Struct Conn

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pub struct Conn { /* private fields */ }

Expand description

§A Trillium HTTP connection.

A Conn represents both the request and response of a http connection, as well as any application state that is associated with that connection.

§`with_{attribute}` naming convention

A convention that is used throughout trillium is that any interface that is named with_{attribute} will take ownership of the conn, set the attribute and return the conn, enabling chained calls like:

use trillium_testing::TestServer;

struct MyState(&'static str);
async fn handler(mut conn: trillium::Conn) -> trillium::Conn {
    conn.with_response_header("content-type", "text/plain")
        .with_state(MyState("hello"))
        .with_body("hey there")
        .with_status(418)
}

let app = TestServer::new(handler).await;
app.get("/")
    .await
    .assert_status(418)
    .assert_body("hey there")
    .assert_header("content-type", "text/plain");

If you need to set a property on the conn without moving it, set_{attribute} associated functions will be your huckleberry, as is conventional in other rust projects.

§State

Every trillium Conn contains a state type which is a set that contains at most one element for each type. State is the primary way that handlers attach data to a conn as it passes through a tuple handler. State access should generally be implemented by libraries using a private type and exposed with a ConnExt trait. See library patterns for more elaboration and examples.

§In relation to `trillium_http::Conn`

trillium::Conn is currently implemented as an abstraction on top of a trillium_http::Conn. In particular, trillium::Conn boxes the transport so that application code can be written without transport generics. See Transport for further reading on this.

Implementations§

Source §

impl Conn

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pub fn ok(self, body: impl Into<Body>) -> Conn

Conn::ok is a convenience function for the common pattern of setting a body and a 200 status in one call. It is exactly identical to conn.with_status(200).with_body(body).halt()

See Body::new_streaming and Body::new_with_trailers to construct a body from an AsyncRead or BodySource

use trillium::Conn;
use trillium_testing::TestServer;

let handler = |conn: Conn| async move { conn.ok("hello") };
let app = TestServer::new(handler).await;
app.get("/").await.assert_ok().assert_body("hello");

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pub fn status(&self) -> Option<Status>

returns the response status for this Conn, if it has been set.

use trillium::Conn;
use trillium_testing::TestServer;

let handler = |mut conn: Conn| async move {
    assert!(conn.status().is_none());
    conn.set_status(200);
    assert_eq!(conn.status().unwrap(), trillium_http::Status::Ok);
    conn.ok("pass")
};
let app = TestServer::new(handler).await;
app.get("/").await.assert_ok();

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pub fn set_status(&mut self, status: impl TryInto<Status>) -> &mut Conn

assigns a status to this response. see Conn::status for example usage

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pub fn with_status(self, status: impl TryInto<Status>) -> Conn

sets the response status for this Conn and returns it. note that this does not set the halted status.

use trillium::Conn;
use trillium_testing::TestServer;

let handler = |conn: Conn| async move { conn.with_status(418) };
let app = TestServer::new(handler).await;
app.get("/").await.assert_status(418);

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pub fn with_body(self, body: impl Into<Body>) -> Conn

Sets the response body from any impl Into<Body> and returns the Conn for fluent chaining. Note that this does not set the response status or halted. See Conn::ok for a function that does both of those.

See Body::new_streaming and Body::new_with_trailers to construct a body from an AsyncRead or BodySource

use trillium::Conn;
use trillium_testing::TestServer;

let handler = |conn: Conn| async move { conn.with_body("hello") };
let app = TestServer::new(handler).await;
app.get("/").await.assert_body_contains("hello");

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pub fn set_body(&mut self, body: impl Into<Body>) -> &mut Conn

Sets the response body from any impl Into<Body>. Note that this does not set the response status or halted.

See Body::new_streaming and Body::new_with_trailers to construct a body from an AsyncRead or BodySource

use trillium::Conn;
use trillium_testing::TestServer;

let handler = |mut conn: Conn| async move {
    conn.set_body("hello");
    assert_eq!(conn.response_len(), Some(5));
    conn.ok("pass")
};
let app = TestServer::new(handler).await;
app.get("/").await.assert_ok();

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pub fn take_response_body(&mut self) -> Option<Body>

Removes the response body from the Conn

use trillium::Conn;
use trillium_testing::TestServer;

let handler = |mut conn: Conn| async move {
    conn.set_body("hello");
    let body = conn.take_response_body().unwrap();
    assert_eq!(body.len(), Some(5));
    assert_eq!(conn.response_len(), None);
    conn.ok("pass")
};
let app = TestServer::new(handler).await;
app.get("/").await.assert_ok();

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pub fn response_body(&self) -> Option<&Body>

Borrows the response body from the Conn

use trillium::Conn;
use trillium_testing::TestServer;

let handler = |mut conn: Conn| async move {
    conn.set_body("hello");
    let body = conn.response_body().unwrap();
    assert_eq!(body.len(), Some(5));
    assert!(body.is_static());
    assert_eq!(body.static_bytes(), Some(&b"hello"[..]));
    conn.ok("pass")
};
let app = TestServer::new(handler).await;
app.get("/").await.assert_ok();

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pub fn state<T>(&self) -> Option<&T>
where T: Send + Sync + 'static,

Attempts to retrieve a &T from the state set

use trillium::Conn;
use trillium_testing::TestServer;

struct Hello;
let handler = |mut conn: Conn| async move {
    assert!(conn.state::<Hello>().is_none());
    conn.insert_state(Hello);
    assert!(conn.state::<Hello>().is_some());
    conn.ok("pass")
};
let app = TestServer::new(handler).await;
app.get("/").await.assert_ok();

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pub fn state_mut<T>(&mut self) -> Option<&mut T>
where T: Send + Sync + 'static,

Attempts to retrieve a &mut T from the state set

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pub fn insert_state<T>(&mut self, state: T) -> Option<T>
where T: Send + Sync + 'static,

Inserts a new type into the state set. See Conn::state for an example.

Returns the previously-set instance of this type, if any

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pub fn with_state<T>(self, state: T) -> Conn
where T: Send + Sync + 'static,

Puts a new type into the state set and returns the Conn. this is useful for fluent chaining

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pub fn take_state<T>(&mut self) -> Option<T>
where T: Send + Sync + 'static,

Removes a type from the state set and returns it, if present

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pub fn state_entry<T>(&mut self) -> Entry<'_, T>
where T: Send + Sync + 'static,

Returns an Entry for the state typeset that can be used with functions like Entry::or_insert, Entry::or_insert_with, Entry::and_modify, and others.

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pub fn shared_state<T>(&self) -> Option<&T>
where T: Send + Sync + 'static,

Attempts to borrow a T from the immutable shared state set

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pub async fn request_body(&mut self) -> ReceivedBody<'_, Box<dyn Transport>>

Returns a ReceivedBody that references this Conn. The Conn retains all data and holds the singular transport, but the ReceivedBody provides an interface to read body content.

See also: Conn::request_body_string for a convenience function when the content is expected to be utf8.

§Examples

use trillium::Conn;
use trillium_testing::TestServer;

let handler = |mut conn: Conn| async move {
    let request_body = conn.request_body().await;
    assert_eq!(request_body.content_length(), Some(12));
    assert_eq!(request_body.read_string().await.unwrap(), "request body");
    conn.ok("pass")
};
let app = TestServer::new(handler).await;
app.post("/").with_body("request body").await.assert_ok();

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pub async fn request_body_string(&mut self) -> Result<String, Error>

Convenience function to read the content of a request body as a String.

§Errors

This will return an error variant if either there is an IO failure on the underlying transport or if the body content is not a utf8 string.

§Examples

use trillium::Conn;
use trillium_testing::TestServer;

let handler = |mut conn: Conn| async move {
    assert_eq!(conn.request_body_string().await.unwrap(), "request body");
    conn.ok("pass")
};
let app = TestServer::new(handler).await;
app.post("/").with_body("request body").await.assert_ok();

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pub fn response_len(&self) -> Option<u64>

if there is a response body for this conn and it has a known fixed length, it is returned from this function

use trillium::Conn;
use trillium_testing::TestServer;

let handler = |conn: Conn| async move { conn.with_body("hello") };
let app = TestServer::new(handler).await;
app.get("/").await.assert_body_contains("hello");

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pub fn method(&self) -> Method

returns the request method for this conn.

use trillium::Conn;
use trillium_http::Method;
use trillium_testing::TestServer;

let handler = |conn: Conn| async move {
    assert_eq!(conn.method(), Method::Get);
    conn.ok("pass")
};
let app = TestServer::new(handler).await;
app.get("/").await.assert_ok();

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pub fn response_headers(&self) -> &Headers

Borrow the response headers

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pub fn response_headers_mut(&mut self) -> &mut Headers

Mutably borrow the response headers

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pub fn request_headers(&self) -> &Headers

Borrow the request headers

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pub fn request_headers_mut(&mut self) -> &mut Headers

Mutably borrow request headers

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pub fn request_trailers(&self) -> Option<&Headers>

Borrow the request trailers, if any

Trailers are only populated after reading a request body that includes trailers to completion.

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pub fn with_response_header( self, header_name: impl Into<HeaderName<'static>>, header_value: impl Into<HeaderValues>, ) -> Conn

Insert a header name and value/values into the response headers and return the conn.

For a slight performance improvement, use a KnownHeaderName as the first argument instead of a str.

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pub fn insert_response_header( &mut self, header_name: impl Into<HeaderName<'static>>, header_value: impl Into<HeaderValues>, )

Insert a header name and value/values into the response headers.

For a slight performance improvement, use a KnownHeaderName.

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pub fn path(&self) -> &str

returns the path for this request. note that this may not represent the entire http request path if running nested routers.

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pub fn querystring(&self) -> &str

returns query part of the request path

use trillium::Conn;
use trillium_testing::TestServer;

let handler = |conn: Conn| async move {
    let querystring = conn.querystring();
    if querystring == "c&d=e" {
        conn.ok("has query")
    } else {
        conn.ok("no query")
    }
};
let app = TestServer::new(handler).await;
app.get("/a/b?c&d=e").await.assert_body("has query");
app.get("/a/b").await.assert_body("no query");

§Parsing

Trillium does not include a querystring parsing library, as there is no universal standard for querystring encodings of arrays, but several library options exist, inluding:

QueryStrong (by the author of trillium) serde_qs querystring serde_querystring

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pub const fn halt(self) -> Conn

sets the halted attribute of this conn, preventing later processing in a given tuple handler. returns the conn for fluent chaining

use trillium::Conn;
use trillium_testing::TestServer;

let handler = |conn: Conn| async move { conn.halt() };
let app = TestServer::new(handler).await;
app.get("/").await.assert_status(404);

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pub const fn set_halted(&mut self, halted: bool) -> &mut Conn

sets the halted attribute of this conn. see Conn::halt.

use trillium::Conn;
use trillium_testing::TestServer;

let handler = |mut conn: Conn| async move {
    assert!(!conn.is_halted());
    conn.set_halted(true);
    assert!(conn.is_halted());
    conn.ok("pass")
};
let app = TestServer::new(handler).await;
app.get("/").await.assert_ok();

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pub const fn is_halted(&self) -> bool

retrieves the halted state of this conn. see Conn::halt.

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pub fn is_secure(&self) -> bool

predicate function to indicate whether the connection is secure. note that this does not necessarily indicate that the transport itself is secure, as it may indicate that trillium_http is behind a trusted reverse proxy that has terminated tls and provided appropriate headers to indicate this.

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pub fn start_time(&self) -> Instant

The Instant that the first header bytes for this conn were received, before any processing or parsing has been performed.

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pub fn into_inner<T>(self) -> Conn<T>
where T: Transport,

transforms this trillium::Conn into a trillium_http::Conn with the specified transport type. Please note that this will panic if you attempt to downcast from trillium’s boxed transport into the wrong transport type. Also note that this is a lossy conversion, dropping the halted state and any nested router path data.

§Panics

This will panic if you attempt to downcast to the wrong Transport type.

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pub fn peer_ip(&self) -> Option<IpAddr>

retrieves the remote ip address for this conn, if available.

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pub fn set_peer_ip(&mut self, peer_ip: Option<IpAddr>) -> &mut Conn

sets the remote ip address for this conn.

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pub fn push_path(&mut self, path: String)

for router implementations. pushes a route segment onto the path

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pub fn pop_path(&mut self)

for router implementations. removes a route segment onto the path

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pub async fn cancel_on_disconnect<'a, Fut>( &'a mut self, fut: Fut, ) -> Option<<Fut as Future>::Output>
where Fut: Future + Send + 'a,

Cancels and drops the future if reading from the transport results in an error or empty read

If the client disconnects from the conn’s transport, this function will return None. If the future completes without disconnection, this future will return Some containing the output of the future.

The use of this method is not advised if your connected http client employs pipelining (rarely seen in the wild), as it will buffer an unbounded number of requests

Note that the inner future cannot borrow conn, so you will need to clone or take any information needed to execute the future prior to executing this method.

§Example

async fn something_slow_and_cancel_safe() -> String {
    String::from("this was not actually slow")
}
async fn handler(mut conn: Conn) -> Conn {
    match conn
        .cancel_on_disconnect(async { something_slow_and_cancel_safe().await })
        .await
    {
        Some(returned_body) => conn.ok(returned_body),
        None => conn,
    }
}

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pub async fn is_disconnected(&mut self) -> bool

Check if the transport is connected by testing attempting to read from the transport

§Example

This is best to use at appropriate points in a long-running handler, like:

async fn handler(mut conn: Conn) -> Conn {
    for _ in 0..100 {
        if conn.is_disconnected().await {
            return conn;
        }
        something_slow_but_not_cancel_safe().await;
    }
    conn.ok("ok!")
}