feat(mpps): add service for modality performed procedure step

CHANGELOG.md

@@ -9,6 +9,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
 
+- MPPS-RS (Modality Performed Procedure Step) support for the DIMSE backend: the Create, Update and
+  Retrieve transactions are translated into N-CREATE, N-SET and N-GET requests. The timeout can be
+  configured with the new `mpps-rs.timeout` option.
+
 ### Changed
 
 ### Fixed

Cargo.toml

@@ -65,6 +65,7 @@ aws-credential-types = { version = "1.2.13", optional = true }
 testcontainers = "0.27.3"
 dicom-test-files = "0.4.0"
 dicom-web = "0.6.0"
+reqwest = { version = "0.13.2", default-features = false, features = ["json"] }
 
 [lints.rust]
 unsafe_code = "forbid"

README.md

@@ -177,6 +177,25 @@ https://www.dicomstandard.org/news-dir/current/docs/sups/sup246.pdf
 | limit         | Return only {n} results                 |       ✅       |
 | offset        | Skip {n} results                        |       ✅       |
 
+### Report Modality Performed Procedure Steps (MPPS-RS)
+
+https://dicom.nema.org/medical/dicom/current/output/chtml/part18/chapter_15.html
+
+The DIMSE backend translates the transactions into N-CREATE, N-SET and N-GET requests of the
+Modality Performed Procedure Step SOP Classes.
+
+#### Transactions
+
+| Transaction | Method | URI Template                                                   | Support Status |
+| ----------- | ------ | -------------------------------------------------------------- | :------------: |
+| Create      | POST   | `/modality-performed-procedure-steps/{mppsUID}`                |       ✅       |
+| Update      | POST   | `/modality-performed-procedure-steps/{mppsUID}?update`         |       ✅       |
+| Retrieve    | GET    | `/modality-performed-procedure-steps/{mppsUID}{?includefield}` |      ✅¹       |
+
+¹ Requires a PACS that supports the Modality Performed Procedure Step Retrieve SOP Class.
+
+Only the `application/dicom+json` media type is supported.
+
 ### Manage worklist items (UPS-RS)
 
 https://www.dicomstandard.org/using/dicomweb/workflow-ups-rs

docs/topics/configuration.md

@@ -197,6 +197,8 @@ aets:
       timeout: 3000
     stow-rs:
       timeout: 3000
+    mpps-rs:
+      timeout: 3000
 ```
 
 Each AET (regardless of the backend) has additional settings specific to the DICOMweb endpoints.
@@ -236,6 +238,11 @@ Each AET (regardless of the backend) has additional settings specific to the DIC
     This is the timeout for a single operation (e.g. receiving a DIMSE-C response primitive).
     If you want to set a timeout for the total execution time, use the <code>server.http.request-timeout</code> option instead.
     </def>
+    <def title="mpps-rs.timeout" id="dicomweb.mpps-rs.timeout">
+    How many milliseconds to wait until a MPPS-RS request should time out.
+    This is the timeout for a single operation (e.g. receiving a N-CREATE-RSP, N-SET-RSP or N-GET-RSP).
+    Defaults to <code>30000</code>.
+    </def>
 </deflist>
 
 ## S3 Backend Config

src/api/mod.rs

@@ -12,6 +12,7 @@ use serde::{Deserialize, Deserializer};
 
 mod aets;
 mod home;
+pub mod mpps;
 pub mod mwl;
 pub mod qido;
 pub mod stow;
@@ -27,7 +28,8 @@ pub fn routes(base_path: &str) -> Router<AppState> {
 				.merge(qido::routes())
 				.merge(wado::routes())
 				.merge(stow::routes())
-				.merge(mwl::routes()),
+				.merge(mwl::routes())
+				.merge(mpps::routes()),
 		);
 
 	// axum no longer supports nesting at the root

src/api/mpps/mod.rs

@@ -0,0 +1,5 @@
+mod routes;
+mod service;
+
+pub use routes::routes;
+pub use service::*;

src/api/mpps/routes.rs

@@ -0,0 +1,120 @@
+use crate::api::mpps::{
+	MppsCreateRequest, MppsError, MppsRetrieveQueryParameters, MppsRetrieveRequest,
+	MppsUpdateRequest,
+};
+use crate::backend::ServiceProvider;
+use crate::utils::dicom_json::DicomJsonBody;
+use crate::AppState;
+use axum::body::Body;
+use axum::extract::{Path, RawQuery};
+use axum::http::header::CONTENT_TYPE;
+use axum::http::StatusCode;
+use axum::response::{IntoResponse, Response};
+use axum::routing::post;
+use axum::Router;
+use axum_extra::extract::Query;
+use dicom_json::DicomJson;
+use tracing::instrument;
+
+const APPLICATION_DICOM_JSON: &str = "application/dicom+json";
+
+/// HTTP Router for the Modality Performed Procedure Step Service.
+/// <https://dicom.nema.org/medical/dicom/current/output/chtml/part18/chapter_15.html>
+pub fn routes() -> Router<AppState> {
+	Router::new().route(
+		"/modality-performed-procedure-steps/{mpps_uid}",
+		post(create_or_update).get(retrieve),
+	)
+}
+
+/// The Create and Update Transaction share the same method and resource, but the Update
+/// Transaction requires the `update` query parameter, which has no value.
+/// This cannot be deserialized into an `Option`, as an empty value deserializes to `None`.
+fn is_update(query: Option<&str>) -> bool {
+	query.is_some_and(|query| {
+		query
+			.split('&')
+			.any(|parameter| parameter.split('=').next() == Some("update"))
+	})
+}
+
+fn disabled() -> Response {
+	(
+		StatusCode::SERVICE_UNAVAILABLE,
+		"MPPS-RS endpoint is disabled",
+	)
+		.into_response()
+}
+
+/// Create Transaction and Update Transaction.
+/// <https://dicom.nema.org/medical/dicom/current/output/chtml/part18/sect_15.4.html>
+/// <https://dicom.nema.org/medical/dicom/current/output/chtml/part18/sect_15.5.html>
+#[instrument(skip_all)]
+async fn create_or_update(
+	provider: ServiceProvider,
+	Path((_aet, mpps_uid)): Path<(String, String)>,
+	RawQuery(query): RawQuery,
+	DicomJsonBody(data_set): DicomJsonBody,
+) -> Response {
+	let Some(mpps) = provider.mpps else {
+		return disabled();
+	};
+
+	let result = if is_update(query.as_deref()) {
+		match MppsUpdateRequest::new(mpps_uid, data_set) {
+			Ok(request) => mpps.update(request).await.map(|()| StatusCode::OK),
+			Err(err) => Err(err),
+		}
+	} else {
+		match MppsCreateRequest::new(mpps_uid, data_set) {
+			Ok(request) => mpps.create(request).await.map(|()| StatusCode::CREATED),
+			Err(err) => Err(err),
+		}
+	};
+
+	result.map_or_else(MppsError::into_response, IntoResponse::into_response)
+}
+
+/// Retrieve Transaction.
+/// <https://dicom.nema.org/medical/dicom/current/output/chtml/part18/sect_15.6.html>
+#[instrument(skip_all)]
+async fn retrieve(
+	provider: ServiceProvider,
+	Path((_aet, mpps_uid)): Path<(String, String)>,
+	Query(parameters): Query<MppsRetrieveQueryParameters>,
+) -> Response {
+	let Some(mpps) = provider.mpps else {
+		return disabled();
+	};
+
+	let request = match MppsRetrieveRequest::new(mpps_uid, parameters) {
+		Ok(request) => request,
+		Err(err) => return err.into_response(),
+	};
+
+	match mpps.retrieve(request).await {
+		Ok(data_set) => Response::builder()
+			.status(StatusCode::OK)
+			.header(CONTENT_TYPE, APPLICATION_DICOM_JSON)
+			.body(Body::from(
+				serde_json::to_string(&DicomJson::from(data_set)).unwrap(),
+			))
+			.unwrap(),
+		Err(err) => err.into_response(),
+	}
+}
+
+#[cfg(test)]
+mod tests {
+	use super::*;
+
+	#[test]
+	fn detects_update_parameter() {
+		assert!(is_update(Some("update")));
+		assert!(is_update(Some("update=")));
+		assert!(is_update(Some("foo=bar&update")));
+		assert!(!is_update(None));
+		assert!(!is_update(Some("")));
+		assert!(!is_update(Some("updated")));
+	}
+}