Actualizar un documento de Firestore en una transacción

Actualizar un documento de Firestore en una transacción

Páginas de documentación que incluyen esta muestra de código

Para ver la muestra de código usada en contexto, consulta la siguiente documentación:

Muestra de código

Go

ref := client.Collection("cities").Doc("SF")
err := client.RunTransaction(ctx, func(ctx context.Context, tx *firestore.Transaction) error {
	doc, err := tx.Get(ref) // tx.Get, NOT ref.Get!
	if err != nil {
		return err
	}
	pop, err := doc.DataAt("population")
	if err != nil {
		return err
	}
	return tx.Set(ref, map[string]interface{}{
		"population": pop.(int64) + 1,
	}, firestore.MergeAll)
})
if err != nil {
	// Handle any errors appropriately in this section.
	log.Printf("An error has occurred: %s", err)
}

Java

// Initialize doc
final DocumentReference docRef = db.collection("cities").document("SF");
City city = new City("SF");
city.setCountry("USA");
city.setPopulation(860000L);
docRef.set(city).get();

// run an asynchronous transaction
ApiFuture<Void> futureTransaction = db.runTransaction(transaction -> {
  // retrieve document and increment population field
  DocumentSnapshot snapshot = transaction.get(docRef).get();
  long oldPopulation = snapshot.getLong("population");
  transaction.update(docRef, "population", oldPopulation + 1);
  return null;
});
// block on transaction operation using transaction.get()

Node.js

// Initialize document
const cityRef = db.collection('cities').doc('SF');
await cityRef.set({
  name: 'San Francisco',
  state: 'CA',
  country: 'USA',
  capital: false,
  population: 860000
});

try {
  await db.runTransaction(async (t) => {
    const doc = await t.get(cityRef);

    // Add one person to the city population.
    // Note: this could be done without a transaction
    //       by updating the population using FieldValue.increment()
    const newPopulation = doc.data().population + 1;
    t.update(cityRef, {population: newPopulation});
  });

  console.log('Transaction success!');
} catch (e) {
  console.log('Transaction failure:', e);
}

PHP

$cityRef = $db->collection('samples/php/cities')->document('SF');
$db->runTransaction(function (Transaction $transaction) use ($cityRef) {
    $snapshot = $transaction->snapshot($cityRef);
    $newPopulation = $snapshot['population'] + 1;
    $transaction->update($cityRef, [
        ['path' => 'population', 'value' => $newPopulation]
    ]);
});

Python

transaction = db.transaction()
city_ref = db.collection(u'cities').document(u'SF')

@firestore.transactional
def update_in_transaction(transaction, city_ref):
    snapshot = city_ref.get(transaction=transaction)
    transaction.update(city_ref, {
        u'population': snapshot.get(u'population') + 1
    })

update_in_transaction(transaction, city_ref)

Ruby

city_ref = firestore.doc "#{collection_path}/SF"

firestore.transaction do |tx|
  new_population = tx.get(city_ref).data[:population] + 1
  puts "New population is #{new_population}."
  tx.update city_ref, { population: new_population }
end

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