velesdb_server/handlers/
match_query.rs

1//! MATCH query handler for REST API (EPIC-045 US-007).
2//!
3//! Provides endpoint for executing graph pattern matching queries.
4
5// EPIC-058 US-007: MATCH query handler now wired to /collections/{name}/match
6
7use axum::{
8    extract::{Path, State},
9    http::StatusCode,
10    Json,
11};
12use serde::{Deserialize, Serialize};
13use std::collections::HashMap;
14use std::sync::Arc;
15use utoipa::ToSchema;
16
17use crate::types::VELESQL_CONTRACT_VERSION;
18use crate::AppState;
19
20/// Request body for MATCH query execution.
21#[derive(Debug, Deserialize, ToSchema)]
22pub struct MatchQueryRequest {
23    /// VelesQL MATCH query string.
24    pub query: String,
25    /// Query parameters (e.g., vectors, values).
26    #[serde(default)]
27    pub params: HashMap<String, serde_json::Value>,
28    /// Query vector for similarity scoring (EPIC-058 US-007).
29    #[serde(default)]
30    pub vector: Option<Vec<f32>>,
31    /// Similarity threshold (0.0 to 1.0, default 0.0).
32    #[serde(default)]
33    pub threshold: Option<f32>,
34}
35
36/// Single result from MATCH query.
37#[derive(Debug, Serialize, ToSchema)]
38pub struct MatchQueryResultItem {
39    /// Variable bindings from pattern matching.
40    pub bindings: HashMap<String, u64>,
41    /// Similarity score (if similarity() was used).
42    #[serde(skip_serializing_if = "Option::is_none")]
43    pub score: Option<f32>,
44    /// Traversal depth.
45    pub depth: u32,
46    /// Projected properties from RETURN clause (EPIC-058 US-007).
47    #[serde(skip_serializing_if = "HashMap::is_empty")]
48    pub projected: HashMap<String, serde_json::Value>,
49}
50
51/// Response for MATCH query execution.
52#[derive(Debug, Serialize, ToSchema)]
53pub struct MatchQueryResponse {
54    /// Query results.
55    pub results: Vec<MatchQueryResultItem>,
56    /// Execution time in milliseconds.
57    pub took_ms: u64,
58    /// Number of results.
59    pub count: usize,
60    /// Response metadata.
61    pub meta: MatchQueryMeta,
62}
63
64/// Metadata section for MATCH query responses.
65#[derive(Debug, Serialize, ToSchema)]
66pub struct MatchQueryMeta {
67    /// VelesQL contract version used by this response.
68    pub velesql_contract_version: String,
69}
70
71/// Error response for MATCH query.
72#[derive(Debug, Serialize, ToSchema)]
73pub struct MatchQueryError {
74    /// Error message.
75    pub error: String,
76    /// Error code.
77    pub code: String,
78    /// Actionable hint for developers.
79    #[serde(skip_serializing_if = "Option::is_none")]
80    pub hint: Option<String>,
81    /// Optional details for diagnostics.
82    #[serde(skip_serializing_if = "Option::is_none")]
83    pub details: Option<serde_json::Value>,
84}
85
86/// Execute a MATCH query on a collection.
87///
88/// # Endpoint
89///
90/// `POST /collections/{name}/match`
91///
92/// # Example Request
93///
94/// ```json
95/// {
96///   "query": "MATCH (a:Person)-[:KNOWS]->(b) WHERE similarity(a.vec, $v) > 0.8 RETURN a.name",
97///   "params": {
98///     "v": [0.1, 0.2, 0.3]
99///   }
100/// }
101/// ```
102///
103/// # Errors
104///
105/// Returns error tuple with status code and JSON error in these cases:
106/// - `404 NOT_FOUND` - Collection not found
107/// - `400 BAD_REQUEST` - Parse error or not a MATCH query
108/// - `500 INTERNAL_SERVER_ERROR` - Execution error
109#[utoipa::path(
110    post,
111    path = "/collections/{name}/match",
112    tag = "graph",
113    params(("name" = String, Path, description = "Collection name")),
114    request_body = MatchQueryRequest,
115    responses(
116        (status = 200, description = "Match query results", body = MatchQueryResponse),
117        (status = 400, description = "Parse error or invalid query", body = MatchQueryError),
118        (status = 404, description = "Collection not found", body = MatchQueryError),
119        (status = 500, description = "Internal server error", body = MatchQueryError)
120    )
121)]
122pub async fn match_query(
123    Path(collection_name): Path<String>,
124    State(state): State<Arc<AppState>>,
125    Json(request): Json<MatchQueryRequest>,
126) -> Result<Json<MatchQueryResponse>, (StatusCode, Json<MatchQueryError>)> {
127    let start = std::time::Instant::now();
128
129    let collection = state
130        .db
131        .get_vector_collection(&collection_name)
132        .ok_or_else(|| {
133            mk_match_error(
134                StatusCode::NOT_FOUND,
135                format!("Collection '{}' not found", collection_name),
136                "COLLECTION_NOT_FOUND",
137                "Create the collection first or correct the collection name in the route",
138                Some(serde_json::json!({ "collection": collection_name })),
139            )
140        })?;
141
142    let match_clause = parse_match_clause(&request.query)?;
143    validate_threshold(request.threshold)?;
144
145    let results = execute_match(&collection, &match_clause, &request)?;
146
147    let count = results.len();
148    #[allow(clippy::cast_possible_truncation)]
149    let took_ms = start.elapsed().as_millis() as u64;
150
151    Ok(Json(MatchQueryResponse {
152        results,
153        took_ms,
154        count,
155        meta: MatchQueryMeta {
156            velesql_contract_version: VELESQL_CONTRACT_VERSION.to_string(),
157        },
158    }))
159}
160
161/// Build a match query error tuple.
162fn mk_match_error(
163    status: StatusCode,
164    error: String,
165    code: &str,
166    hint: &str,
167    details: Option<serde_json::Value>,
168) -> (StatusCode, Json<MatchQueryError>) {
169    (
170        status,
171        Json(MatchQueryError {
172            error,
173            code: code.to_string(),
174            hint: Some(hint.to_string()),
175            details,
176        }),
177    )
178}
179
180/// Parse a query string and extract the MATCH clause.
181fn parse_match_clause(
182    query_str: &str,
183) -> Result<velesdb_core::velesql::MatchClause, (StatusCode, Json<MatchQueryError>)> {
184    let query = velesdb_core::velesql::Parser::parse(query_str).map_err(|e| {
185        mk_match_error(
186            StatusCode::BAD_REQUEST,
187            format!("Parse error: {}", e),
188            "PARSE_ERROR",
189            "Check MATCH syntax and bound parameters",
190            None,
191        )
192    })?;
193
194    query.match_clause.ok_or_else(|| {
195        mk_match_error(
196            StatusCode::BAD_REQUEST,
197            "Query is not a MATCH query".to_string(),
198            "NOT_MATCH_QUERY",
199            "Use MATCH (...) RETURN ... or call /query for SELECT statements",
200            None,
201        )
202    })
203}
204
205/// Validate that threshold (if provided) is in [0.0, 1.0].
206fn validate_threshold(threshold: Option<f32>) -> Result<(), (StatusCode, Json<MatchQueryError>)> {
207    if let Some(t) = threshold {
208        if !(0.0..=1.0).contains(&t) {
209            return Err(mk_match_error(
210                StatusCode::BAD_REQUEST,
211                format!("Invalid threshold: {}. Must be between 0.0 and 1.0", t),
212                "INVALID_THRESHOLD",
213                "Provide threshold in inclusive range [0.0, 1.0]",
214                Some(serde_json::json!({ "threshold": t })),
215            ));
216        }
217    }
218    Ok(())
219}
220
221/// Execute a MATCH query, dispatching to similarity or plain variant.
222fn execute_match(
223    collection: &velesdb_core::collection::VectorCollection,
224    match_clause: &velesdb_core::velesql::MatchClause,
225    request: &MatchQueryRequest,
226) -> Result<Vec<MatchQueryResultItem>, (StatusCode, Json<MatchQueryError>)> {
227    let raw_results = if let Some(ref vector) = request.vector {
228        let threshold = request.threshold.unwrap_or(0.0);
229        collection.execute_match_with_similarity(match_clause, vector, threshold, &request.params)
230    } else {
231        collection.execute_match(match_clause, &request.params)
232    };
233
234    raw_results
235        .map(|results| {
236            results
237                .into_iter()
238                .map(|r| MatchQueryResultItem {
239                    bindings: r.bindings,
240                    score: r.score,
241                    depth: r.depth,
242                    projected: r.projected,
243                })
244                .collect()
245        })
246        .map_err(|e| {
247            mk_match_error(
248                StatusCode::INTERNAL_SERVER_ERROR,
249                format!("Execution error: {}", e),
250                "EXECUTION_ERROR",
251                "Validate graph labels/properties and parameter types for this collection",
252                None,
253            )
254        })
255}
256
257#[cfg(test)]
258mod tests {
259    use super::*;
260
261    #[test]
262    fn test_match_query_request_deserialize() {
263        let json = r#"{
264            "query": "MATCH (a:Person)-[:KNOWS]->(b) RETURN a.name",
265            "params": {}
266        }"#;
267
268        let request: MatchQueryRequest = serde_json::from_str(json).unwrap();
269        assert!(request.query.contains("MATCH"));
270        assert!(request.params.is_empty());
271    }
272
273    #[test]
274    fn test_match_query_response_serialize() {
275        let response = MatchQueryResponse {
276            results: vec![MatchQueryResultItem {
277                bindings: HashMap::from([("a".to_string(), 123)]),
278                score: Some(0.95),
279                depth: 1,
280                projected: HashMap::new(),
281            }],
282            took_ms: 15,
283            count: 1,
284            meta: MatchQueryMeta {
285                velesql_contract_version: VELESQL_CONTRACT_VERSION.to_string(),
286            },
287        };
288
289        let json = serde_json::to_string(&response).unwrap();
290        assert!(json.contains("bindings"));
291        assert!(json.contains("0.95"));
292    }
293
294    #[test]
295    fn test_match_query_response_with_projected_properties() {
296        let mut projected = HashMap::new();
297        projected.insert("author.name".to_string(), serde_json::json!("John Doe"));
298
299        let response = MatchQueryResponse {
300            results: vec![MatchQueryResultItem {
301                bindings: HashMap::from([("author".to_string(), 42)]),
302                score: Some(0.92),
303                depth: 1,
304                projected,
305            }],
306            took_ms: 10,
307            count: 1,
308            meta: MatchQueryMeta {
309                velesql_contract_version: VELESQL_CONTRACT_VERSION.to_string(),
310            },
311        };
312
313        let json = serde_json::to_string(&response).unwrap();
314        assert!(json.contains("John Doe"));
315        assert!(json.contains("author.name"));
316    }
317}
velesdb_server/handlers/match_query.rs

velesdb_server/handlers/
match_query.rs
