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