doido-controller 0.0.9

Action Controller + routing + Tower middleware for Doido: handlers, Context, responses, filters, routes! DSL, sessions, and middleware stacks.
Documentation 
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use crate::cookies::CookieJar;
use crate::flash::Flash;
use crate::session::{CookieSessionStore, EncryptedCookieSessionStore, Session};
use axum::{
    body::Body,
    extract::{FromRequestParts, RawPathParams, Request},
    http::{header, HeaderValue, StatusCode},
    response::Response,
};
use doido_model::sea_orm::DatabaseConnection;
use serde::de::DeserializeOwned;
use serde::Serialize;
use std::collections::BTreeMap;

/// Maximum request body size accepted by [`Context::form`]/[`Context::body_json`].
const MAX_BODY_BYTES: usize = 2 * 1024 * 1024;

/// Cookie name for the encrypted session.
const SESSION_COOKIE: &str = "_doido_session";
/// Cookie name for the flash.
const FLASH_COOKIE: &str = "_doido_flash";

/// Per-request context passed to every action.
pub struct Context {
    pub(crate) parts: http::request::Parts,
    /// Taken (set to `None`) once read by [`form`](Self::form)/[`body_json`](Self::body_json).
    pub(crate) body: Option<Body>,
    /// Matched path parameters (e.g. `id` from `/posts/{id}`), in route order.
    pub(crate) path_params: Vec<(String, String)>,
    /// Encrypted session, loaded from the session cookie on first access.
    pub(crate) session: Option<Session>,
    /// Flash bag, loaded from the flash cookie on first access.
    pub(crate) flash: Option<Flash>,
    /// Snapshot of the incoming flash, used to sweep it after one request.
    pub(crate) flash_loaded: BTreeMap<String, String>,
    /// Cookie jar, built from the request `Cookie` header on first access.
    pub(crate) cookies: Option<CookieJar>,
}

impl Context {
    /// Central constructor used by the `#[controller]` macro. Splits the request,
    /// captures matched path params, and retains the body for later reads.
    pub async fn build(req: Request) -> Self {
        let (mut parts, body) = req.into_parts();
        let path_params = Self::extract_path_params(&mut parts).await;
        Self {
            parts,
            body: Some(body),
            path_params,
            session: None,
            flash: None,
            flash_loaded: BTreeMap::new(),
            cookies: None,
        }
    }

    async fn extract_path_params(parts: &mut http::request::Parts) -> Vec<(String, String)> {
        match RawPathParams::from_request_parts(parts, &()).await {
            Ok(params) => params
                .iter()
                .map(|(k, v)| (k.to_string(), v.to_string()))
                .collect(),
            Err(_) => Vec::new(),
        }
    }

    pub fn from_request_parts(parts: http::request::Parts) -> Self {
        Self {
            parts,
            body: None,
            path_params: Vec::new(),
            session: None,
            flash: None,
            flash_loaded: BTreeMap::new(),
            cookies: None,
        }
    }

    pub fn from_request(parts: http::request::Parts, body: Body) -> Self {
        Self {
            parts,
            body: Some(body),
            path_params: Vec::new(),
            session: None,
            flash: None,
            flash_loaded: BTreeMap::new(),
            cookies: None,
        }
    }

    /// The application's database connection (global pool installed at boot).
    pub fn db(&self) -> &'static DatabaseConnection {
        doido_model::pool::pool()
    }

    /// A matched path parameter by name, e.g. `ctx.param("id")` for `/posts/{id}`.
    pub fn param(&self, name: &str) -> Option<&str> {
        self.path_params
            .iter()
            .find(|(k, _)| k == name)
            .map(|(_, v)| v.as_str())
    }

    /// Deserialize a URL-encoded (form) request body. Consumes the body.
    pub async fn form<T: DeserializeOwned>(&mut self) -> doido_core::Result<T> {
        let bytes = self.read_body().await?;
        serde_urlencoded::from_bytes(&bytes)
            .map_err(|e| doido_core::anyhow::anyhow!("form deserialization failed: {e}"))
    }

    /// Deserialize a JSON request body. Consumes the body.
    pub async fn body_json<T: DeserializeOwned>(&mut self) -> doido_core::Result<T> {
        let bytes = self.read_body().await?;
        serde_json::from_slice(&bytes)
            .map_err(|e| doido_core::anyhow::anyhow!("JSON body deserialization failed: {e}"))
    }

    async fn read_body(&mut self) -> doido_core::Result<Vec<u8>> {
        let body = self
            .body
            .take()
            .ok_or_else(|| doido_core::anyhow::anyhow!("request body already consumed"))?;
        let bytes = axum::body::to_bytes(body, MAX_BODY_BYTES)
            .await
            .map_err(|e| doido_core::anyhow::anyhow!("failed to read request body: {e}"))?;
        Ok(bytes.to_vec())
    }

    /// Deserialize typed params from the request URI query string.
    pub fn params<T: serde::de::DeserializeOwned>(&self) -> doido_core::Result<T> {
        let query = self.parts.uri.query().unwrap_or("");
        serde_urlencoded::from_str(query)
            .map_err(|e| doido_core::anyhow::anyhow!("params deserialization failed: {e}"))
    }

    /// The query string as strong [`Params`](crate::params::Params), for
    /// `require`/`permit` allowlisting before use.
    pub fn query_params(&self) -> crate::params::Params {
        let query = self.parts.uri.query().unwrap_or("");
        let pairs: Vec<(String, String)> = serde_urlencoded::from_str(query).unwrap_or_default();
        let mut map = serde_json::Map::new();
        for (k, v) in pairs {
            map.insert(k, serde_json::Value::String(v));
        }
        crate::params::Params::new(serde_json::Value::Object(map))
    }

    /// Render a Tera view to an HTML 200 response.
    ///
    /// `template` is resolved by the global [`doido_view`] engine (installed at
    /// boot) against `app/views`, with the `.html.tera` suffix added — e.g.
    /// `"posts/index"` → `app/views/posts/index.html.tera`. A render failure (or
    /// an uninitialised engine) yields a `500`.
    pub fn render(&self, template: &str, data: serde_json::Value) -> Response {
        match doido_view::render(template, &data) {
            Ok(html) => Response::builder()
                .status(StatusCode::OK)
                .header(header::CONTENT_TYPE, "text/html; charset=utf-8")
                .body(Body::from(html))
                .expect("valid html response"),
            Err(error) => {
                tracing::error!(%error, template, "view render failed");
                Response::builder()
                    .status(StatusCode::INTERNAL_SERVER_ERROR)
                    .body(Body::from("Internal Server Error"))
                    .expect("valid 500 response")
            }
        }
    }

    /// Return a JSON 200 response.
    pub fn json<T: Serialize>(&self, data: T) -> Response {
        let body = serde_json::to_vec(&data).unwrap_or_default();
        Response::builder()
            .status(StatusCode::OK)
            .header(header::CONTENT_TYPE, "application/json")
            .body(Body::from(body))
            .unwrap()
    }

    /// Return a 302 redirect.
    pub fn redirect_to(&self, location: impl AsRef<str>) -> Response {
        Response::builder()
            .status(StatusCode::FOUND)
            .header(
                header::LOCATION,
                HeaderValue::from_str(location.as_ref()).unwrap(),
            )
            .body(Body::empty())
            .unwrap()
    }

    /// Return a response with an explicit status code and empty body.
    /// `code` must be a valid HTTP status code (100–999).
    pub fn status(&self, code: u16) -> Response {
        Response::builder()
            .status(code)
            .body(Body::empty())
            .unwrap()
    }

    /// Get a request header by name (lowercase).
    pub fn header(&self, name: &str) -> Option<&http::HeaderValue> {
        self.parts.headers.get(name)
    }

    /// Send raw bytes as a response (Rails `send_data`). When `filename` is set,
    /// a `Content-Disposition: attachment` header prompts a download.
    pub fn send_data(&self, data: Vec<u8>, content_type: &str, filename: Option<&str>) -> Response {
        let mut builder = Response::builder()
            .status(StatusCode::OK)
            .header(header::CONTENT_TYPE, content_type);
        if let Some(name) = filename {
            builder = builder.header(
                header::CONTENT_DISPOSITION,
                format!("attachment; filename=\"{name}\""),
            );
        }
        builder
            .body(Body::from(data))
            .expect("valid send_data response")
    }

    /// Send a file's contents as a response (Rails `send_file`). `content_type`
    /// defaults to `application/octet-stream`; the file name is used for the
    /// download disposition.
    pub async fn send_file(
        &self,
        path: impl AsRef<std::path::Path>,
        content_type: Option<&str>,
    ) -> doido_core::Result<Response> {
        let path = path.as_ref();
        let data = tokio::fs::read(path)
            .await
            .map_err(|e| doido_core::anyhow::anyhow!("send_file failed to read {path:?}: {e}"))?;
        let content_type = content_type.unwrap_or("application/octet-stream");
        let filename = path.file_name().and_then(|n| n.to_str());
        Ok(self.send_data(data, content_type, filename))
    }

    /// The negotiated response [`Format`](crate::respond::Format): a `.json` or
    /// `.html` path extension wins, otherwise the `Accept` header is inspected;
    /// anything else is `Any`.
    pub fn negotiated_format(&self) -> crate::respond::Format {
        use crate::respond::Format;
        let path = self.parts.uri.path();
        if path.ends_with(".json") {
            return Format::Json;
        }
        if path.ends_with(".html") {
            return Format::Html;
        }
        match self
            .parts
            .headers
            .get(header::ACCEPT)
            .and_then(|a| a.to_str().ok())
        {
            Some(accept) if accept.contains("application/json") => Format::Json,
            Some(accept) if accept.contains("text/html") => Format::Html,
            _ => Format::Any,
        }
    }

    /// Begin format-based content negotiation (Rails `respond_to`).
    pub fn respond_to(&self) -> crate::respond::RespondTo {
        crate::respond::RespondTo::new(self.negotiated_format())
    }

    /// Whether the request's `If-None-Match` matches `etag` (or is `*`).
    pub fn etag_matches(&self, etag: &str) -> bool {
        match self
            .parts
            .headers
            .get(header::IF_NONE_MATCH)
            .and_then(|v| v.to_str().ok())
        {
            Some("*") => true,
            Some(inm) => inm.split(',').map(str::trim).any(|t| t == etag),
            None => false,
        }
    }

    fn if_modified_since_matches(&self, last_modified: &str) -> bool {
        self.parts
            .headers
            .get(header::IF_MODIFIED_SINCE)
            .and_then(|v| v.to_str().ok())
            .map(|v| v == last_modified)
            .unwrap_or(false)
    }

    /// HTTP conditional-GET check (Rails `fresh_when`): if the request's
    /// validators match `etag` (`If-None-Match`) or `last_modified`
    /// (`If-Modified-Since`), return a `304 Not Modified` echoing the validators;
    /// otherwise return `None` and render normally (setting the same validators).
    pub fn fresh_when(&self, etag: Option<&str>, last_modified: Option<&str>) -> Option<Response> {
        let fresh = etag.map(|e| self.etag_matches(e)).unwrap_or(false)
            || last_modified
                .map(|lm| self.if_modified_since_matches(lm))
                .unwrap_or(false);
        if !fresh {
            return None;
        }
        let mut builder = Response::builder().status(StatusCode::NOT_MODIFIED);
        if let Some(e) = etag {
            builder = builder.header(header::ETAG, e);
        }
        if let Some(lm) = last_modified {
            builder = builder.header(header::LAST_MODIFIED, lm);
        }
        Some(builder.body(Body::empty()).expect("valid 304 response"))
    }

    /// The plain/signed cookie jar (Rails `cookies` / `cookies.signed`). Reads
    /// parse the request `Cookie` header; staged writes are flushed to
    /// `Set-Cookie` after the action runs (see [`commit_to_response`]).
    ///
    /// [`commit_to_response`]: Self::commit_to_response
    pub fn cookies(&mut self) -> &mut CookieJar {
        if self.cookies.is_none() {
            let header = self
                .parts
                .headers
                .get(header::COOKIE)
                .and_then(|v| v.to_str().ok());
            self.cookies = Some(CookieJar::from_header(header, crate::secret::key_base()));
        }
        self.cookies.as_mut().expect("cookie jar just set")
    }

    /// The encrypted session (Rails `session`). Loaded from the session cookie on
    /// first access and re-encrypted into the response afterwards.
    pub fn session(&mut self) -> &mut Session {
        if self.session.is_none() {
            let store = EncryptedCookieSessionStore::default();
            let session = self
                .raw_cookie(SESSION_COOKIE)
                .and_then(|raw| store.decode(&raw))
                .unwrap_or_default();
            self.session = Some(session);
        }
        self.session.as_mut().expect("session just set")
    }

    /// The flash (Rails `flash`): messages set on one request and read on the
    /// next. Messages set this request are carried forward in a cookie; a flash
    /// that is only read is swept so it lives exactly one following request.
    pub fn flash(&mut self) -> &mut Flash {
        if self.flash.is_none() {
            let store = CookieSessionStore::new(crate::secret::key_base());
            let flash = self
                .raw_cookie(FLASH_COOKIE)
                .map(|raw| Flash::from_cookie(&store, &raw))
                .unwrap_or_default();
            self.flash_loaded = flash.iter().map(|(k, v)| (k.clone(), v.clone())).collect();
            self.flash = Some(flash);
        }
        self.flash.as_mut().expect("flash just set")
    }

    /// Read a raw incoming cookie value by name from the request `Cookie` header.
    fn raw_cookie(&self, name: &str) -> Option<String> {
        let header = self.parts.headers.get(header::COOKIE)?.to_str().ok()?;
        header
            .split(';')
            .filter_map(|pair| pair.trim().split_once('='))
            .find(|(k, _)| *k == name)
            .map(|(_, v)| v.to_string())
    }

    /// Flush any session/flash/cookie changes into the response `Set-Cookie`
    /// headers. Called by the `#[controller]` macro after the action; a no-op
    /// when the action never touched session/flash/cookies.
    pub fn commit_to_response(&self, response: &mut Response) {
        let secret = crate::secret::key_base();

        if let Some(session) = &self.session {
            let value = EncryptedCookieSessionStore::new(secret.clone()).encode(session);
            append_cookie(
                response,
                &format!("{SESSION_COOKIE}={value}; Path=/; HttpOnly; SameSite=Lax"),
            );
        }

        if let Some(flash) = &self.flash {
            let current: BTreeMap<String, String> =
                flash.iter().map(|(k, v)| (k.clone(), v.clone())).collect();
            if current != self.flash_loaded {
                // New messages set this request → carry them to the next one.
                if current.is_empty() {
                    append_cookie(response, &format!("{FLASH_COOKIE}=; Path=/; Max-Age=0"));
                } else {
                    let value = flash.to_cookie(&CookieSessionStore::new(secret.clone()));
                    append_cookie(
                        response,
                        &format!("{FLASH_COOKIE}={value}; Path=/; HttpOnly; SameSite=Lax"),
                    );
                }
            } else if !self.flash_loaded.is_empty() {
                // Read-only this request → expire so it lives exactly one request.
                append_cookie(response, &format!("{FLASH_COOKIE}=; Path=/; Max-Age=0"));
            }
        }

        if let Some(jar) = &self.cookies {
            for header_value in jar.to_set_cookie_headers() {
                append_cookie(response, &header_value);
            }
        }
    }
}

/// Append a `Set-Cookie` header value to a response (multiple are allowed).
fn append_cookie(response: &mut Response, value: &str) {
    if let Ok(header_value) = HeaderValue::from_str(value) {
        response
            .headers_mut()
            .append(header::SET_COOKIE, header_value);
    }
}

/// Lets a `#[controller]` action body evaluate to either a [`Response`] or a
/// `Result<Response, E>`. The macro wraps every action body in
/// `into_action_response()`, so actions can use `?` for fallible work (DB calls,
/// body parsing) and an `Err` becomes a `500` response.
pub trait IntoActionResponse {
    fn into_action_response(self) -> Response;
}

impl IntoActionResponse for Response {
    fn into_action_response(self) -> Response {
        self
    }
}

impl<E: std::fmt::Display> IntoActionResponse for Result<Response, E> {
    fn into_action_response(self) -> Response {
        match self {
            Ok(response) => response,
            Err(error) => {
                tracing::error!(%error, "action returned an error");
                Response::builder()
                    .status(StatusCode::INTERNAL_SERVER_ERROR)
                    .body(Body::from("Internal Server Error"))
                    .expect("static 500 response is valid")
            }
        }
    }
}

// `Context` must stay `Send` so controller handler futures (which hold a
// `&mut Context` across `.await`) satisfy axum's `Handler` bound.
const _: fn() = || {
    fn assert_send<T: Send>() {}
    assert_send::<Context>();
};