Xamarin Rest Example

Simple WebServer and Mobile App using Rest with abilities to SYNC data

Mobile instructions

All configs can be defined in Init methods on each class:

• RestService.cs
• SQLiteRepository.cs
• SyncService.cs

These methods should be called at the initalization of the app, at App.xaml.cs

protected override void OnStart ()
{
  // Handle when your app starts
  SQLiteRepository.Init();
  RestService.Init();
  SyncService.Init();
}

Configuring SQLiteRepository

Define database manipulation before app starts at SQLiteRepository.cs Init method

public static void Init()
{
    db.CreateTable<Pessoa>();
    db.CreateTable<Empresa>();
}

Configuring RestService

Define Rest Uri's that Sync mecanism will be calling at RestService.cs Init method

var pessoaHolder = new RestHolder<Pessoa> {
    SyncUri = "pessoa/sync?date=",
    SyncDeletedUri = "pessoa/syncDeleted?date=",
    InsertUri = "pessoa/insert",
    UpdateUri = "pessoa/update",
    DeleteUri = "pessoa/delete/{0}"
};

var empresaHolder = new RestHolder<Empresa> {
    SyncUri = "empresa/sync?date=",
    InsertUri = "empresa/insert",
    UpdateUri = "empresa/update",
    DeleteUri = "empresa/delete/{0}"
};

Uri's is not required, but will have a default value defined by <T> class name + method rest name. Ex: <entity>/insert

Delete Uri's must have arg0 ID. Ex: <entity>/delete/{0}

Configuring SyncService

Define Sync features that can sync data periodically at SyncService.cs Init method.

• AutoSync
• AutoSyncDeleted

public static void Init()
{
    SyncService.StartAutoSync<Pessoa>();
    SyncService.StartAutoSync<Empresa>();

    SyncService.StartAutoSyncDeleted<Pessoa>();
}

Both StartAutoSync and StartAutoSync have it's own TimeSpan to periodically sync data at SyncService.cs static attribute. Default value is set to try a sync each 5 seconds and must be changed hardcoded by now

private static readonly TimeSpan syncTimeSpan = new TimeSpan(0, 0, 5);
private static readonly TimeSpan syncDeleteTimeSpan = new TimeSpan(0, 0, 5);

StartAutoSync creates a timer that execute a rest call to SyncUri and autoSync in background

StartAutoSyncDeleted creates a timer that execute a rest call to SyncDeletedUri and autoSync deleted entities in background

Watcher functionality (Subscribe)

It is possible to create a watcher, that will execute a block of code whenever a Sync or SyncDeleted of class happens

// ...

subscription = new Subscription<Pessoa>( () => {
    Device.BeginInvokeOnMainThread( async () => {
        MyListView.ItemsSource = await SQLiteRepository.Query<Pessoa>("SELECT * FROM " + typeof(Pessoa).Name);
    });
});
  
// ...

The lambda block of code above is called whenever a Sync or SyncDeleted of Pessoa.cs is completed by SyncService.cs auto sync method. This example execute a query to refresh the MyListView.ItemSource after a sync ends. Device.BeginInvokeOnMainThread must be used in this case, because MyListView has to be executed on MainThread

Unsubscribe watcher

To unsubscribe a watcher, just call Unsubscribe method at object instance