DatastoreRequest

DatastoreRequest

Handle logic for Datastore API operations. Handles request logic for Datastore.

Creates requests to the Datastore endpoint. Designed to be inherited by the Datastore and Transaction classes.

Constructor

new DatastoreRequest()

Methods

allocateIds(key, options, callback)

Generate IDs without creating entities.

Parameters:
Name Type Description
key Key

The key object to complete.
options number | object

Either the number of IDs to allocate or an options object for further customization of the request.

Properties
Name Type Attributes Description
allocations number

How many IDs to allocate.
gaxOptions object <optional>

Request configuration options, outlined here: https://googleapis.github.io/gax-nodejs/global.html#CallOptions.
callback function

The callback function.

Properties
Name Type Attributes Description
err error <nullable>

An error returned while making this request
keys array

The generated IDs
apiResponse object

The full API response.
Example
const incompleteKey = datastore.key(['Company']);

//-
// The following call will create 100 new IDs from the Company kind, which
// exists under the default namespace.
//-
datastore.allocateIds(incompleteKey, 100, (err, keys) => {});

//-
// Or, if you're using a transaction object.
//-
const transaction = datastore.transaction();

transaction.run((err) => {
  if (err) {
    // Error handling omitted.
  }

  transaction.allocateIds(incompleteKey, 100, (err, keys) => {
    if (err) {
      // Error handling omitted.
    }

    transaction.commit((err) => {
      if (!err) {
        // Transaction committed successfully.
      }
    });
  });
});

//-
// You may prefer to create IDs from a non-default namespace by providing
an
// incomplete key with a namespace. Similar to the previous example, the
call
// below will create 100 new IDs, but from the Company kind that exists
under
// the "ns-test" namespace.
//-
const incompleteKey = datastore.key({
  namespace: 'ns-test',
  path: ['Company']
});

function callback(err, keys, apiResponse) {}

datastore.allocateIds(incompleteKey, 100, callback);

//-
// Returns a Promise if callback is omitted.
//-
datastore.allocateIds(incompleteKey, 100).then((data) => {
  const keys = data[0];
  const apiResponse = data[1];
});

createReadStream(keys, optionsopt)

Retrieve the entities as a readable object stream.

Parameters:
Name Type Attributes Description
keys Key | Array.<Key>

Datastore key object(s).
options object <optional>

Optional configuration. See Datastore#get for a complete list of options.
Throws:

If at least one Key object is not provided.

Type
Error
Example
const keys = [
  datastore.key(['Company', 123]),
  datastore.key(['Product', 'Computer'])
];

datastore.createReadStream(keys)
  .on('error', (err) =>  {})
  .on('data', (entity) => {
    // entity is an entity object.
  })
  .on('end', () => {
    // All entities retrieved.
  });

delete(key, gaxOptionsopt, callback)

Delete all entities identified with the specified key(s).

Parameters:
Name Type Attributes Description
key Key | Array.<Key>

Datastore key object(s).
gaxOptions object <optional>

Request configuration options, outlined here: https://googleapis.github.io/gax-nodejs/global.html#CallOptions.
callback function

The callback function.

Properties
Name Type Attributes Description
err error <nullable>

An error returned while making this request
apiResponse object

The full API response.
Example
const key = datastore.key(['Company', 123]);
datastore.delete(key, (err, apiResp) => {});

//-
// Or, if you're using a transaction object.
//-
const transaction = datastore.transaction();

transaction.run((err) => {
  if (err) {
    // Error handling omitted.
  }

  transaction.delete(key);

  transaction.commit((err) => {
    if (!err) {
      // Transaction committed successfully.
    }
  });
});

//-
// Delete multiple entities at once.
//-
datastore.delete([
  datastore.key(['Company', 123]),
  datastore.key(['Product', 'Computer'])
], (err, apiResponse) => {});

//-
// Returns a Promise if callback is omitted.
//-
datastore.delete().then((data) => {
  const apiResponse = data[0];
});

get(keys, optionsopt, callback)

Retrieve the entities identified with the specified key(s) in the current transaction. Get operations require a valid key to retrieve the key-identified entity from Datastore.

Parameters:
Name Type Attributes Description
keys Key | Array.<Key>

Datastore key object(s).
options object <optional>

Optional configuration.

Properties
Name Type Attributes Default Description
consistency string <optional>

Specify either strong or eventual. If not specified, default values are chosen by Datastore for the operation. Learn more about strong and eventual consistency here.
gaxOptions object <optional>

Request configuration options, outlined here: https://googleapis.github.io/gax-nodejs/global.html#CallOptions.
wrapNumbers boolean | IntegerTypeCastOptions <optional>
 false

Wrap values of integerValue type in Datastore#Int objects. If a boolean, this will wrap values in Datastore#Int objects. If an object, this will return a value returned by wrapNumbers.integerTypeCastFunction. Please see IntegerTypeCastOptions for options descriptions.
callback function

The callback function.

Properties
Name Type Attributes Description
err error <nullable>

An error returned while making this request
entity object | Array.<object>

The entity object(s) which match the provided keys.
Throws:

If at least one Key object is not provided.

Type
Error
Example
//-
// Get a single entity.
//-
const key = datastore.key(['Company', 123]);

datastore.get(key, (err, entity) => {});

//-
// Or, if you're using a transaction object.
//-
const transaction = datastore.transaction();

transaction.run((err) => {
  if (err) {
    // Error handling omitted.
  }

  transaction.get(key, (err, entity) => {
    if (err) {
      // Error handling omitted.
    }

    transaction.commit((err) => {
      if (!err) {
        // Transaction committed successfully.
      }
    });
  });
});

//-
// Get multiple entities at once with a callback.
//-
const keys = [
  datastore.key(['Company', 123]),
  datastore.key(['Product', 'Computer'])
];

datastore.get(keys, (err, entities) => {});

//-
// Below is how to update the value of an entity with the help of the
// `save` method.
//-
datastore.get(key, (err, entity) => {
  if (err) {
    // Error handling omitted.
  }

  entity.newValue = true;

  datastore.save({
    key: key,
    data: entity
  }, (err) => {});
});

//-
// Returns a Promise if callback is omitted.
//-
datastore.get(keys).then((data) => {
  const entities = data[0];
});

merge(entities, callback)

Merge the specified object(s). If a key is incomplete, its associated object is inserted and the original Key object is updated to contain the generated ID. For example, if you provide an incomplete key (one without an ID), the request will create a new entity and have its ID automatically assigned. If you provide a complete key, the entity will be get the data from datastore and merge with the data specified. By default, all properties are indexed. To prevent a property from being included in all indexes, you must supply an excludeFromIndexes array.

Maps to Datastore#save, forcing the method to be merge.

Parameters:
Name Type Description
entities object | Array.<object>

Datastore key object(s).

Properties
Name Type Attributes Description
key Key

Datastore key object.
excludeFromIndexes Array.<string> <optional>

Exclude properties from indexing using a simple JSON path notation. See the examples in Datastore#save to see how to target properties at different levels of nesting within your entity.
data object

Data to merge to the same for provided key.
callback function

The callback function.

Properties
Name Type Attributes Description
err error <nullable>

An error returned while making this request
apiResponse object

The full API response.

runQuery(query, optionsopt, callbackopt)

Datastore allows you to query entities by kind, filter them by property filters, and sort them by a property name. Projection and pagination are also supported.

The query is run, and the results are returned as the second argument to your callback. A third argument may also exist, which is a query object that uses the end cursor from the previous query as the starting cursor for the next query. You can pass that object back to this method to see if more results exist.

Parameters:
Name Type Attributes Description
query Query

Query object.
options object <optional>

Optional configuration.

Properties
Name Type Attributes Default Description
consistency string <optional>

Specify either strong or eventual. If not specified, default values are chosen by Datastore for the operation. Learn more about strong and eventual consistency here.
gaxOptions object <optional>

Request configuration options, outlined here: https://googleapis.github.io/gax-nodejs/global.html#CallOptions.
wrapNumbers boolean | IntegerTypeCastOptions <optional>
 false

Wrap values of integerValue type in Datastore#Int objects. If a boolean, this will wrap values in Datastore#Int objects. If an object, this will return a value returned by wrapNumbers.integerTypeCastFunction. Please see IntegerTypeCastOptions for options descriptions.
callback function <optional>

The callback function. If omitted, a readable stream instance is returned.

Properties
Name Type Attributes Description
err error <nullable>

An error returned while making this request
entities Array.<object>

A list of entities.
info object

An object useful for pagination.

Properties
Name Type Attributes Description
endCursor string <nullable>

Use this in a follow-up query to begin from where these results ended.
moreResults string

Datastore responds with one of:

- Datastore#MORE_RESULTS_AFTER_LIMIT: There *may* be more
  results after the specified limit.
- Datastore#MORE_RESULTS_AFTER_CURSOR: There *may* be more
  results after the specified end cursor.
- Datastore#NO_MORE_RESULTS: There are no more results.
Example
//-
// Where you see `transaction`, assume this is the context that's relevant
to
// your use, whether that be a Datastore or a Transaction object.
//-
const query = datastore.createQuery('Lion');

datastore.runQuery(query, (err, entities, info) => {
  // entities = An array of records.

  // Access the Key object for an entity.
  const firstEntityKey = entities[0][datastore.KEY];
});

//-
// Or, if you're using a transaction object.
//-
const transaction = datastore.transaction();

transaction.run((err) => {
  if (err) {
    // Error handling omitted.
  }

  transaction.runQuery(query, (err, entities) => {
    if (err) {
      // Error handling omitted.
    }

    transaction.commit((err) => {
      if (!err) {
        // Transaction committed successfully.
      }
    });
  });
});

//-
// A keys-only query returns just the keys of the result entities instead
of
// the entities themselves, at lower latency and cost.
//-
const keysOnlyQuery = datastore.createQuery('Lion').select('__key__');

datastore.runQuery(keysOnlyQuery, (err, entities) => {
  const keys = entities.map((entity) => {
    return entity[datastore.KEY];
  });
});

//-
// Returns a Promise if callback is omitted.
//-
datastore.runQuery(query).then((data) => {
  const entities = data[0];
});

runQueryStream(query, optionsopt)

Get a list of entities as a readable object stream.

See Datastore#runQuery for a list of all available options.

Parameters:
Name Type Attributes Description
query Query

Query object.
options object <optional>

Optional configuration.

Properties
Name Type Attributes Description
gaxOptions object <optional>

Request configuration options, outlined here: https://googleapis.github.io/gax-nodejs/global.html#CallOptions.
Example
datastore.runQueryStream(query)
  .on('error', console.error)
  .on('data', (entity) => {
    // Access the Key object for this entity.
    const key = entity[datastore.KEY];
  })
  .on('info', (info) => {})
  .on('end', () => {
    // All entities retrieved.
  });

//-
// If you anticipate many results, you can end a stream early to prevent
// unnecessary processing and API requests.
//-
datastore.runQueryStream(query)
  .on('data', (entity) => {
    this.end();
  });