@opengis/fastify-table/server/plugins/pg/funcs/getMeta.js

core-plugins

import getPG from './getPG.js';

const data = {};

// decorator
export default async function getMeta(opt, nocache) {
  const pg = opt?.pg || getPG({ name: 'client' });
  if (!pg) return { error: 'pg connection not established', status: 400 };
  const table1 = opt?.table || opt;
  const table = pg.pk[table1] ? table1 : table1?.replace?.(/"/g, '');

  if (pg?.options?.database && data[pg.options.database]?.[table] && !nocache) return data[pg.options.database][table];

  if (!pg?.tlist?.includes(table)) {
    return { error: `${table} - not found`, status: 400 };
  }

  const { fields = [] } = await pg.query(`select * from ${table} limit 0`);
  const pks1 = await pg.query(`SELECT json_object_agg(c.conrelid::regclass, a.attname) as pks1 
  FROM pg_constraint c 
    left join pg_attribute a on c.conrelid=a.attrelid and a.attnum = c.conkey[1] 
  WHERE c.contype='p'::"char" and c.conrelid::regclass = $1::regclass`, [table]).then(el => el.rows[0].pks1 || {});

  const pk = table.startsWith('public.')
    ? (pks1[table.replace('public.', '')] || pks1[table.replace('public.', '')])
    : (pks1[table] || pks1[table]);

  const geomAttr = fields.find((el) => pg.pgType?.[el.dataTypeID] === 'geometry')?.name; // change geometry text to geometry code

  const dbColumns = await pg.query(`select json_object_agg(
    attname, 
    json_build_object(
      'title', pg_catalog.col_description(attrelid,attnum)
      /*,'type', atttypid::regtype */
    )
  ) from pg_catalog.pg_attribute a 
  where attrelid=$1::regclass and attnum>0`, [table]).then(el => el.rows?.[0]?.json_object_agg || {});

  fields.forEach(el => Object.assign(el, { ...dbColumns[el.name] || {} }));

  const res = {
    pk, columns: fields, geom: geomAttr, view: pg.relkinds?.[table] === 'v',
  };
  if (!data[pg.options.database]) {
    data[pg.options.database] = {};
  }
  data[pg.options.database][table] = res;
  return res;
}