From 43ff6dc9d395707dcd1d20f8f6145901ed057d06 Mon Sep 17 00:00:00 2001
From: Quentin Gliech <quenting@element.io>
Date: Wed, 24 Jul 2024 15:44:08 +0200
Subject: [PATCH] doc: auto-generate the API schema in the documentation

---
 crates/handlers/src/bin/api-schema.rs | 72 +++++++++++++++++++++++++++
 docs/api.schema.json                  | 50 +++++++++++++++++++
 misc/update.sh                        |  2 +
 3 files changed, 124 insertions(+)
 create mode 100644 crates/handlers/src/bin/api-schema.rs
 create mode 100644 docs/api.schema.json

diff --git a/crates/handlers/src/bin/api-schema.rs b/crates/handlers/src/bin/api-schema.rs
new file mode 100644
index 00000000..788560b0
--- /dev/null
+++ b/crates/handlers/src/bin/api-schema.rs
@@ -0,0 +1,72 @@
+// Copyright 2022 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#![forbid(unsafe_code)]
+#![deny(
+    clippy::all,
+    clippy::str_to_string,
+    rustdoc::broken_intra_doc_links,
+    clippy::future_not_send
+)]
+#![warn(clippy::pedantic)]
+
+use std::io::Write;
+
+/// This is a dummy state, it should never be used.
+///
+/// We use it to generate the API schema, which doesn't execute any request.
+#[derive(Clone)]
+struct DummyState;
+
+macro_rules! impl_from_request_parts {
+    ($type:ty) => {
+        #[axum::async_trait]
+        impl axum::extract::FromRequestParts<DummyState> for $type {
+            type Rejection = std::convert::Infallible;
+
+            async fn from_request_parts(
+                _parts: &mut axum::http::request::Parts,
+                _state: &DummyState,
+            ) -> Result<Self, Self::Rejection> {
+                unimplemented!("This is a dummy state, it should never be used")
+            }
+        }
+    };
+}
+
+macro_rules! impl_from_ref {
+    ($type:ty) => {
+        impl axum::extract::FromRef<DummyState> for $type {
+            fn from_ref(_input: &DummyState) -> Self {
+                unimplemented!("This is a dummy state, it should never be used")
+            }
+        }
+    };
+}
+
+impl_from_request_parts!(mas_storage::BoxRepository);
+impl_from_request_parts!(mas_storage::BoxClock);
+impl_from_request_parts!(mas_handlers::BoundActivityTracker);
+impl_from_ref!(mas_keystore::Keystore);
+
+fn main() -> Result<(), Box<dyn std::error::Error>> {
+    let (api, _) = mas_handlers::admin_api_router::<DummyState>();
+    let mut stdout = std::io::stdout();
+    serde_json::to_writer_pretty(&mut stdout, &api)?;
+
+    // Make sure we end with a newline
+    stdout.write_all(b"\n")?;
+
+    Ok(())
+}
diff --git a/docs/api.schema.json b/docs/api.schema.json
new file mode 100644
index 00000000..33e9c21a
--- /dev/null
+++ b/docs/api.schema.json
@@ -0,0 +1,50 @@
+{
+  "openapi": "3.1.0",
+  "info": {
+    "title": "Matrix Authentication Service admin API",
+    "version": ""
+  },
+  "servers": [
+    {
+      "url": "{base}",
+      "variables": {
+        "base": {
+          "default": "/",
+          "description": null
+        }
+      }
+    }
+  ],
+  "paths": {},
+  "components": {
+    "securitySchemes": {
+      "oauth2": {
+        "type": "oauth2",
+        "flows": {
+          "clientCredentials": {
+            "refreshUrl": "/oauth2/token",
+            "tokenUrl": "/oauth2/token",
+            "scopes": {
+              "urn:mas:admin": "Grant access to the admin API"
+            }
+          },
+          "authorizationCode": {
+            "authorizationUrl": "/authorize",
+            "tokenUrl": "/oauth2/token",
+            "refreshUrl": "/oauth2/token",
+            "scopes": {
+              "urn:mas:admin": "Grant access to the admin API"
+            }
+          }
+        }
+      }
+    }
+  },
+  "security": [
+    {
+      "oauth2": [
+        "urn:mas:admin"
+      ]
+    }
+  ]
+}
diff --git a/misc/update.sh b/misc/update.sh
index 0ad0f61b..9f9f26ab 100644
--- a/misc/update.sh
+++ b/misc/update.sh
@@ -5,12 +5,14 @@ set -eu
 export SQLX_OFFLINE=1
 BASE_DIR="$(dirname "$0")/.."
 CONFIG_SCHEMA="${BASE_DIR}/docs/config.schema.json"
+API_SCHEMA="${BASE_DIR}/docs/api.schema.json"
 GRAPHQL_SCHEMA="${BASE_DIR}/frontend/schema.graphql"
 POLICIES_SCHEMA="${BASE_DIR}/policies/schema/"
 
 set -x
 cargo run -p mas-config > "${CONFIG_SCHEMA}"
 cargo run -p mas-handlers --bin graphql-schema > "${GRAPHQL_SCHEMA}"
+cargo run -p mas-handlers --bin api-schema > "${API_SCHEMA}"
 cargo run -p mas-i18n-scan -- --update "${BASE_DIR}/templates/" "${BASE_DIR}/translations/en.json"
 OUT_DIR="${POLICIES_SCHEMA}" cargo run -p mas-policy --features jsonschema