shift_proxy/routes/
mod.rs

1//! Route handlers for the SHIFT proxy.
2
3pub mod anthropic;
4pub mod google;
5pub mod health;
6pub mod openai;
7pub mod passthrough;
8
9use crate::ProxyState;
10use axum::body::Bytes;
11use axum::extract::DefaultBodyLimit;
12use axum::extract::State;
13use axum::http::{HeaderMap, Uri};
14use axum::response::Response;
15use axum::routing::{any, get, post};
16use axum::Router;
17
18/// Maximum request body size: 200 MB.
19/// AI payloads with base64 images can be large (50MB+). This limit prevents
20/// unbounded memory consumption from malicious clients while accommodating
21/// legitimate multi-image payloads.
22const MAX_BODY_SIZE: usize = 200 * 1024 * 1024;
23
24/// Fallback handler for `POST /messages` (without the `/v1` prefix).
25///
26/// Some clients (e.g. OpenCode with a misconfigured `baseURL` that omits `/v1`)
27/// send requests to `/messages` instead of `/v1/messages`. Rather than returning
28/// a 404 "Unknown route" error, we rewrite the URI to `/v1/messages` and delegate
29/// to the standard Anthropic handler.
30async fn messages_fallback_handler(
31    state: State<ProxyState>,
32    uri: Uri,
33    headers: HeaderMap,
34    body: Bytes,
35) -> Response {
36    let query = uri.query().map(|q| format!("?{}", q)).unwrap_or_default();
37    let rewritten: Uri = format!("/v1/messages{}", query)
38        .parse()
39        .expect("/v1/messages is a valid URI");
40
41    anthropic::anthropic_handler(state, rewritten, headers, body).await
42}
43
44/// Fallback handler for `POST /responses` (without the `/v1` prefix).
45///
46/// Codex CLI sets `openai_base_url = "http://localhost:8787"` and then sends
47/// requests to `/responses` (the OpenAI Responses API). We rewrite to
48/// `/v1/responses` so the OpenAI handler builds the correct upstream URL.
49async fn responses_fallback_handler(
50    state: State<ProxyState>,
51    uri: Uri,
52    headers: HeaderMap,
53    body: Bytes,
54) -> Response {
55    let query = uri.query().map(|q| format!("?{}", q)).unwrap_or_default();
56    let rewritten: Uri = format!("/v1/responses{}", query)
57        .parse()
58        .expect("/v1/responses is a valid URI");
59
60    openai::openai_handler(state, rewritten, headers, body).await
61}
62
63/// Build the complete proxy router with all routes.
64pub fn build_router(state: ProxyState) -> Router {
65    Router::new()
66        // Health and stats
67        .route("/health", get(health::health_handler))
68        .route("/stats", get(health::stats_handler))
69        // Provider-specific routes (with optimization)
70        .route("/v1/messages", post(anthropic::anthropic_handler))
71        .route("/v1/chat/completions", post(openai::openai_handler))
72        .route("/v1/responses", post(openai::openai_handler))
73        // Fallback: bare paths without /v1 prefix (resilience for misconfigured clients)
74        .route("/messages", post(messages_fallback_handler))
75        .route("/responses", post(responses_fallback_handler))
76        // Google routes (passthrough only)
77        .route("/v1beta/models/{*path}", post(google::google_handler))
78        .route("/v1/models/{*path}", post(google::google_handler))
79        // Catch-all passthrough for all HTTP methods (not just POST).
80        // Some provider APIs use GET (list models), PUT, DELETE, etc.
81        .fallback(any(passthrough::passthrough_handler))
82        // Explicit body size limit — prevents OOM from malicious payloads.
83        .layer(DefaultBodyLimit::max(MAX_BODY_SIZE))
84        .with_state(state)
85}
shift_proxy/routes/mod.rs

shift_proxy/routes/
mod.rs
