Crate rust_web_server 

rust-web-server

An HTTP/1.1, HTTP/2, and HTTP/3 (QUIC) server, reverse proxy, and application framework in one crate. HTTP/1.1 parsing, routing, middleware, JSON, WebSocket, and SSE are implemented in-crate; HTTP/2 and HTTP/3 framing use the h2 and quinn/h3 crates, and TLS uses rustls.

Use as a library

Add to Cargo.toml:

[dependencies]
rust-web-server = "17"

Quick start

use rust_web_server::prelude::*;

fn hello(_: &Request, _: &PathParams, _: &ConnectionInfo, _: &()) -> Response {
    Response::text(STATUS_CODE_REASON_PHRASE.n200_ok, "Hello, world!")
}

fn main() {
    let app = App::with_state(()).get("/hello", hello);
    let (listener, pool) = Server::setup().unwrap();
    Server::run(listener, pool, app);
}

See DEVELOPER.md for the full building blocks reference and use case examples.

Modules

app

application

Application: the type a server runs for every request.

async_state

Async-capable state-aware application — requires the http2 feature (tokio).

blocklist

Runtime IP blocklist middleware.

body

Request and response bodies.

cache

In-memory response cache middleware.

canary

Weighted canary / A-B traffic splitting middleware.

circuit_breaker

Circuit breaker state machine and retry middleware.

client_hint

compression

config_binding

Typed configuration binding — read environment variables into strongly-typed structs.

config_check

rws --check: validate rws.config.toml without starting the server — the counterpart of nginx -t / caddy validate.

config_reload

Hot configuration reload.

config_watch

Reload when the config file or a certificate changes (watch = true, #10).

controller

Controllers: one unit of request handling for App.

cookie

core

Small shared utilities: base64, sha256 (SHA-256, HMAC-SHA256) and the New trait (a constructor used across the crate, much like Default).

cors

di

Lightweight type-keyed dependency injection container.

entry_point

error

ext

extract

feature

Runtime feature toggles.

header

HTTP header fields.

http

http_client

Outbound HTTP/1.1 client.

ingress

Kubernetes Ingress watcher and router.

ip_filter

IP address allowlist and denylist middleware.

json

A dependency-free JSON parser and serializer.

language

log

macros

Declarative routing macro.

maintenance

Maintenance mode middleware.

mcp

Model Context Protocol (MCP) server — HTTP Streamable HTTP transport.

metrics

Server-wide and per-route Prometheus metrics.

middleware

Composable middleware pipeline.

mime_type

null

Null: a value representing JSON null, with FromStr (failing with ParseNullError), Display, Clone, Debug, PartialEq and New.

otel

OpenTelemetry-compatible distributed tracing.

pagination

Pagination result types (Page<T>, CursorPage<T>) and an RFC 8288 Link header builder.

prelude

Convenience re-exports for writing handlers and running the server.

proxy

Reverse proxy middleware with round-robin load balancing.

proxy_config

Config-driven proxy application.

range

Byte ranges (RFC 9110 §14) and response bodies.

rate_limit

request

HTTP requests: Request and its parser.

request_id

Request ID / correlation ID middleware.

request_log

In-memory ring buffer of recent HTTP requests.

response

HTTP responses: Response, its writers and the upstream-response parser.

rewrite

Request and response rewriting middleware.

router

scheduler

Background task scheduler — a @Scheduled-style runner for fixed-rate, fixed-delay, and cron-expression tasks.

schema

JSON Schema for Rust types, for MCP tool inputSchema/outputSchema.

server

The listeners and connection loops.

server_config

Typed server configuration.

service_discovery

Dynamic backend pool with pluggable discovery sources.

session

Server-side session management.

sse

Server-Sent Events (SSE).

state

Shared application state and state-aware routing.

symbol

tcp_proxy

Layer-4 TCP proxy.

test_client

thread_pool

timeout

Per-route request timeouts.

udp_proxy

Layer-4 UDP proxy.

url

URL helpers: percent encoding (URL::percent_encode / percent_decode), query strings (URL::build_query / parse_query) and whole URLs (URL::build / parse, a panic-free RFC 3986 parser). URL::parse_request_target gives a request’s path and query without inventing a scheme and host. Percent encoding is what lets a query value carry a space (%20), = (%3D) or & (%26). Examples: src/url/example/.

validate

virtual_host

websocket

WebSocket protocol support — RFC 6455.

ws_proxy

WebSocket reverse proxy.

Macros

routes

Build a routing app from a declarative table.