say every 24 hours.
3) As data is cached on server and it doesn't need to fetch it from db every time, communication with flex will be much faster
Regards,
Tejas