axum_api_kit/
lib.rs

1//! Shared response types for Axum JSON APIs.
2//!
3//! Provides building blocks that every Axum CRUD service needs but always
4//! re-defines from scratch:
5//!
6//! - [`ApiError`] - a machine-readable JSON error body with `code`, `message`, and optional
7//!   `details`, plus factory helpers that return `(StatusCode, Json<ApiError>)` tuples ready
8//!   for use with Axum's [`IntoResponse`](axum::response::IntoResponse). Supports `From`
9//!   conversions for common error types. With the optional `validator` feature enabled,
10//!   also supports converting `validator::ValidationErrors` into structured field errors.
11//!   With the optional `sqlx` feature enabled, also supports converting `sqlx::Error` into
12//!   semantically correct HTTP status codes (404, 409, 422, 503, 500).
13//! - [`ListResponse<T>`] - a generic offset/limit paginated collection response with `data`,
14//!   `total`, `limit`, and `offset` fields.
15//! - [`CursorResponse<T>`] - a generic cursor-based paginated collection response for large
16//!   datasets or feeds, with `data`, `next_cursor`, and `has_more` fields.
17//! - [`HealthResponse`] - a health-check response with `status` field supporting `ok`,
18//!   `degraded`, and `unhealthy` states.
19//!
20//! With optional feature flags enabled, the kit also provides request extractors that
21//! reject with an [`ApiError`] body on failure:
22//!
23//! - `ValidatedJson<T>` (feature `validator`) - deserializes a JSON body and runs
24//!   `validator` validation before the handler runs.
25//! - `Pagination` and `CursorPagination` (feature `extract`) - parse `limit`/`offset` and
26//!   `cursor`/`limit` query parameters into typed values, with `list_response` /
27//!   `cursor_response` helpers that build the matching response type.
28//!
29//! It also ships observability middleware:
30//!
31//! - `propagate_request_id` and `trace_requests` (feature `trace`) - assign an
32//!   `x-request-id` correlation id (extractable via `RequestId`) and emit a structured
33//!   `tracing` event with method, path, status, and latency for each request.
34//!
35//! And service-wiring helpers:
36//!
37//! - `health_routes` and `liveness` (feature `router`) - a `Router` exposing `/healthz` and
38//!   `/readyz` probes backed by `HealthResponse`.
39//! - `cors_allowing` and `cors_permissive` (feature `cors`) - build a `tower_http`
40//!   `CorsLayer` with sensible defaults.
41//!
42//! With the `openapi` feature, all four response types derive `utoipa::ToSchema` so they
43//! can be referenced from a `utoipa` `OpenApi` document and appear in generated specs.
44//!
45//! # Quick Start
46//!
47//! ```rust,no_run
48//! use axum::{Json, http::StatusCode, response::IntoResponse};
49//! use axum_api_kit::{ApiError, ListResponse, CursorResponse, HealthResponse};
50//! use serde::Serialize;
51//!
52//! #[derive(Serialize)]
53//! struct Item { id: String }
54//!
55//! async fn list_items() -> impl IntoResponse {
56//!     let items = vec![Item { id: "1".into() }];
57//!     Json(ListResponse { data: items, total: 1, limit: 50, offset: 0 })
58//! }
59//!
60//! async fn feed_items(cursor: Option<String>) -> impl IntoResponse {
61//!     let items = vec![Item { id: "1".into() }];
62//!     CursorResponse { data: items, next_cursor: Some("abc".into()), has_more: true }
63//! }
64//!
65//! async fn get_item() -> impl IntoResponse {
66//!     ApiError::not_found("item not found")
67//! }
68//!
69//! async fn health() -> impl IntoResponse {
70//!     HealthResponse::ok()
71//! }
72//! ```
73
74#[cfg(feature = "cors")]
75mod cors;
76mod cursor;
77mod error;
78mod health;
79mod list;
80#[cfg(feature = "extract")]
81mod pagination;
82#[cfg(feature = "router")]
83mod router;
84#[cfg(feature = "trace")]
85mod trace;
86#[cfg(feature = "validator")]
87mod validated;
88
89#[cfg(feature = "cors")]
90pub use cors::{cors_allowing, cors_permissive};
91pub use cursor::CursorResponse;
92pub use error::ApiError;
93pub use health::HealthResponse;
94pub use list::ListResponse;
95#[cfg(feature = "extract")]
96pub use pagination::{CursorPagination, Pagination};
97#[cfg(feature = "router")]
98pub use router::{health_routes, liveness};
99#[cfg(feature = "trace")]
100pub use trace::{propagate_request_id, trace_requests, RequestId, REQUEST_ID_HEADER};
101#[cfg(feature = "validator")]
102pub use validated::ValidatedJson;
axum_api_kit/lib.rs

axum_api_kit/
lib.rs
