await _table.PullItemsAsync(); hangs the app

[kmostofi]

Hi,
I followed the documentation and your tutorial video to set up the backend database. The API response and from the client side, I get a successful response.

`var connectionString = new UriBuilder { Scheme = "file", Path = "dynamo.sqlite", Query = "?mode=rwc" }.Uri.ToString();
store = new OfflineSQLiteStore(connectionString);

                store.DefineTable<Tin_Members>();

                optionsDb = new DatasyncClientOptions
                {
                    OfflineStore = store,
                };

                _client = new DatasyncClient(Constants.ServiceUri, optionsDb);

                await _client.InitializeOfflineStoreAsync();

                _table = _client.GetOfflineTable<Tbl_Members>();`

And this is the synch method

` public async Task RefreshMembersAsync()
{
await InitializeAsync();

        await _table.PushItemsAsync();
      **### _await _table.PullItemsAsync();_**

        return;
    }`

When it hits PullItemAsync , nothing happens and the app hangs.

Please note that model are matching with backend models.

Could you please advice what I am missing?

Kind regards,
Kamal

[adrianhall]

What video? I haven't done a video! :-)

In any case, there is not enough to go on here. Some things you need to provide:

1. What does your model look like, on both the server side and client side?
2. What does the controller look like on the server side?
3. If you turn off offline (and just use a remote table), does it work?
4. Turn on logging on the client side - what is going on?

[adrianhall]

That's very strange. I'm not going to be able to diagnose this without investing significant debugging time and access to the complete code (neither of which I don't have). It's something to do with the Newtonsoft.Json deserialization.

[kmostofi]

Hi,
I got data with the remote table when I read directly from the remote server. However, when I try to use the offline sync, I get the following error message when it tries to PullItemSync await _table.PullItemsAsync();.

**Set JArray values with invalid key value: "version". Int32 array index expected.**

` private async Task InitializeAsync()
{
if (_initialized)
{
return;
}

        try
        {
            await _asyncLock.WaitAsync();
            if (_initialized)
            {
                return;
            }

            if (RemoteToLocalService.StorageDb == null ||
             RemoteToLocalService.StorageDb.Length == 0) RemoteToLocalService.GetLocalDb();
            try
            {
                var connectionString = new UriBuilder { Scheme = "file", Path = RemoteToLocalService.StorageDb, Query = "?mode=rwc" }.Uri.ToString();
                store = new OfflineSQLiteStore(connectionString);

                store.DefineTable<Tin_Members>();

                optionsDb = new DatasyncClientOptions
                {
                    OfflineStore = store,
                    IdGenerator = (table) => $"{table}-{Guid.NewGuid().ToString("D").ToUpperInvariant()}",
                    // HttpPipeline = new HttpMessageHandler[] { new LoggingHandler() },
                };

                _client = new DatasyncClient(Constants.ServiceUri, optionsDb);

                await _client.InitializeOfflineStoreAsync();

                _table = _client.GetOfflineTable<Tin_Members>();

                await _table.PushItemsAsync();
                await _table.PullItemsAsync();

                _initialized = true;
            }
            catch (Exception ex)
            { throw ex; }

        }
        catch (Exception)
        {
            // Re-throw the exception.
            throw;
        }
        finally
        {
            _asyncLock.Release();
        }
    }`

The sqlite created and also the table exist in the offline database.

Any thought?

Many thanks,
Kamal

[adrianhall]

As I've said, there is nothing wrong with your code, so something else must be going on. I cannot reproduce your error except when I'm explicitly setting Newtonsoft.Json settings. This being the case, there is nothing else I can do unless you can come up with an explicit xUnit test that shows the error.

[kmostofi]

Hi.
I am sorry to bother you again. After digging into the json, I found the API return a nest object of table (data). I tested the API and the result in postman as follows:

{ "items": [ { "lastName": "!=!enc!=!inYXm3x7xxNGXmeDArALuf7w==", "firstName": "!=!enc!=!JOf4Fu2xxk2kzakIxKU4/iCQ==", "gender": 0, "aboutMe": "", "age": 25, "email": "!=!enc!=!YujjVamvY6pxxVApGgy9OhKKf+3aXLwFY6q7qWGZYdCpw=", "phone": "!=!enc!=!igWODLaxx2BNEpDp3WCTwhvg==", "pinCode": xxx6, "city": "London", "country": "Bangladesh", "dob": "xxx8", "confirmation_Code": "517587", "confirmation_Date": "2023-07-16T00:00:00", "hidden": true, "popularity": 1, "accountType": 16, "isPrivate": false, "relationTypeItem": "0", "filterByAge": "18,75", "filterbyRegion": "London,United Kingdom : Bangladesh", "membership": 1, "instaProfilePhoto": "", "fbName": "", "fbProfilePhoto": "", "twitterUserName": "", "twitterProfilePhoto": "", "filterByGender": 14.0, "profilePhoto": "https://xxxxxxxx.blob.core.windows.net/tp27398ffffff.jpg", "id": "0000e5f404cdcf4932xa19a2f9vd867f20b1", "updatedAt": "2023-07-16T15:10:36.234+00:00", "version": "AAAAAAACv4k=", "deleted": false } ], "count": null, "nextLink": "https://localhost:7017/tables/Members?ZUMO-API-VERSION=3.0.0&$skip=1" }

When I run the app, the pullitemasync fails and throws the following error as I mentioned above.
Set JArray values with invalid key value: "version". Int32 array index expected.

Could the issue be related to the nested Json?

What is your thought?

Kind regards,
Kamal

[adrianhall]

No, that's not it. The list operation is an object which wraps the list of items. You can see the model in both the server and the client code.

The response from the server is as expected. You are having a JSON decoding issue for the version - it is not decoding the version correctly. I do not know why, since the client code sets up the Newtonsoft.JSON settings appropriately. My suspicion is that you have something else ALSO setting up Newtonsoft.JSON - which is what I've said previously.

[kmostofi]

Thanks for the confirmation.
When I test the API, postman returns the nested array but after the publication to Azure, data returns in the root nest.

[adrianhall]

Questions:

1. Does the mobile app work when talking to your local API, which has the correct response?
2. What does the response look like when you deploy to Azure?
3. How are you deploying to Azure? What environment variables are available? What service is hosting?

[kmostofi]

Answer: I use the postman and the local API works nicely. It returns the data in the nested format (Items).

Answer: Response is 200 after deployment to Azure.

• Answer: I use Visual Studio Mac to publish the API to Azure. Mobile App Services and Asp app service plan is running.

Do I need to set API management?

[adrianhall]

Nope - API Management is not required.

[adrianhall]

"Response is 200" doesn't tell me what the response looks like - just the status code, which is almost irrelevant. You need to post actual output.

[kmostofi]

I posted the response result above from local API,, which is
{ "items": [ { "lastName": "!=!enc!=!inYXm3x7xxNGXmeDArALuf7w==", "firstName": "!=!enc!=!JOf4Fu2xxk2kzakIxKU4/iCQ==", "gender": 0, "aboutMe": "", "age": 25, "email": "!=!enc!=!YujjVamvY6pxxVApGgy9OhKKf+3aXLwFY6q7qWGZYdCpw=", "phone": "!=!enc!=!igWODLaxx2BNEpDp3WCTwhvg==", "pinCode": xxx6, "city": "London", "country": "Bangladesh", "dob": "xxx8", "confirmation_Code": "517587", "confirmation_Date": "2023-07-16T00:00:00", "hidden": true, "popularity": 1, "accountType": 16, "isPrivate": false, "relationTypeItem": "0", "filterByAge": "18,75", "filterbyRegion": "London,United Kingdom : Bangladesh", "membership": 1, "instaProfilePhoto": "", "fbName": "", "fbProfilePhoto": "", "twitterUserName": "", "twitterProfilePhoto": "", "filterByGender": 14.0, "profilePhoto": "https://xxxxxxxx.blob.core.windows.net/tp27398ffffff.jpg", "id": "0000e5f404cdcf4932xa19a2f9vd867f20b1", "updatedAt": "2023-07-16T15:10:36.234+00:00", "version": "AAAAAAACv4k=", "deleted": false } ], "count": null, "nextLink": "https://localhost:7017/tables/Members?ZUMO-API-VERSION=3.0.0&$skip=1" }

and from azure app service, I get the following result:

[ { "lastName": "!=!enc!=!inYXm3x7xxNGXmeDArALuf7w==", "firstName": "!=!enc!=!JOf4Fu2xxk2kzakIxKU4/iCQ==", "gender": 0, "aboutMe": "", "age": 25, "email": "!=!enc!=!YujjVamvY6pxxVApGgy9OhKKf+3aXLwFY6q7qWGZYdCpw=", "phone": "!=!enc!=!igWODLaxx2BNEpDp3WCTwhvg==", "pinCode": xxx6, "city": "London", "country": "Bangladesh", "dob": "xxx8", "confirmation_Code": "517587", "confirmation_Date": "2023-07-16T00:00:00", "hidden": true, "popularity": 1, "accountType": 16, "isPrivate": false, "relationTypeItem": "0", "filterByAge": "18,75", "filterbyRegion": "London,United Kingdom : Bangladesh", "membership": 1, "instaProfilePhoto": "", "fbName": "", "fbProfilePhoto": "", "twitterUserName": "", "twitterProfilePhoto": "", "filterByGender": 14.0, "profilePhoto": "https://xxxxxxxx.blob.core.windows.net/tp27398ffffff.jpg", "id": "0000e5f404cdcf4932xa19a2f9vd867f20b1", "updatedAt": "2023-07-16T15:10:36.234+00:00", "version": "AAAAAAACv4k=", "deleted": false } ]

[adrianhall]

But that makes no sense - it's telling me that you are not running the same code in App Service vs. locally. If you were running the same code and the same environment, then the outputs would be the same.