get_item ¶

def get_item(
    self,
    table_name: "capo_dynamodb.types.table_arn.TableArn",
    key: "capo_dynamodb.types.key.Key",
    *,
    config_overrides: Optional[DynamoDBClientConfig] = None,
    attributes_to_get: Optional[
        "capo_dynamodb.types.attribute_name_list.AttributeNameList"
    ] = None,
    consistent_read: Optional[
        "capo_dynamodb.types.consistent_read.ConsistentRead"
    ] = None,
    return_consumed_capacity: Optional[
        "capo_dynamodb.types.return_consumed_capacity.ReturnConsumedCapacity"
    ] = None,
    projection_expression: Optional[
        "capo_dynamodb.types.projection_expression.ProjectionExpression"
    ] = None,
    expression_attribute_names: Optional[
        "capo_dynamodb.types.expression_attribute_name_map.ExpressionAttributeNameMap"
    ] = None,
) -> "capo_dynamodb.types.get_item_output.GetItemOutput":
    """<p>The <code>GetItem</code> operation returns a set of attributes for the item with the given primary key. If there is no matching item, <code>GetItem</code> does not return any data and there will be no <code>Item</code> element in the response.</p> <p> <code>GetItem</code> provides an eventually consistent read by default. If your application requires a strongly consistent read, set <code>ConsistentRead</code> to <code>true</code>. Although a strongly consistent read might take more time than an eventually consistent read, it always returns the last updated value.</p>

    Args:
        table_name: <p>The name of the table containing the requested item. You can also provide the Amazon Resource Name (ARN) of the table in this parameter.</p>
        key: <p>A map of attribute names to <code>AttributeValue</code> objects, representing the primary key of the item to retrieve.</p> <p>For the primary key, you must provide all of the attributes. For example, with a simple primary key, you only need to provide a value for the partition key. For a composite primary key, you must provide values for both the partition key and the sort key.</p>
        attributes_to_get: <p>This is a legacy parameter. Use <code>ProjectionExpression</code> instead. For more information, see <a href="https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/LegacyConditionalParameters.AttributesToGet.html">AttributesToGet</a> in the <i>Amazon DynamoDB Developer Guide</i>.</p>
        consistent_read: <p>Determines the read consistency model: If set to <code>true</code>, then the operation uses strongly consistent reads; otherwise, the operation uses eventually consistent reads.</p>
        projection_expression: <p>A string that identifies one or more attributes to retrieve from the table. These attributes can include scalars, sets, or elements of a JSON document. The attributes in the expression must be separated by commas.</p> <p>If no attribute names are specified, then all attributes are returned. If any of the requested attributes are not found, they do not appear in the result.</p> <p>For more information, see <a href="https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Expressions.AccessingItemAttributes.html">Specifying Item Attributes</a> in the <i>Amazon DynamoDB Developer Guide</i>.</p>
        expression_attribute_names: <p>One or more substitution tokens for attribute names in an expression. The following are some use cases for using <code>ExpressionAttributeNames</code>:</p> <ul> <li> <p>To access an attribute whose name conflicts with a DynamoDB reserved word.</p> </li> <li> <p>To create a placeholder for repeating occurrences of an attribute name in an expression.</p> </li> <li> <p>To prevent special characters in an attribute name from being misinterpreted in an expression.</p> </li> </ul> <p>Use the <b>#</b> character in an expression to dereference an attribute name. For example, consider the following attribute name:</p> <ul> <li> <p> <code>Percentile</code> </p> </li> </ul> <p>The name of this attribute conflicts with a reserved word, so it cannot be used directly in an expression. (For the complete list of reserved words, see <a href="https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/ReservedWords.html">Reserved Words</a> in the <i>Amazon DynamoDB Developer Guide</i>). To work around this, you could specify the following for <code>ExpressionAttributeNames</code>:</p> <ul> <li> <p> <code>{"#P":"Percentile"}</code> </p> </li> </ul> <p>You could then use this substitution in an expression, as in this example:</p> <ul> <li> <p> <code>#P = :val</code> </p> </li> </ul> <note> <p>Tokens that begin with the <b>:</b> character are <i>expression attribute values</i>, which are placeholders for the actual value at runtime.</p> </note> <p>For more information on expression attribute names, see <a href="https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Expressions.AccessingItemAttributes.html">Specifying Item Attributes</a> in the <i>Amazon DynamoDB Developer Guide</i>.</p>

    Raises:
        capo_dynamodb.errors.internal_server_error.InternalServerError: <p>An error occurred on the server side.</p>
        capo_dynamodb.errors.invalid_endpoint_exception.InvalidEndpointException
        capo_dynamodb.errors.provisioned_throughput_exceeded_exception.ProvisionedThroughputExceededException: <p>The request was denied due to request throttling. For detailed information about why the request was throttled and the ARN of the impacted resource, find the <a href="https://docs.aws.amazon.com/amazondynamodb/latest/APIReference/API_ThrottlingReason.html">ThrottlingReason</a> field in the returned exception. The Amazon Web Services SDKs for DynamoDB automatically retry requests that receive this exception. Your request is eventually successful, unless your retry queue is too large to finish. Reduce the frequency of requests and use exponential backoff. For more information, go to <a href="https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Programming.Errors.html#Programming.Errors.RetryAndBackoff">Error Retries and Exponential Backoff</a> in the <i>Amazon DynamoDB Developer Guide</i>.</p>
        capo_dynamodb.errors.request_limit_exceeded.RequestLimitExceeded: <p>Throughput exceeds the current throughput quota for your account. For detailed information about why the request was throttled and the ARN of the impacted resource, find the <a href="https://docs.aws.amazon.com/amazondynamodb/latest/APIReference/API_ThrottlingReason.html">ThrottlingReason</a> field in the returned exception. Contact <a href="https://aws.amazon.com/support">Amazon Web Services Support</a> to request a quota increase.</p>
        capo_dynamodb.errors.resource_not_found_exception.ResourceNotFoundException: <p>The operation tried to access a nonexistent table or index. The resource might not be specified correctly, or its status might not be <code>ACTIVE</code>.</p>
        capo_dynamodb.errors.throttling_exception.ThrottlingException: <p>The request was denied due to request throttling. For detailed information about why the request was throttled and the ARN of the impacted resource, find the <a href="https://docs.aws.amazon.com/amazondynamodb/latest/APIReference/API_ThrottlingReason.html">ThrottlingReason</a> field in the returned exception.</p>
        capo_dynamodb.errors.UnknownServiceError: The service returned an error code this client does not model.

    Examples:
        To read an item from a table
        This example retrieves an item from the Music table. The table has a partition key and a sort key (Artist and SongTitle), so you must specify both of these attributes.

        >>> client.get_item(table_name='Music', key={'Artist': {'S': 'Acme Band'}, 'SongTitle': {'S': 'Happy Day'}})
    """

    def _handler(
        req: "OperationRequest[capo_dynamodb.types.get_item_input.GetItemInput]",
    ) -> OperationResponse["capo_dynamodb.types.get_item_output.GetItemOutput"]:
        import capo_dynamodb._operations.dynamo_db_20120810.get_item

        output, http_response = (
            capo_dynamodb._operations.dynamo_db_20120810.get_item.get_item(
                req.options, req.input
            )
        )
        return OperationResponse(output=output, response=http_response)

    interceptors_, options_ = self.operation_options(
        config_overrides, OperationLogging("GetItem")
    )
    input_: capo_dynamodb.types.get_item_input.GetItemInput = {
        "table_name": table_name,
        "key": key,
    }
    if attributes_to_get is not None:
        input_["attributes_to_get"] = attributes_to_get
    if consistent_read is not None:
        input_["consistent_read"] = consistent_read
    if return_consumed_capacity is not None:
        input_["return_consumed_capacity"] = return_consumed_capacity
    if projection_expression is not None:
        input_["projection_expression"] = projection_expression
    if expression_attribute_names is not None:
        input_["expression_attribute_names"] = expression_attribute_names

    response = execute_pipeline(
        OperationRequest(input=input_, options=options_),
        handler=_handler,
        interceptors=list(interceptors_),
    )
    response.response.close()
    return response.output