Struct ClientBuilder 

pub struct ClientBuilder { /* private fields */ }

Builder for constructing a Client with custom configuration.

Implementations

impl ClientBuilder

pub fn new() -> Self

Create a new builder with defaults (30s timeout, 3 retries, exponential backoff).

pub fn base_url(self, url: impl Into<String>) -> Self

Set a base URL that is prepended to all relative paths.

pub fn timeout(self, timeout: Duration) -> Self

Set the request timeout.

pub fn retries(self, retries: u32) -> Self

Set the maximum number of retries.

Shapes the built-in middleware::RetryMiddleware (feature retry, default-on). For custom retry behavior, register a middleware::RetryMiddleware with a full middleware::RetryConfig via ClientBuilder::with_middleware.

pub fn retry_bounds(self, initial: Duration, max: Duration) -> Self

Set the initial and maximum retry backoff durations.

pub fn with_middleware(self, middleware: impl Middleware) -> Self

Register custom middleware to run outermost — wrapping the built-in retry/breaker stack — observing each logical request once.

Middleware registered first runs outermost; see the middleware module docs for the full ordering semantics.

pub fn default_header(self, key: &'static str, value: &'static str) -> Self

Add a default header applied to every request (infallible for compile-time string literals).

Panics

Panics if key or value is not a valid HTTP header string — this is a caller programming error, not a runtime condition. Use default_headers with a HeaderMap for a fallible variant.

pub fn default_headers(self, headers: HeaderMap) -> Self

Set multiple default headers applied to every request.

pub fn user_agent(self, agent: &'static str) -> Self

Set the User-Agent header.

pub fn reqwest_builder(self, builder: ClientBuilder) -> Self

Add a raw reqwest::ClientBuilder for advanced configuration.

pub fn build(self) -> Client

Build the Client.

Panics

Panics if the underlying reqwest::Client cannot be built. This should only happen due to process-startup defects (e.g. invalid TLS config), not from user input at runtime.

pub fn try_build(self) -> Result<Client, FetchError>

Build the Client, returning a FetchError on failure.

Trait Implementations

impl Default for ClientBuilder

fn default() -> Self

Returns the “default value” for a type.