PgNonNullReferencesPlugin.js

// License: MIT

module.exports = async function MakeNonNullableReferencesPlugin(builder, { pgConfig }) {
	async function getPolicies() {
		const { rows } = await pgConfig.query({
			text: `SELECT DISTINCT polrelid::text, true FROM pg_policy WHERE polcmd IN ('r', '*')`,
			rowMode: 'array'
		});
		return new Map(rows);
	}

	let policies = await getPolicies();

	builder.hook('GraphQLObjectType:fields:field', (field, build, context) => {
		const GraphQLNonNull = build.graphql.GraphQLNonNull;
		const {
			scope: {
				isMutationPayload,
				isPgForwardRelationField,
				pgIntrospection,
				pgIntrospectionTable,
				pgFieldIntrospection
			}
		} = context;
		const pgTableIntrospection = pgIntrospectionTable || pgIntrospection;

		if (isMutationPayload) {
			return field;
		}

		if (!isPgForwardRelationField || !pgTableIntrospection) {
			return field;
		}

		const hasRowLevelReadSecurity = policies.get(pgFieldIntrospection.classId);
		if (hasRowLevelReadSecurity) {
			return field;
		}

		const allKeysAreNonNull = pgFieldIntrospection.keyAttributeNums.every((num) =>
			pgTableIntrospection.attributes.find((attribute) =>
				attribute.num === num && attribute.isNotNull)
		);
		if (!allKeysAreNonNull) {
			return field;
		}

		return {
			...field,
			type: new GraphQLNonNull(field.type)
		};
	});
};