Collections

Classes for representing collections for the Google Cloud Firestore API.

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

Bases: object

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, document_id=None)

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).
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.

document(document_id=None)

Create a sub-document underneath the current collection.

Parameters

document_id (Optional[str]) – The document identifier within the current collection. If not provided, will default to a random 20 character string composed of digits, uppercase and lowercase and letters.
Returns

The child document.
Return type

DocumentReference

end_at(document_fields)

End query at a cursor with this collection as parent.

See end_at() for more information on this method.

Parameters

document_fields (Union[DocumentSnapshot, dict, list, tuple]) – A document snapshot or a dictionary/list/tuple of fields representing a query results cursor. A cursor is a collection of values that represent a position in a query result set.
Returns

A query with cursor.
Return type

Query

end_before(document_fields)

End query before a cursor with this collection as parent.

See end_before() for more information on this method.

Parameters

document_fields (Union[DocumentSnapshot, dict, list, tuple]) – A document snapshot or a dictionary/list/tuple of fields representing a query results cursor. A cursor is a collection of values that represent a position in a query result set.
Returns

A query with cursor.
Return type

Query

get(transaction=None)

Deprecated alias for stream().

property id()

The collection identifier.

Returns

The last component of the path.
Return type

str

limit(count)

Create a limited query with this collection as parent.

See limit() for more information on this method.

Parameters

count (int) – Maximum number of documents to return that match the query.
Returns

A limited query.
Return type

Query

list_documents(page_size=None)

List all subdocuments of the current collection.

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

offset(num_to_skip)

Skip to an offset in a query with this collection as parent.

See offset() for more information on this method.

Parameters

num_to_skip (int) – The number of results to skip at the beginning of query results. (Must be non-negative.)
Returns

An offset query.
Return type

Query

on_snapshot(callback)

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()

order_by(field_path, **kwargs)

Create an “order by” query with this collection as parent.

See order_by() for more information on this method.

Parameters
- field_path (str) – A field path (.-delimited list of field names) on which to order the query results.
- kwargs (Dict[str, *[Any](types.md#google.cloud.firestore_v1.types.Any)]*) – The keyword arguments to pass along to the query. The only supported keyword is direction, see order_by() for more information.
Returns

An “order by” query.
Return type

Query

property parent()

Document that owns the current collection.

Returns

The parent document, if the current collection is not a top-level collection.
Return type

Optional[DocumentReference]

select(field_paths)

Create a “select” query with this collection as parent.

See select() for more information on this method.

Parameters

field_paths (Iterable[str, **...]) – An iterable of field paths (.-delimited list of field names) to use as a projection of document fields in the query results.
Returns

A “projected” query.
Return type

Query

start_after(document_fields)

Start query after a cursor with this collection as parent.

See start_after() for more information on this method.

Parameters

document_fields (Union[DocumentSnapshot, dict, list, tuple]) – A document snapshot or a dictionary/list/tuple of fields representing a query results cursor. A cursor is a collection of values that represent a position in a query result set.
Returns

A query with cursor.
Return type

Query

start_at(document_fields)

Start query at a cursor with this collection as parent.

See start_at() for more information on this method.

Parameters

document_fields (Union[DocumentSnapshot, dict, list, tuple]) – A document snapshot or a dictionary/list/tuple of fields representing a query results cursor. A cursor is a collection of values that represent a position in a query result set.
Returns

A query with cursor.
Return type

Query

stream(transaction=None)

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.
Yields

DocumentSnapshot – The next document that fulfills the query.

where(field_path, op_string, value)

Create a “where” query with this collection as parent.

See where() for more information on this method.

Parameters
- field_path (str) – A field path (.-delimited list of field names) for the field to filter on.
- op_string (str) – A comparison operation in the form of a string. Acceptable values are <, <=, ==, >= and >.
- value (Any) – The value to compare the field against in the filter. If value is None or a NaN, then == is the only allowed operation.
Returns

A filtered query.
Return type

Query