Struct EventSourceBuilder 

pub struct EventSourceBuilder { /* private fields */ }

A builder for configuring an EventSource connection.

Example

use std::{num::NonZeroUsize, time::Duration};
use sse_reqwest_client::{RequestBuilderExt, EventSourceBuilder, SseRetryConfig};

let client = reqwest::Client::new();
let req = client.get("https://api.example.com/stream");

// Create a stream with a strict 1MB payload limit and a custom retry delay
let stream = req.into_event_source_builder()
    .retry_config(SseRetryConfig::new())
    .initial_reconnection_time(Duration::from_secs(5))
    .max_payload_size(NonZeroUsize::new(1024 * 1024).unwrap())
    .build();

Implementations

impl EventSourceBuilder

pub fn new(req: RequestBuilder) -> Self

Creates a new builder wrapping the given reqwest::RequestBuilder.

pub fn retry_config(self, retry_config: SseRetryConfig) -> Self

Applies a custom retry configuration for automatic reconnections.

pub fn initial_reconnection_time(self, reconnection_time: Duration) -> Self

Sets the base delay to wait before attempting to reconnect.

This delay may be overridden by the server using retry events.

pub fn max_payload_size(self, max_payload_size: NonZeroUsize) -> Self

Configures the maximum allowed byte size for a single event payload.

pub fn last_event_id(self, id: impl Into<Arc<str>>) -> Self

Sets the initial Last-Event-ID to send with the first connection request.

This is useful for resuming a dropped stream from a previously saved state.

pub fn retry_transient_errors(self, retry: bool) -> Self

Enables automatic retries for transient HTTP status codes.

By default, the EventSource strictly follows the WHATWG specification and will permanently close the stream on any non-200 HTTP response.

Setting this to true allows the client to automatically back off and retry when encountering temporary proxy or server issues. The following status codes are considered transient:

• 408 Request Timeout
• 429 Too Many Requests
• 502 Bad Gateway
• 503 Service Unavailable
• 504 Gateway Timeout

pub fn successful_connection_threshold(self, threshold: Duration) -> Self

Sets the minimum duration a connection must remain open to be considered “successful” and reset the exponential backoff counter. Defaults to 5 seconds.

pub fn build(self) -> EventSource

Consumes the builder and returns the configured EventSource.

Trait Implementations

impl Debug for EventSourceBuilder

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

Formats the value using the given formatter.