Struct RequestBuilder 

pub struct RequestBuilder<'a, P: Phase = Query> { /* private fields */ }

Typestate request builder. Writes directly into a RequestWriter’s buffer — no intermediate storage, no stream type parameter.

Phase type parameter enforces correct wire ordering at compile time: query parameters before headers, headers before body.

Implementations

impl<'a> RequestBuilder<'a, Query>

pub fn query(self, key: &str, value: &str) -> Self

Add a query parameter. Percent-encodes key and value per RFC 3986.

pub fn query_raw(self, key: &str, value: &str) -> Self

Add a pre-encoded query parameter. No percent-encoding applied.

Caller is responsible for correct encoding. Validates no CR/LF.

pub fn header(self, name: &str, value: &str) -> RequestBuilder<'a, Headers>

Add a request header. Transitions to the headers phase.

pub fn body(self, body: &[u8]) -> RequestBuilder<'a, Ready>

Set the request body. Transitions to the ready phase.

pub fn body_writer<F, E>(self, f: F) -> RequestBuilder<'a, Ready>

where F: FnOnce(&mut BodyWriter<'_>) -> Result<(), E>, E: Into<Box<dyn Error + Send + Sync>>,

Write the body directly into the buffer via a closure.

Zero-alloc: the closure writes into the WriteBuf’s spare region via BodyWriter (implements std::io::Write). Content-Length is computed and backfilled automatically.

let req = writer.post("/order")
    .body_writer(|w| serde_json::to_writer(w, &order))
    .finish()?;

pub fn body_fixed( self, len: usize, f: impl FnOnce(&mut [u8]), ) -> RequestBuilder<'a, Ready>

Write a fixed-size body via closure with direct &mut [u8] access.

The caller specifies the exact body size upfront. Content-Length is written with exact digits (no backfill). The closure receives a zeroed &mut [u8] slice of exactly len bytes to write into.

For binary wire formats (SBE, FIX, protobuf) where the message size is known at construction time.

let req = writer.post("/order")
    .body_fixed(128, |buf| {
        order.encode_sbe(buf);
    })
    .finish()?;

pub fn finish(self) -> Result<Request<'a>, RestError>

Finish building. Returns the assembled request bytes.

impl<'a> RequestBuilder<'a, Headers>

pub fn header(self, name: &str, value: &str) -> Self

Add a request header.

pub fn body(self, body: &[u8]) -> RequestBuilder<'a, Ready>

Set the request body. Transitions to the ready phase.

pub fn body_writer<F, E>(self, f: F) -> RequestBuilder<'a, Ready>

where F: FnOnce(&mut BodyWriter<'_>) -> Result<(), E>, E: Into<Box<dyn Error + Send + Sync>>,

Write the body directly into the buffer via a closure.

Same as RequestBuilder<Query>::body_writer — see its docs.

pub fn body_fixed( self, len: usize, f: impl FnOnce(&mut [u8]), ) -> RequestBuilder<'a, Ready>

Write a fixed-size body via closure with direct &mut [u8] access.

Same as RequestBuilder<Query>::body_fixed — see its docs.

pub fn finish(self) -> Result<Request<'a>, RestError>

Finish building. Returns the assembled request bytes.

impl<'a> RequestBuilder<'a, Ready>

pub fn finish(self) -> Result<Request<'a>, RestError>

Finish building. Returns the assembled request bytes.