NOTE: this documentation applies to PostGraphile v4.1.0+

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
• Replacing the schema with a mocked version or a derivative version (e.g. stitching it with another schema)
• Integrating with third-party libraries

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 (e.g. a derivative).

PLEASE NOTE: some third party tooling mutates the existing GraphQL schema which is likely to cause issues. Please use only tools that treat GraphQL schemas as immutable; if you cannot then try building a sacrificial schema that delegates to the PostGraphile schema but can be mutated.

Example

const { makeProcessSchemaPlugin } = require("graphile-utils");

module.exports = makeProcessSchemaPlugin(schema => {
  return addThirdPartyEnhancementsToSchema(schema);
});

You can also use makeProcessSchemaPlugin to replace the current schema with a stitched schema and run it from within the PostGraphile server:

const { makeProcessSchemaPlugin } = require("graphile-utils");

module.exports = makeProcessSchemaPlugin(schema => {
  return stitchOtherSchemasInto(schema);
});