moonasgi
MoonBit-dialect ASGI 3.0 — the load-bearing server↔app SEAM (Scope / Receive / Send) that the moon* full-stack web suite (mooncat, moonapi, moonrpc, moongql, moonzero) is built around.
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moon add Lfan-ke/moonasgi@0.7.0
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README#moonasgi
MoonBit-dialect ASGI 3.0 — the load-bearing server↔app SEAM.
moonasgi is the backend-agnostic protocol seam every server and framework in the moon* full-stack suite is built around. One typed contract — Scope / Receive / Send — isolates async-transport churn in a single server adapter, so the framework repos (moonapi, moonorm, moonrpc, moongql, moonzero) never depend on moonbitlang/async directly.
flowchart LR
net["native async<br/>(sockets, TLS, HTTP/1.1, HTTP/2)"] --> cat["mooncat<br/>(ASGI server)"]
cat -->|"Scope / Receive / Send"| asgi(["**moonasgi**<br/>SEAM"])
asgi --> api["moonapi"]
asgi --> rpc["moonrpc"]
asgi --> gql["moongql"]
asgi --> zero["moonzero"]
api --> orm["moonorm"]#The contract
pub enum Scope {
Http(HttpScope)
WebSocket(WebSocketScope)
Lifespan(LifespanScope)
}
pub type Receive = async () -> Event // pull the next inbound event
pub type Send = async (Event) -> Unit // push an outbound event
pub type AsgiApp = async (Scope, Receive, Send) -> UnitApplications are usually written against the ergonomic sugar, which the server lifts onto AsgiApp:
pub type Handler = (Request) -> Response
pub type Middleware = (Handler) -> HandlerEvent is a typed sum over the full http / websocket / lifespan message sets in both directions — including the standard extension messages — replacing ASGI's stringly-typed message dicts.
#TestClient
Drive any application in-process, with no socket, on every backend. The TestClient is built on the synchronous run_http_app core: it fabricates a scope, feeds the request body in, runs the app, and reassembles the outbound event stream into a captured response.
let client = TestClient::new(handler) // or ::from_stream / ::from_app
let r = client.post("/echo", body=b"payload")
assert_eq(r.status, 200)
assert_eq(r.text(), "payload")It reassembles a streamed multi-chunk body, captures response trailers, server-push promises, early hints, and the path-send target, and can stream a chunked request body in via request(..., chunks=[...]).
#WebSocket
WebSocket app logic is testable in-process too, through the synchronous core ws_run — the WebSocket analog of run_http. A WebSocketHandler is written in the connect / receive / disconnect shape; the TestClient drives a whole connection and captures the result as a WsTestSession.
let client = TestClient::new(handler)
let session = client.websocket(
path="/chat",
handler=WebSocketHandler::echo(subprotocol=Some("chat")),
send=[Text("hello"), Binary(b"\x01\x02")],
)
assert_eq(session.accepted, true)
assert_eq(session.subprotocol, Some("chat"))
assert_eq(session.texts(), ["hello"])A handler can Accept (negotiating a subprotocol and response headers), Reject with a bare close code, or DenyHttp with a full HTTP response (the websocket.http.response extension). ws_run_app is the escape hatch for apps whose control flow is not the connect/receive/disconnect fold — it hands the whole inbound stream and full scope to the app.
#Lifespan
The lifespan protocol has the same shape as the http and WebSocket cores. A LifespanHandler is written as a startup and a shutdown hook; run_lifespan drives it over the inbound LifespanStartup / LifespanShutdown events and returns the replies a server sends. Startup seeds scope.state in place — the map a server then copies onto every request scope, which is how a DB pool or loaded config reaches each request. A failed startup short-circuits: the server never proceeds to shutdown, exactly as ASGI pins.
let app = LifespanHandler::new(
on_startup=fn(scope) {
scope.state["db_pool"] = Json::string("pool://greet") // seeded in place
Complete
},
)
let out = run_lifespan(app, Lifespan(scope), [LifespanStartup])
assert_eq(out == [LifespanStartupComplete], true)#Scope-aware core
The ergonomic Handler sees a Request — method, path, query, headers, body. A framework needs more: root_path for mounted sub-apps, extensions to gate a feature on what the server advertises, client for security, and state seeded by lifespan. run_http_scoped hands the app the full HttpScope alongside the drained body, and run_http_app is the Request-level wrapper over it.
run_http_scoped(fn(scope, body) {
let prefix = scope.state.get("greeting_prefix") // lifespan-seeded
[HttpResponseStart(status=200, headers=[], trailers=false),
HttpResponseBody(body, more_body=false)]
}, Http(scope), inbound)#HTTP/2 and HTTP/3
http_version on the scope is "1.0", "1.1", "2", or "3" — the SEAM is transport-agnostic, so an app runs unchanged whichever version served the request. The one place the version leaks into wiring is the request line: an HTTP/2 (RFC 7540 §8.1.2.3) or HTTP/3 request carries it as pseudo-headers (:method, :scheme, :authority, :path) interleaved with the ordinary fields, and ASGI has no slot for them in scope["headers"]. HttpScope::from_h2_headers owns that lowering so every h2/h2c/h3 transport in the suite (mooncat) produces the same scope from the same HEADERS block — pseudo-headers consumed into the typed fields, host synthesised from :authority, and no :-prefixed header ever reaching the app.
let scope = HttpScope::from_h2_headers([
(":method", "POST"), (":scheme", "https"),
(":authority", "example.test"), (":path", "/items?page=2"),
("content-type", "application/json"),
])
// -> Ok: http_method="POST", scheme="https", path="/items",
// query_string=b"page=2", headers=[("host","example.test"), ...]A malformed pseudo-header set — a missing required one, a duplicate, an unknown :foo, or a pseudo-header after an ordinary field — returns Err(Http2HeaderError) naming the first violation, so the transport can answer RST_STREAM(PROTOCOL_ERROR) instead of forwarding a bad scope.
#Conformance
run_conformance() is a table-driven harness that drives every Event variant and every Scope field through run_http / ws_run / TestClient and asserts round-trip fidelity — a value put in comes back unchanged, and no two distinct events or scope shapes are confused. It returns a ConformanceReport naming any failing check, so a downstream server can self-verify the seam wiring:
let report = run_conformance()
assert_eq(report.ok(), true)The harness also runs a negative table: ASGI pins the order an app may emit messages in, and validate_events(scope, events) walks an outbound stream and names the first violation — a body before the response starts, a second http.response.start, a websocket frame before the handshake is accepted, a lifespan shutdown reply before startup, and the rest. A server can run it over its own emissions to reject a buggy app early.
let bad = [HttpResponseBody(body=b"x", more_body=false)] // no start
assert_eq(validate_events(scope, bad) == Some(BodyBeforeStart), true)#Extensions & streaming
The standard ASGI extensions are modelled as typed events and scope fields, not stringly-typed dicts:
- http.response.trailers — StreamingResponse.trailers; lowered to HttpResponseStart{trailers: true} + a terminating HttpResponseTrailers.
- http.response.push — HttpResponsePush{path, headers}.
- http.response.pathsend — HttpResponsePathSend{path}.
- http.response.zerocopysend — HttpResponseZeroCopySend{fd, offset, count, more_body}; captured by the TestClient as TestResponse.zerocopysend.
- http.response.early_hint — HttpResponseEarlyHint{links}; StreamingResponse.early_hints, lowered to 103 Early Hints messages ahead of the response.
- http.response.debug — HttpResponseDebug{info}; an out-of-band info payload with no protocol meaning, valid anywhere in the response.
- websocket.http.response — WebSocketHttpResponseStart / WebSocketHttpResponseBody, to deny a handshake with a full HTTP response.
- tls — TlsExtension carried on the scope's extensions.
A server advertises what it honours via the typed Extensions capability flags; response streaming (multiple HttpResponseBody with more_body: true) is modelled by StreamingResponse and driven by run_http_stream. spec_version is negotiated numerically with AsgiVersion::at_least, and each sub-protocol carries its own default — AsgiVersion::http() / websocket() (2.5, the 2024-06-05 revision) and lifespan() (2.0). The 2.5 websocket revision adds reason to WebSocketDisconnect, threaded to a handler's on_disconnect(code, reason).
#Compliance matrix
Every ASGI 3.0 spec feature, and the test that exercises it. conformance is run_conformance()'s in-suite battery; test names are the whitebox tests.
| Spec feature | Modelled as | Covered by |
|---|---|---|
| http scope (all fields incl. state, raw_path, root_path) | HttpScope | conformance scope/http-fields |
| websocket scope (incl. subprotocols, state) | WebSocketScope | conformance scope/ws-fields |
| lifespan scope (incl. state) | LifespanScope | conformance scope/lifespan-fields |
| asgi version / spec_version (2.5 http+ws, 2.0 lifespan) | AsgiVersion | conformance spec_version/*; test "per-subprotocol asgi spec_version defaults" |
| spec_version numeric negotiation | AsgiVersion::at_least | test "AsgiVersion negotiates spec_version numerically" |
| Every http/ws/lifespan message, both directions | Event (25 variants) | conformance event/*; test "SEAM scope and event variants construct" |
| Full scope reaches a framework (state, root_path, extensions) | run_http_scoped | conformance scoped/*; test "greet: moonapi http routing round-trips…" |
| lifespan.startup / .shutdown (complete / failed, in-place state) | LifespanHandler / run_lifespan | conformance lifespan/*; test "greet: lifespan startup seeds state…" |
| http.request drain (streamed more_body) | run_http / TestClient | test "TestClient streams a chunked request body into the handler" |
| http.disconnect | HttpDisconnect | conformance event/* |
| http.response.start + .body round-trip | Response / run_http | conformance http/roundtrip; test "run_http drains a chunked body…" |
| Response streaming (more_body: true chunks) | StreamingResponse / run_http_stream | test "TestClient reassembles a streaming multi-chunk response body" |
| websocket.connect / .accept / .receive / .send / .close | WebSocketHandler / ws_run | test "ws_run echoes text and binary frames…" |
| websocket.disconnect (2.5 reason) | WebSocketDisconnect | test "on_disconnect receives the 2.5 close code and reason" |
| Handshake reject (bare close) | WsAccept::Reject | test "ws handler can reject the handshake with a close code" |
| ext http.response.trailers | StreamingResponse.trailers | test "TestClient captures response trailers" |
| ext http.response.push | HttpResponsePush | test "TestClient captures server push and pathsend" |
| ext http.response.pathsend | HttpResponsePathSend | test "TestClient captures server push and pathsend" |
| ext http.response.zerocopysend | HttpResponseZeroCopySend | test "zerocopysend and debug extensions round-trip…" |
| ext http.response.early_hint | HttpResponseEarlyHint | test "early-hint extension round-trips through the TestClient" |
| ext http.response.debug | HttpResponseDebug | test "zerocopysend and debug extensions round-trip…" |
| ext websocket.http.response (denial) | WsAccept::DenyHttp | test "ws handler can deny the handshake with a full HTTP response" |
| ext tls | TlsExtension | test "Extensions builder advertises capabilities and TLS data" |
| Message-ordering rules (all message sets) | validate_events | conformance order/*; test "validator names the violation…" |
| HTTP/2·3 pseudo-header → scope lowering (:method/:scheme/:authority/:path, host synthesis, malformed rejection) | HttpScope::from_h2_headers / Http2HeaderError | conformance h2/* |
| http_version transport-agnostic seam ("1.1" / "2" / "3") | HttpScope.http_version | conformance h2/seam-agnostic |
The one spec feature with no direct model is the C-level file object in http.response.zerocopysend: this seam is socket-free by design, so the file descriptor is carried as an Int fd and the actual sendfile is the server adapter's (mooncat) job.
#Consumed by
The seam is the only thing the server and the frameworks share. Each binds to a specific slice of it.
mooncat — the ASGI server. Owns the async Receive / Send and the native transport, binds AsgiApp, and drives every core: it drains the http request body, runs run_lifespan at boot and teardown, and drives WebSocket connections. It copies LifespanScope.state onto each HttpScope.state, serialises the outbound Event stream (HttpResponseStart / HttpResponseBody / HttpResponseTrailers / the extension messages) to the socket, and can run validate_events over an app's emissions to reject a buggy app before writing.
moonapi — the web framework. Binds at the scope level through run_http_scoped, because it reads what the ergonomic Request drops: HttpScope.root_path (mounted sub-apps), extensions (gate a response push or path-send on what the server advertises), client (security), and state (the lifespan-seeded pool / config). It returns Response and StreamingResponse, serves its OpenAPI document as an ordinary response, and registers LifespanHandler startup / shutdown hooks that mooncat runs.
moonzero — the service assembler. Stacks its middleware (request-id, CORS, logging, recovery) as Middleware values and folds them over a Handler with compose, outermost-first.
The greet: * whitebox tests assemble a representative app across all three shapes and drive it through these exact seam points, so the seam is proven greet-ready before any consuming repo is wired up.
#Design
- Zero dependencies. The seam is pure types plus a small sugar layer; the concrete moonbitlang/async transport types live only in the mooncat adapter. Async or backend churn stops at the seam (see the isolation contract).
- Faithful, not approximate. This is a complete transliteration of ASGI 3.0 into MoonBit idiom — the typed Scope/Event shape is the dialect, not a subset.
#Status
v0 — the SEAM (Scope, Event, Receive/Send/AsgiApp, Request/Response, Handler/Middleware) plus the full ASGI-extension event set (push, pathsend, zero-copy send, trailers, early hints, debug, WebSocket denial, TLS), StreamingResponse response streaming, the synchronous run_http, run_http_scoped, run_lifespan, and ws_run cores, the TestClient in-process driver for both HTTP and WebSocket, the run_conformance round-trip harness (416 checks) with its validate_events ordering table, HttpScope::from_h2_headers HTTP/2·3 pseudo-header lowering, and typed Extensions/tls/spec_version (2.5) scope metadata — 40 tests, warning-clean across every backend. The async Handler → AsgiApp runtime adapter lands with mooncat, which owns the native async transport.
#License
Apache-2.0.
#AsgiApp
The load-bearing ASGI callable: (scope, receive, send). Every server binds
to this shape and every framework in the suite ultimately compiles down to it.
#Handler
The ergonomic request→response function most handlers are written as. The
synchronous sugar the suite lifts onto AsgiApp at the server boundary.
#Middleware
A handler transformer that wraps a downstream Handler to add cross-cutting
behaviour. Composed as an onion where the first registered is outermost.
#Receive
Pull the next inbound event. The async awaitable an application calls to read
request body chunks, websocket frames, or lifespan signals.
#Send
Push an outbound event. The async awaitable an application calls to emit
response start/body, websocket frames, or lifespan completion.
#StreamHandler
A streaming handler: produces a StreamingResponse (multi-chunk body,
optional trailers) instead of a single buffered Response. Driven by
run_http_stream and the TestClient.
#AsgiVersion
The asgi sub-dict every scope carries: the ASGI protocol version
("3.0") and the spec_version of the concrete http / websocket / lifespan
sub-spec the server implements. Applications negotiate optional behaviour
against spec_version with at_least.
#AsgiVersion::at_least
Strict spec_version negotiation: is this scope's sub-spec at least
major.minor? Parses the dotted spec_version (non-digit runs count as 0)
and compares numerically, so "2.4".at_least(major=2, minor=3) is true.
An application guards a version-gated feature with this instead of string
equality.
#AsgiVersion::default
The default ASGI handshake: protocol 3.0, sub-spec 2.5 (the current
HTTP / WebSocket spec revision, 2024-06-05). An alias of http — the common
case.
#AsgiVersion::http
The HTTP handshake: protocol 3.0, HTTP sub-spec 2.5. This is the revision
that carries state, the extension message set (http.response.trailers /
http.response.push / http.response.pathsend / http.response.early_hint),
and the raw_path guarantee.
#AsgiVersion::lifespan
The Lifespan handshake: protocol 3.0, lifespan sub-spec 2.0 (the revision
that carries state). Lifespan versions independently of http/websocket, so
a lifespan scope must not borrow the http spec_version.
#AsgiVersion::websocket
The WebSocket handshake: protocol 3.0, WebSocket sub-spec 2.5 — the
revision that adds reason to the disconnect event, alongside state and the
websocket.http.response denial extension.
#ConformanceReport
The outcome of the ASGI 3.0 conformance harness: how many round-trip checks
ran, how many passed, and the names of any that failures. A clean run has
an empty failures. Reusable beyond the test suite — a server or framework
built on the seam can call run_conformance to self-verify the wiring.
#ConformanceReport::ok
Whether every conformance check passed (no failures recorded).
#Event
pub(all) enum Event {
HttpRequest(body~ : Bytes, more_body~ : Bool)
HttpDisconnect
HttpResponseStart(status~ : Int, headers~ : Array[(String, String)], trailers~ : Bool)
HttpResponseBody(body~ : Bytes, more_body~ : Bool)
HttpResponseTrailers(headers~ : Array[(String, String)], more_trailers~ : Bool)
HttpResponsePush(path~ : String, headers~ : Array[(String, String)])
HttpResponsePathSend(path~ : String)
HttpResponseZeroCopySend(fd~ : Int, offset~ : Int?, count~ : Int?, more_body~ : Bool)
HttpResponseDebug(info~ : Json)
HttpResponseEarlyHint(links~ : Array[String])
WebSocketConnect
WebSocketReceive(text~ : String?, bytes~ : Bytes?)
WebSocketDisconnect(code~ : Int, reason~ : String?)
WebSocketAccept(subprotocol~ : String?, headers~ : Array[(String, String)])
WebSocketSendText(String)
WebSocketSendBytes(Bytes)
WebSocketClose(code~ : Int, reason~ : String)
WebSocketHttpResponseStart(status~ : Int, headers~ : Array[(String, String)])
WebSocketHttpResponseBody(body~ : Bytes, more_body~ : Bool)
LifespanStartup
LifespanShutdown
LifespanStartupComplete
LifespanStartupFailed(message~ : String)
LifespanShutdownComplete
LifespanShutdownFailed(message~ : String)
} derive(Eq)A protocol event flowing between server and application. Replaces ASGI's
stringly-typed message dicts with a typed sum covering the http / websocket /
lifespan message sets in both directions, including the standard extension
messages (server push, path-send, zero-copy send, response trailers, early
hints, debug, and WebSocket denial with a full HTTP response).
#EventOrderError
pub(all) enum EventOrderError {
BodyBeforeStart
DuplicateResponseStart
EarlyHintAfterStart
BodyAfterComplete
UnexpectedTrailers
TrailersBeforeBody
MissingResponseStart
IncompleteBody
MissingTrailers
EventAfterComplete
FrameBeforeAccept
DuplicateAccept
EventAfterClose
DenialBodyBeforeStart
DenialAfterAccept
AcceptAfterDenial
IncompleteDenial
MissingHandshakeReply
DuplicateLifespanReply
ShutdownBeforeStartup
NonResponseEvent
} derive(Eq)Why an outbound event stream is malformed. ASGI pins the order an application
may emit messages in — a body before the response starts, a second start, a
websocket frame before the handshake is accepted, and so on are all protocol
violations. validate_events walks a stream and names the first violation it
finds; a well-formed stream returns None. A server can run this over its own
emissions to catch a buggy app early, and the conformance harness drives a
negative table through it.
#EventOrderError::describe
A one-line human description of the violation, used in conformance failure
names and server logs.
#Extensions
pub(all) struct Extensions {
tls : TlsExtension?
http_response_push : Bool
http_response_trailers : Bool
http_response_pathsend : Bool
http_response_early_hint : Bool
websocket_http_response : Bool
} derive(Eq)The scope's extensions map, modelled as typed capability flags plus the
one extension that carries data (tls). A server sets a flag to advertise
that it will honour the matching outbound event — an application checks the
flag before emitting HttpResponsePush / HttpResponsePathSend /
HttpResponseEarlyHint / HttpResponseTrailers /
WebSocketHttpResponseStart, exactly as an ASGI app tests
"http.response.push" in scope["extensions"].
#Extensions::enable_early_hint
Advertise the early-hints extension (http.response.early_hint): the server
will forward HttpResponseEarlyHint messages as 103 Early Hints
informational responses ahead of the final status.
#Extensions::enable_pathsend
Advertise the path-send extension (http.response.pathsend).
#Extensions::enable_push
Advertise the server-push extension (http.response.push).
#Extensions::enable_trailers
Advertise the response-trailers extension (http.response.trailers).
#Extensions::enable_websocket_http_response
Advertise the WebSocket-denial-with-response extension
(websocket.http.response).
#Extensions::none
No extensions advertised: every capability off, no TLS data. The starting
point servers and tests build from with the enable_* / with_tls helpers.
#Extensions::with_tls
Attach tls extension data to a connection scope.
#Http2HeaderError
pub(all) enum Http2HeaderError {
MissingMethod
MissingScheme
MissingPath
EmptyPath
DuplicatePseudoHeader(String)
UnknownPseudoHeader(String)
PseudoHeaderAfterRegular(String)
} derive(Eq)Why a HEADERS frame does not map onto an HttpScope field-by-field: an
HTTP/2 (RFC 7540 §8.1.2.3) or HTTP/3 request carries its request line as four
pseudo-headers — :method, :scheme, :authority, :path — interleaved
with the ordinary fields, and ASGI reserves no slot for them in
scope["headers"]. A conforming server must consume the pseudo-headers into
the scope's typed fields and hand the application only the ordinary headers,
with host synthesised from :authority. moonasgi owns that lowering so
every h2/h2c/h3 transport in the suite (mooncat) produces the same scope from
the same frame, and an app never sees a :-prefixed header.
A malformed pseudo-header set — a missing required one, a duplicate, an
unknown :foo, or a pseudo-header after an ordinary field — is rejected with
the exact Http2HeaderError, matching RFC 7540's "malformed request"
treatment, so the transport can answer RST_STREAM(PROTOCOL_ERROR) instead
of forwarding a bad scope.
#HttpScope
pub(all) struct HttpScope {
http_version : String
http_method : String
scheme : String
path : String
raw_path : Bytes
query_string : Bytes
root_path : String
headers : Array[(String, String)]
client : (String, Int)?
server : (String, Int)?
asgi : AsgiVersion
extensions : Extensions
state : Map[String, Json]
}HTTP connection scope (ASGI type == "http"). raw_path / query_string
stay Bytes because they are not guaranteed valid UTF-8; header names follow
ASGI's lowercased-latin1 convention. asgi carries the version handshake,
extensions the advertised server capabilities, and state is
per-connection scratch copied from the lifespan state.
#HttpScope::from_h2_headers
fn HttpScope::from_h2_headers(headers : Array[(String, String)], http_version? : String, root_path? : String, client? : (String, Int)?, server? : (String, Int)?, extensions? : Extensions, asgi? : AsgiVersion, state? : Map[String, Json]) -> Result[HttpScope, Http2HeaderError]Lower an HTTP/2 (or HTTP/3) request's HEADERS block — pseudo-headers and
ordinary fields in wire order — into an HttpScope, the way a conforming
ASGI server consumes a frame. :method, :scheme and :path become the
scope's http_method / scheme / path (with the query string split off
:path); the returned headers are the ordinary fields only, with host
synthesised at the front from :authority (replacing any host the peer
also sent, per RFC 7540 §8.1.2.3). http_version defaults to "2"; pass
"3" for an HTTP/3 transport, which shares this pseudo-header contract.
The remaining scope fields (root_path, client, server, extensions,
asgi, state) are supplied by the server exactly as for HttpScope::new.
Returns Err naming the first violation for a malformed pseudo-header set,
so the SEAM never hands a framework a scope with a :-prefixed header or a
missing request-line field.
#HttpScope::new
fn HttpScope::new(http_method~ : String, path~ : String, http_version? : String, scheme? : String, raw_path? : Bytes, query_string? : Bytes, root_path? : String, headers? : Array[(String, String)], client? : (String, Int)?, server? : (String, Int)?, asgi? : AsgiVersion, extensions? : Extensions, state? : Map[String, Json]) -> HttpScopeBuild an HttpScope with ASGI's usual defaults filled in — http_version
"1.1", scheme "http", empty query/headers/state, the default asgi
handshake, and no extensions. raw_path defaults to the UTF-8 encoding of
path. The ergonomic constructor servers and the TestClient build scopes
through, so callers spell only what differs from the common case.
#LifespanHandler
pub(all) struct LifespanHandler {
on_startup : (LifespanScope) -> LifespanReply
on_shutdown : (LifespanScope) -> LifespanReply
}A synchronous lifespan application in the startup / shutdown shape, the
lifespan analog of the http Handler and the WebSocket WebSocketHandler.
on_startup runs once at boot: it seeds the scope's state in place (the map
the server then copies onto every request scope — a DB pool handle, a loaded
config) and returns Complete or Failed. on_shutdown runs once at
teardown to release those resources. Driven in-process by run_lifespan, so
boot/teardown logic is testable on every backend without an async runtime —
the faithful synchronous core the async server (mooncat) lifts onto the
lifespan protocol.
#LifespanHandler::new
fn LifespanHandler::new(on_startup? : (LifespanScope) -> LifespanReply, on_shutdown? : (LifespanScope) -> LifespanReply) -> LifespanHandlerBuild a LifespanHandler. Both phases default to succeeding without doing
anything, so a caller overrides only the phase it needs — an app that just
wants a startup hook leaves on_shutdown alone.
#LifespanReply
An application's answer to a lifespan phase: Complete when startup or
shutdown succeeded, or Failed with a message the server logs and (for
startup) aborts the boot on. Mirrors the two replies ASGI allows to each
lifespan message — lifespan.startup.complete / .failed and
lifespan.shutdown.complete / .failed.
#LifespanScope
Lifespan scope (ASGI type == "lifespan"): a single run spanning process
startup and shutdown, whose state seeds every request scope. Carries its
own asgi handshake — lifespan versions independently (sub-spec 2.0), so
it does not borrow the http/websocket spec_version.
#LifespanScope::new
Build a LifespanScope with the lifespan asgi handshake (sub-spec 2.0)
and an empty state by default.
#PushPromise
A server-side push promise captured by the TestClient: the pushed path
and the request headers the server would send for it (http.response.push).
#PushPromise::header
First push-request header matching name.
#Request
An inbound HTTP request in ergonomic form: the request line, headers, and the
fully-read body. The sugar over HttpScope plus a drained Receive, so a
Handler never touches the async transport directly.
#Response
An outbound HTTP response: status, headers, and the full body. Mutable so
middleware can decorate it before the server serialises it into
HttpResponseStart + HttpResponseBody.
#Response::events
Serialise a Response into the outbound event pair a server sends: an
HttpResponseStart carrying status and headers (no trailers), then a single
HttpResponseBody with the whole body and more_body: false. The public
Response::events for callers that want the lowered form directly.
#Response::header
Look up the first response header matching name, same convention as
Request::header.
#Response::json
An application/json response whose body is the UTF-8 encoding of value
serialised with Json::stringify. The ergonomic constructor for a JSON reply.
#Response::new
Build a response from raw bytes.
#Scope
The connection scope: one value per HTTP request, WebSocket connection, or
lifespan run. It carries the immutable connection metadata a server hands to
an application, mirroring ASGI 3.0's scope dict as a typed sum.
#StreamingResponse
A streamed outbound response: the status line, headers, an ordered list of
body chunks each emitted as its own HttpResponseBody, and optional
trailing trailers. Models ASGI response streaming (multiple body messages
with more_body: true) and the http.response.trailers extension without
an async transport. events lowers it to the exact event sequence a server
would send. early_hints (the http.response.early_hint extension) are the
103 Early Hints messages emitted ahead of the final response, each element
a list of Link header values.
#StreamingResponse::events
Lower a streamed response to the outbound events a server sends: one
HttpResponseEarlyHint per early-hint message (before the response starts),
then an HttpResponseStart (with trailers set when any are present), then
one HttpResponseBody per chunk — more_body: true on all but the last —
and, if there are trailers, a terminating HttpResponseTrailers. An empty
chunks still yields a single empty final body, so the stream is always
well-formed.
#StreamingResponse::new
fn StreamingResponse::new(chunks~ : Array[Bytes], status? : Int, headers? : Array[(String, String)], trailers? : Array[(String, String)], early_hints? : Array[Array[String]]) -> StreamingResponseBuild a StreamingResponse. status defaults to 200, headers,
trailers and early_hints to empty; chunks is the ordered body, each
element becoming one HttpResponseBody frame.
#TestClient
pub(all) struct TestClient {
app : (Request) -> Array[Event]
root_path : String
base_headers : Array[(String, String)]
client : (String, Int)?
server : (String, Int)?
extensions : Extensions
}An in-process application driver — the ASGI TestClient — built on the
synchronous run_http_app core, so it needs no socket and runs on every
backend. It builds a synthetic http scope, feeds the request body in as
HttpRequest events, runs the application, and reassembles the outbound
stream into a TestResponse. app is the event-emitting application; the
new / from_stream constructors adapt a Handler / StreamHandler.
#TestClient::delete
fn TestClient::delete(self : TestClient, path : String, headers? : Array[(String, String)]) -> TestResponseDELETE path.
#TestClient::from_app
fn TestClient::from_app(app : (Request) -> Array[Event], root_path? : String, base_headers? : Array[(String, String)], client? : (String, Int)?, server? : (String, Int)?, extensions? : Extensions) -> TestClientBuild a TestClient from a raw event-emitting application (the shape
run_http_app drives). Defaults mirror a typical test harness: empty
root_path, no base headers, a ("testclient", 50000) client peer, a
("testserver", 80) server, and no advertised extensions.
#TestClient::from_stream
fn TestClient::from_stream(handler : (Request) -> StreamingResponse, root_path? : String, base_headers? : Array[(String, String)], client? : (String, Int)?, server? : (String, Int)?, extensions? : Extensions) -> TestClientBuild a TestClient from a streaming StreamHandler (multi-chunk body,
optional trailers).
#TestClient::get
fn TestClient::get(self : TestClient, path : String, headers? : Array[(String, String)]) -> TestResponseGET path.
#TestClient::head
fn TestClient::head(self : TestClient, path : String, headers? : Array[(String, String)]) -> TestResponseHEAD path.
#TestClient::new
fn TestClient::new(handler : (Request) -> Response, root_path? : String, base_headers? : Array[(String, String)], client? : (String, Int)?, server? : (String, Int)?, extensions? : Extensions) -> TestClientBuild a TestClient from a unary Handler.
#TestClient::patch
fn TestClient::patch(self : TestClient, path : String, body? : Bytes, headers? : Array[(String, String)]) -> TestResponsePATCH path with body.
#TestClient::post
fn TestClient::post(self : TestClient, path : String, body? : Bytes, headers? : Array[(String, String)]) -> TestResponsePOST path with body.
#TestClient::put
fn TestClient::put(self : TestClient, path : String, body? : Bytes, headers? : Array[(String, String)]) -> TestResponsePUT path with body.
#TestClient::request
fn TestClient::request(self : TestClient, http_method~ : String, path~ : String, headers? : Array[(String, String)], body? : Bytes, http_version? : String, chunks? : Array[Bytes]) -> TestResponseDrive one request through the application and capture the response. Splits
path into path + query string, merges the client's base_headers before
the per-request headers, builds an http scope (carrying the client's
root_path / peers / advertised extensions), feeds the body in, runs the
app, and reassembles the outbound stream. Pass chunks to stream the request
body as several HttpRequest events.
#TestClient::websocket
fn TestClient::websocket(self : TestClient, path~ : String, handler~ : WebSocketHandler, send? : Array[WsMessage], headers? : Array[(String, String)], subprotocols? : Array[String], disconnect? : Int?) -> WsTestSessionDrive a WebSocketHandler through a full connection in-process and capture
the result. Opens a WebSocketConnect, feeds each send message in as a
WebSocketReceive, then (unless disconnect is None) a
WebSocketDisconnect with the given close code, runs the handler through the
synchronous ws_run core, and reassembles the server's outbound frames into a
WsTestSession. No socket — testable on every backend, the WebSocket
counterpart of request.
#TestClient::websocket_app
fn TestClient::websocket_app(self : TestClient, path~ : String, app~ : (WebSocketScope, Array[Event]) -> Array[Event], send? : Array[WsMessage], headers? : Array[(String, String)], subprotocols? : Array[String], disconnect? : Int?) -> WsTestSessionDrive a general (WebSocketScope, Array[Event]) -> Array[Event] application
through a full connection in-process. Like websocket, but for an app that
consumes the whole inbound stream directly (the ws_run_app escape hatch)
rather than the connect/receive/disconnect fold.
#TestResponse
pub(all) struct TestResponse {
status : Int
headers : Array[(String, String)]
body : Bytes
trailers : Array[(String, String)]
pushes : Array[PushPromise]
pathsend : String?
zerocopysend : ZeroCopySend?
debug : Array[Json]
early_hints : Array[Array[String]]
} derive(Eq)The materialised result of driving an application in-process: the response
status and headers, the body reassembled from every HttpResponseBody
chunk, the trailing headers gathered from HttpResponseTrailers, any push
promises, the pathsend path if the app used the path-send extension, the
last zerocopysend handoff, every debug info payload, and the
early_hints (each a 103 message's Link values). The captured,
sans-transport analog of what a real client would observe.
#TestResponse::header
First response header matching name (ASGI lowercased-name convention).
#TestResponse::json
The response body parsed as JSON. Raises @json.ParseError if the body is
not valid JSON, mirroring a real client's .json().
#TestResponse::text
The response body decoded as UTF-8 (lossy: invalid sequences become the
replacement character), for asserting on text responses.
#TestResponse::trailer
First trailing header matching name.
#TlsExtension
The tls extension's per-connection data (ASGI TLS extension). Present in a
scope's extensions only when the connection is TLS-terminated by the
server. Certificates are PEM text; tls_version / cipher_suite are the
numeric IANA identifiers, None when the server does not expose them.
#WebSocketHandler
A synchronous WebSocket application in the connect / receive / disconnect
shape, the WebSocket analog of the http Handler. on_connect decides the
handshake from the scope; on_receive maps each inbound WsMessage to the
frames to send back (it may Close); on_disconnect runs when the client
goes away, carrying the close code and the optional close reason (ASGI
2.5). Driven in-process by ws_run and the
TestClient, so accept/subprotocol/echo/close logic is testable on every
backend without an async socket — the faithful synchronous core the async
server (mooncat) lifts onto AsgiApp.
#WebSocketHandler::echo
An echo handler: accept the handshake (optionally negotiating subprotocol),
then send every received message straight back — text as text, binary as
binary. The canonical WebSocket smoke test.
#WebSocketHandler::new
fn WebSocketHandler::new(on_connect? : (WebSocketScope) -> WsAccept, on_receive? : (WsMessage) -> Array[WsSend], on_disconnect? : (Int, String?) -> Array[WsSend]) -> WebSocketHandlerBuild a WebSocketHandler. on_connect defaults to accepting the handshake
with no chosen subprotocol and no extra headers; on_receive and
on_disconnect default to doing nothing. Callers override only the phases
they care about.
#WebSocketScope
pub(all) struct WebSocketScope {
http_version : String
scheme : String
path : String
raw_path : Bytes
query_string : Bytes
root_path : String
headers : Array[(String, String)]
client : (String, Int)?
server : (String, Int)?
subprotocols : Array[String]
asgi : AsgiVersion
extensions : Extensions
state : Map[String, Json]
}WebSocket connection scope (ASGI type == "websocket"). scheme is
"ws"/"wss"; subprotocols are the client-offered values. Carries the
same asgi handshake and extensions capabilities as an http scope.
#WebSocketScope::new
fn WebSocketScope::new(path~ : String, http_version? : String, scheme? : String, raw_path? : Bytes, query_string? : Bytes, root_path? : String, headers? : Array[(String, String)], client? : (String, Int)?, server? : (String, Int)?, subprotocols? : Array[String], asgi? : AsgiVersion, extensions? : Extensions, state? : Map[String, Json]) -> WebSocketScopeBuild a WebSocketScope with ASGI's usual defaults filled in — scheme
"ws", empty query/headers/subprotocols/state, the default asgi
handshake, and no extensions. raw_path defaults to the UTF-8 encoding of
path.
#WsAccept
The application's answer to a WebSocketConnect, mirroring the three replies
ASGI allows to an opening handshake: Accept it (optionally choosing a
subprotocol and adding response headers), Reject it with a bare close
code (ASGI closes the handshake with websocket.close), or DenyHttp it with
a full HTTP response (the websocket.http.response extension — a real status
- headers + body instead of a bare close).
#WsMessage
A message crossing a WebSocket in either direction: a UTF-8 Text frame or a
Binary frame. The ergonomic form of WebSocketReceive / WebSocketSendText
/ WebSocketSendBytes, so a WebSocketHandler reasons over messages instead
of raw events.
#WsSend
pub(all) enum WsSend {
SendText(String)
SendBinary(Bytes)
Close(code~ : Int, reason~ : String)
} derive(Eq)An outbound action a WebSocketHandler takes while the connection is open:
send a SendText / SendBinary frame, or Close the connection with a code
and reason. A Close ends the handler's send stream — the driver stops
pulling further inbound messages, mirroring a server that has closed the
socket.
#WsTestSession
pub(all) struct WsTestSession {
accepted : Bool
subprotocol : String?
accept_headers : Array[(String, String)]
messages : Array[WsMessage]
closed : Bool
close_code : Int?
close_reason : String?
denial : TestResponse?
} derive(Eq)The materialised result of driving a WebSocket connection in-process: whether
the handshake was accepted, the negotiated subprotocol and accept_headers,
every server→client message (messages), whether the server closed and with
what close_code / close_reason, and — when the handshake was denied with
the websocket.http.response extension — the captured HTTP denial response.
The WebSocket analog of TestResponse.
#WsTestSession::header
First accept-response header matching name.
#WsTestSession::texts
The server→client messages that were text frames, decoded to their strings
(binary frames are skipped). The ergonomic assertion target for an echo/chat
exchange.
#ZeroCopySend
A http.response.zerocopysend message captured by the TestClient: the open
file descriptor the app handed off, and the optional byte offset / count.
The sans-transport analog of the server performing the zero-copy send.
#compose
Compose middlewares over a base handler. The first element is the outermost
wrapper, matching registration order.
#run_conformance
Run the ASGI 3.0 conformance harness: a table-driven battery that drives every
Event variant and every Scope field through run_http, ws_run, and the
TestClient, asserting round-trip fidelity — a value put in comes back
unchanged, and no two distinct events or scope shapes are confused — and a
negative table that asserts validate_events rejects every malformed ordering
(a body before the response starts, a websocket frame before the handshake, a
lifespan shutdown reply before startup, and the rest) with the exact
violation. Returns a ConformanceReport naming any check that failed, so the
suite (and any downstream server) can assert ok().
#run_http
The synchronous counterpart of to_asgi: drive a Handler over an already
materialised inbound event sequence and return the outbound events a server
would send — [HttpResponseStart, HttpResponseBody] for an http scope, []
otherwise. A thin run_http_app wrapper over Response::events, the
sans-transport core to_asgi mirrors with async receive/send.
#run_http_app
The Request-level sans-transport core: drain the http request body from
inbound, hand the assembled Request to app, and return the outbound
events app emits. The ergonomic wrapper over run_http_scoped for apps
that only need the request line, headers, and body — every server and the
TestClient drive a Handler through it. Non-http scopes yield [].
#run_http_scoped
The scope-aware sans-transport core: drain the http request body from
inbound (accumulating HttpRequest chunks until more_body is false) and
hand app the full HttpScope alongside the assembled body, returning the
outbound events app emits. This is the seam a framework binds to — a
framework reads what the ergonomic Request drops: root_path (for mounted
sub-apps), extensions (to gate a feature on what the server advertises),
client/server peers, the asgi handshake, and state (the map a
lifespan startup seeds and the server copies onto every request scope). It is
the synchronous analog of the ASGI (scope, receive, send) callable for the
common drain-then-handle shape; run_http_app is the Request-level wrapper
over it. Non-http scopes yield [].
#run_http_stream
Drive a streaming StreamHandler over an inbound event sequence, returning
the full outbound stream — HttpResponseStart, one HttpResponseBody per
chunk (more_body: true on all but the last), and a trailing
HttpResponseTrailers when the response carries trailers. The streaming
counterpart of run_http.
#run_lifespan
Drive a LifespanHandler over a materialised inbound event stream, folding it
into the outbound replies a server would send. LifespanStartup runs
on_startup and emits LifespanStartupComplete or LifespanStartupFailed; a
failed startup ends the run, since ASGI has the server abort the boot and
never send lifespan.shutdown. LifespanShutdown runs on_shutdown and
emits the matching shutdown reply. The handler mutates scope.state in place
during startup, exactly as an ASGI app populates scope["state"]. This is the
synchronous lifespan core mirroring run_http / ws_run; a non-lifespan
scope yields [].
#to_asgi
Lift a synchronous Handler onto the load-bearing AsgiApp the server binds
to. For an http scope it drains the request body — looping receive() and
accumulating HttpRequest chunks until more_body is false — assembles a
Request, runs the handler, then emits HttpResponseStart followed by a
single HttpResponseBody. Non-http scopes (websocket, lifespan) are no-ops:
this sugar covers request→response handlers only. Shares its drain, request
assembly, and response serialisation with run_http, which tests the same
logic without the async transport.
#validate_events
Validate an outbound event stream against the ordering rules for its scope,
dispatching to the http / websocket / lifespan validator. The public entry a
server calls to check an application's emissions before writing them to the
wire.
#validate_http_response
Validate the outbound event stream an application emits for an http request,
against ASGI's http response ordering: at most one HttpResponseStart, no
body or pathsend/zerocopysend before it, early hints only ahead of it, a body
stream that terminates once (more_body: false), trailers only when the start
promised them and only after the body completes, and nothing after the
response is fully sent. HttpResponseDebug carries no protocol meaning and is
accepted anywhere; HttpResponsePush is accepted before or during the
response. Returns the first violation, or None for a well-formed complete
response.
#validate_lifespan_replies
Validate the outbound replies an application emits for a lifespan run: a
startup reply (LifespanStartupComplete / LifespanStartupFailed) before a
shutdown reply (LifespanShutdownComplete / LifespanShutdownFailed), each
phase answered at most once. Returns the first violation, or None.
#validate_ws_response
Validate the outbound event stream an application emits for a websocket
connection, against ASGI's handshake ordering: the connect must be answered
with an WebSocketAccept, a WebSocketClose, or a denial
(WebSocketHttpResponseStart + body); frames are only legal once accepted;
nothing follows a close or a completed denial; a denial cannot mix with an
accept. Returns the first violation, or None for a well-formed stream.
#ws_run
Drive a WebSocketHandler over an inbound event sequence, returning the
outbound events a server would send. The WebSocket counterpart of run_http:
a WebSocket scope is driven through drive_ws; any other scope yields [],
since this sugar covers websocket connections only.
#ws_run_app
The general sans-transport WebSocket core: hand the whole inbound event
stream and the WebSocketScope to app and return the outbound events it
emits. The escape hatch under ws_run for applications whose control flow is
not the connect/receive/disconnect fold — an app is free to inspect every
scope field (subprotocols, headers, extensions, state) and emit any sequence.
Non-websocket scopes yield []. The WebSocket analog of run_http_app.
MoonBit-dialect ASGI 3.0 — the load-bearing server↔app SEAM (Scope / Receive / Send) that the moon* full-stack web suite (mooncat, moonapi, moonrpc, moongql, moonzero) is built around.
asgimoonbitwebserver-interfaceasynchttp
0.7.0
Apache-2.0
Updated 17 days ago
608 downloads