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احصل على البيانات مع Cloud Firestore

هناك طريقتان لاسترداد البيانات المخزنة في Cloud Firestore. يمكن استخدام أي من هاتين الطريقتين مع المستندات أو مجموعات المستندات أو نتائج الاستعلامات:

  • استدعاء طريقة للحصول على البيانات.
  • قم بتعيين مستمع لتلقي أحداث تغيير البيانات.

عندما تقوم بتعيين مستمع ، يرسل Cloud Firestore المستمع الخاص بك لقطة أولية للبيانات ، ثم لقطة أخرى في كل مرة يتغير فيها المستند.

بيانات المثال

للبدء ، اكتب بعض البيانات عن المدن حتى نتمكن من النظر في طرق مختلفة لقراءتها مرة أخرى:

الويب
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"] });
سويفت
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"]
    ])
ج موضوعية
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"]
}];
  

جافا

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)
جافا
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();
بايثون
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
});
اذهب
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
	}
}
بي أتش بي
$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);
وحدة
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 }
    })
);
سي #
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.");
روبي
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
)

احصل على وثيقة

يوضح المثال التالي كيفية استرداد محتويات مستند واحد باستخدام get() :

الويب
var docRef = db.collection("cities").doc("SF");

docRef.get().then(function(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(function(error) {
    console.log("Error getting document:", error);
});
سويفت
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")
    }
}
ج موضوعية
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");
  }
}];
  

جافا

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)
        }
جافا
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!");
}
بايثون
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());
}
اذهب
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)
بي أتش بي
$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());
}
وحدة
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));
  }
});
سي #
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);
}
روبي
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

خيارات المصدر

لمنصات بدعم حاليا، يمكنك تعيين source خيار للتحكم في كيفية get تستخدم دعوة مخبأ حاليا.

افتراضيا، get والدعوة محاولة لجلب وثيقة آخر لقطة من قاعدة البيانات الخاصة بك. على الأنظمة الأساسية التي تدعم وضع عدم الاتصال ، ستستخدم مكتبة العميل ذاكرة التخزين المؤقت دون اتصال إذا كانت الشبكة غير متوفرة أو إذا انتهت مهلة الطلب.

يمكنك تحديد خيار source في استدعاء get() لتغيير السلوك الافتراضي. يمكنك الجلب من قاعدة البيانات فقط وتجاهل ذاكرة التخزين المؤقت دون اتصال ، أو يمكنك الجلب من ذاكرة التخزين المؤقت غير المتصلة فقط. فمثلا:

الويب
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(function(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(function(error) {
    console.log("Error getting cached document:", error);
});
سويفت
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")
  }
}
ج موضوعية
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);
  }
}];
  

جافا

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)
    }
}
جافا

غير مدعوم في Java SDK.

بايثون

غير مدعوم في 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

غير مدعوم في Node.js SDK.

اذهب

غير مدعوم في Go SDK.

بي أتش بي

غير مدعوم في PHP SDK.

وحدة

غير مدعوم في Unity SDK.

سي #

غير مدعوم في C # SDK.

روبي

غير مدعوم في Ruby SDK.

كائنات مخصصة

استرد المثال السابق محتويات المستند كخريطة ، ولكن في بعض اللغات يكون استخدام نوع كائن مخصص أكثر ملاءمة. في إضافة البيانات ، قمت بتعريف فئة City التي استخدمتها لتحديد كل مدينة. يمكنك إعادة المستند إلى كائن City :

الويب

لاستخدام كائنات مخصصة ، يجب عليك تحديد وظيفة FirestoreDataConverter لفصلك الدراسي. فمثلا:

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)
    }
}
اتصل بمحول البيانات من خلال عمليات القراءة الخاصة بك. بعد التحويل ، يمكنك الوصول إلى أساليب الكائنات المخصصة:
db.collection("cities").doc("LA")
  .withConverter(cityConverter)
  .get().then(function(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(function(error) {
      console.log("Error getting document:", error)
    });
  
سويفت

لدعم تسلسل النوع التلقائي في Swift ، يجب أن يتوافق النوع الخاص بك مع بروتوكول Codable ويجب عليك تضمين pod 'FirebaseFirestoreSwift' كعنصر تبعية لمشروعك.

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 sum 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)")
    }
}
  
ج موضوعية

في Objective-C ، يجب عليك القيام بذلك يدويًا.

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");
  }
}];
  

جافا

هام: يجب أن يكون لكل فئة مخصصة مُنشئ عام لا يأخذ أي وسيطات. بالإضافة إلى ذلك ، يجب أن يتضمن الفصل الدراسي جامعًا عامًا لكل ملكية.

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>()
}
  
جافا

يجب أن يكون لكل فئة مخصصة مُنشئ عام لا يأخذ أي وسيطات. بالإضافة إلى ذلك ، يجب أن يتضمن الفصل الدراسي جامعًا عامًا لكل ملكية.

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!");
}
بايثون
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

يستخدم Node.js كائنات JavaScript.

اذهب
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)
بي أتش بي

لا ينطبق على PHP.

وحدة
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));
  }
});
سي #
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);
}
روبي

لا ينطبق على روبي.

احصل على مستندات متعددة من مجموعة

يمكنك أيضًا استرداد مستندات متعددة بطلب واحد عن طريق الاستعلام عن المستندات في المجموعة. على سبيل المثال ، يمكنك استخدام where() للاستعلام عن جميع المستندات التي تفي بشرط معين ، ثم استخدام get() لاسترداد النتائج:

الويب
db.collection("cities").where("capital", "==", true)
    .get()
    .then(function(querySnapshot) {
        querySnapshot.forEach(function(doc) {
            // doc.data() is never undefined for query doc snapshots
            console.log(doc.id, " => ", doc.data());
        });
    })
    .catch(function(error) {
        console.log("Error getting documents: ", error);
    });
سويفت
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())")
            }
        }
}
ج موضوعية
[[[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);
        }
      }
    }];
  

جافا

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)
        }
جافا
//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));
}
بايثون
# 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());
});
اذهب
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())
}
بي أتش بي
$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());
    }
}
وحدة
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("");
  };
});
سي #
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("");
}
روبي
cities_ref = firestore.col collection_path

query = cities_ref.where "capital", "=", true

query.get do |city|
  puts "#{city.document_id} data: #{city.data}."
end

بشكل افتراضي ، يسترد Cloud Firestore جميع المستندات التي تلبي الاستعلام بترتيب تصاعدي حسب معرّف المستند ، ولكن يمكنك طلب البيانات التي يتم إرجاعها والحد منها .

احصل على جميع المستندات في مجموعة

بالإضافة إلى ذلك ، يمكنك استرداد جميع المستندات في مجموعة عن طريق حذف عامل التصفية where() بالكامل:

الويب
db.collection("cities").get().then(function(querySnapshot) {
    querySnapshot.forEach(function(doc) {
        // doc.data() is never undefined for query doc snapshots
        console.log(doc.id, " => ", doc.data());
    });
});
سويفت
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())")
        }
    }
}
ج موضوعية
[[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);
        }
      }
    }];
  

جافا

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)
        }
جافا
//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));
}
بايثون
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());
});
اذهب
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())
}
بي أتش بي
$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());
    }
}
وحدة
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
سي #
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("");
}
روبي
cities_ref = firestore.col collection_path
cities_ref.get do |city|
  puts "#{city.document_id} data: #{city.data}."
end

احصل على مستندات متعددة من مجموعة تجميع

تتكون مجموعة التجميع من جميع المجموعات التي لها نفس المعرف. على سبيل المثال ، إذا كان كل مستند في مجموعة cities الخاصة بك يحتوي على مجموعة فرعية تسمى landmarks ، فإن كل المجموعات الفرعية landmarks تنتمي إلى نفس مجموعة المجموعة. بشكل افتراضي ، تسترد الاستعلامات النتائج من مجموعة واحدة في قاعدة البيانات الخاصة بك. استخدم استعلام مجموعة المجموعة لاسترداد النتائج من مجموعة مجموعة بدلاً من مجموعة واحدة.

سرد المجموعات الفرعية من المستند

getCollections() طريقة getCollections() لمكتبات عميل خادم Cloud Firestore جميع المجموعات الفرعية لمرجع المستند.

لا يمكن استرداد قائمة المجموعات باستخدام مكتبات عميل الويب / الجوال. يجب عليك فقط البحث عن أسماء المجموعات كجزء من المهام الإدارية في بيئات الخادم الموثوق بها. إذا وجدت أنك بحاجة إلى هذه الإمكانية في مكتبات عميل الجوال / الويب ، ففكر في إعادة هيكلة بياناتك بحيث يمكن التنبؤ بأسماء المجموعات الفرعية.

الويب

غير متوفر في مكتبة عميل الويب.

سويفت

غير متوفر في مكتبة عميل iOS.

ج موضوعية

غير متوفر في مكتبة العميل Objective-C.

جافا

غير متوفر في مكتبة عميل Android.

Kotlin + KTX

غير متوفر في مكتبة عميل Android.

جافا
Iterable<CollectionReference> collections =
    db.collection("cities").document("SF").listCollections();

for (CollectionReference collRef : collections) {
  System.out.println("Found subcollection with id: " + collRef.getId());
}
بايثون
collections = db.collection('cities').document('SF').collections()
for collection in collections:
    for doc in collection.stream():
        print(f'{doc.id} => {doc.to_dict()}')
C ++

غير متوفر في مكتبة العميل 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);
});
اذهب
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)
}
بي أتش بي
$cityRef = $db->collection('cities')->document('SF');
$collections = $cityRef->collections();
foreach ($collections as $collection) {
    printf('Found subcollection with id: %s' . PHP_EOL, $collection->id());
}
وحدة
// This is not yet supported in the Unity SDK.
سي #
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);
}
روبي
city_ref = firestore.doc "#{collection_path}/SF"
city_ref.cols do |col|
  puts col.collection_id
end

تعرف على المزيد حول أنواع الاستعلامات المختلفة.