Struct ResponseContext 

pub struct ResponseContext {
    pub status: u16,
    pub headers: HeaderMap,
    pub body: Vec<u8>,
    pub was_sse: bool,
    pub json: Option<Value>,
    pub json_mutated: bool,
    pub rpc_error: Option<(i64, String)>,
    pub upstream_us: Option<u64>,
}

Response-side state threaded through the response middleware chain.

Middleware mutate body and json in place. Handlers instantiate after reading the upstream body and finalize by building an axum::Response from (status, headers, body).

Fields

status: u16

headers: HeaderMap

body: Vec<u8>

Serialized response body — what gets returned to the client. Held verbatim from the upstream until EncodeResponseJson overwrites it. When no middleware mutates json, this retains the original bytes byte-for-byte (preserving SSE framing, key order, etc.).

was_sse: bool

True when the upstream sent SSE-wrapped JSON. DecodeResponseJson sets it; EncodeResponseJson reads it to decide whether to re-wrap.

json: Option<Value>

Parsed JSON view of the body. Populated by DecodeResponseJson; mutated by later middleware; serialized back into body by EncodeResponseJson only when json_mutated is set.

json_mutated: bool

Signals that some middleware mutated json. Set by any middleware that takes json.as_mut() or reassigns json. EncodeResponseJson skips re-serialization when false, leaving body untouched — the byte-pass fast path.

rpc_error: Option<(i64, String)>

JSON-RPC error extracted from json (when present).

upstream_us: Option<u64>

Implementations

impl ResponseContext

pub fn new( status: u16, headers: HeaderMap, body: Vec<u8>, upstream_us: Option<u64>, ) -> Self

pub fn json_mut(&mut self) -> Option<&mut Value>

Mutable access to the parsed JSON value, marking it as mutated so EncodeResponseJson will re-serialize. Prefer this over direct json.as_mut() — forgetting to set the flag causes silent staleness.