dataservices-api/client/sql/35_precheck_functions.sql
Mario de Frutos 3eee68c56e _OBS_Precheck and OBS_MetadataValidator
New functions to perform a precheck for the user data and metadata
parameters that are going to be used to execute a OBS_GetData operation.

Doing this before the OBD_GetData we are able to check if we're going to
have problems with the current request. Is useful because right now
we're using the *_Exception_Safe functions which return NULL in case we
have an exception, this leads to execute the whole request even if we
know beforehand that it's going to fail.
2017-08-09 12:26:41 +02:00

55 lines
2.2 KiB
PL/PgSQL

CREATE OR REPLACE FUNCTION cdb_dataservices_client._OBS_PreCheck(
source_query text,
parameters json
) RETURNS boolean AS $$
DECLARE
errors text[];
validator_errors text[];
validator_error text;
valid boolean;
geoms record;
BEGIN
errors := (ARRAY[])::TEXT[];
FOR geoms IN EXECUTE format('SELECT ST_GeometryType(the_geom) as geom_type,
bool_and(st_isvalid(the_geom)) as valid,
avg(st_npoints(the_geom)) as avg_vertex,
ST_SetSRID(ST_Extent(the_geom), 4326) as extent,
count(*)::INT as numgeoms
FROM (%s) as _source
GROUP BY ST_GeometryType(the_geom)', source_query)
LOOP
IF geoms.geom_type NOT IN ('ST_Polygon', 'ST_MultiPolygon', 'ST_Point') THEN
errors := array_append(errors, format($data$'Geometry type %s not supported'$data$, geoms.geom_type));
END IF;
IF geoms.valid IS FALSE THEN
errors := array_append(errors, 'There are invalid geometries in the input data, please try to fix them');
END IF;
-- 1000 vertex for a geometry is a limit we have in the obs_getdata function. You can check here
-- https://github.com/CartoDB/observatory-extension/blob/1.6.0/src/pg/sql/41_observatory_augmentation.sql#L813
IF geoms.avg_vertex > 1000 THEN
errors := array_append(errors, 'The average number of vertices per geometry is greater than 1000, please try to simplify them');
END IF;
-- OBS specific part
EXECUTE 'SELECT valid, errors
FROM cdb_dataservices_client.OBS_MetadataValidation($1, $2, $3, $4)'
INTO valid, validator_errors
USING geoms.extent, geoms.geom_type, parameters, geoms.numgeoms;
IF valid is FALSE THEN
FOR validator_error IN EXECUTE 'SELECT unnest($1)' USING validator_errors
LOOP
errors := array_append(errors, validator_error);
END LOOP;
END IF;
END LOOP;
IF CARDINALITY(errors) > 0 THEN
RAISE EXCEPTION '%', errors;
END IF;
RETURN TRUE;
END;
$$ LANGUAGE 'plpgsql';