Ohkami

Ohkami - [狼] wolf in Japanese - is a performant, declarative, and runtime-flexible web framework for Rust.

• macro-less and type-safe APIs for declarative, ergonomic code
• runtime-flexible ： tokio, smol, nio, glommio, monoio, compio and worker (Cloudflare Workers), lambda (AWS Lambda)
• good performance, no-network testing, well-structured middlewares, Server-Sent Events, WebSocket, highly integrated OpenAPI document generation, ...

Quick Start

1. Add to dependencies :

[dependencies]
ohkami = { version = "0.24", features = ["rt_tokio"] }
tokio  = { version = "1",    features = ["full"] }

2. Write your first code with Ohkami : examples/quick_start

use ohkami::{Ohkami, Route};
use ohkami::claw::{Path, status};

async fn health_check() -> status::NoContent {
    status::NoContent
}

async fn hello(Path(name): Path<&str>) -> String {
    format!("Hello, {name}!")
}

#[tokio::main]
async fn main() {
    Ohkami::new((
        "/healthz"
            .GET(health_check),
        "/hello/:name"
            .GET(hello),
    )).howl("localhost:3000").await
}

3. Run and check the behavior :

$ cargo run

$ curl http://localhost:3000/healthz
$ curl http://localhost:3000/hello/your_name
Hello, your_name!

Core APIs

Ohkami

Ohkami is the main entry point of Ohkami application: a collection of Routes and Fangs, and provides .howl()/.howls() method to run the application.

Ohkami::new((
    // global fangs
    Fang1,
    Fang2,
    // routes
    "/hello"
        .GET(hello_handler)
        .POST(hello_post_handler),
    "/goodbye"
        .GET((
            // local fangs
            Fang3,
            Fang4,
            goodbye_handler // handler
        )),
)).howl("localhost:3000").await;

.howls() (tls feature only) is used to run Ohkami with TLS (HTTPS) support upon rustls ecosystem.

howl(s) supports graceful shutdown by Ctrl-C ( SIGINT ) on native runtimes.

Route

Route is the core trait to define Ohkami's routing:

• .GET(), .POST(), .PUT(), .PATCH(), .DELETE(), .OPTIONS() to define API endpoints
• .By({another Ohkami}) to nest Ohkamis
• .Mount({directory path}) to serve static directory (pre-compressed files with gzip, deflate, br, zstd are supported)

Here GET, POST, etc. takes a handler function:

async fn({FromRequest type},*) -> {IntoResponse type}

On native runtimes, whole a handler must be Send + Sync + 'static and the return future must be Send + 'static.

fangs

Ohkami's request handling system is called fang; all handlers and middlewares are built on it.

/* simplified for description */

pub trait Fang<Inner: FangProc> {
    type Proc: FangProc;
    fn chain(&self, inner: Inner) -> Self::Proc;
}

pub trait FangProc {
    async fn bite<'b>(&'b self, req: &'b mut Request) -> Response;
}

built-ins:

• BasicAuth, Cors, Csrf, Jwt (authentication/security)
• Context (reuqest context)
• Enamel (security headers; experimantal)
• Timeout (handling timeout; native runtimes only)
• openapi::Tag (tag for OpenAPI document generation; openapi feature only)

Ohkami provides FangAction utility trait to implement Fang trait easily:

/* simplified for description */

pub trait FangAction {
    async fn fore<'a>(&'a self, req: &'a mut Request) -> Result<(), Response> {
        // default implementation is empty
        Ok(())
    }
    
    async fn back<'a>(&'a self, res: &'a mut Response) {
        // default implementation is empty
    }
}

Additionally, you can apply fangs both as global fangs to an Ohkami or as local fangs to a specific handler (described below).

claws

Ohkami provides claw API: handler parts designed for declarative way to extract request data and construct response data:

• content - typed content {extracted from request / for response} of specific format
  • built-ins: Json<T>, Text<T>, Html<T>, UrlEncoded<T>, Multipart<T>
• param - typed parameters extracted from request
  • built-ins: Path<P>, Query<T>
• header - types for specific header extracted from request
  • built-ins: types for standard request headers
• status - types for response with specific status code
  • built-ins: types for standard response status codes

( here T means a type that implements serde::Deserialize for request and serde::Serialize for response, and P means a type that implements FromParam or a tuple of such types. )

The number of path parameters extracted by Path is automatically asserted to be the same or less than the number of path parameters contained in the route path when the handler is registered to routing.

async fn handler0(
    Path(param): Path<FromParamType>,
) -> Json<SerializeType> {
    // ...
}

async fn handler1(
    Json(req): Json<Deserialize0>,
    Path((param0, param1)): Path<(FromParam0, FromParam1)>,
    Query(query): Query<Deserialize1>,
) -> status::Created<Json<Serialize0>> {
    // ...
}

Feature flags

"rt_tokio", "rt_smol", "rt_nio", "rt_glommio", "rt_monoio", "rt_compio" : native async runtime

• tokio v1.*.*
• smol v2.*.*
• nio v0.0.*
• glommio v0.9.*
• monoio v0.2.*
• compio v0.15.*

"rt_worker" : Cloudflare Workers

• worker v0.6.*

Ohkami has first-class support for Cloudflare Workers:

• #[worker] macro to define a Worker
• #[bindings], ws::SessionMap helper
• better DurableObject
• not require Send Sync bound for handlers or fangs
• worker_openapi.js script to generate OpenAPI document from #[worker] fn

And also maintains useful project template. Run :

npm create cloudflare ＜project dir＞ -- --template https://github.com/ohkami-rs/templates/worker

then ＜project dir＞ will have wrangler.jsonc, package.json and a Rust library crate.

#[ohkami::worker] async? fn({bindings}?) -> Ohkami is the Worker definition.

Local dev by npm run dev and deploy by npm run deploy !

See

• worker* temaplates in template repository
• worker* samples in samples directory
• #[worker]'s documentation comment in macro definitions

for wokring examples and detailed usage of #[worker] (and/or openapi).

"rt_lambda" : AWS Lambda

• lambda_runtime v0.14.* with tokio

Both Function URLs and API Gateway are supported, and WebSocket is not supported.

cargo lambda will be good partner. Let's run :

cargo lambda new ＜project dir＞ --template https://github.com/ohkami-rs/templates

lambda_runtime::run(your_ohkami) make you_ohkami run on Lambda Function.

Local dev by

cargo lambda watch

and deploy by

cargo lambda build --release [--compiler cargo] [and more]
cargo lambda deploy [--role ＜arn-of-a-iam-role＞] [and more]

See

• README of template
• Cargo Lambda document

for details.

"sse" : Server-Sent Events

Ohkami responds with HTTP/1.1 Transfer-Encoding: chunked.
Use some reverse proxy to do with HTTP/2,3.

use ohkami::{Ohkami, Route};
use ohkami::sse::DataStream;
use tokio::time::{sleep, Duration};

async fn handler() -> DataStream {
    DataStream::new(|mut s| async move {
        s.send("starting streaming...");
        for i in 1..=5 {
            sleep(Duration::from_secs(1)).await;
            s.send(format!("MESSAGE #{i}"));
        }
        s.send("streaming finished!");
    })
}

#[tokio::main]
async fn main() {
    Ohkami::new((
        "/sse".GET(handler),
    )).howl("localhost:3020").await
}

"ws" : WebSocket

use ohkami::{Ohkami, Route};
use ohkami::ws::{WebSocketContext, WebSocket, Message};

async fn echo_text(ctx: WebSocketContext<'_>) -> WebSocket {
    ctx.upgrade(|mut conn| async move {
        while let Ok(Some(Message::Text(text))) = conn.recv().await {
            conn.send(text).await.expect("failed to send text");
        }
    })
}

#[tokio::main]
async fn main() {
    Ohkami::new((
        "/ws".GET(echo_text),
    )).howl("localhost:3030").await
}

• On "rt_worker", both normal ( stateless ) WebSocket and WebSocket on Durable Object are available!
• On "rt_lambda", WebSocket is currently not supported.

"openapi" : OpenAPI document generation

"openapi" provides highly integrated OpenAPI support.

This enables macro-less, as consistent as possible OpenAPI document generation, where most of the consistency between document and behavior is automatically assured by Ohkami's internal work.

Only you have to

• Derive openapi::Schema for all your schema structs
• Make your Ohkami call .generate(openapi::OpenAPI { ... })

to generate consistent OpenAPI document.

You don't need to take care of writing accurate methods, paths, parameters, contents, ... for this OpenAPI feature; All they are done by Ohkami.

Of course, you can flexibly

• customize schemas by manual implemetation of Schema trait
• customize descriptions or other parts by #[operation] attribute and openapi_* hooks of FromRequest, IntoResponse, Fang (Action)
• put tags for grouping operations by openapi::Tag fang

use ohkami::{Ohkami, Route};
use ohkami::claw::{Json, status};
use ohkami::openapi;

// Derive `Schema` trait to generate
// the schema of this struct in OpenAPI document.
#[derive(Deserialize, openapi::Schema)]
struct CreateUser<'req> {
    name: &'req str,
}

#[derive(Serialize, openapi::Schema)]
// `#[openapi(component)]` to define it as component
// in OpenAPI document.
#[openapi(component)]
struct User {
    id: usize,
    name: String,
}

async fn create_user(
    Json(CreateUser { name }): Json<CreateUser<'_>>
) -> status::Created<Json<User>> {
    status::Created(Json(User {
        id: 42,
        name: name.to_string()
    }))
}

// (optionally) Set operationId, summary,
// or override descriptions by `operation` attribute.
#[openapi::operation({
    summary: "...",
    200: "List of all users",
})]
/// This doc comment is used for the
/// `description` field of OpenAPI document
async fn list_users() -> Json<Vec<User>> {
    Json(vec![])
}

#[tokio::main]
async fn main() {
    let o = Ohkami::new((
        "/users"
            .GET(list_users)
            .POST(create_user),
    ));

    // This make your Ohkami spit out `openapi.json`
    // ( the file name is configurable by `.generate_to` ).
    o.generate(openapi::OpenAPI {
        title: "Users Server",
        version: "0.1.0",
        servers: &[
            openapi::Server::at("localhost:5000"),
        ]
    });

    o.howl("localhost:5000").await;
}

• Currently, only JSON is supported as the document format.
• When the binary size matters, you should prepare a feature flag activating ohkami/openapi in your package, and put all your codes around openapi behind that feature via #[cfg(feature = ...)] or #[cfg_attr(feature = ...)].
• In rt_worker, .generate is not available because Ohkami can't have access to your local filesystem by wasm32 binary on Minifalre. So ohkami provides a CLI tool to generate document from #[ohkami::worker] Ohkami with openapi feature.

"tls"

HTTPS support up on rustls ecosystem.

• Call howls ( as https to http, wss to ws ) instead of howl to run with TLS.
• You must prepare your own certificate and private key files.
• Currently, only HTTP/1.1 over TLS is supported.

Example :

$ openssl req -x509 -newkey rsa:4096 -nodes -keyout server.key -out server.crt -days 365 -subj "/CN=localhost"

[dependencies]
ohkami = { version = "0.24", features = ["rt_tokio", "tls"] }
tokio  = { version = "1",    features = ["full"] }
rustls = { version = "0.23", features = ["ring"] }
rustls-pemfile = "2.2"

use ohkami::{Ohkami, Route};
use rustls::ServerConfig;
use rustls::pki_types::{CertificateDer, PrivateKeyDer};
use std::fs::File;
use std::io::BufReader;

async fn hello() -> &'static str {
    "Hello, secure ohkami!"
}

#[tokio::main]
async fn main() -> std::io::Result<()> {
    // Initialize rustls crypto provider
    rustls::crypto::ring::default_provider().install_default()
        .expect("Failed to install rustls crypto provider");

    // Load certificates and private key
    let cert_file = File::open("server.crt")?;
    let key_file = File::open("server.key")?;
    
    let cert_chain = rustls_pemfile::certs(&mut BufReader::new(cert_file))
        .map(|cd| cd.map(CertificateDer::from))
        .collect::<Result<Vec<_>, _>>()?;
    
    let key = rustls_pemfile::read_one(&mut BufReader::new(key_file))?
        .map(|p| match p {
            rustls_pemfile::Item::Pkcs1Key(k) => PrivateKeyDer::Pkcs1(k),
            rustls_pemfile::Item::Pkcs8Key(k) => PrivateKeyDer::Pkcs8(k),
            _ => panic!("Unexpected private key type"),
        })
        .expect("Failed to read private key");

    // Build TLS configuration
    let tls_config = ServerConfig::builder()
        .with_no_client_auth()
        .with_single_cert(cert_chain, key)
        .expect("Failed to build TLS configuration");

    // Create and run Ohkami with HTTPS
    Ohkami::new((
        "/".GET(hello),
    )).howls("0.0.0.0:8443", tls_config).await;
    
    Ok(())
}

$ cargo run

$ curl https://localhost:8443 --insecure  # for self-signed certificate
Hello, secure ohkami!

For localhost-testing with browser (or curl without --insecure), mkcert is highly recommended.

"nightly" : nightly-only functionalities

• try response
• internal performance optimizations

Snippets

Typed content

use ohkami::claw::{Json, status};
use ohkami::serde::{Deserialize, Serialize};

/* Deserialize for request */
#[derive(Deserialize)]
struct CreateUserRequest<'req> {
    name:     &'req str,
    password: &'req str,
}

/* Serialize for response */
#[derive(Serialize)]
struct User {
    name: String,
}

async fn create_user(
    Json(req): Json<CreateUserRequest<'_>>
) -> status::Created<Json<User>> {
    status::Created(Json(
        User {
            name: String::from(req.name)
        }
    ))
}

Typed params

use ohkami::{Ohkami, Route};
use ohkami::claw::{Path, Query, Json};
use ohkami::serde::{Deserialize, Serialize};

#[tokio::main]
async fn main() {
    Ohkami::new((
        "/hello/:name/:n"
            .GET(hello_n),
        "/hello/:name"
            .GET(hello),
        "/search"
            .GET(search),
    )).howl("localhost:5000").await
}

async fn hello(Path(name): Path<&str>) -> String {
    format!("Hello, {name}!")
}

async fn hello_n(
    Path((name, n)): Path<(&str, usize)>
) -> String {
    vec![format!("Hello, {name}!"); n].join(" ")
}

#[derive(Deserialize)]
struct SearchQuery<'q> {
    #[serde(rename = "q")]
    keyword: &'q str,
    lang:    &'q str,
}

#[derive(Serialize)]
struct SearchResult {
    title: String,
}

async fn search(
    Query(query): Query<SearchQuery<'_>>
) -> Json<Vec<SearchResult>> {
    Json(vec![
        SearchResult { title: String::from("ohkami") },
    ])
}

Middlewares

use ohkami::{Ohkami, Route, FangAction, Request, Response};

#[derive(Clone)]
struct GreetingFang(usize);

/* utility trait; automatically impl `Fang` trait */
impl FangAction for GreetingFang {
    async fn fore<'a>(&'a self, req: &'a mut Request) -> Result<(), Response> {
        let Self(id) = self;
        println!("[{id}] Welcome request!: {req:?}");
        Ok(())
    }
    async fn back<'a>(&'a self, res: &'a mut Response) {
        let Self(id) = self;
        println!("[{id}] Go, response!: {res:?}");
    }
}

#[tokio::main]
async fn main() {
    Ohkami::new((
        // register *global fangs* to an Ohkami
        GreetingFang(1),
        "/hello"
            .GET(|| async {"Hello, fangs!"})
            .POST((
                // register *local fangs* to a handler
                GreetingFang(2),
                || async {"I'm `POST /hello`!"}
            ))
    )).howl("localhost:3000").await
}

Database connection management with Context fang

use ohkami::{Ohkami, Route};
use ohkami::claw::status;
use ohkami::fang::Context;
use sqlx::postgres::{PgPoolOptions, PgPool};

#[tokio::main]
async fn main() {
    let pool = PgPoolOptions::new()
        .connect("postgres://ohkami:password@localhost:5432/db").await
        .expect("failed to connect");

    Ohkami::new((
        Context::new(pool),
        "/users".POST(create_user),
    )).howl("localhost:5050").await
}

async fn create_user(
    Context(pool): Context<'_, PgPool>,
) -> status::Created {
    //...

    status::Created(())
}

Typed errors

use ohkami::{Response, IntoResponse};
use ohkami::claw::{Path, Json};
use ohkami::serde::Serialize;
use ohkami::fang::Context;

enum MyError {
    Sqlx(sqlx::Error),
}
impl IntoResponse for MyError {
    fn into_response(self) -> Response {
        match self {
            Self::Sqlx(e) => Response::InternalServerError(),
        }
    }
}

#[derive(Serialize)]
struct User {
    id: u32,
    name: String,
}

async fn get_user(
    Path(id): Path<u32>,
    Context(pool): Context<'_, sqlx::PgPool>,
) -> Result<Json<User>, MyError> {
    let sql = r#"
        SELECT name FROM users WHERE id = $1
    "#;
    let name = sqlx::query_scalar::<_, String>(sql)
        .bind(id as i64)
        .fetch_one(pool)
        .await
        .map_err(MyError::Sqlx)?;

    Ok(Json(User { id, name }))
}

thiserror may improve such error conversion:

    let name = sqlx::query_salor_as::<_, String>(sql)
        .bind(id)
        .fetch_one(pool)
        // .await
        // .map_err(MyError::Sqlx)?;
        .await?;

Static directory serving

use ohkami::{Ohkami, Route};

#[tokio::main]
async fn main() {
    Ohkami::new((
        "/".Mount("./dist"),
    )).howl("0.0.0.0:3030").await
}

File upload

Multipart built-in claw and File helper:

use ohkami::claw::{status, content::{Multipart, File}};
use ohkami::serde::Deserialize;

#[derive(Deserialize)]
struct FormData<'req> {
    #[serde(rename = "account-name")]
    account_name: Option<&'req str>,
    pics: Vec<File<'req>>,
}

async fn post_submit(
    Multipart(data): Multipart<FormData<'_>>
) -> status::NoContent {
    println!("\n\
        ===== submit =====\n\
        [account name] {:?}\n\
        [  pictures  ] {} files (mime: [{}])\n\
        ==================",
        data.account_name,
        data.pics.len(),
        data.pics.iter().map(|f| f.mimetype).collect::<Vec<_>>().join(", "),
    );

    status::NoContent
}

Pack of Ohkamis

use ohkami::{Ohkami, Route};
use ohkami::claw::{Json, status};
use serde::Serialize;

#[derive(Serialize)]
struct User {
    name: String
}

async fn list_users() -> Json<Vec<User>> {
    Json(vec![
        User { name: String::from("actix") },
        User { name: String::from("axum") },
        User { name: String::from("ohkami") },
    ])
}

async fn create_user() -> status::Created<Json<User>> {
    status::Created(Json(User {
        name: String::from("ohkami web framework")
    }))
}

async fn health_check() -> status::NoContent {
    status::NoContent
}

#[tokio::main]
async fn main() {
    // ...

    let users_ohkami = Ohkami::new((
        "/"
            .GET(list_users)
            .POST(create_user),
    ));

    Ohkami::new((
        "/healthz"
            .GET(health_check),
        "/api/users"
            .By(users_ohkami), // nest by `By`
    )).howl("localhost:5000").await
}

Testing

use ohkami::{Ohkami, Route};
use ohkami::testing::*; // <--

fn hello_ohkami() -> Ohkami {
    Ohkami::new((
        "/hello".GET(|| async {"Hello, world!"}),
    ))
}

#[cfg(test)]
#[tokio::test]
async fn test_my_ohkami() {
    let t = hello_ohkami().test();

    let req = TestRequest::GET("/");
    let res = t.oneshot(req).await;
    assert_eq!(res.status(), Status::NotFound);

    let req = TestRequest::GET("/hello");
    let res = t.oneshot(req).await;
    assert_eq!(res.status(), Status::OK);
    assert_eq!(res.text(), Some("Hello, world!"));
}

DI by generics

use ohkami::{Ohkami, Route, Response, IntoResponse};
use ohkami::claw::{Json, Path};
use ohkami::fang::Context;
use ohkami::serde::Serialize;

//////////////////////////////////////////////////////////////////////
/// errors

enum MyError {
    Sqlx(sqlx::Error),
}
impl IntoResponse for MyError {
    fn into_response(self) -> Response {
        match self {
            Self::Sqlx(e) => Response::InternalServerError(),
        }
    }
}

//////////////////////////////////////////////////////////////////////
/// repository

trait UserRepository: Send + Sync + 'static {
    fn get_user_by_id(
        &self,
        id: i64,
    ) -> impl Future<Output = Result<UserRow, MyError>> + Send;
}

#[derive(sqlx::FromRow)]
struct UserRow {
    id: i64,
    name: String,
}

#[derive(Clone)]
struct PostgresUserRepository(sqlx::PgPool);
impl UserRepository for PostgresUserRepository {
    async fn get_user_by_id(&self, id: i64) -> Result<UserRow, MyError> {
        let sql = r#"
            SELECT id, name FROM users WHERE id = $1
        "#;
        sqlx::query_as::<_, UserRow>(sql)
            .bind(id)
            .fetch_one(&self.0)
            .await
            .map_err(MyError::Sqlx)
    }
}

//////////////////////////////////////////////////////////////////////
/// routes

#[derive(Serialize)]
struct User {
    id: u32,
    name: String,
}

async fn get_user<R: UserRepository>(
    Path(id): Path<u32>,
    Context(r): Context<'_, R>,
) -> Result<Json<User>, MyError> {
    let user_row = r.get_user_by_id(id as i64).await?;

    Ok(Json(User {
        id: user_row.id as u32,
        name: user_row.name,
    }))
}

fn users_ohkami<R: UserRepository>() -> Ohkami {
    Ohkami::new((
        "/:id".GET(get_user::<R>),
    ))
}

//////////////////////////////////////////////////////////////////////
/// entry point

#[tokio::main]
async fn main() {
    let pool = sqlx::PgPool::connect("postgres://ohkami:password@localhost:5432/db")
        .await
        .expect("failed to connect to database");
    
    Ohkami::new((
        Context::new(PostgresUserRepository(pool)),
        "/users".By(users_ohkami::<PostgresUserRepository>()),
    )).howl("0.0.0.0:4040").await
}

Supported protocols

• HTTP/1.1
• HTTP/2
• HTTP/3
• HTTPS
• Server-Sent Events
• WebSocket

MSRV ( Minimum Supported Rust Version )

Latest stable

License

Ohkami is licensed under MIT LICENSE ( LICENSE or https://opensource.org/licenses/MIT ).