Add migration to adapt old files data to new file model

[Re #1543]

* This only take into consideration those files that are already
stored in GCS. Other files stored in the database in base64 format or
public URLs pointing to other sources are going to be migrated by
code. We'll develop an admin API for that use case.

backend/resources/migrations/192-migrate-files-to-file-table.up.sql

@@ -0,0 +1,206 @@
+BEGIN;
+--;;
+-- Create temporary tables transition data old data to the new table.
+CREATE TABLE temp_entity_images (
+  id UUID,
+  entity_id INTEGER,
+  entity_type TEXT,
+  object_key TEXT NOT NULL,
+  name TEXT NOT NULL,
+  type TEXT NOT NULL,
+  extension TEXT,
+  visibility FILE_VISIBILITY NOT NULL
+);
+--;;
+CREATE TABLE temp_entity_thumbnails (
+  id UUID,
+  entity_id INTEGER,
+  entity_type TEXT,
+  object_key TEXT NOT NULL,
+  name TEXT NOT NULL,
+  type TEXT NOT NULL,
+  extension TEXT,
+  visibility FILE_VISIBILITY NOT NULL
+);
+--;;
+-- Add foreign keys to all tables that uses files in their model to
+-- point to the File table.
+ALTER TABLE organisation
+ADD COLUMN logo_id UUID REFERENCES file (id) ON DELETE SET NULL;
+--;;
+ALTER TABLE stakeholder
+ADD COLUMN picture_id UUID REFERENCES file (id) ON DELETE SET NULL,
+ADD COLUMN cv_id UUID REFERENCES file (id) ON DELETE SET NULL;
+--;;
+ALTER TABLE event
+ADD COLUMN image_id UUID REFERENCES file (id) ON DELETE SET NULL,
+ADD COLUMN thumbnail_id UUID REFERENCES file (id) ON DELETE SET NULL;
+--;;
+ALTER TABLE policy
+ADD COLUMN image_id UUID REFERENCES file (id) ON DELETE SET NULL,
+ADD COLUMN thumbnail_id UUID REFERENCES file (id) ON DELETE SET NULL;
+--;;
+ALTER TABLE technology
+ADD COLUMN image_id UUID REFERENCES file (id) ON DELETE SET NULL,
+ADD COLUMN thumbnail_id UUID REFERENCES file (id) ON DELETE SET NULL;
+--;;
+ALTER TABLE initiative
+ADD COLUMN image_id UUID REFERENCES file (id) ON DELETE SET NULL,
+ADD COLUMN thumbnail_id UUID REFERENCES file (id) ON DELETE SET NULL;
+--;;
+ALTER TABLE resource
+ADD COLUMN image_id UUID REFERENCES file (id) ON DELETE SET NULL,
+ADD COLUMN thumbnail_id UUID REFERENCES file (id) ON DELETE SET NULL;
+--;;
+ALTER TABLE case_study
+ADD COLUMN image_id UUID REFERENCES file (id) ON DELETE SET NULL,
+ADD COLUMN thumbnail_id UUID REFERENCES file (id) ON DELETE SET NULL;
+--;;
+
+-- Gather all the entity images and only process those pointing to
+-- GCS. This is done for both images and thumbnails. We are going to
+-- store thumbnails in the same folder as the normal images for
+-- historic reasons. Because there was no distinction between images
+-- and thumbnails in the previous implementations. So when moving the
+-- existing images to the new bucket structure we can't distinguish
+-- between both types easily.
+WITH entity_images AS (
+	SELECT id AS entity_id, 'organisation' AS entity_type, logo AS image
+	FROM organisation
+	UNION
+	SELECT id AS entity_id, 'event' AS entity_type, image AS image
+	FROM event
+	UNION
+	SELECT id AS entity_id, 'policy' AS entity_type, image AS image
+	FROM policy
+	UNION
+	SELECT id AS entity_id, 'initiative' AS entity_type, qimage AS image
+	FROM initiative
+	UNION
+	SELECT id AS entity_id, 'resource' AS entity_type, image AS image
+	FROM resource
+	UNION
+	SELECT id AS entity_id, 'technology' AS entity_type, image AS image
+	FROM technology
+	UNION
+	SELECT id AS entity_id, 'case_study' AS entity_type, image AS image
+	FROM case_study
+)
+-- Just images that were previously in GCS.
+INSERT INTO temp_entity_images (id, entity_id, entity_type, object_key, name, type, extension, visibility)
+SELECT uuid_generate_v4(),
+       entity_id,
+       entity_type,
+       replace(image, 'https://storage.googleapis.com/akvo-unep-gpml/images', concat_ws('/', entity_type, 'images')) AS object_key,
+       substring(image from 'images\/([a-zA-Z0-9_]+)\.') AS name,
+       concat_ws('/', 'image',lower(substring(image FROM '\.([^\.]*)$'))) AS type,
+       substring(image FROM '\.([^\.]*)$') AS extension,
+       'public' AS visibility
+FROM entity_images
+WHERE image ilike 'https://storage.googleapis.com%'
+      -- The following takes care of both NULLs and empty string with
+      -- or without spaces.
+      AND coalesce(TRIM(image), '') != '';
+--;;
+WITH entity_thumbnails AS (
+	SELECT id AS entity_id, 'event' AS entity_type, thumbnail
+	FROM event
+	UNION
+	SELECT id AS entity_id, 'policy' AS entity_type, thumbnail
+	FROM policy
+	UNION
+	SELECT id AS entity_id, 'initiative' AS entity_type, thumbnail
+	FROM initiative
+	UNION
+	SELECT id AS entity_id, 'resource' AS entity_type, thumbnail
+	FROM resource
+	UNION
+	SELECT id AS entity_id, 'technology' AS entity_type, thumbnail
+	FROM technology
+	UNION
+	SELECT id AS entity_id, 'case_study' AS entity_type, thumbnail
+	FROM case_study
+)
+-- Just the thumbnails that were previously in GCS.
+INSERT INTO temp_entity_thumbnails (id, entity_id, entity_type, object_key, name, type, extension, visibility)
+SELECT uuid_generate_v4(),
+       entity_id,
+       entity_type,
+       replace(thumbnail, 'https://storage.googleapis.com/akvo-unep-gpml/images', concat_ws('/', entity_type, 'images')) AS object_key,
+       substring(thumbnail from 'images\/([a-zA-Z0-9_]+)\.') AS name,
+       concat_ws('/', 'image',lower(substring(thumbnail FROM '\.([^\.]*)$'))) AS type,
+       substring(thumbnail FROM '\.([^\.]*)$') AS extension,
+       'public' AS visibility
+FROM entity_thumbnails
+WHERE thumbnail ilike 'https://storage.googleapis.com%'
+      -- The following takes care of both NULLs and empty string with
+      -- or without spaces.
+      AND coalesce(TRIM(thumbnail), '') != '';
+--;;
+-- Insert all the new records into the File table and update the
+-- foreign keys in the entity tables to point to their files.
+INSERT INTO file (id, object_key, name, type, extension, visibility)
+SELECT id, object_key, name, type, extension, visibility
+FROM temp_entity_images;
+--;;
+INSERT INTO file (id, object_key, name, type, extension, visibility)
+SELECT id, object_key, name, type, extension, visibility
+FROM temp_entity_thumbnails;
+--;;
+UPDATE organisation SET logo_id = tmp.id
+FROM temp_entity_images tmp
+WHERE tmp.entity_id = organisation.id AND tmp.entity_type = 'organisation';
+--;;
+UPDATE event SET image_id = tmp.id
+FROM temp_entity_images tmp
+WHERE tmp.entity_id = event.id AND tmp.entity_type = 'event';
+--;;
+UPDATE event SET thumbnail_id = tmp.id
+FROM temp_entity_thumbnails tmp
+WHERE tmp.entity_id = event.id AND tmp.entity_type = 'event';
+--;;
+UPDATE technology SET image_id = tmp.id
+FROM temp_entity_images tmp
+WHERE tmp.entity_id = technology.id AND tmp.entity_type = 'technology';
+--;;
+UPDATE technology SET thumbnail_id = tmp.id
+FROM temp_entity_thumbnails tmp
+WHERE tmp.entity_id = technology.id AND tmp.entity_type = 'technology';
+--;;
+UPDATE policy SET image_id = tmp.id
+FROM temp_entity_images tmp
+WHERE tmp.entity_id = policy.id AND tmp.entity_type = 'policy';
+--;;
+UPDATE policy SET thumbnail_id = tmp.id
+FROM temp_entity_thumbnails tmp
+WHERE tmp.entity_id = policy.id AND tmp.entity_type = 'policy';
+--;;
+UPDATE initiative SET image_id = tmp.id
+FROM temp_entity_images tmp
+WHERE tmp.entity_id = initiative.id AND tmp.entity_type = 'initiative';
+--;;
+UPDATE initiative SET thumbnail_id = tmp.id
+FROM temp_entity_thumbnails tmp
+WHERE tmp.entity_id = initiative.id AND tmp.entity_type = 'initiative';
+--;;
+UPDATE case_study SET image_id = tmp.id
+FROM temp_entity_images tmp
+WHERE tmp.entity_id = case_study.id AND tmp.entity_type = 'case_study';
+--;;
+UPDATE case_study SET thumbnail_id = tmp.id
+FROM temp_entity_thumbnails tmp
+WHERE tmp.entity_id = case_study.id AND tmp.entity_type = 'case_study';
+--;;
+UPDATE resource SET image_id = tmp.id
+FROM temp_entity_images tmp
+WHERE tmp.entity_id = resource.id AND tmp.entity_type = 'resource';
+--;;
+UPDATE resource SET thumbnail_id = tmp.id
+FROM temp_entity_thumbnails tmp
+WHERE tmp.entity_id = resource.id AND tmp.entity_type = 'resource';
+--;;
+-- Drop the temporary tables as they fulfilled their purpose.
+DROP TABLE temp_entity_images;
+DROP TABLE temp_entity_thumbnails;
+--;;
+COMMIT;