Duplicate records for the a single saveInBackground Call because Internet provider block response

[oazya500]

Internet provider some time block response to device and device request to save object again because the response is error all off request success and save the object but device receive error response because internet provider block the site in response to device and show this web to device

http://82.114.160.94/webadmin/deny/

some time response success and device stop to request again but it save object some time to 4 times

it is big Issues

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[ioscargalvan]

I am too experiencing this issue. Do you have a workaround on this ?

[oazya500]

we want parse server team solve this issue .

you can workaround this issue by create randome number when create object and query that number before save in cloud and response that object if it is already saved
to sure it is uniq number you can take another value like datacreate or any other value

it is big Issues for me because always has duplicated values

[ioscargalvan]

This is a ground breaking issue for me. I'm changing from parse to firecloud, let's see how it goes.

[flovilmart]

You’l’ have The same issue anywhere you try to save some data on a server and when no confirmation that the server saved the data actually comes to the client. Abd if you’re better off with firecloud, good for you!

[ioscargalvan]

Yeah, you're right. But this issue has been becoming more and more present. Don't get me wrong, is there anyway I can assist you? Because this issue (seems to me) is new. I have been using parse server for a few months and it never ever showed up before.

[flovilmart]

Does it show up for you? And if it shows up, we need a bit more than sometimes, on peculiar network conditions etc....

[ioscargalvan]

Ok, I'll try to go as deep as possible.

In the last week and a half, it happened to me 4 times. I have been experiencing issues with my internet connection, and whenever I was having issues with my connection and called the method saveInBackground(), LogCat kept telling me a proxy status of NODATA (which, I assume means that Android couldn't connect to internet). Then, after the connection was successful, Parse notified that the object was saved successfully (and this is where the data is duplicated). I think is relevant to say that the notification came only once.

If I can be of any more help, just ask :).

[oazya500]

I do not know how network is work for blocking site . I remember I was test my app for some android version and one off the version always fail . I try more and more and take some time to know the site is blocked for that version . but all other version it is work fine . when I ran vpn app for that version who is always fail . the app works fine . I did not know why it is blocked for that version only . my be Is random function to block some sites

[acinader]

This has definitely been an issue for us. We have solved it now, but it took some time.

1. our first pass was: when we save objects, create a unique id for the object on the client. A beforeSave hook would do a query for the unique id, if it found a dupe, it would not save the object.

While it did work sometimes, we found that we would still occasionally get duplicate objects when a client had a bad internet connection.

2. So, we created an afterSave hook that would query for all objects saved in the last ten min and mark any that had the same unique id as a dupe. this solution has proven to be robust.

There is probably a better general solution to our afterSave hook, like a periodic timer that checks each class for dupes, or something, but it would require our client SDK's to make a GUID for each object before sending it to the server. Something kinda like what you get from an object persistent service in java like hibernate.

I think that a general solution baked into the SDK's (and ideally documented with a solution for the REST API), would be a valuable addition to parse.

Thoughts and/or questions most welcome!

[oazya500]

some pic for blocking site if the site can not work from out side off my country

[oazya500]

I think the best way to solve this it is make device before save object is pending Id from server when the id come to device for first time start to save all object . when the second id came . check the object if it is has id do not change id or save the object again .

this also will work even if you have enable local data storage . this is simple solution but I will know if the team work to solve this problem It will Offers best off my solution

[montymxb]

@acinader I do like the idea of the clients setting a unique id before submitting it to the server. Same object coming in more than once could be screened out by the hooks, the server itself, or even another sdk.

[oazya500]

@montymxb but if you enable local data store you will not know Which of the duplicate object must be remove

also you will not to sure if the id is uniq even if you query the last 10 mint . but you can say it is uniq id if you query last 10 mint

[montymxb]

@oazya500 You would have to respect the uuid in a local data store as well, so ideally you wouldn't have duplicates there either. This is up to the implementation to guard against.

As for uniqueness, on the client end, you would have to check the server and anything else (like a local datastore) to ensure it's not duplicating an existing entry. Essentially, ACID compliance, with individual requests completing (and being unique) or being rejected outright.

[flovilmart]

That would work in theory, in practice this is moving the ID generation on the client and hope there’s no conflicts :/