Schema endpoint

crates/pile-client/src/lib.rs

@@ -10,7 +10,9 @@ use std::pin::Pin;
 use thiserror::Error;
 use tracing::{trace, warn};
 
-pub use pile_dataset::serve::{ItemsResponse, LookupRequest, LookupResponse};
+pub use pile_dataset::serve::{
+	FieldSpec, FieldsResponse, ItemsResponse, LookupRequest, LookupResponse,
+};
 
 #[derive(Debug, Error)]
 pub enum ClientError {
@@ -197,6 +199,14 @@ impl DatasetClient {
 		Ok(FieldResponse { content_type, data })
 	}
 
+	/// `GET /schema` — retrieve this dataset's schema.
+	pub async fn schema(&self) -> Result<FieldsResponse, ClientError> {
+		let url = format!("{}/schema", self.base_url);
+		trace!(url, "GET /schema");
+		let resp = self.client.get(url).send().await?;
+		check_status(resp).await?.json().await.map_err(Into::into)
+	}
+
 	/// `GET /items` — paginate over all items in this dataset, ordered by (source, key).
 	pub async fn list_items(
 		&self,

crates/pile-config/src/lib.rs

@@ -1,4 +1,4 @@
-use serde::Deserialize;
+use serde::{Deserialize, Serialize};
 use std::{collections::HashMap, fmt::Debug, path::PathBuf};
 
 use crate::{objectpath::ObjectPath, pattern::GroupPattern};
@@ -61,7 +61,7 @@ pub enum Source {
 // MARK: schema
 //
 
-#[derive(Debug, Clone, Deserialize)]
+#[derive(Debug, Clone, Deserialize, Serialize)]
 pub struct FieldSpec {
 	/// How to find this field in a data entry
 	pub path: Vec<ObjectPath>,

crates/pile-dataset/src/serve/mod.rs

@@ -23,10 +23,13 @@ pub use field::*;
 mod items;
 pub use items::*;
 
+mod schema;
+pub use schema::*;
+
 #[derive(OpenApi)]
 #[openapi(
 	tags(),
-	paths(lookup, item_get, get_extract, items_list, get_field),
+	paths(lookup, item_get, get_extract, items_list, get_field, get_schema),
 	components(schemas(
 		LookupRequest,
 		LookupResponse,
@@ -55,6 +58,7 @@ impl Datasets {
 			.route("/extract", get(get_extract))
 			.route("/field", get(get_field))
 			.route("/items", get(items_list))
+			.route("/schema", get(get_schema))
 			.with_state(self.clone());
 
 		if let Some(prefix) = prefix {

crates/pile-dataset/src/serve/schema.rs

@@ -0,0 +1,31 @@
+use axum::{
+	Json,
+	extract::State,
+	http::StatusCode,
+	response::{IntoResponse, Response},
+};
+use std::{collections::HashMap, sync::Arc};
+
+pub use pile_config::FieldSpec;
+
+use crate::Datasets;
+
+pub type FieldsResponse = HashMap<String, FieldSpec>;
+
+/// Retrieve this dataset's schema.
+#[utoipa::path(
+	get,
+	path = "/schema",
+	responses(
+		(status = 200, description = "This dataset's schema"),
+	)
+)]
+pub async fn get_schema(State(state): State<Arc<Datasets>>) -> Response {
+	let fields: FieldsResponse = state
+		.config
+		.schema
+		.iter()
+		.map(|(k, v)| (k.as_str().to_owned(), v.clone()))
+		.collect();
+	(StatusCode::OK, Json(fields)).into_response()
+}