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Search API Reference

backend.api.search

backend.api.search

Provides a FastAPI router with an endpoint to search datasets using OpenSearch. Supports optional vector search via sentence-transformers when available.

This module exposes router with a POST /api/v1/search endpoint that accepts a SearchQueryRequest payload and returns search results, totals, and aggregations.

search(req) async

Search datasets using hybrid keyword and semantic vector search.

Combines BM25 full-text matching against title and description with k-NN vector search using sentence embeddings. Supports optional filtering by source domain, dataset type, temporal range, and spatial bounding box.

Parameters:

Name Type Description Default
req SearchQueryRequest

Query parameters including: - keywords: optional free-text to match and vectorize - source: optional list or single source/domain - types: optional list or single type - temporal_start / temporal_end: ISO date strings to filter temporal coverage - bbox: bounding box [min_lon, min_lat, max_lon, max_lat] - limit: number of results to return - offset: pagination offset

required

Returns:

Type Description

A dict with: - total: total number of matching datasets. - results: list of dataset source documents (plot fields stripped). - aggregations: facet counts for sources_count and types_count

Raises:

Type Description
HTTPException

If required backends or dependencies are missing or an error occurs while querying the search backend.

Source code in backend/api/search.py
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@router.post("/api/v1/search")
async def search(req: SearchQueryRequest):
    """
    Search datasets using hybrid keyword and semantic vector search.

    Combines BM25 full-text matching against `title` and `description` with
    k-NN vector search using sentence embeddings. Supports optional filtering
    by source domain, dataset type, temporal range, and spatial bounding box.

    Args:
        req (SearchQueryRequest): Query parameters including:
            - `keywords`: optional free-text to match and vectorize
            - `source`: optional list or single source/domain
            - `types`: optional list or single type
            - `temporal_start` / `temporal_end`: ISO date strings to filter temporal coverage
            - `bbox`: bounding box [min_lon, min_lat, max_lon, max_lat]
            - `limit`: number of results to return
            - `offset`: pagination offset

    Returns:
        A dict with:
            - `total`: total number of matching datasets.
            - `results`: list of dataset source documents (plot fields stripped).
            - `aggregations`: facet counts for `sources_count` and `types_count`

    Raises:
        HTTPException: If required backends or dependencies are missing or an
            error occurs while querying the search backend.
    """
    try:
        client = get_client()
    except RuntimeError as exc:
        raise HTTPException(status_code=500, detail=str(exc))

    filter_clauses = []
    should_clauses = []
    query_vector = None

    if req.keywords:
        query_vector = build_query_vector(req.keywords)

    if isinstance(req.source, list):
        source_values = [item for item in req.source if item]
        if source_values:
            filter_clauses.append({"terms": {"domain": source_values}})
    elif req.source:
        filter_clauses.append({"term": {"domain": {"value": req.source}}})

    if isinstance(req.types, list):
        type_values = [item for item in req.types if item]
        if type_values:
            filter_clauses.append({"terms": {"types": type_values}})
    elif req.types:
        filter_clauses.append({"term": {"types": {"value": req.types}}})

    # Temporal overlap: ensure dataset window overlaps requested window
    if req.temporal_start:
        # dataset.end >= temporal_start
        filter_clauses.append({"range": {"temporal_coverage.end": {"gte": req.temporal_start}}})
    if req.temporal_end:
        # dataset.start <= temporal_end
        filter_clauses.append({"range": {"temporal_coverage.start": {"lte": req.temporal_end}}})

    if req.bbox:
        try:
            min_lon, min_lat, max_lon, max_lat = req.bbox
        except Exception:
            raise HTTPException(status_code=400, detail="Invalid bbox format; expected [min_lon, min_lat, max_lon, max_lat]")

        envelope = [[min_lon, max_lat], [max_lon, min_lat]]
        filter_clauses.append(
            {
                "geo_shape": {
                    "spatial_coverage.bbox": {
                        "shape": {"type": "envelope", "coordinates": envelope},
                        "relation": "intersects",
                    }
                }
            }
        )

    if req.keywords:
        try:
            description_fields = description_fields_for(req.description_source)
        except ValueError as exc:
            # A typo'd source must not silently fall back to the default arm.
            raise HTTPException(status_code=400, detail=str(exc))
        should_clauses.append(
            {
                "multi_match": {
                    "query": req.keywords,
                    "fields": description_fields,
                }
            }
        )
        should_clauses.append(
            {
                "knn": {
                    "dataset_vector": {
                        "vector": query_vector,
                        "k": 10,
                    }
                }
            }
        )

    query_bool = {"filter": filter_clauses}
    if should_clauses:
        query_bool["should"] = should_clauses
        query_bool["minimum_should_match"] = 1  # Require at least one text or vector match when keywords are present

    payload = {
        "query": {"bool": query_bool},
        "aggs": {
            "sources_count": {"terms": {"field": "domain"}},
            "types_count": {"terms": {"field": "types"}},
        },
    }
    # print("RAW OPENSEARCH PAYLOAD:", json.dumps(payload, indent=2))

    try:
        resp = client.search(index="auctus_catalog_master", body=payload, size=req.limit, from_=req.offset)
    except Exception as exc:
        raise HTTPException(status_code=503, detail=f"Search backend error: {exc}")

    hits = resp.get("hits", {}).get("hits", [])
    total = resp.get("hits", {}).get("total")
    if isinstance(total, dict):
        total_count = total.get("value", 0)
    else:
        total_count = int(total or 0)

    results = []
    for h in hits:
        src = h.get("_source", {})

        # Remove large plot objects from profiler_metadata.columns
        prof = src.get("profiler_metadata")
        if isinstance(prof, dict):
            cols = prof.get("columns")
            if isinstance(cols, list):
                for c in cols:
                    if isinstance(c, dict) and "plot" in c:
                        c.pop("plot", None)

        results.append(src)

    aggregations = resp.get("aggregations", {})

    return {"total": total_count, "results": results, "aggregations": aggregations}