Reading Documents

Call a collection with an ID to get a document handle. odm.users('jane') and odm.users.doc('jane') are the same.

Read once

get() returns the model, or null when the document does not exist.

final user = await odm.users('jane').get();

if (user != null) {
  print('Found ${user.name}');
} else {
  print('No such user');
}

To check whether a document exists, compare the result with null.

Cache or server only

Pass GetOptions to choose where the read comes from. GetOptions and Source are exported by firestore_odm.

final cached = await odm.users('jane').get(
  const GetOptions(source: Source.cache),
);

Listen for changes

stream emits the document now and after every change. It emits null while the document does not exist.

final subscription = odm.users('jane').stream.listen((user) {
  if (user == null) {
    print('Deleted');
  } else {
    print('Updated: ${user.name}');
  }
});

// Cancel when you no longer need updates, for example in dispose().
await subscription.cancel();

Each read of stream starts a new listener. In a Flutter widget, create the stream once (for example in initState) and pass it to a StreamBuilder.

To read many documents, see Fetching Data.