Make migrations pretty.

supabase/migrations/20240409190001_bus_funcs.sql

@@ -1,67 +0,0 @@
--- extensions
-CREATE EXTENSION IF NOT EXISTS "plv8" SCHEMA pg_catalog;
-CREATE EXTENSION IF NOT EXISTS "pg_cron" SCHEMA pg_catalog;
-CREATE EXTENSION IF NOT EXISTS "pg_net" SCHEMA extensions;
-
--- request ID is inserted by first cron job,
--- then second cron job updates from net._http_response table.
-create table if not exists raw_bus_positions (
-  id BIGINT GENERATED ALWAYS AS IDENTITY,
-  request_id INT not null,
-  created TIMESTAMP WITH TIME ZONE not null default now(),
-  response_status INT null,
-  response_json JSONB null
-);
-
--- used to help craft the API URL. Requires plv8 extension.
--- because we are lazy. just use javascript in the database. why not?
-create or replace function to_straeto_querystring(jsonb) returns text
-language plv8 strict immutable as $$
-  const obj = $1;
-  return Object.keys(obj).map(function(variableName) {
-    const variableValue = obj[variableName];
-    if (typeof variableValue == 'object') {
-      return encodeURIComponent(variableName) + '=' + encodeURIComponent(JSON.stringify(variableValue));
-    } else {
-      return encodeURIComponent(variableName) + '=' + encodeURIComponent(variableValue);
-    }
-  }).join('&');
-$$;
-
-create or replace function create_straeto_parameters(bus_routes text[]) returns jsonb
-language plpgsql as $$
-  declare query_params jsonb;
-  begin
-    query_params := '{
-      "operationName": "BusLocationByRoute",
-      "variables": { "trips":[], "routes": [] },
-      "extensions": {
-        "persistedQuery": {
-          "version": 1,
-          "sha256Hash": "8f9ee84171961f8a3b9a9d1a7b2a7ac49e7e122e1ba1727e75cfe3a94ff3edb8"
-        }
-      }
-    }'::jsonb;
-
-    select into query_params
-		jsonb_set(query_params, '{variables, routes}', array_to_json(bus_routes)::jsonb);
-    return query_params;
-  end
-$$;
-
-create or replace function create_api_url(bus_routes text[]) returns text language sql as $$
-  select concat(
-    'https://straeto.is/graphql?',
-    to_straeto_querystring(create_straeto_parameters(bus_routes))
-  );
-$$;
-
-create or replace function gather_bus_data()
-returns void language sql
-as $$
-  insert into raw_bus_positions (request_id) select
-  net.http_get(
-    url := create_api_url(array['1', '2', '3']),
-    headers := '{"Content-Type": "application/json"}'::jsonb
-  );
-$$;

supabase/migrations/20240409190001_initial.sql

@@ -0,0 +1,14 @@
+-- extensions
+CREATE EXTENSION IF NOT EXISTS "plv8" SCHEMA pg_catalog;
+CREATE EXTENSION IF NOT EXISTS "pg_cron" SCHEMA pg_catalog;
+CREATE EXTENSION IF NOT EXISTS "pg_net" SCHEMA extensions;
+
+-- request ID is inserted by first cron job, then a trigger handles
+-- insertion of response.
+CREATE TABLE IF NOT EXISTS raw_bus_positions (
+  id BIGINT GENERATED ALWAYS AS IDENTITY,
+  request_id INT NOT NULL,
+  created TIMESTAMP WITH TIME ZONE NOT NULL DEFAULT NOW(),
+  response_status INT NULL,
+  response_json JSONB NULL
+);

supabase/migrations/20240409210612_bus_funcs.sql

@@ -0,0 +1,57 @@
+-- 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 OR REPLACE FUNCTION gather_bus_data()
+RETURNS void LANGUAGE sql
+as $$
+  INSERT INTO raw_bus_positions (request_id) SELECT
+  net.http_get(
+    url := build_api_url(array['1', '2', '3']),
+    headers := '{"Content-Type": "application/json"}'::jsonb
+  );
+$$;

supabase/migrations/20240410070316_scheduled-jobs.sql

@@ -1,5 +1,5 @@
 -- downloads data async into the http response table.
-select
+SELECT
   cron.schedule(
     'download-bus-data',
     '5 seconds',
@@ -8,9 +8,9 @@ select
     $$
   );
 
--- copies data into a more permanent tabe/more useful format. note:
+-- copies data into a more permanent tabe/more useful format. note: in
--- supabase has an issue where you cannot delete these triggers
+-- supabase, you cannot delete triggers on net._http_response
--- directly, but a cascading delete of the trigger function also
+-- directly. but a cascading delete of the trigger function also
 -- removes the trigger itself.
 CREATE FUNCTION copy_to_raw_table() RETURNS trigger LANGUAGE plpgsql AS $$
   BEGIN
@@ -21,14 +21,19 @@ CREATE FUNCTION copy_to_raw_table() RETURNS trigger LANGUAGE plpgsql AS $$
     -- with newer values difficult. The API also provides a
     -- lastUpdated value. we require that raw.created is at or after
     -- that value to be updated.
-    update raw_bus_positions raw
+    UPDATE raw_bus_positions raw
-       set response_json = NEW.content::jsonb,
+       SET response_json = NEW.content::jsonb->'data'->'BusLocationByRoute',
            response_status = NEW.status_code
-     where raw.request_id = NEW.id
+     WHERE raw.request_id = NEW.id
        -- fairly generous constraint to account for long requests.
-       and raw.created >= (NEW.created - '30 seconds'::interval)
+       AND raw.created >= (NEW.created - '30 seconds'::interval)
-       and raw.created >= (NEW.content::jsonb->'data'->'BusLocationByRoute'->>'lastUpdate')::timestamptz
+       -- the response must be at or after we actually sent the request.
-       and raw.response_json is null;
+       AND raw.created >= (NEW.content::jsonb->'data'->'BusLocationByRoute'->>'lastUpdate')::timestamptz
+       AND NEW.status_code = 200
+       AND raw.response_json IS NULL;
+
+      -- what if we want to stream other data? we can do multiple updates in
+      -- different tables, where the request id is.
     RETURN NULL; -- this is an AFTER trigger
   END;
 $$;