Struct perspective_client::Client

pub struct Client { /* private fields */ }

An instance of a Client is a unique connection to a single perspective_server::Server, whether locally in-memory or remote over some transport like a WebSocket.

The browser and node.js libraries both support the websocket(url) constructor, which connects to a remote perspective_server::Server instance over a WebSocket transport.

In the browser, the worker() constructor creates a new Web Worker perspective_server::Server and returns a Client connected to it.

In node.js, a pre-instantied Client connected synhronously to a global singleton perspective_server::Server is the default module export.

JavaScript Examples

Create a Web Worker perspective_server::Server in the browser and return a Client instance connected for it:

import perspective from "@finos/perspective";
const client = await perspective.worker();

Create a WebSocket connection to a remote perspective_server::Server:

import perspective from "@finos/perspective";
const client = await perspective.websocket("ws://locahost:8080/ws");

Access the synchronous client in node.js:

import { default as client } from "@finos/perspective";

Python Examples

Create a perspective_server::Server and a local, synchronous Client instance connected for it:

import perspective;
server = perspective.Server()
client = server.new_local_client();

Examples

Create a perspective_server::Server and a synchronous Client via the perspective crate:

use perspective::server::Server;
use perspective::LocalClient;

let server = Server::default();
let client = perspective::LocalClient::new(&server);

Implementations

impl Client

pub fn new_with_callback<T>(send_request: T) -> Self

where T: for<'a> Fn(&'a [u8]) -> BoxFuture<'a, Result<(), Box<dyn Error + Send + Sync>>> + 'static + Sync + Send,

Create a new client instance with a closure that handles message dispatch. See Client::new for details.

pub fn new<T>(client_handler: T) -> Self

where T: ClientHandler + 'static + Sync + Send,

Create a new Client instance with ClientHandler.

pub async fn handle_response<'a>(&'a self, msg: &'a [u8]) -> ClientResult<bool>

Handle a message from the external message queue. Client::handle_response is part of the low-level message-handling API necessary to implement new transports for a Client connection to a local-or-remote perspective_server::Server, and doesn’t generally need to be called directly by “users” of a Client once connected.

pub async fn init(&self) -> ClientResult<()>

pub async fn table( &self, input: TableData, options: TableInitOptions, ) -> ClientResult<Table>

Creates a new Table from either a schema or data.

The Client::table factory function can be initialized with either a schema (see Table::schema), or data in one of these formats:

• Apache Arrow
• CSV
• JSON row-oriented
• JSON column-oriented

When instantiated with data, the schema is inferred from this data. While this is convenient, inferrence is sometimes imperfect e.g. when the input is empty, null or ambiguous. For these cases, Client::table can first be instantiated with a explicit schema.

When instantiated with a schema, the resulting Table is empty but with known column names and column types. When subsqeuently populated with Table::update, these columns will be coerced to the schema’s type. This behavior can be useful when Client::table’s column type inferences doesn’t work.

The resulting Table is virtual, and invoking its methods dispatches events to the perspective_server::Server this Client connects to, where the data is stored and all calculation occurs.

Arguments

• arg - Either schema or initialization data.
• options - Optional configuration which provides one of:
  • limit - The max number of rows the resulting Table can store.
  • index - The column name to use as an index column. If this Table is being instantiated by data, this column name must be present in the data.
  • name - The name of the table. This will be generated if it is not provided.

JavaScript Examples

Load a CSV from a string:

const table = await client.table("x,y\n1,2\n3,4");

Load an Arrow from an ArrayBuffer:

import * as fs from "node:fs/promises";
const table2 = await client.table(await fs.readFile("superstore.arrow"));

Create a table with an index:

const table = await client.table(data, { index: "Row ID" });

Python Examples

Load a CSV from a str:

table = client.table("x,y\n1,2\n3,4")

Examples

Load a CSV from a String:

let opts = TableInitOptions::default();
let data = TableData::Update(UpdateData::Csv("x,y\n1,2\n3,4".into()));
let table = client.table(data, opts).await?;

pub async fn open_table(&self, entity_id: String) -> ClientResult<Table>

Opens a Table that is hosted on the perspective_server::Server that is connected to this Client.

The name property of TableInitOptions is used to identify each Table. Table names can be looked up for each Client via Client::get_hosted_table_names.

JavaScript Examples

Get a virtual Table named “table_one” from this Client

const tables = await client.open_table("table_one");

Python Examples

tables = client.open_table("table_one");

Examples

let tables = client.open_table("table_one").await;

pub async fn get_hosted_table_names(&self) -> ClientResult<Vec<String>>

Retrieves the names of all tables that this client has access to.

name is a string identifier unique to the Table (per Client), which can be used in conjunction with Client::open_table to get a Table instance without the use of Client::table constructor directly (e.g., one created by another Client).

JavaScript Examples

const tables = await client.get_hosted_table_names();

Python Examples

tables = client.get_hosted_table_names();

Examples

let tables = client.get_hosted_table_names().await;

pub async fn system_info(&self) -> ClientResult<SystemInfo>

Provides the SystemInfo struct, implementation-specific metadata about the perspective_server::Server runtime such as Memory and CPU usage.

For WebAssembly servers, this method includes the WebAssembly heap size.

JavaScript Examples

const info = await client.system_info();

Trait Implementations

impl Clone for Client

fn clone(&self) -> Client

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Client

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.