makeProcessSchemaPlugin

This plugin enables a way of processing the schema after it's built.

Use cases include:

• Printing the schema SDL to a file
• Uploading the schema SDL to a network service
• Checking the schema against your persisted queries
• Validating the schema against your custom logic
• Exporting the executable schema (in JavaScript) to a file
• Replacing the schema with a mocked version or a derivative version (e.g. stitching it with another schema)
• Integrating with third-party libraries

Signature

function makeProcessSchemaPlugin(
  process: (schema: GraphQLSchema) => GraphQLSchema,
): GraphileConfig.Plugin;

The plugin accepts one argument: a schema processing function which will be called with the generated schema and must either return the same schema (e.g. if you're doing a read-only operation, or mutating the schema directly) or return an alternative schema (typically a derivative).

info

The callback to this plugin operates synchronously. If you need to do asynchronous work then be sure to handle any errors that may occur, and note that the result of the asynchronous work will not affect the return result of this plugin (and thus the schema being used by your server).

danger

Because PostGraphile schemas use Grafast plan resolvers, third party tooling that manipulate traditional resolvers are likely to break the schema, and not achieve the goals set out. For example, graphql-shield is currently not compatible with Grafast plans.

Example: exporting the schema as exportable code

import { makeProcessSchemaPlugin } from "postgraphile/utils";
import { exportSchema } from "graphile-export";

const ExportSchemaPlugin = makeProcessSchemaPlugin((schema) => {
  exportSchema(schema, `${process.cwd()}/exported-schema.mjs`, {
    mode: "typeDefs",
  }).catch((e) => {
    console.error(e);
  });
  return schema;
});