Module streaming 

Real-time price streaming with pluggable provider backends.

This module provides a Stream-based API for receiving real-time price updates, similar to Kotlin Flow or Rx observables.

Overview

A StreamSource trait abstracts the provider-specific transport and wire protocol. Yahoo (YahooStreamSource) is the reference implementation, with additional providers (e.g. Polygon) supported through the same abstraction.

This module handles:

• Provider-agnostic reconnection logic
• Subscription management with automatic heartbeats
• Protobuf message decoding (Yahoo)
• A clean Stream API for consuming updates

Example

use finance_query::streaming::PriceStream;
use futures::StreamExt;

// Subscribe to symbols
let mut stream = PriceStream::subscribe(["AAPL", "NVDA", "TSLA"]).await?;

// Process updates as they arrive
while let Some(price) = stream.next().await {
    println!("{}: ${:.2} ({:+.2}%)",
        price.id,
        price.price,
        price.change_percent
    );
}

Structs

AlertEvaluator

Evaluates AlertRules against a price feed, tracking the per-symbol history that crossing conditions need.

AlertEvent

A fired alert, carrying the tick that triggered it.

AlertRule

A symbol paired with the condition that should trigger an alert.

AlertStream

A Stream<Item = AlertEvent> over any price stream.

Batched

A stream that yields Vec<T> batches collected over a time window.

BookLevel

One price level of an order book.

DepthStream

A subscription to level-2 order-book depth.

DepthStreamBuilder

Builder for a DepthStream.

EconomicStream

A continuous subscription to economic-series releases.

EconomicStreamBuilder

Builder for an EconomicStream with a custom poll interval.

Greeks

Option greeks for a contract.

NewsStream

A continuous subscription to one or more RSS/Atom sources.

NewsStreamBuilder

Builder for creating a NewsStream with custom configuration.

OptionContractUpdate

A live update for one options contract.

OptionsChainStream

A live subscription to one or more options chains.

OptionsChainStreamBuilder

Builder for an OptionsChainStream.

OrderBookUpdate

A depth-of-book update: both sides, best level first.

PriceStream

A streaming price subscription that yields real-time price updates.

PriceStreamBuilder

Builder for creating price streams with custom configuration

PriceUpdate

Real-time price update from Yahoo Finance WebSocket.

SeriesUpdate

A newly published (or revised) observation for an economic series.

TradeStream

A subscription to every trade print for the given symbols.

TradeStreamBuilder

Builder for a TradeStream.

TradeTick

A single executed trade.

Enums

AlertCondition

A predicate over incoming price ticks.

AlertConditionKind

Which predicate an AlertCondition applies, without its threshold.

AssetClass

Asset class of a Polygon real-time cluster.

MarketHoursType

Market hours type enumeration

OptionType

Option type enumeration

PriceSource

Which upstream backend a PriceStream connects to.

QuoteType

Quote type enumeration

StreamError

Errors that can occur during streaming

Traits

AlertExt

Adds alerts to every price stream.

StreamBatchExt

Adds batched to every Stream.

Type Aliases

StreamResult

Result type for streaming operations