Collections

Classes for representing collections for the Google Cloud Firestore API.

class google.cloud.firestore_v1.collection.CollectionReference(*path, **kwargs)

Bases: google.cloud.firestore_v1.base_collection.BaseCollectionReference

A reference to a collection in a Firestore database.

The collection may already exist or this class can facilitate creation of documents within the collection.

  • Parameters

    • path (Tuple[str, **...]) – The components in the collection path. This is a series of strings representing each collection and sub-collection ID, as well as the document IDs for any documents that contain a sub-collection.

    • kwargs (dict) – The keyword arguments for the constructor. The only supported keyword is client and it must be a Client if provided. It represents the client that created this collection reference.

  • Raises

    • ValueError – if

      * the path is empty * there are an even number of elements * a collection ID in path is not a string * a document ID in path is not a string

    • TypeError – If a keyword other than client is used.

add(document_data: dict, document_id: Optional[str] = None, retry: google.api_core.retry.Retry = <_MethodDefault._DEFAULT_VALUE:

Create a document in the Firestore database with the provided data.

  • Parameters

    • document_data (dict) – Property names and values to use for creating the document.

    • document_id (Optional[str]) – The document identifier within the current collection. If not provided, an ID will be automatically assigned by the server (the assigned ID will be a random 20 character string composed of digits, uppercase and lowercase letters).

    • retry (google.api_core.retry.Retry) – Designation of what errors, if any, should be retried. Defaults to a system-specified policy.

    • timeout (float) – The timeout for this request. Defaults to a system-specified value.

  • Returns

    Pair of

    • The update_time when the document was created/overwritten.

    • A document reference for the created document.

  • Return type

    Tuple[google.protobuf.timestamp_pb2.Timestamp, DocumentReference]

  • Raises

    Conflict – If document_id is provided and the document already exists.

get(transaction: Optional[google.cloud.firestore_v1.transaction.Transaction] = None, retry: google.api_core.retry.Retry = <_MethodDefault._DEFAULT_VALUE:

Read the documents in this collection.

This sends a RunQuery RPC and returns a list of documents returned in the stream of RunQueryResponse messages.

  • Parameters

    • transaction – (Optional[Transaction]): An existing transaction that this query will run in.

    • retry (google.api_core.retry.Retry) – Designation of what errors, if any, should be retried. Defaults to a system-specified policy.

    • timeout (float) – The timeout for this request. Defaults to a system-specified value.

If a transaction is used and it already has write operations added, this method cannot be used (i.e. read-after-write is not allowed).

  • Returns

    The documents in this collection that match the query.

  • Return type

    list

list_documents(page_size: Optional[int] = None, retry: google.api_core.retry.Retry = <_MethodDefault._DEFAULT_VALUE:

List all subdocuments of the current collection.

  • Parameters

    • page_size (Optional[int]]) – The maximum number of documents in each page of results from this request. Non-positive values are ignored. Defaults to a sensible value set by the API.

    • retry (google.api_core.retry.Retry) – Designation of what errors, if any, should be retried. Defaults to a system-specified policy.

    • timeout (float) – The timeout for this request. Defaults to a system-specified value.

  • Returns

    iterator of subdocuments of the current collection. If the collection does not exist at the time of snapshot, the iterator will be empty

  • Return type

    Sequence[DocumentReference]

on_snapshot(callback: Callable)

Monitor the documents in this collection.

This starts a watch on this collection using a background thread. The provided callback is run on the snapshot of the documents.

  • Parameters

    callback (Callable[[CollectionSnapshot], NoneType]) – a callback to run when a change occurs.

Example

from google.cloud import firestore_v1

db = firestore_v1.Client() collection_ref = db.collection(u’users’)

def on_snapshot(collection_snapshot, changes, read_time):

for doc in collection_snapshot.documents:

    print(u’{} => {}’.format(doc.id, doc.to_dict()))

Watch this collection

collection_watch = collection_ref.on_snapshot(on_snapshot)

Terminate this watch

collection_watch.unsubscribe()

stream(transaction: Optional[google.cloud.firestore_v1.transaction.Transaction] = None, retry: google.api_core.retry.Retry = <_MethodDefault._DEFAULT_VALUE:

Read the documents in this collection.

This sends a RunQuery RPC and then returns an iterator which consumes each document returned in the stream of RunQueryResponse messages.

NOTE: The underlying stream of responses will time out after the max_rpc_timeout_millis value set in the GAPIC client configuration for the RunQuery API. Snapshots not consumed from the iterator before that point will be lost.

If a transaction is used and it already has write operations added, this method cannot be used (i.e. read-after-write is not allowed).

  • Parameters

    • transaction (Optional[Transaction]) – An existing transaction that the query will run in.

    • retry (google.api_core.retry.Retry) – Designation of what errors, if any, should be retried. Defaults to a system-specified policy.

    • timeout (float) – The timeout for this request. Defaults to a system-specified value.

  • Yields

    DocumentSnapshot – The next document that fulfills the query.