Questions on litesync

Bernardo

WebSocket is not supported. No plans to work on it.

I don't recommend these tricks like tunneling. There is no guarantee that they will work.

Check if it is possible to run LiteSync on port 80. If the server only has limit on port numbers but does not check protocol (content) then it may work.

But the best approach is to ask for the admin to open a port on the firewall dedicated to LiteSync, to avoid common crawler traffic on port 80 and 443.

If it is not possible, make sure to enable encryption on LiteSync (both primary and secondary nodes) to avoid problems. This is recommended in any way, but becomes a requirement if using port 80/443.

https://litesync.io/en/sqlite-encryption.html

jhay006

Bernardo
got it ! thanks 🙂

anyways i got it working on websocket yesterday,

btw , the one i mention using c, i don't know if it is a bit outdated or it is just different when in c++

#include <sqlite3.h>

char *uri = "file:app.db?node=secondary&connect=tcp://server:port";

int main() {
  sqlite3 *db;
  /* open the database */
  sqlite3_open(uri, &db);
  /* check if the db is ready */
  while(1){
    char *json_str = sqlite3_query_value_str(db, "PRAGMA sync_status");     
    BOOL db_is_ready = strstr(json_str, "\"db_is_ready\": true") > 0;
    sqlite3_free(json_str);
    if (db_is_ready) break;
    sleep_ms(250);
  }
  /* access the database */
  start_access(db);
}

The code inside while loop , i changed it to sqlite3_exec,

Bernardo

I updated the example code to include the implementation of sqlite3_query_value_str function

Thank you for informing!

Bernardo

There is now example for C++ using sqlite_modern_cpp as well

jhay006

Bernardo thank you 🙂

btw , is there any other ports beside the one we used for bind ?

file:app.db?bind=tcp://server:port = example , i used port 1234 here , then is there a hidden port tcp/udp that used for notification ?

this is related on the websocket connection , on localhost , it is fully working but when i add it to an upstream server after the handshake, it doesn't sync. heheheh

Bernardo

There is a UDP one but it is disabled by default, it may not affect.
But you really need websocket? Just bind to port 80 on the primary node:

file:app.db?node=primary&bind=tcp://0.0.0.0:80

Using encryption:

file:app.db?node=primary&bind=tcp://0.0.0.0:80&cipher=xrc4&key=testing

jhay006

Bernardo i see , will try this thanks

jhay006

btw ,
regarding on your below respone

Conflicts on insertions are avoided with the different row id numbering. There is no conflict resolution in place. The commands are processed in the order they reach the primary node(s)

does it mean , if client 1 and client 2 add a record on a table exactly same time but with different ID's
it will save both records ?

what about , they edit the same record example row ID number 1 with name and age , both changed it at the exact same time

client 1 changed age to 22
client 2 changed age to 23
? How will litesync treat it ?

does the last write wins ? i mean both changes successfully saved and sync at the same exact time , but i believe since its sqlite , the changes will be queued and whichever the last write will win ?

Bernardo

Yes.

Clients 1 and 2 write to the local database first, only then these changes are sent to the primary node(s) for synchronization.

If they are creating new records, then these records will have different row ids, and there is no conflict.

If they are modifying the same record using an UPDATE command, the last one to reach the primary nodes will overwrite the data send by the first one. And both nodes will end up having the content of the last node that sent the data to the primary node. So it does not matter the time in which they wrote to the record, what matters it the order in which the changes reach the primary node(s).

jhay006

okay thanks for that 🙂 ,

The last question is , how can i contribute ? since source code is only available for commercial license ,
but i want to contribute for this project , is there something i can do to contribute ?

Thanks

Bernardo

The wrappers for different programming languages are open source

You can check them here:

https://github.com/litesync
https://gitlab.com/litesync

jhay006

Bernardo

is there any update documentation for compiling the source code ? all of the wrappers included on the first line says
"First follow the instructions to compile and install LiteSync from the source code "

but this link is not found
https://gitlab.com/litesync/litesync-release

Bernardo

Only for those with a commercial license

It also says "or use the pre-compiled binaries"

jhay006

copy thanks

btw , where can i find this header ?
#include <sqlite_modern_cpp.h>

Bernardo

https://github.com/SqliteModernCpp/sqlite_modern_cpp

jhay006

Bernardo thank you , is there a way to check if litesync is disconnected from the tcp and force reconnect? , also is there a way to trigger the sync . ?

Bernardo

Nope. It is all automatic

jhay006

Bernardo sometimes it doesn't sync.
it happens on android/ios app

sync is active at first launch of the app , or a phone restart then reopen the app

but if i just close the app from its task manager, then reopen it , any changes will not sync anymore unless i close it again then reopen it will trigger the sync but any changes will not sync until i repeat the process

so what i did to resolve it temporary is when i execute an insert
i just need to close the current connection
then reconnect
then run the sql to insert it to local
then close again then reconnect after the insert query to trigger the sync function

Bernardo

I was not able to reproduce the problem
Maybe is it the Android version?
I use an old version of Android and the sample project works just fine there
I can switch between apps, the one stays in the background, and when coming back to it it is fully functional
Are you following the structure of the sample project (Java / Android Studio)?
Maybe it is something related to the "activities"

jhay006

okay im good with mobile app ,
i saw .NET there is it possible to work with ASP.net ?