Add database upgrade file 22.

This defines a replace_placeholders() function, taking as arguments
a text string and either a timestamp or a sequence / point pair. It
uses the latter arguments to find metadata from which it can extract
relevant information and replace it into the text string wherever the
appropriate placeholders appear. For instance, given a call such as
replace_placeholders('The position is @POS@', NULL, 11, 2600) it will
replace '@POS@' with the position of point 2600 in sequence 11, if it
exists (or leave the placeholder untouched otherwise).

A scan_placeholders() procedure is also defined, which calls the above
function on the entire event log.

Fixes #229.
This commit is contained in:
D. Berge
2022-05-12 21:45:56 +02:00
parent 1da02738b0
commit c7f3f565cd

View File

@@ -0,0 +1,229 @@
-- Fix not being able to edit a time-based event.
--
-- New schema version: 0.3.9
--
-- ATTENTION:
--
-- ENSURE YOU HAVE BACKED UP THE DATABASE BEFORE RUNNING THIS SCRIPT.
--
--
-- NOTE: This upgrade affects all schemas in the database.
-- NOTE: Each application starts a transaction, which must be committed
-- or rolled back.
--
-- This defines a replace_placeholders() function, taking as arguments
-- a text string and either a timestamp or a sequence / point pair. It
-- uses the latter arguments to find metadata from which it can extract
-- relevant information and replace it into the text string wherever the
-- appropriate placeholders appear. For instance, given a call such as
-- replace_placeholders('The position is @POS@', NULL, 11, 2600) it will
-- replace '@POS@' with the position of point 2600 in sequence 11, if it
-- exists (or leave the placeholder untouched otherwise).
--
-- A scan_placeholders() procedure is also defined, which calls the above
-- function on the entire event log.
--
-- To apply, run as the dougal user:
--
-- psql <<EOF
-- \i $THIS_FILE
-- COMMIT;
-- EOF
--
-- NOTE: It can be applied multiple times without ill effect.
--
BEGIN;
CREATE OR REPLACE PROCEDURE show_notice (notice text) AS $$
BEGIN
RAISE NOTICE '%', notice;
END;
$$ LANGUAGE plpgsql;
CREATE OR REPLACE PROCEDURE pg_temp.upgrade_survey_schema (schema_name text) AS $outer$
BEGIN
RAISE NOTICE 'Updating schema %', schema_name;
-- We need to set the search path because some of the trigger
-- functions reference other tables in survey schemas assuming
-- they are in the search path.
EXECUTE format('SET search_path TO %I,public', schema_name);
CREATE OR REPLACE FUNCTION replace_placeholders (
text_in text, tstamp timestamptz, sequence integer, point integer
)
RETURNS text
AS $$
DECLARE
position geometry;
metadata jsonb;
text_out text;
json_query text;
json_result jsonb;
expect_recursion boolean := false;
BEGIN
text_out := text_in;
-- We only get a position if we are going to need it…
IF regexp_match(text_out, '@DMS@|@POS@|@DEG@') IS NOT NULL THEN
position := ST_Transform(event_position(tstamp, sequence, point), 4326);
END IF;
-- …and likewise with the metadata.
IF regexp_match(text_out, '@BSP@|@WD@|@CMG@|@EN@|@GRID@|@(\$\..*?)@@') IS NOT NULL THEN
metadata := event_meta(tstamp, sequence, point);
END IF;
-- We shortcut the evaluation if neither of the above regexps matched
IF position IS NULL AND metadata IS NULL THEN
RETURN text_out;
END IF;
IF position('@DMS@' IN text_out) != 0 THEN
text_out := replace(text_out, '@DMS@', ST_AsLatLonText(position));
END IF;
IF position('@POS@' IN text_out) != 0 THEN
text_out := replace(text_out, '@POS@', replace(ST_AsLatLonText(position, 'D.DDDDDD'), ' ', ', '));
END IF;
IF position('@DEG@' IN text_out) != 0 THEN
text_out := replace(text_out, '@DEG@', replace(ST_AsLatLonText(position, 'D.DDDDDD'), ' ', ', '));
END IF;
IF position('@EN@' IN text_out) != 0 THEN
IF metadata ? 'easting' AND metadata ? 'northing' THEN
text_out := replace(text_out, '@EN@', (metadata->>'easting') || ', ' || (metadata->>'northing'));
END IF;
END IF;
IF position('@GRID@' IN text_out) != 0 THEN
IF metadata ? 'easting' AND metadata ? 'northing' THEN
text_out := replace(text_out, '@GRID@', (metadata->>'easting') || ', ' || (metadata->>'northing'));
END IF;
END IF;
IF position('@CMG@' IN text_out) != 0 THEN
IF metadata ? 'bearing' THEN
text_out := replace(text_out, '@CMG@', metadata->>'bearing');
END IF;
END IF;
IF position('@BSP@' IN text_out) != 0 THEN
IF metadata ? 'speed' THEN
text_out := replace(text_out, '@BSP@', round((metadata->>'speed')::numeric * 3600 / 1852, 1)::text);
END IF;
END IF;
IF position('@WD@' IN text_out) != 0 THEN
IF metadata ? 'waterDepth' THEN
text_out := replace(text_out, '@WD@', metadata->>'waterDepth');
END IF;
END IF;
json_query := (regexp_match(text_out, '@(\$\..*?)@@'))[1];
IF json_query IS NOT NULL THEN
json_result := jsonb_path_query_array(metadata, json_query::jsonpath);
IF jsonb_array_length(json_result) = 1 THEN
text_out := replace(text_out, '@'||json_query||'@@', json_result->>0);
ELSE
text_out := replace(text_out, '@'||json_query||'@@', json_result::text);
END IF;
-- There might be multiple JSONPath queries, so we may have to recurse
expect_recursion := true;
END IF;
IF expect_recursion IS TRUE AND text_in != text_out THEN
--RAISE NOTICE 'Recursing %', text_out;
-- We don't know if we have found all the JSONPath expression
-- so we do another pass.
RETURN replace_placeholders(text_out, tstamp, sequence, point);
ELSE
RETURN text_out;
END IF;
END;
$$ LANGUAGE plpgsql;
COMMENT ON FUNCTION replace_placeholders (text, timestamptz, integer, integer) IS
'Replace certain placeholder strings in the input text with data obtained from shot or real-time data.';
CREATE OR REPLACE PROCEDURE scan_placeholders ()
LANGUAGE sql
AS $$
-- We update non read-only events via the event_log view to leave a trace
-- of the fact that placeholders were replaced (and when).
-- Note that this will not replace placeholders of old edits.
UPDATE event_log
SET remarks = replace_placeholders(remarks, tstamp, sequence, point)
FROM (
SELECT id
FROM event_log e
WHERE
(meta->'readonly')::boolean IS NOT TRUE AND (
regexp_match(remarks, '@DMS@|@POS@|@DEG@') IS NOT NULL OR
regexp_match(remarks, '@BSP@|@WD@|@CMG@|@EN@|@GRID@|@(\$\..*?)@@') IS NOT NULL
)
) t
WHERE event_log.id = t.id;
-- And then we update read-only events directly on the event_log_full table
-- (as of this version of the schema we're prevented from updating read-only
-- events via event_log anyway).
UPDATE event_log_full
SET remarks = replace_placeholders(remarks, tstamp, sequence, point)
FROM (
SELECT uid
FROM event_log_full e
WHERE
(meta->'readonly')::boolean IS TRUE AND (
regexp_match(remarks, '@DMS@|@POS@|@DEG@') IS NOT NULL OR
regexp_match(remarks, '@BSP@|@WD@|@CMG@|@EN@|@GRID@|@(\$\..*?)@@') IS NOT NULL
)
) t
WHERE event_log_full.uid = t.uid;
$$;
COMMENT ON PROCEDURE scan_placeholders () IS
'Run replace_placeholders() on the entire event log.';
END;
$outer$ LANGUAGE plpgsql;
CREATE OR REPLACE PROCEDURE pg_temp.upgrade () AS $outer$
DECLARE
row RECORD;
BEGIN
FOR row IN
SELECT schema_name FROM information_schema.schemata
WHERE schema_name LIKE 'survey_%'
ORDER BY schema_name
LOOP
CALL pg_temp.upgrade_survey_schema(row.schema_name);
END LOOP;
END;
$outer$ LANGUAGE plpgsql;
CALL pg_temp.upgrade();
CALL show_notice('Cleaning up');
DROP PROCEDURE pg_temp.upgrade_survey_schema (schema_name text);
DROP PROCEDURE pg_temp.upgrade ();
CALL show_notice('Updating db_schema version');
INSERT INTO public.info VALUES ('version', '{"db_schema": "0.3.9"}')
ON CONFLICT (key) DO UPDATE
SET value = public.info.value || '{"db_schema": "0.3.9"}' WHERE public.info.key = 'version';
CALL show_notice('All done. You may now run "COMMIT;" to persist the changes');
DROP PROCEDURE show_notice (notice text);
--
--NOTE Run `COMMIT;` now if all went well
--