jokull/supabase/migrations/20240409210612_bus_funcs.sql

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2024-04-10 07:11:23 +00:00
-- encode straeto API params into the query string by the graphql API.
-- yes, javascript in the database: the lazy way.
CREATE OR REPLACE FUNCTION encode_straeto_querystring(obj jsonb) RETURNS text
LANGUAGE plv8 STRICT IMMUTABLE AS $$
return Object.keys(obj).map(function(variableName) {
const variableValue = obj[variableName];
if (typeof variableValue == 'object') {
return encodeURIComponent(variableName) + '=' + encodeURIComponent(JSON.stringify(variableValue));
} else {
return encodeURIComponent(variableName) + '=' + encodeURIComponent(variableValue);
}
}).join('&');
$$;
CREATE OR REPLACE FUNCTION create_straeto_parameters(bus_routes text[]) RETURNS jsonb
LANGUAGE plpgsql AS $$
DECLARE query_params jsonb;
BEGIN
-- This is the unencoded GraphQL request payload.
query_params := '{
"operationName": "BusLocationByRoute",
"variables": { "trips":[], "routes": [] },
"extensions": {
"persistedQuery": {
"version": 1,
"sha256Hash": "8f9ee84171961f8a3b9a9d1a7b2a7ac49e7e122e1ba1727e75cfe3a94ff3edb8"
}
}
}'::jsonb;
-- Add requested bus routes to the `routes` GraphQL variable.
SELECT INTO query_params
jsonb_set(query_params, '{variables, routes}', array_to_json(bus_routes)::jsonb);
RETURN query_params;
END
$$;
-- Builds the full request URL to download bus positions of the given
-- route numbers.
CREATE OR REPLACE FUNCTION build_api_url(bus_routes text[]) RETURNS text LANGUAGE sql AS $$
SELECT concat(
'https://straeto.is/graphql?',
encode_straeto_querystring(create_straeto_parameters(bus_routes))
);
$$;
-- Called by a scheduled job to request data on a timer. A trigger
-- handles insertion of the response after record initially inserted.
CREATE TABLE IF NOT EXISTS raw_bus_position_requests(
request_id int,
created TIMESTAMP WITH TIME ZONE NOT NULL DEFAULT NOW()
);
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CREATE OR REPLACE FUNCTION gather_bus_data()
RETURNS void LANGUAGE sql
as $$
INSERT INTO raw_bus_position_requests (request_id) SELECT
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net.http_get(
url := build_api_url(array['1', '2', '3']),
headers := '{"Content-Type": "application/json"}'::jsonb
);
$$;