Query Firebase Firestore documents by the ID

Question

As I got from 'Cloud Firestore Data Model' guide "each document is identified by a name." Is it possible to query a collection by that document identifier (which is the name or ID)?

For example, documents in the collection "Things" have IDs: 0, 1, 2 etc.:

Is it possible to query documents which IDs are less than 100?

Michael Lehenbauer · Accepted Answer · 2018-01-26T18:45:00.807

45

You can query by documentId using the special sentinel FieldPath.documentId(), e.g.:

const querySnap = collection.where(firebase.firestore.FieldPath.documentId(), '<', '100').get();

But be aware that document IDs are strings and therefore this will include documents with ID '0' or '1', but not '2' since '2' > '100' lexicographically.

So if you want a numeric query, you'll need to write the document ID as a numeric field in the document and then do a normal query on it.

edited Jan 26 '18 at 18:45

answered Jan 26 '18 at 18:03

Michael Lehenbauer

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Is there an equivalent for python? I could not find it! – Aníbal Rivero Feb 28 '18 at 15:47
@AníbalRivero It might not be implemented yet. You may want to open an issue on https://github.com/GoogleCloudPlatform/google-cloud-python/issues – Michael Lehenbauer Mar 19 '18 at 01:08
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Any idea if this is possible inside `firebaseConnect` using [`react-redux-firebase`](https://github.com/prescottprue/react-redux-firebase)? – Blundering Philosopher Mar 28 '19 at 08:48
@BlunderingPhilosopher have you found any way to do that? – leoxs Jan 02 '20 at 15:04
Angular - make sure to ```import * as firebase from 'firebase/app';``` – Jonathan May 03 '20 at 20:30
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@AníbalRivero they added the python equivalent, still testing... google.cloud.firestore_v1.field_path.FieldPath.document_id() – sillo01 Sep 09 '20 at 00:52
The equivalent for (firebase.firestore.FieldPath.documentId()) in Python is to simply mention the static value directly => `__name__` [Source: /google/cloud/firestore_v1/field_path.py] – ilike2breakthngs Mar 01 '22 at 17:06

score 18 · Answer 2 · edited Nov 10 '21 at 12:46

18

In python, you should use full documents names

from google.cloud import firestore
from google.cloud.firestore_v1.field_path import FieldPath

db = firestore.Client()
colRef = db.collection(u'docs')
filter = [db.document(u'docs/doc1'), db.collection(u'docs/doc3')]
query = colRef.where(FieldPath.document_id(), u'in', filter)

edited Nov 10 '21 at 12:46

Safwan

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answered Sep 09 '20 at 01:56

sillo01

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Solved my problem. This usage seems not documented elsewhere. – Josan Sep 26 '20 at 03:33
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Note: the `in` filter only accepts a maximum of 10 entries before throwing an error, so be ready if you have this in production code... – bsplosion Nov 05 '21 at 01:06

Carlo Nyte · Answer 3 · 2022-06-29T22:23:48.977

I was struggling to find this for the Golang Firebase SDK but finally got it. Hope this helps somebody out there!

package main
    
import (
  "context"
  "fmt"
  "log"

  "cloud.google.com/go/firestore"
  firebase "firebase.google.com/go/v4"
  "google.golang.org/api/option"
)

type (
  Car struct {
    ID    string
    Name  string  `firestore:"name"`
    Make  string  `firestore:"make"`
    Price float64 `firestore:"make"`
  }
)

func main() {
  ctx := context.Background()

  // Use a service account
  options := option.WithCredentialsFile("PATH/TO/SERVICE/FILE.json")

  // Set project id
  conf := &firebase.Config{ProjectID: "PROJECT_NAME"}

  // Initialize app
  app, err := firebase.NewApp(ctx, conf, options)
  if err != nil {
    log.Fatal(err)
  }

  // Get firestore client
  client, err := app.Firestore(ctx)
  if err != nil {
    log.Fatal(err)
  }
  defer client.Close()

  collectionRef := client.Collection("CAR_COLLECTION")
  
  // Create docment list of documents from "CAR_COLLECTION"
  var skipDocs []*firestore.DocumentRef
  idList := []string{"001", "002", "003"}
  for _, id := range idList {
    skipDocs = append(skipDocs, collectionRef.Doc(id))
  }

  // firestore.DocumentID == "__name__" 
  docs, err := collectionRef.Where(firestore.DocumentID, "not-in", skipDocs).Documents(ctx).GetAll()
  if err != nil {
    log.Fatal(err)
  }

  var carList []Car
  for _, doc := range docs {
    var car Car

    // Unmarshall item
    doc.DataTo(&car)
    car.ID = doc.Ref.ID

    // Add car to list
    carList = append(carList, car)
  }

  // Print car list
  fmt.Println(carList)
}

Query Firebase Firestore documents by the ID

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