Ada dua cara untuk mengambil data yang tersimpan di Cloud Firestore. Kedua metode ini dapat digunakan dengan dokumen, koleksi dokumen, atau hasil kueri:
- Memanggil metode untuk mendapatkan datanya.
- Menyetel pemroses untuk menerima peristiwa perubahan data.
Saat Anda menyetel pemroses, Cloud Firestore akan mengirimi pemroses sebuah snapshot awal data, dan kemudian snapshot lain setiap kali dokumen berubah.
Data contoh
Untuk memulai, tulis beberapa data mengenai kota agar kami dapat melihat berbagai cara untuk membacanya kembali:
Web
var citiesRef = db.collection("cities");
citiesRef.doc("SF").set({
name: "San Francisco", state: "CA", country: "USA",
capital: false, population: 860000,
regions: ["west_coast", "norcal"] });
citiesRef.doc("LA").set({
name: "Los Angeles", state: "CA", country: "USA",
capital: false, population: 3900000,
regions: ["west_coast", "socal"] });
citiesRef.doc("DC").set({
name: "Washington, D.C.", state: null, country: "USA",
capital: true, population: 680000,
regions: ["east_coast"] });
citiesRef.doc("TOK").set({
name: "Tokyo", state: null, country: "Japan",
capital: true, population: 9000000,
regions: ["kanto", "honshu"] });
citiesRef.doc("BJ").set({
name: "Beijing", state: null, country: "China",
capital: true, population: 21500000,
regions: ["jingjinji", "hebei"] });
Swift
let citiesRef = db.collection("cities")
citiesRef.document("SF").setData([
"name": "San Francisco",
"state": "CA",
"country": "USA",
"capital": false,
"population": 860000,
"regions": ["west_coast", "norcal"]
])
citiesRef.document("LA").setData([
"name": "Los Angeles",
"state": "CA",
"country": "USA",
"capital": false,
"population": 3900000,
"regions": ["west_coast", "socal"]
])
citiesRef.document("DC").setData([
"name": "Washington D.C.",
"country": "USA",
"capital": true,
"population": 680000,
"regions": ["east_coast"]
])
citiesRef.document("TOK").setData([
"name": "Tokyo",
"country": "Japan",
"capital": true,
"population": 9000000,
"regions": ["kanto", "honshu"]
])
citiesRef.document("BJ").setData([
"name": "Beijing",
"country": "China",
"capital": true,
"population": 21500000,
"regions": ["jingjinji", "hebei"]
])
Objective-C
FIRCollectionReference *citiesRef = [self.db collectionWithPath:@"cities"];
[[citiesRef documentWithPath:@"SF"] setData:@{
@"name": @"San Francisco",
@"state": @"CA",
@"country": @"USA",
@"capital": @(NO),
@"population": @860000,
@"regions": @[@"west_coast", @"norcal"]
}];
[[citiesRef documentWithPath:@"LA"] setData:@{
@"name": @"Los Angeles",
@"state": @"CA",
@"country": @"USA",
@"capital": @(NO),
@"population": @3900000,
@"regions": @[@"west_coast", @"socal"]
}];
[[citiesRef documentWithPath:@"DC"] setData:@{
@"name": @"Washington D.C.",
@"country": @"USA",
@"capital": @(YES),
@"population": @680000,
@"regions": @[@"east_coast"]
}];
[[citiesRef documentWithPath:@"TOK"] setData:@{
@"name": @"Tokyo",
@"country": @"Japan",
@"capital": @(YES),
@"population": @9000000,
@"regions": @[@"kanto", @"honshu"]
}];
[[citiesRef documentWithPath:@"BJ"] setData:@{
@"name": @"Beijing",
@"country": @"China",
@"capital": @(YES),
@"population": @21500000,
@"regions": @[@"jingjinji", @"hebei"]
}];
Java
CollectionReference cities = db.collection("cities");
Map<String, Object> data1 = new HashMap<>();
data1.put("name", "San Francisco");
data1.put("state", "CA");
data1.put("country", "USA");
data1.put("capital", false);
data1.put("population", 860000);
data1.put("regions", Arrays.asList("west_coast", "norcal"));
cities.document("SF").set(data1);
Map<String, Object> data2 = new HashMap<>();
data2.put("name", "Los Angeles");
data2.put("state", "CA");
data2.put("country", "USA");
data2.put("capital", false);
data2.put("population", 3900000);
data2.put("regions", Arrays.asList("west_coast", "socal"));
cities.document("LA").set(data2);
Map<String, Object> data3 = new HashMap<>();
data3.put("name", "Washington D.C.");
data3.put("state", null);
data3.put("country", "USA");
data3.put("capital", true);
data3.put("population", 680000);
data3.put("regions", Arrays.asList("east_coast"));
cities.document("DC").set(data3);
Map<String, Object> data4 = new HashMap<>();
data4.put("name", "Tokyo");
data4.put("state", null);
data4.put("country", "Japan");
data4.put("capital", true);
data4.put("population", 9000000);
data4.put("regions", Arrays.asList("kanto", "honshu"));
cities.document("TOK").set(data4);
Map<String, Object> data5 = new HashMap<>();
data5.put("name", "Beijing");
data5.put("state", null);
data5.put("country", "China");
data5.put("capital", true);
data5.put("population", 21500000);
data5.put("regions", Arrays.asList("jingjinji", "hebei"));
cities.document("BJ").set(data5);
Kotlin+KTX
val cities = db.collection("cities")
val data1 = hashMapOf(
"name" to "San Francisco",
"state" to "CA",
"country" to "USA",
"capital" to false,
"population" to 860000,
"regions" to listOf("west_coast", "norcal")
)
cities.document("SF").set(data1)
val data2 = hashMapOf(
"name" to "Los Angeles",
"state" to "CA",
"country" to "USA",
"capital" to false,
"population" to 3900000,
"regions" to listOf("west_coast", "socal")
)
cities.document("LA").set(data2)
val data3 = hashMapOf(
"name" to "Washington D.C.",
"state" to null,
"country" to "USA",
"capital" to true,
"population" to 680000,
"regions" to listOf("east_coast")
)
cities.document("DC").set(data3)
val data4 = hashMapOf(
"name" to "Tokyo",
"state" to null,
"country" to "Japan",
"capital" to true,
"population" to 9000000,
"regions" to listOf("kanto", "honshu")
)
cities.document("TOK").set(data4)
val data5 = hashMapOf(
"name" to "Beijing",
"state" to null,
"country" to "China",
"capital" to true,
"population" to 21500000,
"regions" to listOf("jingjinji", "hebei")
)
cities.document("BJ").set(data5)
Java
CollectionReference cities = db.collection("cities");
List<ApiFuture<WriteResult>> futures = new ArrayList<>();
futures.add(cities.document("SF").set(new City("San Francisco", "CA", "USA", false, 860000L,
Arrays.asList("west_coast", "norcal"))));
futures.add(cities.document("LA").set(new City("Los Angeles", "CA", "USA", false, 3900000L,
Arrays.asList("west_coast", "socal"))));
futures.add(cities.document("DC").set(new City("Washington D.C.", null, "USA", true, 680000L,
Arrays.asList("east_coast"))));
futures.add(cities.document("TOK").set(new City("Tokyo", null, "Japan", true, 9000000L,
Arrays.asList("kanto", "honshu"))));
futures.add(cities.document("BJ").set(new City("Beijing", null, "China", true, 21500000L,
Arrays.asList("jingjinji", "hebei"))));
// (optional) block on operation
ApiFutures.allAsList(futures).get();
Python
class City(object):
def __init__(self, name, state, country, capital=False, population=0,
regions=[]):
self.name = name
self.state = state
self.country = country
self.capital = capital
self.population = population
self.regions = regions
@staticmethod
def from_dict(source):
# ...
def to_dict(self):
# ...
def __repr__(self):
return(
f'City(\
name={self.name}, \
country={self.country}, \
population={self.population}, \
capital={self.capital}, \
regions={self.regions}\
)'
)
cities_ref = db.collection(u'cities')
cities_ref.document(u'BJ').set(
City(u'Beijing', None, u'China', True, 21500000, [u'hebei']).to_dict())
cities_ref.document(u'SF').set(
City(u'San Francisco', u'CA', u'USA', False, 860000,
[u'west_coast', u'norcal']).to_dict())
cities_ref.document(u'LA').set(
City(u'Los Angeles', u'CA', u'USA', False, 3900000,
[u'west_coast', u'socal']).to_dict())
cities_ref.document(u'DC').set(
City(u'Washington D.C.', None, u'USA', True, 680000,
[u'east_coast']).to_dict())
cities_ref.document(u'TOK').set(
City(u'Tokyo', None, u'Japan', True, 9000000,
[u'kanto', u'honshu']).to_dict())
C++
CollectionReference cities = db->Collection("cities");
cities.Document("SF").Set({
{"name", FieldValue::String("San Francisco")},
{"state", FieldValue::String("CA")},
{"country", FieldValue::String("USA")},
{"capital", FieldValue::Boolean(false)},
{"population", FieldValue::Integer(860000)},
{"regions", FieldValue::Array({FieldValue::String("west_coast"),
FieldValue::String("norcal")})},
});
cities.Document("LA").Set({
{"name", FieldValue::String("Los Angeles")},
{"state", FieldValue::String("CA")},
{"country", FieldValue::String("USA")},
{"capital", FieldValue::Boolean(false)},
{"population", FieldValue::Integer(3900000)},
{"regions", FieldValue::Array({FieldValue::String("west_coast"),
FieldValue::String("socal")})},
});
cities.Document("DC").Set({
{"name", FieldValue::String("Washington D.C.")},
{"state", FieldValue::Null()},
{"country", FieldValue::String("USA")},
{"capital", FieldValue::Boolean(true)},
{"population", FieldValue::Integer(680000)},
{"regions",
FieldValue::Array({FieldValue::String("east_coast")})},
});
cities.Document("TOK").Set({
{"name", FieldValue::String("Tokyo")},
{"state", FieldValue::Null()},
{"country", FieldValue::String("Japan")},
{"capital", FieldValue::Boolean(true)},
{"population", FieldValue::Integer(9000000)},
{"regions", FieldValue::Array({FieldValue::String("kanto"),
FieldValue::String("honshu")})},
});
cities.Document("BJ").Set({
{"name", FieldValue::String("Beijing")},
{"state", FieldValue::Null()},
{"country", FieldValue::String("China")},
{"capital", FieldValue::Boolean(true)},
{"population", FieldValue::Integer(21500000)},
{"regions", FieldValue::Array({FieldValue::String("jingjinji"),
FieldValue::String("hebei")})},
});
Node.js
const citiesRef = db.collection('cities');
await citiesRef.doc('SF').set({
name: 'San Francisco', state: 'CA', country: 'USA',
capital: false, population: 860000
});
await citiesRef.doc('LA').set({
name: 'Los Angeles', state: 'CA', country: 'USA',
capital: false, population: 3900000
});
await citiesRef.doc('DC').set({
name: 'Washington, D.C.', state: null, country: 'USA',
capital: true, population: 680000
});
await citiesRef.doc('TOK').set({
name: 'Tokyo', state: null, country: 'Japan',
capital: true, population: 9000000
});
await citiesRef.doc('BJ').set({
name: 'Beijing', state: null, country: 'China',
capital: true, population: 21500000
});
Go
cities := []struct {
id string
c City
}{
{id: "SF", c: City{Name: "San Francisco", State: "CA", Country: "USA", Capital: false, Population: 860000}},
{id: "LA", c: City{Name: "Los Angeles", State: "CA", Country: "USA", Capital: false, Population: 3900000}},
{id: "DC", c: City{Name: "Washington D.C.", Country: "USA", Capital: true, Population: 680000}},
{id: "TOK", c: City{Name: "Tokyo", Country: "Japan", Capital: true, Population: 9000000}},
{id: "BJ", c: City{Name: "Beijing", Country: "China", Capital: true, Population: 21500000}},
}
for _, c := range cities {
_, err := client.Collection("cities").Doc(c.id).Set(ctx, c.c)
if err != nil {
return err
}
}
PHP
$citiesRef = $db->collection('cities');
$citiesRef->document('SF')->set([
'name' => 'San Francisco',
'state' => 'CA',
'country' => 'USA',
'capital' => false,
'population' => 860000
]);
$citiesRef->document('LA')->set([
'name' => 'Los Angeles',
'state' => 'CA',
'country' => 'USA',
'capital' => false,
'population' => 3900000
]);
$citiesRef->document('DC')->set([
'name' => 'Washington D.C.',
'state' => null,
'country' => 'USA',
'capital' => true,
'population' => 680000
]);
$citiesRef->document('TOK')->set([
'name' => 'Tokyo',
'state' => null,
'country' => 'Japan',
'capital' => true,
'population' => 9000000
]);
$citiesRef->document('BJ')->set([
'name' => 'Beijing',
'state' => null,
'country' => 'China',
'capital' => true,
'population' => 21500000
]);
printf('Added example cities data to the cities collection.' . PHP_EOL);
Unity
CollectionReference citiesRef = db.Collection("cities");
citiesRef.Document("SF").SetAsync(new Dictionary<string, object>(){
{ "Name", "San Francisco" },
{ "State", "CA" },
{ "Country", "USA" },
{ "Capital", false },
{ "Population", 860000 }
}).ContinueWithOnMainThread(task =>
citiesRef.Document("LA").SetAsync(new Dictionary<string, object>(){
{ "Name", "Los Angeles" },
{ "State", "CA" },
{ "Country", "USA" },
{ "Capital", false },
{ "Population", 3900000 }
})
).ContinueWithOnMainThread(task =>
citiesRef.Document("DC").SetAsync(new Dictionary<string, object>(){
{ "Name", "Washington D.C." },
{ "State", null },
{ "Country", "USA" },
{ "Capital", true },
{ "Population", 680000 }
})
).ContinueWithOnMainThread(task =>
citiesRef.Document("TOK").SetAsync(new Dictionary<string, object>(){
{ "Name", "Tokyo" },
{ "State", null },
{ "Country", "Japan" },
{ "Capital", true },
{ "Population", 9000000 }
})
).ContinueWithOnMainThread(task =>
citiesRef.Document("BJ").SetAsync(new Dictionary<string, object>(){
{ "Name", "Beijing" },
{ "State", null },
{ "Country", "China" },
{ "Capital", true },
{ "Population", 21500000 }
})
);
C#
CollectionReference citiesRef = db.Collection("cities");
await citiesRef.Document("SF").SetAsync(new Dictionary<string, object>(){
{ "Name", "San Francisco" },
{ "State", "CA" },
{ "Country", "USA" },
{ "Capital", false },
{ "Population", 860000 }
});
await citiesRef.Document("LA").SetAsync(new Dictionary<string, object>(){
{ "Name", "Los Angeles" },
{ "State", "CA" },
{ "Country", "USA" },
{ "Capital", false },
{ "Population", 3900000 }
});
await citiesRef.Document("DC").SetAsync(new Dictionary<string, object>(){
{ "Name", "Washington D.C." },
{ "State", null },
{ "Country", "USA" },
{ "Capital", true },
{ "Population", 680000 }
});
await citiesRef.Document("TOK").SetAsync(new Dictionary<string, object>(){
{ "Name", "Tokyo" },
{ "State", null },
{ "Country", "Japan" },
{ "Capital", true },
{ "Population", 9000000 }
});
await citiesRef.Document("BJ").SetAsync(new Dictionary<string, object>(){
{ "Name", "Beijing" },
{ "State", null },
{ "Country", "China" },
{ "Capital", true },
{ "Population", 21500000 }
});
Console.WriteLine("Added example cities data to the cities collection.");
Ruby
cities_ref = firestore.col collection_path
cities_ref.doc("SF").set(
name: "San Francisco",
state: "CA",
country: "USA",
capital: false,
population: 860_000
)
cities_ref.doc("LA").set(
name: "Los Angeles",
state: "CA",
country: "USA",
capital: false,
population: 3_900_000
)
cities_ref.doc("DC").set(
name: "Washington D.C.",
state: nil,
country: "USA",
capital: true,
population: 680_000
)
cities_ref.doc("TOK").set(
name: "Tokyo",
state: nil,
country: "Japan",
capital: true,
population: 9_000_000
)
cities_ref.doc("BJ").set(
name: "Beijing",
state: nil,
country: "China",
capital: true,
population: 21_500_000
)
Mendapatkan dokumen
Contoh berikut menunjukkan cara mengambil konten dari sebuah dokumen menggunakan get():
Web
var docRef = db.collection("cities").doc("SF");
docRef.get().then((doc) => {
if (doc.exists) {
console.log("Document data:", doc.data());
} else {
// doc.data() will be undefined in this case
console.log("No such document!");
}
}).catch((error) => {
console.log("Error getting document:", error);
});
Swift
let docRef = db.collection("cities").document("SF")
docRef.getDocument { (document, error) in
if let document = document, document.exists {
let dataDescription = document.data().map(String.init(describing:)) ?? "nil"
print("Document data: \(dataDescription)")
} else {
print("Document does not exist")
}
}
Objective-C
FIRDocumentReference *docRef =
[[self.db collectionWithPath:@"cities"] documentWithPath:@"SF"];
[docRef getDocumentWithCompletion:^(FIRDocumentSnapshot *snapshot, NSError *error) {
if (snapshot.exists) {
// Document data may be nil if the document exists but has no keys or values.
NSLog(@"Document data: %@", snapshot.data);
} else {
NSLog(@"Document does not exist");
}
}];
Java
DocumentReference docRef = db.collection("cities").document("SF");
docRef.get().addOnCompleteListener(new OnCompleteListener<DocumentSnapshot>() {
@Override
public void onComplete(@NonNull Task<DocumentSnapshot> task) {
if (task.isSuccessful()) {
DocumentSnapshot document = task.getResult();
if (document.exists()) {
Log.d(TAG, "DocumentSnapshot data: " + document.getData());
} else {
Log.d(TAG, "No such document");
}
} else {
Log.d(TAG, "get failed with ", task.getException());
}
}
});
Kotlin+KTX
val docRef = db.collection("cities").document("SF")
docRef.get()
.addOnSuccessListener { document ->
if (document != null) {
Log.d(TAG, "DocumentSnapshot data: ${document.data}")
} else {
Log.d(TAG, "No such document")
}
}
.addOnFailureListener { exception ->
Log.d(TAG, "get failed with ", exception)
}
Java
DocumentReference docRef = db.collection("cities").document("SF");
// asynchronously retrieve the document
ApiFuture<DocumentSnapshot> future = docRef.get();
// ...
// future.get() blocks on response
DocumentSnapshot document = future.get();
if (document.exists()) {
System.out.println("Document data: " + document.getData());
} else {
System.out.println("No such document!");
}
Python
doc_ref = db.collection(u'cities').document(u'SF')
doc = doc_ref.get()
if doc.exists:
print(f'Document data: {doc.to_dict()}')
else:
print(u'No such document!')
C++
DocumentReference doc_ref = db->Collection("cities").Document("SF");
doc_ref.Get().OnCompletion([](const Future<DocumentSnapshot>& future) {
if (future.error() == Error::kErrorOk) {
const DocumentSnapshot& document = *future.result();
if (document.exists()) {
std::cout << "DocumentSnapshot id: " << document.id() << '\n';
} else {
std::cout << "no such document\n";
}
} else {
std::cout << "Get failed with: " << future.error_message() << '\n';
}
});
Node.js
const cityRef = db.collection('cities').doc('SF');
const doc = await cityRef.get();
if (!doc.exists) {
console.log('No such document!');
} else {
console.log('Document data:', doc.data());
}
Go
dsnap, err := client.Collection("cities").Doc("SF").Get(ctx)
if err != nil {
return nil, err
}
m := dsnap.Data()
fmt.Printf("Document data: %#v\n", m)
PHP
$docRef = $db->collection('cities')->document('SF');
$snapshot = $docRef->snapshot();
if ($snapshot->exists()) {
printf('Document data:' . PHP_EOL);
print_r($snapshot->data());
} else {
printf('Document %s does not exist!' . PHP_EOL, $snapshot->id());
}
Unity
DocumentReference docRef = db.Collection("cities").Document("SF");
docRef.GetSnapshotAsync().ContinueWithOnMainThread(task =>
{
DocumentSnapshot snapshot = task.Result;
if (snapshot.Exists) {
Debug.Log(String.Format("Document data for {0} document:", snapshot.Id));
Dictionary<string, object> city = snapshot.ToDictionary();
foreach (KeyValuePair<string, object> pair in city) {
Debug.Log(String.Format("{0}: {1}", pair.Key, pair.Value));
}
} else {
Debug.Log(String.Format("Document {0} does not exist!", snapshot.Id));
}
});
C#
DocumentReference docRef = db.Collection("cities").Document("SF");
DocumentSnapshot snapshot = await docRef.GetSnapshotAsync();
if (snapshot.Exists)
{
Console.WriteLine("Document data for {0} document:", snapshot.Id);
Dictionary<string, object> city = snapshot.ToDictionary();
foreach (KeyValuePair<string, object> pair in city)
{
Console.WriteLine("{0}: {1}", pair.Key, pair.Value);
}
}
else
{
Console.WriteLine("Document {0} does not exist!", snapshot.Id);
}
Ruby
doc_ref = firestore.doc "#{collection_path}/SF"
snapshot = doc_ref.get
if snapshot.exists?
puts "#{snapshot.document_id} data: #{snapshot.data}."
else
puts "Document #{snapshot.document_id} does not exist!"
end
Opsi Sumber
Untuk platform dengan dukungan offline, Anda dapat menyetel opsi source untuk mengontrol bagaimana panggilan get menggunakan cache offline.
Secara default, panggilan get akan mencoba mengambil snapshot dokumen terbaru dari database Anda. Pada platform dengan dukungan offline, library klien akan menggunakan cache offline jika jaringan tidak tersedia atau jika waktu permintaan habis.
Anda dapat menentukan opsi source dalam panggilan get() untuk mengubah perilaku default. Anda hanya dapat mengambil dari database dan mengabaikan cache offline, atau Anda dapat mengambil hanya dari cache offline. Contoh:
Web
var docRef = db.collection("cities").doc("SF");
// Valid options for source are 'server', 'cache', or
// 'default'. See https://firebase.google.com/docs/reference/js/firebase.firestore.GetOptions
// for more information.
var getOptions = {
source: 'cache'
};
// Get a document, forcing the SDK to fetch from the offline cache.
docRef.get(getOptions).then((doc) => {
// Document was found in the cache. If no cached document exists,
// an error will be returned to the 'catch' block below.
console.log("Cached document data:", doc.data());
}).catch((error) => {
console.log("Error getting cached document:", error);
});
Swift
let docRef = db.collection("cities").document("SF")
// Force the SDK to fetch the document from the cache. Could also specify
// FirestoreSource.server or FirestoreSource.default.
docRef.getDocument(source: .cache) { (document, error) in
if let document = document {
let dataDescription = document.data().map(String.init(describing:)) ?? "nil"
print("Cached document data: \(dataDescription)")
} else {
print("Document does not exist in cache")
}
}
Objective-C
FIRDocumentReference *docRef =
[[self.db collectionWithPath:@"cities"] documentWithPath:@"SF"];
// Force the SDK to fetch the document from the cache. Could also specify
// FIRFirestoreSourceServer or FIRFirestoreSourceDefault.
[docRef getDocumentWithSource:FIRFirestoreSourceCache
completion:^(FIRDocumentSnapshot *snapshot, NSError *error) {
if (snapshot != NULL) {
// The document data was found in the cache.
NSLog(@"Cached document data: %@", snapshot.data);
} else {
// The document data was not found in the cache.
NSLog(@"Document does not exist in cache: %@", error);
}
}];
Java
DocumentReference docRef = db.collection("cities").document("SF");
// Source can be CACHE, SERVER, or DEFAULT.
Source source = Source.CACHE;
// Get the document, forcing the SDK to use the offline cache
docRef.get(source).addOnCompleteListener(new OnCompleteListener<DocumentSnapshot>() {
@Override
public void onComplete(@NonNull Task<DocumentSnapshot> task) {
if (task.isSuccessful()) {
// Document found in the offline cache
DocumentSnapshot document = task.getResult();
Log.d(TAG, "Cached document data: " + document.getData());
} else {
Log.d(TAG, "Cached get failed: ", task.getException());
}
}
});
Kotlin+KTX
val docRef = db.collection("cities").document("SF")
// Source can be CACHE, SERVER, or DEFAULT.
val source = Source.CACHE
// Get the document, forcing the SDK to use the offline cache
docRef.get(source).addOnCompleteListener { task ->
if (task.isSuccessful) {
// Document found in the offline cache
val document = task.result
Log.d(TAG, "Cached document data: ${document?.data}")
} else {
Log.d(TAG, "Cached get failed: ", task.exception)
}
}
Java
Tidak didukung di Java SDK.
Python
Tidak didukung di Python SDK.
C++
DocumentReference doc_ref = db->Collection("cities").Document("SF");
Source source = Source::kCache;
doc_ref.Get(source).OnCompletion([](const Future<DocumentSnapshot>& future) {
if (future.error() == Error::kErrorOk) {
const DocumentSnapshot& document = *future.result();
if (document.exists()) {
std::cout << "Cached document id: " << document.id() << '\n';
} else {
}
} else {
std::cout << "Cached get failed: " << future.error_message() << '\n';
}
});
Node.js
Tidak didukung di Node.js SDK.
Go
Tidak didukung di Go SDK.
PHP
Tidak didukung di PHP SDK.
Unity
Tidak didukung di Unity SDK.
C#
Tidak didukung di C# SDK.
Ruby
Tidak didukung di Ruby SDK.
Objek kustom
Contoh sebelumnya mengambil konten dokumen sebagai peta, tetapi dalam beberapa bahasa akan lebih mudah untuk menggunakan jenis objek kustom. Di bagian Tambahkan Data, Anda menentukan class City yang di gunakan untuk menentukan setiap kota. Anda dapat mengembalikan dokumen ke objek City:
Web
Untuk menggunakan objek kustom, Anda harus menentukan fungsi FirestoreDataConverter untuk class Anda. Contoh:
class City {
constructor (name, state, country ) {
this.name = name;
this.state = state;
this.country = country;
}
toString() {
return this.name + ', ' + this.state + ', ' + this.country;
}
}
// Firestore data converter
var cityConverter = {
toFirestore: function(city) {
return {
name: city.name,
state: city.state,
country: city.country
};
},
fromFirestore: function(snapshot, options){
const data = snapshot.data(options);
return new City(data.name, data.state, data.country);
}
};
Memanggil pengonversi data dengan operasi baca Anda. Setelah konversi, Anda dapat mengakses metode objek kustom:
db.collection("cities").doc("LA")
.withConverter(cityConverter)
.get().then((doc) => {
if (doc.exists){
// Convert to City object
var city = doc.data();
// Use a City instance method
console.log(city.toString());
} else {
console.log("No such document!");
}}).catch((error) => {
console.log("Error getting document:", error);
});
Swift
Untuk mendukung serialisasi jenis otomatis di Swift, jenisnya harus sesuai dengan protokol Codable, dan Anda harus menyertakan pod 'FirebaseFirestoreSwift' sebagai dependensi project Anda.
let docRef = db.collection("cities").document("BJ")
docRef.getDocument { (document, error) in
// Construct a Result type to encapsulate deserialization errors or
// successful deserialization. Note that if there is no error thrown
// the value may still be `nil`, indicating a successful deserialization
// of a value that does not exist.
//
// There are thus three cases to handle, which Swift lets us describe
// nicely with built-in Result types:
//
// Result
// /\
// Error Optional<City>
// /\
// Nil City
let result = Result {
try document?.data(as: City.self)
}
switch result {
case .success(let city):
if let city = city {
// A `City` value was successfully initialized from the DocumentSnapshot.
print("City: \(city)")
} else {
// A nil value was successfully initialized from the DocumentSnapshot,
// or the DocumentSnapshot was nil.
print("Document does not exist")
}
case .failure(let error):
// A `City` value could not be initialized from the DocumentSnapshot.
print("Error decoding city: \(error)")
}
}
Objective-C
Dalam Objective-C, Anda harus melakukannya secara manual.
FIRDocumentReference *docRef =
[[self.db collectionWithPath:@"cities"] documentWithPath:@"BJ"];
[docRef getDocumentWithCompletion:^(FIRDocumentSnapshot *snapshot, NSError *error) {
FSTCity *city = [[FSTCity alloc] initWithDictionary:snapshot.data];
if (city != nil) {
NSLog(@"City: %@", city);
} else {
NSLog(@"Document does not exist");
}
}];
Java
Penting: Setiap class kustom harus memiliki konstruktor publik yang tidak membutuhkan argumen. Selain itu, class tersebut harus menyertakan public getter untuk setiap properti.
DocumentReference docRef = db.collection("cities").document("BJ");
docRef.get().addOnSuccessListener(new OnSuccessListener<DocumentSnapshot>() {
@Override
public void onSuccess(DocumentSnapshot documentSnapshot) {
City city = documentSnapshot.toObject(City.class);
}
});
Kotlin+KTX
val docRef = db.collection("cities").document("BJ")
docRef.get().addOnSuccessListener { documentSnapshot ->
val city = documentSnapshot.toObject<City>()
}
Java
Setiap class kustom harus memiliki konstruktor publik yang tidak memerlukan argumen. Selain itu, class tersebut harus menyertakan public getter untuk setiap properti.
DocumentReference docRef = db.collection("cities").document("BJ");
// asynchronously retrieve the document
ApiFuture<DocumentSnapshot> future = docRef.get();
// block on response
DocumentSnapshot document = future.get();
City city = null;
if (document.exists()) {
// convert document to POJO
city = document.toObject(City.class);
System.out.println(city);
} else {
System.out.println("No such document!");
}
Python
doc_ref = db.collection(u'cities').document(u'BJ') doc = doc_ref.get() city = City.from_dict(doc.to_dict()) print(city)
C++
// This is not yet supported.
Node.js
Node.js menggunakan objek JavaScript.
Go
dsnap, err := client.Collection("cities").Doc("BJ").Get(ctx)
if err != nil {
return nil, err
}
var c City
dsnap.DataTo(&c)
fmt.Printf("Document data: %#v\n", c)
PHP
Tidak berlaku untuk PHP.
Unity
DocumentReference docRef = db.Collection("cities").Document("BJ");
docRef.GetSnapshotAsync().ContinueWith((task) =>
{
var snapshot = task.Result;
if (snapshot.Exists)
{
Debug.Log(String.Format("Document data for {0} document:", snapshot.Id));
City city = snapshot.ConvertTo<City>();
Debug.Log(String.Format("Name: {0}", city.Name));
Debug.Log(String.Format("State: {0}", city.State));
Debug.Log(String.Format("Country: {0}", city.Country));
Debug.Log(String.Format("Capital: {0}", city.Capital));
Debug.Log(String.Format("Population: {0}", city.Population));
}
else
{
Debug.Log(String.Format("Document {0} does not exist!", snapshot.Id));
}
});
C#
DocumentReference docRef = db.Collection("cities").Document("BJ");
DocumentSnapshot snapshot = await docRef.GetSnapshotAsync();
if (snapshot.Exists)
{
Console.WriteLine("Document data for {0} document:", snapshot.Id);
City city = snapshot.ConvertTo<City>();
Console.WriteLine("Name: {0}", city.Name);
Console.WriteLine("State: {0}", city.State);
Console.WriteLine("Country: {0}", city.Country);
Console.WriteLine("Capital: {0}", city.Capital);
Console.WriteLine("Population: {0}", city.Population);
}
else
{
Console.WriteLine("Document {0} does not exist!", snapshot.Id);
}
Ruby
Tidak berlaku untuk Ruby.
Mendapatkan beberapa dokumen dari koleksi
Anda juga dapat mengambil beberapa dokumen dengan 1 permintaan, dengan membuat kueri dokumen dalam koleksi. Misalnya, Anda dapat menggunakan where() guna membuat kueri untuk semua dokumen yang memenuhi kondisi tertentu, kemudian menggunakan get() untuk mengambil hasilnya:
Web
db.collection("cities").where("capital", "==", true)
.get()
.then((querySnapshot) => {
querySnapshot.forEach((doc) => {
// doc.data() is never undefined for query doc snapshots
console.log(doc.id, " => ", doc.data());
});
})
.catch((error) => {
console.log("Error getting documents: ", error);
});
Swift
db.collection("cities").whereField("capital", isEqualTo: true)
.getDocuments() { (querySnapshot, err) in
if let err = err {
print("Error getting documents: \(err)")
} else {
for document in querySnapshot!.documents {
print("\(document.documentID) => \(document.data())")
}
}
}
Objective-C
[[[self.db collectionWithPath:@"cities"] queryWhereField:@"capital" isEqualTo:@(YES)]
getDocumentsWithCompletion:^(FIRQuerySnapshot *snapshot, NSError *error) {
if (error != nil) {
NSLog(@"Error getting documents: %@", error);
} else {
for (FIRDocumentSnapshot *document in snapshot.documents) {
NSLog(@"%@ => %@", document.documentID, document.data);
}
}
}];
Java
db.collection("cities")
.whereEqualTo("capital", true)
.get()
.addOnCompleteListener(new OnCompleteListener<QuerySnapshot>() {
@Override
public void onComplete(@NonNull Task<QuerySnapshot> task) {
if (task.isSuccessful()) {
for (QueryDocumentSnapshot document : task.getResult()) {
Log.d(TAG, document.getId() + " => " + document.getData());
}
} else {
Log.d(TAG, "Error getting documents: ", task.getException());
}
}
});
Kotlin+KTX
db.collection("cities")
.whereEqualTo("capital", true)
.get()
.addOnSuccessListener { documents ->
for (document in documents) {
Log.d(TAG, "${document.id} => ${document.data}")
}
}
.addOnFailureListener { exception ->
Log.w(TAG, "Error getting documents: ", exception)
}
Java
//asynchronously retrieve multiple documents
ApiFuture<QuerySnapshot> future =
db.collection("cities").whereEqualTo("capital", true).get();
// future.get() blocks on response
List<QueryDocumentSnapshot> documents = future.get().getDocuments();
for (DocumentSnapshot document : documents) {
System.out.println(document.getId() + " => " + document.toObject(City.class));
}
Python
# Note: Use of CollectionRef stream() is prefered to get()
docs = db.collection(u'cities').where(u'capital', u'==', True).stream()
for doc in docs:
print(f'{doc.id} => {doc.to_dict()}')
C++
db->Collection("cities")
.WhereEqualTo("capital", FieldValue::Boolean(true))
.Get()
.OnCompletion([](const Future<QuerySnapshot>& future) {
if (future.error() == Error::kErrorOk) {
for (const DocumentSnapshot& document :
future.result()->documents()) {
std::cout << document << '\n';
}
} else {
std::cout << "Error getting documents: " << future.error_message()
<< '\n';
}
});
Node.js
const citiesRef = db.collection('cities');
const snapshot = await citiesRef.where('capital', '==', true).get();
if (snapshot.empty) {
console.log('No matching documents.');
return;
}
snapshot.forEach(doc => {
console.log(doc.id, '=>', doc.data());
});
Go
fmt.Println("All capital cities:")
iter := client.Collection("cities").Where("capital", "==", true).Documents(ctx)
for {
doc, err := iter.Next()
if err == iterator.Done {
break
}
if err != nil {
return err
}
fmt.Println(doc.Data())
}
PHP
$citiesRef = $db->collection('cities');
$query = $citiesRef->where('capital', '=', true);
$documents = $query->documents();
foreach ($documents as $document) {
if ($document->exists()) {
printf('Document data for document %s:' . PHP_EOL, $document->id());
print_r($document->data());
printf(PHP_EOL);
} else {
printf('Document %s does not exist!' . PHP_EOL, $snapshot->id());
}
}
Unity
Query capitalQuery = db.Collection("cities").WhereEqualTo("Capital", true);
capitalQuery.GetSnapshotAsync().ContinueWithOnMainThread(task => {
QuerySnapshot capitalQuerySnapshot = task.Result;
foreach (DocumentSnapshot documentSnapshot in capitalQuerySnapshot.Documents) {
Debug.Log(String.Format("Document data for {0} document:", documentSnapshot.Id));
Dictionary<string, object> city = documentSnapshot.ToDictionary();
foreach (KeyValuePair<string, object> pair in city) {
Debug.Log(String.Format("{0}: {1}", pair.Key, pair.Value));
}
// Newline to separate entries
Debug.Log("");
};
});
C#
Query capitalQuery = db.Collection("cities").WhereEqualTo("Capital", true);
QuerySnapshot capitalQuerySnapshot = await capitalQuery.GetSnapshotAsync();
foreach (DocumentSnapshot documentSnapshot in capitalQuerySnapshot.Documents)
{
Console.WriteLine("Document data for {0} document:", documentSnapshot.Id);
Dictionary<string, object> city = documentSnapshot.ToDictionary();
foreach (KeyValuePair<string, object> pair in city)
{
Console.WriteLine("{0}: {1}", pair.Key, pair.Value);
}
Console.WriteLine("");
}
Ruby
cities_ref = firestore.col collection_path
query = cities_ref.where "capital", "=", true
query.get do |city|
puts "#{city.document_id} data: #{city.data}."
end
Secara default, Cloud Firestore mengambil semua dokumen yang memenuhi permintaan dalam urutan naik menurut ID dokumen, tetapi Anda dapat memesan dan membatasi data yang dikembalikan.
Mendapatkan semua dokumen dalam koleksi
Selain itu, Anda dapat mengambil semua dokumen dalam koleksi dengan menghilangkan filter where() secara keseluruhan:
Web
db.collection("cities").get().then((querySnapshot) => {
querySnapshot.forEach((doc) => {
// doc.data() is never undefined for query doc snapshots
console.log(doc.id, " => ", doc.data());
});
});
Swift
db.collection("cities").getDocuments() { (querySnapshot, err) in
if let err = err {
print("Error getting documents: \(err)")
} else {
for document in querySnapshot!.documents {
print("\(document.documentID) => \(document.data())")
}
}
}
Objective-C
[[self.db collectionWithPath:@"cities"]
getDocumentsWithCompletion:^(FIRQuerySnapshot *snapshot, NSError *error) {
if (error != nil) {
NSLog(@"Error getting documents: %@", error);
} else {
for (FIRDocumentSnapshot *document in snapshot.documents) {
NSLog(@"%@ => %@", document.documentID, document.data);
}
}
}];
Java
db.collection("cities")
.get()
.addOnCompleteListener(new OnCompleteListener<QuerySnapshot>() {
@Override
public void onComplete(@NonNull Task<QuerySnapshot> task) {
if (task.isSuccessful()) {
for (QueryDocumentSnapshot document : task.getResult()) {
Log.d(TAG, document.getId() + " => " + document.getData());
}
} else {
Log.d(TAG, "Error getting documents: ", task.getException());
}
}
});
Kotlin+KTX
db.collection("cities")
.get()
.addOnSuccessListener { result ->
for (document in result) {
Log.d(TAG, "${document.id} => ${document.data}")
}
}
.addOnFailureListener { exception ->
Log.d(TAG, "Error getting documents: ", exception)
}
Java
//asynchronously retrieve all documents
ApiFuture<QuerySnapshot> future = db.collection("cities").get();
// future.get() blocks on response
List<QueryDocumentSnapshot> documents = future.get().getDocuments();
for (QueryDocumentSnapshot document : documents) {
System.out.println(document.getId() + " => " + document.toObject(City.class));
}
Python
docs = db.collection(u'cities').stream()
for doc in docs:
print(f'{doc.id} => {doc.to_dict()}')
C++
db->Collection("cities").Get().OnCompletion(
[](const Future<QuerySnapshot>& future) {
if (future.error() == Error::kErrorOk) {
for (const DocumentSnapshot& document :
future.result()->documents()) {
std::cout << document << '\n';
}
} else {
std::cout << "Error getting documents: " << future.error_message()
<< '\n';
}
});
Node.js
const citiesRef = db.collection('cities');
const snapshot = await citiesRef.get();
snapshot.forEach(doc => {
console.log(doc.id, '=>', doc.data());
});
Go
fmt.Println("All cities:")
iter := client.Collection("cities").Documents(ctx)
for {
doc, err := iter.Next()
if err == iterator.Done {
break
}
if err != nil {
return err
}
fmt.Println(doc.Data())
}
PHP
$citiesRef = $db->collection('cities');
$documents = $citiesRef->documents();
foreach ($documents as $document) {
if ($document->exists()) {
printf('Document data for document %s:' . PHP_EOL, $document->id());
print_r($document->data());
printf(PHP_EOL);
} else {
printf('Document %s does not exist!' . PHP_EOL, $snapshot->id());
}
}
Unity
Query allCitiesQuery = db.Collection("cities");
allCitiesQuery.GetSnapshotAsync().ContinueWithOnMainThread(task =>
{
QuerySnapshot allCitiesQuerySnapshot = task.Result;
foreach (DocumentSnapshot documentSnapshot in allCitiesQuerySnapshot.Documents)
{
Debug.Log(String.Format("Document data for {0} document:", documentSnapshot.Id));
Dictionary<string, object> city = documentSnapshot.ToDictionary();
foreach (KeyValuePair<string, object> pair in city)
{
Debug.Log(String.Format("{0}: {1}", pair.Key, pair.Value));
}
// Newline to separate entries
Debug.Log("");
}
});
Test
C#
Query allCitiesQuery = db.Collection("cities");
QuerySnapshot allCitiesQuerySnapshot = await allCitiesQuery.GetSnapshotAsync();
foreach (DocumentSnapshot documentSnapshot in allCitiesQuerySnapshot.Documents)
{
Console.WriteLine("Document data for {0} document:", documentSnapshot.Id);
Dictionary<string, object> city = documentSnapshot.ToDictionary();
foreach (KeyValuePair<string, object> pair in city)
{
Console.WriteLine("{0}: {1}", pair.Key, pair.Value);
}
Console.WriteLine("");
}
Ruby
cities_ref = firestore.col collection_path
cities_ref.get do |city|
puts "#{city.document_id} data: #{city.data}."
end
Mendapatkan beberapa dokumen dari sebuah grup koleksi
Grup koleksi terdiri dari semua koleksi dengan ID yang sama. Misalnya, jika setiap dokumen dalam koleksi cities memiliki subkoleksi yang disebut landmarks, maka semua subkoleksi landmarks tergabung dalam grup koleksi yang sama. Secara default, kueri mengambil hasil dari satu koleksi di database Anda. Gunakan kueri grup koleksi untuk mengambil hasil dari grup koleksi, bukan dari satu koleksi.
Mencantumkan subkoleksi dokumen
Metode library klien server Cloud Firestore getCollections() mencantumkan semua subkoleksi referensi dokumen.
Pengambilan daftar koleksi tidak dapat dilakukan dengan library klien seluler/web. Anda hanya boleh mencari nama koleksi sebagai bagian dari tugas administratif di lingkungan server yang tepercaya. Jika ternyata Anda memerlukan kemampuan ini pada library klien seluler/web, pertimbangkan untuk membuat ulang struktur data Anda sehingga nama subkoleksi mudah diprediksi.
Web
Tidak tersedia di library klien Web.
Swift
Tidak tersedia di library klien iOS.
Objective-C
Tidak tersedia di library klien Objective-C.
Java
Tidak tersedia di library klien Android.
Kotlin+KTX
Tidak tersedia di library klien Android.
Java
Iterable<CollectionReference> collections =
db.collection("cities").document("SF").listCollections();
for (CollectionReference collRef : collections) {
System.out.println("Found subcollection with id: " + collRef.getId());
}
Python
collections = db.collection('cities').document('SF').collections()
for collection in collections:
for doc in collection.stream():
print(f'{doc.id} => {doc.to_dict()}')
C++
Tidak tersedia di library klien C++.
Node.js
const sfRef = db.collection('cities').doc('SF');
const collections = await sfRef.listCollections();
collections.forEach(collection => {
console.log('Found subcollection with id:', collection.id);
});
Go
iter := client.Collection("cities").Doc("SF").Collections(ctx)
for {
collRef, err := iter.Next()
if err == iterator.Done {
break
}
if err != nil {
return err
}
fmt.Printf("Found collection with id: %s\n", collRef.ID)
}
PHP
$cityRef = $db->collection('cities')->document('SF');
$collections = $cityRef->collections();
foreach ($collections as $collection) {
printf('Found subcollection with id: %s' . PHP_EOL, $collection->id());
}
Unity
// This is not yet supported in the Unity SDK.
C#
DocumentReference cityRef = db.Collection("cities").Document("SF");
IAsyncEnumerable<CollectionReference> subcollections = cityRef.ListCollectionsAsync();
IAsyncEnumerator<CollectionReference> subcollectionsEnumerator = subcollections.GetAsyncEnumerator(default);
while (await subcollectionsEnumerator.MoveNextAsync())
{
CollectionReference subcollectionRef = subcollectionsEnumerator.Current;
Console.WriteLine("Found subcollection with ID: {0}", subcollectionRef.Id);
}
Ruby
city_ref = firestore.doc "#{collection_path}/SF"
city_ref.cols do |col|
puts col.collection_id
end
Pelajari jenis kueri yang berbeda lebih lanjut.